# 3D Printing > 3D Printers (Hardware) >  Dollo 3D Printable 3D Printer

## Brian_Krassenstein

3D printers 3D printing more 3D printers isn't any longer that far-flung of an idea, thanks to initiatives like the RepRap Project. While electronics and other parts keep this complete self-replicating system from being fully realized, advances are getting ever closer. Benjamin Engel and his father have now produced the most self-replicating 3D printer yet, with their Dollo 3D printer. Able to be printed with just 1kg of filament, the Dollo can be 3D printed in about 18 hours. It is also scalable, and the Engels are looking to put their machine on Kickstarter in the near future, for only about $300 and with a planned optional CNC router. Read more details about their clever 3D printer in the full article: http://3dprint.com/63229/dollo-3d-pr...prints-itself/


Below is a photo of the Dollo 3D printer:

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## Feign

Oh man that looks like fun.  Not a workhorse printer by any strech, but probably good for a kids' project (with supervision of course, the hot end is no children's toy.)  Speaking of which, what kind of hotend does it use, is that an E3D Volcano, or is it a proprietary one?
Also, I notice you missed the build plate in the list of non-printed parts, I guess the hot bed is optional?

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## benengel94

> Oh man that looks like fun.  Not a workhorse printer by any strech, but probably good for a kids' project (with supervision of course, the hot end is no children's toy.)  Speaking of which, what kind of hotend does it use, is that an E3D Volcano, or is it a proprietary one?
> Also, I notice you missed the build plate in the list of non-printed parts, I guess the hot bed is optional?


We are going to be making them with e3D hot-ends, but its a modular design and you could make a mount for any hot-end really. Secondly the bed wasn't on the list on non printed parts because we are planning on printing the lower bed, and a heated bed is not needed for milling or laser etching, but if you want to print with ABS then yes a heated bed is needed and not printable, and thirdly its more than just for kinds (although great for kids), if you want you can put some metal rods in it (I made it so you can if you want) and make the printer as large as you want, their is nothing stopping you from making it large enough to print a car, most kinds wont be going that deep into what it is capable of doing.

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## ImShogun

> if you want you can put some metal rods in it (I made it so you can if you want) and make the printer as large as you want


Smart thinking, really. I whish you the best on KS!!

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## wendy

I find it very interesting, very good idea, I would like to see it complete.
www.reprapmall.com

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## spegelius

I've been printing and hacking away with the design for some time and I've got a build that works quite well. The quality isn't very good at the moment but getting there. The design itself is not the problem, getting the parts printed right is. For me the whole process of building this has been a bit of a learning experience in part tolerances and printer calibration  :Smile: . Also I've done some remodeling and new models as needed.

Couple of latest prints:
https://www.dropbox.com/s/u3nggb3wrmjklb4/2016-11-01%2016.28.36.jpg?dl=0
https://www.dropbox.com/s/u510cxwljbilwdy/2016-11-01%2016.29.35.jpg?dl=0
https://www.dropbox.com/s/drrf72g6yuout2b/2016-11-01%2016.29.49.jpg?dl=0

Anyone else with working Dollo or printing one?

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## spegelius

Been creating models and printing stuff quite a lotfor Dollo so here's some updates about my build:
- created a model to attach PSU underneath the frame
- adapter for RAMPS box mount to Dollo bow tie setup (excuse the messy cables)
https://dl.dropboxusercontent.com/u/...2021.59.16.jpg
- printed some extension parts and now Z-axis gows up to 41 cm  :Smile: 
https://dl.dropboxusercontent.com/u/...2021.58.29.jpg
- fixed problem with Z-wobble caused by bent threaded rods. I created a rail setup that makes the bed move straight:
https://dl.dropboxusercontent.com/u/...2021.58.45.jpg
https://dl.dropboxusercontent.com/u/...2021.59.01.jpg
- assorted parts

The build volume is now 120x93x413mm. I haven't yet tried how well very tall prints work, planning to do that this week. I fear that the frame isn't rigid enough and causes too much play, especially when Z-height grows. A short ~3cm box was fine, but doesn't tell anything.

I also printed enough parts to expand X and Y axes so the build volume would be 210x210x413mm. That'll need some more parts for the X and Y rails, though and I'll probably need to lengthen some cables also.

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## spegelius

Yesterday I printed a 40cm model: http://www.thingiverse.com/thing:157102 Z scaled 200%. It went better than expected, my worries about the plastic frame giving too much was unwarranted, at least with this model. There's some distortion at couple of places, probably dues to the slider's not moving equally due to different PLA types used. Also some Z-wobble still, the printed nut is too tight and bent rod twists the bed. Need to print a looser one or figure some kind of joint system, dunno. Anyways, the print went better than I hoped, maybe this'll be a printer yet  :Smile: .

0.3mm layer, Esun green PETG @240C. Roughly 5h 20min
https://dl.dropboxusercontent.com/u/45385735/3dprinting/Dollo/2016-12-14 19.29.30.jpg
https://dl.dropboxusercontent.com/u/45385735/3dprinting/Dollo/2016-12-14 19.29.42.jpg
https://dl.dropboxusercontent.com/u/45385735/3dprinting/Dollo/2016-12-14 19.29.59.jpg

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## spegelius

Some finetuning to Z-axis rails and getting quite good results:
https://dl.dropboxusercontent.com/u/...2020.00.58.jpg
https://dl.dropboxusercontent.com/u/...2020.01.09.jpg
https://dl.dropboxusercontent.com/u/...2020.01.21.jpg
https://dl.dropboxusercontent.com/u/...2020.01.36.jpg

Slight deformation, but I can live with it for now.

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## spegelius

Finally got to expanding my Dollo printer in X and Y axes (sorry about the bad quality, Jolla C doesn't have very good camera...). Needed to print lot of extension parts and ties, also some of the older extensions needed to be replaced as they were printed badly (bad printer, bad settings...)
The axis dimensions are 240mm x 210mm x 435mm (x y z) currently.
https://dl.dropboxusercontent.com/u/...2021.48.22.jpg

I use PETG for the ties, they are bit more flexible than PLA and seem to make tighter joints. Also it helps when joining parts that are printed on different printers and don't have 100% same dimensions.
https://dl.dropboxusercontent.com/u/...2015.51.02.jpg


I also did bit better cable management and designed these clips that attach to the bow tie grooves on the frame. It helps, but there's still room for improvement  :Wink: , especially around the RAMPS box. Z motor wires needed to be extended too.
https://dl.dropboxusercontent.com/u/...2018.25.57.jpg
https://dl.dropboxusercontent.com/u/...2021.48.57.jpg

The bed looks quite small now and is bit too small compared to the X axis. Also the bolt heads stick out and care needs to be taken so that nozzle doesn't hit them. The current bed carriage setup is too flimsy due to the extra lenght, but works for the time being. Need to design much beefier parts and maybe move the rails inside the frame.
https://dl.dropboxusercontent.com/u/...2017.14.46.jpg
https://dl.dropboxusercontent.com/u/...2021.49.27.jpg

The X and Y racks were also updated as more length was needed. For X rack, I did some redesignin of the motor mount and the rack. For Y, I used the leftover X rack (it was two 9cm rack parts joined) on both sides. Also finally found out why I had some artifacts in prints:
1. the bolts that fastens the gears to the motor shafts were bit too long and would hit the rack  once in revolution and cause a bump
2. the rack joints weren't completely smooth, so I took some time to sand them properly
Now they move quite smoothly, without extra bumps.
https://github.com/spegelius/Dollo/b...L/rackv4_4.stl
https://github.com/spegelius/Dollo/b...t_small_v4.stl
https://dl.dropboxusercontent.com/u/...2017.15.05.jpg

Currently printing Benchy (scaled to 200%):
https://dl.dropboxusercontent.com/u/...2015.51.35.jpg

Current problems I need to address:
- frame isn't that rigid, as I've already mentioned. Especially the corners give way too much. So far doesn't seem to affect quality much, when printing moderately slowly, but then again I haven't done too many prints yet. This'll need some experimenting about how to fix. Maybe some corner pieces to make it more stiff
- related to the above, the angles aren't straight. So calibration is needed.
- bed carriage too flimsy.
- X and Y motor gears will probably start slipping after a while. I've seen it happen. Current design use M3 bolts to fasten them to the motor shaft, but the gears are plastic and they start to give after a while, causing backlash. X and Y axes put quite a strain on them as the racks have bit of friction. I've been contemplating about changing the M3 bolts to M4 and also annealing the gears: https://www.youtube.com/watch?v=CZX8eHC7fws. Maybe even drill a hole through the motor shaft for the bolt
- no part cooling fan. Need to design one.
- bed bolt heads.
- other stuff I forget...

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## spegelius

Results of the Benchy print:
- stringing because of too little retraction as I needed to switch to longer bowden tube after extending the axes
- few skipped steps in Y-axis at the lowest layers. Might be that I have the motor mounts tightened bit too tight. No skips after those at the beginning, though.
https://dl.dropboxusercontent.com/u/...2020.00.10.jpg
- X-axis has banding, it doesn't move very smoothly after all. I suspect that this is because the gear's teeth aren't the smoothest and causes small bumps that the hot end mount structure amplifies. Need to reprint it with Prusa MK2 to get better quality.
https://dl.dropboxusercontent.com/u/...2019.59.04.jpg
- Y axis movement is quite good actually
https://dl.dropboxusercontent.com/u/...2019.59.30.jpg
- overall the quality is passable
https://dl.dropboxusercontent.com/u/...2019.59.15.jpg
https://dl.dropboxusercontent.com/u/...2019.59.40.jpg
https://dl.dropboxusercontent.com/u/...2019.59.45.jpg
https://dl.dropboxusercontent.com/u/...2020.00.10.jpg

So there's work to be done for the rack and gear setup if good quality is desired, especially in X-axis. Also simply by doing more prints, the quality might improve to a point when the parts smooth out in use. Or not  :Smile: .

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## spegelius

New bed carriage part in the making, lots stiffer that previous iteration. Also switched to printed bolts

https://dl.dropboxusercontent.com/u/...2014.48.24.jpg
https://dl.dropboxusercontent.com/u/...2014.49.01.jpg
https://dl.dropboxusercontent.com/u/...2012.42.25.jpg

For the translucent part the settings were 3 perimeters and 30% infill. Took almost 9 hours to print on Prusa MK2. Maybe bit overkill, but what the heck... cheap 3D Druck PLA.

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## spegelius

Bed carraige installed and much more stable that the previous iteration:

https://dl.dropboxusercontent.com/u/...2021.39.20.jpg

Also started modeling and printing some parts to stabilize the frame:
https://dl.dropboxusercontent.com/u/...2018.46.05.jpg
https://dl.dropboxusercontent.com/u/...2018.46.13.jpg
https://dl.dropboxusercontent.com/u/...2018.46.38.jpg
https://dl.dropboxusercontent.com/u/...2019.55.11.jpg

For the X-axis, I printed new gear, using Polymax PLA, which should be stronger that regular PLA. Not sure about that, but I guess we'll see:
https://dl.dropboxusercontent.com/u/...2018.46.21.jpg
https://dl.dropboxusercontent.com/u/...2018.46.32.jpg

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## spegelius

Testing the parts stabilizer parts:
https://dl.dropboxusercontent.com/u/...2021.30.47.jpg
https://dl.dropboxusercontent.com/u/...2021.30.55.jpg
https://dl.dropboxusercontent.com/u/...2021.31.00.jpg
https://dl.dropboxusercontent.com/u/...2021.31.28.jpg

Seems to work very well, even with tension only between two corners. Needs more parts so I can tension the whole thing form all corners and from other side, too. Might do some optimization and simplification about the parts, might have overthought things again...  :Smile:

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## spegelius

Hmm it seems Dropbox has changed things and previous links aren't working anymore. Well the link to the Dollo-folder works: https://www.dropbox.com/sh/g2z5027vm...vJxo-6MXa?dl=0

Got the frame stabilized, seems to work fine during printing. Stabilizer parts do restrict access to inside of the printer, I might have to rethink them later. But it works:

https://www.dropbox.com/s/tgeybac7mn...31.33.jpg?dl=0

Had some problems with RAMPS, hot end FET had a broken leg which caused some smoke to erupt. Luckily i have extra LM1117 5V regulators so I could fix the Arduino. I changed the setup so that RAMPS doesn't power the Arduino, instead I installed Octoprint to Raspberry pi and mounted it on the frame. Raspi powers the Arduino, seems to be working well. Now all my printers are run by Octoprint. Had to change hostnames for the Octoprint instances so there's no name collisions in my LAN.

Also installed a bed level sensor to autolevel the bed:
https://www.dropbox.com/s/nfqvuf27nz...38.25.jpg?dl=0
https://www.dropbox.com/s/cjk1auv9ru...13.02.jpg?dl=0

The sensor is  LJ18A3-8-Z/BX, 8mm NPN inductive sensor. Operating voltage is 6-36V, but it seemed to work with 5V. Still, I soldered a voltage divider on it and feed 12V to it, voltage divider lowers the signal voltage to 5V. Marlin config and tuning the distance took some time, but now it seems to work ok.

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## spegelius

For the firts time I've actually been just using Dollo, instead of building or tweaking it. I've been printing these containers in hopes that I can get at least some of my stuff organized. In current form, Sollo is working quite nicely: bed leveling works and seems accurate enough. Prints come out without deviations, and even though they do have some artifacts caused by small bumps on X- and Y-axes, they are perfectly usable. There's not much to actually improve; only thing I really need is a part cooling fan for printing PLA. And quality, but it's good enough for the stuff I'm going to use this thing for. I think I'll buy E3D volcano and print large stuff with 0.8mm nozzle or something.

https://www.dropbox.com/s/5i970in1jm...51.42.jpg?dl=0
https://www.dropbox.com/s/3j1dxi3lwl...52.05.jpg?dl=0
https://www.dropbox.com/s/jne9uhhrdt...52.17.jpg?dl=0

Material: different colors of PETG, mostly Esun. Red is 3DJake and clear is Extrudr

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## Chris_Hinson

Hey, wow, glad to see someone actually made a dollo and got it working. I found the dollo through the reprap wiki a few months ago and was initially disappointing at the lack of available information on it. Despite this, I'm still fascinated by the design and would like to move forward in making one this summer. Any advice on doing so? Should I even bother with the unique z-axis design or try for the normal threaded rod initially? Any advice on 3d printing services to print the parts rather than printing them on the school's printer? What motors would be best to use? I hope someone can help me out here. . .

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## spegelius

> Hey, wow, glad to see someone actually made a dollo and got it working. I found the dollo through the reprap wiki a few months ago and was initially disappointing at the lack of available information on it. Despite this, I'm still fascinated by the design and would like to move forward in making one this summer. Any advice on doing so? Should I even bother with the unique z-axis design or try for the normal threaded rod initially? Any advice on 3d printing services to print the parts rather than printing them on the school's printer? What motors would be best to use? I hope someone can help me out here. . .


Alright, you make 3rd active, or at least interested, person regarding Dollo  :Smile: . Ok so I'll try to give some information about how to go on about building one:

If you are going to print the parts yourself, make sure you have well calibrated machine. Print only few different parts and see how well they fit together. If they are too loose or too tight, you can use scaling option in your Slicer to slightly change the size of the parts. Do this for all the ties and extensions. Also the X and Y rails and motor mounts are good to check.Also if using multiple printers, this goes double of courseAbout printing services I know nothing, I haven't used them. But I'd expect them to have good quality if they do it professionallyMaterial: I used PLA for most of the parts. It's quite rigid and seems to work well. For some of the long ties and bow ties I switched to PETG, mostly because it's bit more flexible and can be used with parts that vary in dimensions (see first bullet, I have too much variation and it's PITA on some parts). PETG might also be better for X and Y axis racks, might slide betterPLA needs lubricant to make the axes move. The problem with friction is heat; PLA heats up fast to 60+ degrees and softens -> it jams. What I'm using successfully is http://www.wurth.fi/site/media/pdf/t...LIKONRASVA.pdf. Sorry it's Finnish, but basically silicon grease, quite thick but works like charm. Longest print on Dollo was over 11h, no problems. I tried a quite runny generic oil but this caused random missed steps and it was evident that it's doesn't work as well when by moving the axes by hand the axes did stick more.Assembly: if the parts fit well, it's quite easy. If needed, sandpaper and file tools are good to have around (along with hammer, heat gun, sharp knife etc.  :Smile:  ). I used sandpaper for X and Y racks to make them smoother, so those can be actually printed to be quite tight and sanded for best fit.Z axis: if you want a printer that produces decent prints, go with the traditional lead screw setup. The original Dollo Z-axis needs work to make it viable. It works, but not well. Tackling it is on my very long to do list  :Smile: Motors: it shouldn't need that powerful steppers, I have these http://www.omc-stepperonline.com/09d...04s-p-122.html for Z-leadscrews and http://www.omc-stepperonline.com/3d-...004s-p-18.html for X and Y. Both types are 2A motors, but I'm not running them at even half of that. This of course how easily the axes move.Electronics: shouldn't really matter as long as it can drive 4 axes (X,Y,Z,E) and few with multiple motors. I think all boards should be capable. However, I've only used chinese RAMPS 1.4 with Dollo. Getting a better board is advisable if you are concerned about how reliable and stable such board is. But since this is kind of a budget endeavor, RAMPS is not a bad deal, even with full graphics display.

I'm still using and upgrading my build. Been tied on other project lately, got a Prometheus system a while back and been tinkering with it.
But this is what I'm working on currently:

https://www.dropbox.com/s/v4k8wru43q...44.43.jpg?dl=0
https://www.dropbox.com/s/jl3k48oa7r...44.50.jpg?dl=0
https://www.dropbox.com/s/zgalspijm7...44.57.jpg?dl=0

A part cooling fan for printing PLA. I've had to redesign couple of X coupler parts to make room under the X-axis, there's not much of it. Will post more pics when I get it finished.

Future ideas: as I saw https://www.bcn3dtechnologies.com/en...r/bcn3d-sigma/ with dual X-carriages, I thought that Dollo could have such setup quite easily: just print another motor mount, gear, hotend mount and extruder, add stepper extender to RAMPS, tune firmware and off you go. Well might need something more than that  :Smile: , but entirely doable.

Edit: again it seems that Dropbox links might not be working. I need to find something better to serve the pics. For now, here's the link to all of the pics: https://www.dropbox.com/sh/g2z5027vm...vJxo-6MXa?dl=0 (hopefully working...)

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## Chris_Hinson

Thanks for the response. The dopbox full of pictures is very useful in helping me visualize the task ahead.  Right now I'm trying to assemble a BOM and approximate cost. Anything you can tell me on that front? On a related note, how long did it take to print all the printed parts? I tried putting a single corner and extention into my schools 3d printer and it estimated ~30 hours to finish

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## spegelius

> Thanks for the response. The dopbox full of pictures is very useful in helping me visualize the task ahead.  Right now I'm trying to assemble a BOM and approximate cost. Anything you can tell me on that front? On a related note, how long did it take to print all the printed parts? I tried putting a single corner and extention into my schools 3d printer and it estimated ~30 hours to finish


Hmm,if I remember correctly, the non-printed parts cost about 170 eur. I had most of the crews already, but buying those isn't a big cost. I didn't try to find the cheapest parts, because getting el cheapo chinese E3Dv6 hotend hascaused way too much trouble. Also wanted to make sure that the motors are powerful enough, just in case.

For the initial build, I think I used around 2 1kg rolls of PLA. Granted, I didn't have the settings tuned for least amount of filament use and I had to reprint some of the stuff after finding out they don't fit. Initial printing took about 2 weeks, with a slow af modded Cube2. Which also made all parts slightly too small. I didn't count the smaller parts as I thought that once I start to build the thing, I'll just print them as I go. Which I did, printing the missing bow ties etc. took few days.

Of course the current models on my github have changed quite a lot so the original BOM isn't valid anymore. Practically all the Z-axis stuff using lead screws is my design and should be documented. Also the racks and motor gears have gone through few iterations. And hotend mount. And other random bits and pieces. I'll see if I can get and updated BOM done soon.

Update on the fan duct: got it installed and working. It's not working 100% yet, the airflow should be directed more to the nozzle. As can be seen on the Benchy pictures below, the chimney hasn't cooled properly. Otherwise the quality is quite good. Well, apart from the retraction jams on the cabin, E3Dv6 clone again... have to do some cooling modifications on it.

https://www.dropbox.com/s/owqvuk6hg9...55.44.jpg?dl=0
https://www.dropbox.com/s/009jbg36zl...56.13.jpg?dl=0
https://www.dropbox.com/s/5haierfr3t...44.12.jpg?dl=0
https://www.dropbox.com/s/yieg0og7pd...44.36.jpg?dl=0

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## spegelius

I couldn't get the PLA working properly, jams too easily. If I heat up the hotend, extrude stuff a bit and let it just sit there like 10 seconds or more, it's already jamming. Works when printing larger parts but small details are no-go. I'll probably need to purchase another hot end if I want to print PLA.

So I switched to PETG, which works without problems. Benchy:
https://www.dropbox.com/s/y5dcid34ep...17.42.jpg?dl=0
https://www.dropbox.com/s/oks15cwh9a...17.52.jpg?dl=0
https://www.dropbox.com/s/6qfgqb6k0e...18.03.jpg?dl=0

Also I did some refactoring on the racks and motor mounts, they had bit too much of looseness and I moved one connector a bit as it was causing and unnecessary hole on the side. Also added a tie groove to help aligning multiple parts.
This time I printed the pieces from black PETG; I want to see if PETG would be better material for the rack setup. It's bit more flexible than PLA. Moving the slide manually seems that it does move more freely than PLA when both are moved without lubricant. Will be testing this once I get it installed on the X-axis properly.

https://www.dropbox.com/s/kg924glwrs...17.27.jpg?dl=0
https://www.dropbox.com/s/g7sihbvgs0...19.33.jpg?dl=0
https://www.dropbox.com/s/lkkf0fd0gx...19.14.jpg?dl=0
https://www.dropbox.com/s/g1l6sbkdr3...19.03.jpg?dl=0
https://www.dropbox.com/s/pwudtiqd9z...18.56.jpg?dl=0

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## spegelius

Been busy with other stuff, but did manage to get new Y-axis parts printed using PETG:

https://www.dropbox.com/s/19u798xw8v...17.05.jpg?dl=0
https://www.dropbox.com/s/cewjcxp2um...17.17.jpg?dl=0
https://www.dropbox.com/s/poj4jaz3t9...17.28.jpg?dl=0

Also designed and printed a jig for aligning the rack parts. Works fine and it's all printed parts:
https://www.dropbox.com/s/w6h7bz2maa...17.44.jpg?dl=0
https://www.dropbox.com/s/lxqlbini98...17.51.jpg?dl=0
https://www.dropbox.com/s/1aovt26rcl...17.58.jpg?dl=0

I used soldering iron to fuse the parts together so the parts don't move in use.
The new racks seems to move more smoothly. I printed few rose stems and the results are quite good:
https://www.dropbox.com/s/a3qu25wn11...00.31.jpg?dl=0
https://www.dropbox.com/s/dlziq1l9xr...00.36.jpg?dl=0
https://www.dropbox.com/s/hmpcpuea74...00.49.jpg?dl=0
https://www.dropbox.com/s/5vt00vjxkw...00.58.jpg?dl=0

There were few skipped steps on the other print, I loosened the Y-mount a bit and set stepper amps bit higher and seems to be working fine now.

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## spegelius

Not much happening with Dollo, nee involved with Prometheus System and it's taking my time. But I did print some extension parts, I'm planning to extend my build from 36xm x 36cm to 48cm x 48cm (outer widths). Z axis will remain the same, would need to get longer lead screws for that. Z-axis provides about 41cm of build volume, which is ebough for now.

One problem with such a large width is that the beams start to drag: even now I can see that Y-axis has ~1 mm sag in the middle. I think I'll have to buy some 8mm threaded rods to keep things straight. But that'll be in future, other projects take all my time now.

Oh I did print this thing to use in sauna:
https://www.dropbox.com/s/tiqx2ir8lm...19.06.jpg?dl=0
https://www.dropbox.com/s/em3lrleot4...19.11.jpg?dl=0
https://www.dropbox.com/s/fb43rvoyj7...19.26.jpg?dl=0

Black PETG, 0.3mm layer, height ~33 cm. Had bit of problem with over-extrusion, changed MK8 hobbed bolt to E3D HobGoblin and forgot to clean eeprom after updating E steps/mm in firmware. And support material was bit pain to remove as it's PETG.
Other than that the print is quite good, even et the top. There's bit more 'wobble' in layers towards the top as the bed isn't very rigid, but still good enough. And it seems to hold water  :Smile:

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## spegelius

Long time no updates on Dollo, Prometheus and my related project, filaswitch g-code post-processor has been taking my time. But I've been meaning to do 2 things: change X and Y stepper drivers to something better than A4988's and use sandpaper to smooth the X and Y rails.
Finally got some time and swapped the Trinamics TMC2100 drivers to Dollo. The difference in worst-case noice level is huge: A4988's had that certain speed area where the movement would just resonate very loudly and it was not nice to listen. With TMC2100, smooth as butter. TMC2100 also have interpolated 256 microsteps, meaning that the controller board sees them as 16 microstep chips, but internally they do 256 microsteps. This should make round surfaces smoother as motors move in smaller increments.

Also took the rails out and sanded the grooves. Especially the joints needed some cleaning, it's been evident that they do cause bit of artifacts to print surfaces. Also checked the motor gears for print artifacts, something I should have done when I printed to gears.

Result seems much better, at least regards the outwards aesthetics of the printer; seems fluid and doesn't sound like something is going to break any minute. Doing 3DBenchy right now, will post result after.

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## spegelius

Slic3r sliced and Dollo printed:
https://www.dropbox.com/s/d2aa6fy0ln...29.19.jpg?dl=0
https://www.dropbox.com/s/exn9xxijcy...29.35.jpg?dl=0
https://www.dropbox.com/s/92ssrx0q6n...29.44.jpg?dl=0
https://www.dropbox.com/s/0banb2ljmy...29.52.jpg?dl=0
https://www.dropbox.com/s/aebsyvnx2z...30.06.jpg?dl=0

Need beefier fan for the part cooling fan, some problems with bridging. Otherwise looking good. And Trinamics drivers seem to remove some moire-effect from the front of the ship.

----------


## Chris_Hinson

Any thought on using this printer to print a dollo?
https://www.imakr.com/us/en/startt-a...d-printer.html

----------


## spegelius

> Any thought on using this printer to print a dollo?
> https://www.imakr.com/us/en/startt-a...d-printer.html


Print volume should be enough. Might need to export smaller rack-part as it's currently 16cm.
Quality seems decent if the example pictures are true. Some calibration prints recommended before printing the parts.
Also it seems to be compatible with S3D and Cura so possible to tune the print settings.

If the printer works reliably, it should be possible to print Dollo with it.

----------


## KoenT

Hi Spegelius,

I am currently printing my own 3D printer from the GitHub repository (https://github.com/benbeezy/Dollo). 
I am printing it with 0.8 mm nozzle on a very stable Ultimaker 2, material PLA. You have any suggestions before I build everything because you might have some experience.

I hope you have time to answer.

Cheers,

----------


## spegelius

Hi,

your printer should be good for printing Dollo. I've printed some of the parts with 0.6mm nozzle, 0.8 should be fine as there's really no need for really detailed parts. Main thing is that they are dimensionally correct and consistent. I've posted some notes about printing the parts in this thread previously.

If you are printing the files from benbeezy's repo, be prepared to have bad experience with the z-axis. It can be made to work, but the print quality won't be good. This is the first print I did with the original z-axis implementation (the blue tower):

2016-09-06 12.25.07.jpg
As you can see it's not very consistent. At that time X and Y axes had problems also, but z was the worst.

But the good thing is that you can reuse most of the stuff sans the z-axis parts and build one with threaded rods. My current setup uses tw0 10mm threaded rods and prints quite nicely:
https://www.dropbox.com/s/3svcs3mya1...45.28.jpg?dl=0
https://www.dropbox.com/s/ey6p6qdcj1...45.06.jpg?dl=0
https://www.dropbox.com/s/8asxd3matt...44.55.jpg?dl=0

Latest models with the z-axis parts for threaded rods are here:
https://github.com/spegelius/Dollo

You'll probably need to modify some parts. Also there no good list of what parts to print... haven't had time to improve Dollo stuff, it's been printing stuff quite a lot lately  :Smile:

----------


## KoenT

Hi, Thanks for the update.

I was also thinking about threaded rods for the Z-movement. Printing gears with some error increase gigantically with perspective to the printing accuracy. I have seen your dropbox photo's and I have to say that you have nice workarounds for multiple issues.

And from your point of view, would it be beneficial to make this 3D printer to save money instead of just buying a RepRap and might I ask how much money you spend to this point or would you suggest of buying one? 

Cheers.

----------


## spegelius

If you are looking for a printer to print parts with fine details and strict tolerances, and want it to be relatively hassle-free, Dollo is probably not a good choice. First, although I've gotten a relatively well working one made, it's not finalized and building one needs some figuring out (I need to clean up the git repo and do proper parts lists and instructions). The printed xy axes cause some small wobbling, which is seen as small artifacts. Also there's no real data how long this kind of printer will work reliably; I'm the only one with working Dollo as far as I know. For me the latest iteration has been working surprisingly stably and consistently, but it might break during the next print. Lot's of unknowns...

So if you want to build Dollo, willingness to tinker is a must  :Smile: . For me, Dollo is more of a experimental project than a workhorse printer (although it's been working quite hard lately...).

Saving money: maybe a bit if going with the cheapest parts and filament. But the cheapest printers from china probably come close so it boils down to what kind of tinkering you are interested: building from from plastic or fixing the cheap Chinese crap  :Smile: . Dollo should be easier to expand so that's one thing going for it.

Money I've spent on Dollo:
- electronics, motors, hotends etc. from Ebay: 100-150 euros. I haven't kept tabs on the costs and some of the parts weren't the cheapest options. Also had to buy real E3D heatbreak for E3Dv6 clone to be able to print PLA, so going with the cheapest parts is not always a good option..
- plastic for the currently used models only: ~2 rolls of PLA/PETG = 60 eur
- plastic for the experimental parts: probably another 2 rolls
- hours spent tinkering: too many to count  :Smile: . Would I do it again? Absolutely. In fact once I get some other projects out of the way, some upgrades and new ideas to work on. And update the README...

----------


## sylviashea

Hello! Thank you a lot for the submission of this post! Once I had the same problem, and could not figure out what was the issue with!

----------


## spegelius

Been thinking about getting some better build instructions done, but haven't even started yet, always other stuff to do. But Dollo itself has been on real use and I have had plans for updates all the time in my head. To that end, I need to print another frame for testing my ideas (got a couple of ideas for printable z-axis that I need to test). So an idea struck me, why not document my build process as I go, telling how I printed the parts, what settings to use, what to consider before printing them, what material to print them from, how to assemble etc.

So here's the target setup I'm aiming for:
- 36cm x 36cm x 24cm cube (X and Y have 2 x 12cm extension beams + corner pieces, Z has one 12cm extension)
- should hold ~20cm heated bed
- same X and Y rack-pinion setup as my current Dollo
- same hot end mount as my current Dollo
- shitload of bow ties etc. needed to connect the parts
- same gears as current Dollo
- some extruder, not important for the sake of this experiment as long as it works if I ever get to actually print something  :Smile: 
- E3Dv6 hotend, RAMPS 1.4, endstops etc. default stuff

What I need to design and prototype:
- better heated bed carriage
- Z-axis prototypes
- ?

So basically all stuff for making a Dollo (sans z-axis) axis and just needs printing, assembling and documenting. Z-axis is moro of a mystery at the moment how it will turn out. Bu I do have a working prototype of a printed ballscrew, just need to figure out how to make a z-axis out of it  :Smile: .

As I already have some frame parts printed that were meant to be used on expanding the current Dollo build, I'll be using them. Though I need to print some more for full frame. So in next post I'll be detailing how to print the frame parts and maybe about building.

----------


## spegelius

So, the frame. Following parts are needed for basic cube (download here: https://github.com/spegelius/Dollo/t...ong_ties/STL):
- corner.stl x4
- extention.stl (should be extension?) x 20

For attaching the parts together, these are needed:
- bow_tie.stl x 112 (my calculation may be off, but print a shitload  :Smile:  )
- long_tie_split.stl x less than bow_ties but still a shitload. Alternatively print long_tie.stl, but the split version is bit more forgiving if the dimensions are too tight

Materials (my preferences, other materials can be used but I haven't tested):
- corner: PLA
- extention: PLA
- bow_tie: PETG or PLA
- long_tie: PETG or PLA

I prefer PETG for the ties because it forgives bit more when part dimensions are off for some reason. On the previous frame I literally hammered couple of PLA ties to the extension grooves so tight that I had to extract them by cutting the out.

Slicer software: I use Prusa Slic3r 1.38.6 and will use it until all parts are done. Not going to be changing things mid-project. I wanted to use KISSlicer 1.62 but it has problems with certain models with errors and don't have time to sort that out. KISS has nice adaptive layer-height feature, but it's a nice-to-have in the scope of this project.
Printers: Prusa MK2 and FrankenCube

Print settings. There are few things to note here, but in general nothing too fancy.
For all parts:
- perimeter first. In my experience the parts are more accurate dimensionally. Overhangs suffer, but meh.
- make sure your printer prints straight. Any slanting will of course translate to the printer frame
- have your printer extrusion, fan, retraction etc. tuned; better print quality, less problems during build
- in general the quality doesn't have to be top notch as long as the dimensions are ok and parts are strong
- brim depends on your bed adhesion

Corner:
- 3x perimeter
- 3-5 bottom/top layers
- 20% infill
- use supports and brim, this is somewhat challenging print
- I've printed these up to 0.3mm layer height, but the quality leaves need for post processing. 0.2mm is a safe bet.

Extention: 
- 2x perimeter
- 3-5 bottom/top layers
- 0.3mm layer, no 
- 10-15% infill
- no supports, assuming your printer does good bridging
- these are quite sturdy pieces even when printing at moderate settings

Ties:
- 2x perimeter
- 4-5 bottom/top layers
- x infill. The parts are too small to have any infill, so in essence they'll be printed 100%

Printing order; first print couple of extentions. Then print one bow_tie and long_tie. See how well the ties fit inside the extention groove. It'll probably be too tight, so got back to the slicer SW and scale the ties in X-direction to 95%. Reprint the scaled ties and testa again. Repeat until the ties are almost possible to insert by hand. Personally I leave them tight enough to need small rubber mallet to help them along.
Now you have the scaling factor for the ties, so it is a good idea to print a coupe of shitloads of them. At least. It's nice to have multiple printers for this  :Smile: .

Post printing:
- remove brim and supports if any
- remove any blobs or other print artifacts if any
- if there's some deformations like buildup on seam, use file to even those out. Especially around the tie grooves
- beweling the edges of the tie grooves helps during assembly

Assembly: this should be quite self explanatory, but I'll leave some pics here for now. If needed, I can provide some explanation later.

Pictures in Dropbox for now, seem I cannot upload pics here:
https://www.dropbox.com/sh/03w07glrn...K7SYqADia?dl=0

----------


## spegelius

Got the parts printed for the frame and also got the frame built:

https://www.dropbox.com/s/cu5r2pws64ikbww/2018-02-06%2021.07.31.jpg?dl=0

Had some issued with the extension parts, the black PLA I have (brand is bq) was oozing quite a lot and the prints weren't that clean. Haven't had that kind of problems before so going to blame this particular roll/brand of filament. Had to spend some time cleaning them, which could have been avoided by switching to another brand. Sadly don't have any other black PLA at the moment and didn't want to mix colors... need to order more.

Next, Y-axis parts. Ordered some stepper motors from Aliexpress, those probably take few weeks to arrive. Got some random leftover motors that I can use for test fitting, but I want a matched pair for the final setup.

----------


## spegelius

Racks (i.e. the rails) for Y and X are done. Took a bit more time than expected, had some problems with the models and had to do some ad hoc improvements.

Again, forum doesn't seem to work so only links available:
https://www.dropbox.com/s/noadqwl7ey...32.40.jpg?dl=0

Models to print:
- 6 x rack_5.stl (or 3 x rack_4 if not enough print area): https://github.com/spegelius/Dollo/b...STL/rack_5.stl
- 6 or 12 x rack_dove_pin.stl (optional): https://github.com/spegelius/Dollo/b...k_dove_pin.stl

Material: PETG. Can be printed in PLA, but I prefer having the racks = PETG and motor mounts = PLA, seems to be a good combination regards wear. PLA vs. PLA seems to wear down faster and PETG vs. PETG sticks too much.

Print settings:
- perimeter first
- brim if needed
- 3x perimeter
- 3-5 bottom/top layers
- 20% infill
- no supports. There's some bridging, but shouldn't be hard to get good results. Using supports with PETG is challenging to remove
- 0.2mm layers. Haven't tried higher, 0.3mm might work fine too

Assembly:
- for the frame size of this build, more than one rack part is needed. To connect the rack parts together, dovetails are used:
https://www.dropbox.com/s/0udrz5jtza...02.28.jpg?dl=0
https://www.dropbox.com/s/aukv4h7wtz...03.05.jpg?dl=0

The parts should be tight but still fit together. Use file/knife to remove material if needed, but be careful not to remove too much.
For proper positioning, the herringbone rack on both of the parts should be level. Also the grooves on the sides should also be on same level.

If the parts seem to be too loose, they can be locked together using the rack dove pins. I used small hammer to force the pins in the slots in the dovetail parts:
https://www.dropbox.com/s/hzhvbcoo1s...14.22.jpg?dl=0
https://www.dropbox.com/s/a4q55ou5nl...17.43.jpg?dl=0

The default size should be very tight, but use slicer scaling if they seem too loose.
Alternatively, soldering iron can be used to weld the parts together, but that's more permanent solution.

After the rack parts are connected, the side grooves need to be sanded so the motor mount will slide properly. Especially where to rack parts are joined needs cleanup. Use something like 180 grit sandpaper wrapped around a rectangular piece and work along the groove with long strokes until the whole length is smooth. There will be a small gap at the junction of the rack parts, but that's ok as long as there's no protrusions along the way.

Next, mounting the racks to the frame (Y axis)

Edit: forgot to mention the experimental rack alignment parts I designed for making sure that the racks are in proper distance from each other. No real need for these as the current dovetail joint seems to be working as it should.
https://github.com/spegelius/Dollo/b...gbone_base.stl
https://github.com/spegelius/Dollo/b..._tool_clip.stl

https://www.dropbox.com/s/tke90sz67g...45.21.jpg?dl=0
https://www.dropbox.com/s/c6a5smx43f...45.57.jpg?dl=0

----------


## spegelius

Although the rack assembly is pretty straightforward, there are few things to consider.

First, for this size of frame and number of rack parts, 3 long bow ties are needed.
Model: https://github.com/spegelius/Dollo/b..._tie_split.stl
or https://github.com/spegelius/Dollo/b...ng_bow_tie.stl, but this will be more difficult to get to proper size.

https://www.dropbox.com/s/0fa2omj75e...23.55.jpg?dl=0

Print settings:
- use same settings and instructions as detailed for long ties. Perimeters first, use slicer scaling if needed etc.

Preparing the frame: First, select the two opposite sides where the racks parts are to be installed. If there's long ties on the top side of the extension parts, remove them.
The frame should look like this: https://www.dropbox.com/s/d9ql5ixzrj...23.31.jpg?dl=0

Next, to get the racks lay flush on top of the frame, it is a good idea to use a file to smooth out the possible rough spots from the top of the frame:
https://www.dropbox.com/s/ahpo64yuqx...23.34.jpg?dl=0

Next, slide a long bow tie to the slot at the end of the extension and then the rack on top of it. Make sure that the herringbone gearing is on the outer side. Use hammer to ease the parts to their place if needed:
https://www.dropbox.com/s/2ryy5bvwmn...31.35.jpg?dl=0

Check that the rack sits flush on top of the frame:
https://www.dropbox.com/s/x1eu1r0cc9...38.03.jpg?dl=0

From the other end of the rack, slide another long bow tie to the slot and use a long stick and hammer to move the tie to the middle of the rack. Use the length of the stick to determine how deep the tie should be moved:
https://www.dropbox.com/s/9fwjmdc3x3...32.37.jpg?dl=0
https://www.dropbox.com/s/4qqpjn1baz...33.07.jpg?dl=0
https://www.dropbox.com/s/zrhkj3p38o...33.20.jpg?dl=0

Repeat on the other side. That's basically it:
https://www.dropbox.com/s/l2gz5g5wz2...37.37.jpg?dl=0

The position of the racks is not very strict, as they can be moved if needed. With hammer. If you can move the racks by hand, they might be too loose and cause problems during printing.

If the racks aren't sitting flush on top of the frame, this might be due to the overhangs on the racks: if there's too much droop, the ties won't be deep enough in the groove and they push the racks up. One solution is to use a knife to remove some material from the ties so they fit better. And for this the split version of the tie works better, because it's easier to modify. Of course scaling the tie in slicer works also so best to print one tie and check the installation before printing the rest.

----------


## spegelius

X-beam parts and assembly.

Parts:
- 2 x extention.stl: https://github.com/spegelius/Dollo/b.../extention.stl
- 2 x x_spacer.stl: https://github.com/spegelius/Dollo/b...L/x_spacer.stl
- 9 x long_tie_split.stl: https://github.com/spegelius/Dollo/b..._tie_split.stl
- 12 x bow_tie.stl: https://github.com/spegelius/Dollo/b...TL/bow_tie.stl
- 3 x long_bow_tie.split: https://github.com/spegelius/Dollo/b..._tie_split.stl
- assembled 2x rack from previous step

Print settings:
- for extention, long ties and bow ties, see previous posts
- x_spacer:
  - material: PLA
  - perimeters first
  - 3 x perimeters
  - 10% infill
  - supports needed

Assembly:
- connect the two extentions together with 3 long ties and 4 bow ties. Then add the x_spacers to the ends of the extentions, 3 long ties and 4 bowties per spacer. Make sure the long_ties don't protrude from the x_spacer part. If they do, they will obstruct X-beam installation in next steps.
https://www.dropbox.com/s/9ebtarzv3h...15.04.jpg?dl=0
https://www.dropbox.com/s/8fbvtmhelx...15.22.jpg?dl=0
https://www.dropbox.com/s/qr30ubikke...20.14.jpg?dl=0

- make sure that the top tie groove is empty
https://www.dropbox.com/s/eiutip00z4...20.19.jpg?dl=0

- use the instructions in the post detailing rack installation to install the rack on top of the x-beam
https://www.dropbox.com/s/xoskei55fr...35.22.jpg?dl=0
https://www.dropbox.com/s/l03ezys3pc...35.36.jpg?dl=0

As with the Y-axis racks, the position of the rack isn't critical, the rack can be moved.

----------


## spegelius

Motor mount parts for X and Y:

6 x motor_mount_small: https://github.com/spegelius/Dollo/b...ount_small.stl

Print settings:
- material: PLA. PETG works too, but it will not slide as easily as PLA does (assuming the racks are printed from PETG)
- perimeters first
- 0.2-0.3mm layers
- 3x perimeters
- 25% infill
- supports optional, I don't use them

After printing, use 3mm drill bit to open the bolt holes. They have 1 layer closed to make the hole overhang cleaner and that needs to be opened
https://www.dropbox.com/s/pb1prhhpi6...09.20.jpg?dl=0

Example of quality when printing PLA that has tendency to jam:
https://www.dropbox.com/s/9x7nfxq87i...09.33.jpg?dl=0

The part looks bad, but after cleaning and removing excess material from the holes, it works fine. Funny thing is that it's printed from same g-code and on same printer as the clear ones are. The black just wants to jam. Go figure...

----------


## spegelius

Motor gears.

Parts:
- 3 x motor_gear.stl:  https://github.com/spegelius/Dollo/b...motor_gear.stl

Print settings:
 - material: PLA. I haven't tried this in PETG so cannot comment on that
 - perimeter first
 - 3-4 perimeters. This one should be tough
 - 60% infill
 - 0.2mm layers
 - maybe use bit higher print temp than normally, if you can get a clean print

Now we get to the vitamins, first time for non-printed parts on this build.
- 3 stepper motors. I ordered these from Aliexpress for 35 euros. No idea how good they are... make sure the motors have a flat part on the shaft.
https://www.dropbox.com/s/uoh9kkk2cv...38.04.jpg?dl=0
https://www.dropbox.com/s/5y8peunudo...38.10.jpg?dl=0
- 3x M3 nuts (optional)
- 3x short M3 grub screws (optional)

https://www.dropbox.com/s/e8kxu1m8vx...29.28.jpg?dl=0

Assembly:
- if you want to use the grub screws, insert the M3 nut into the slot in the gear, use pliers to force it in until it's in line with the hole in the gear and then insert the grub screw and screw it in but not too deep so that it won't obstruct the motor shaft
https://www.dropbox.com/s/1xqitaag0s...37.40.jpg?dl=0
https://www.dropbox.com/s/wj1lemmzvj...38.43.jpg?dl=0

- next, try to slide the gear onto motor shaft. The flat part and the screw should align with the motor shaft flat.
   * Important! If the gear is too tight, don't use excessive force, like hammer unless the motor shaft is supported from the motors back. I hammered away and the motor shaft moved out of position which might not be a good thing. I've yet to test the motor, so I cannot tell if it's broken, but rotating the shaft by hand feels different comapred to other motors.
   * instead of force, better us small file to open up the hole enough for the gear to slide in position. Make sure to use the file evenly on the hole so that the shaft is in the center.
- proper position for the gear is about 2.2mm from the motor body:
https://www.dropbox.com/s/7nemsces57...53.46.jpg?dl=0

- you can check the position with the motor mount part. No need to screw the mount on at this point, just hold it by hand and see how well the gear centers on the rack:
https://www.dropbox.com/s/x1rza55p1j...54.07.jpg?dl=0

- when the gear is in position, tighten the grub screw if you use these

----------


## spegelius

Mounting Y and X axis motors.

Vitamins:
- 9 x 50mm M3 screws
- 3 x stepper motors with gears assembled

Other parts:
- 4 x bow_tie.stl (see previous steps for print info)

Y-axis:
Take one motor, two motor_mount_small parts and 3 50 mm M3 screws . Assemble and screw the screws in only couple of turns:
https://www.dropbox.com/s/y173f3t5ym...31.58.jpg?dl=0
https://www.dropbox.com/s/isyfxwuiz7...06.17.jpg?dl=0

Next, slip the assembly on the rack. If it doesn't fit, open the screws more:
https://www.dropbox.com/s/x682jr7uwu...06.21.jpg?dl=0

Tighten the screws until the mount needs considerable force to move. It's a good idea to move the mount back and forth while tightening the screws. Move the mount through whole length of the rack. Turn back the screws in small increments until the mount moves relatively easily. Don't expect it to be buttery smooth and move freely, there are no bearings here.

Repeat the operation on the other side of the frame:
https://www.dropbox.com/s/sxynn7bevq6b5uo/2018-02-25%2014.47.14.jpg?dl=0

X-axis can be assembled before assembling the motor mount for it, because the motor mount can be slid in and out freely.
To mount the x-beam on the Y-mounts, first move the Y-mounts to the end of the racks:
https://www.dropbox.com/s/dw5t56if961lm7z/2018-02-25%2014.47.33.jpg?dl=0

Then slide the x-beam on the tie slots on the Y-mounts:
https://www.dropbox.com/s/5erg4vkb8fcwiih/2018-02-25%2014.47.52.jpg?dl=0

The bottom of the rack should be approximately on the level with the Y-mount top:
https://www.dropbox.com/s/3bii49ml4e8ngtq/2018-02-25%2014.49.44.jpg?dl=0

Add bow_ties to the bottom of the Y-mount and x_spacer junction. Assemble motor mount for the X-axis same way as for the Y-axis.
https://www.dropbox.com/s/rh7cfco4veirkrs/2018-02-25%2014.54.51.jpg?dl=0

Moving the mounts might seem bit rough and that's expected. These are printed parts so there will always be some unevenness. But in this case things will get better; after a some time printing with Dollo, the parts will adjust to each other and he movement will get somewhat smoother.

----------


## spegelius

Been modeling parts for bed and Z-axis. Previous version of the bed carriage was bit too flimsy, didn't use existing parts and also needed nuts and bolts for assembly. So for the new setup I'm going to be using the extention pieces which should make the carriage quite robust. Z-axis prototyping is also underway.

Wanted to see how well my first Dollo build handles a bit more complicated model so printed a terminator skull. A 28 hour print, with two PLA colors. Enabled M600 command in Marlin so filament change was a breeze. Had some problems with the black PLA jamming. Got the base printed after cranking the speed to 150%.
Result is actually better than I expected.
https://www.dropbox.com/s/2o9km6rlzo...29.50.jpg?dl=0
https://www.dropbox.com/s/3arosjqir4...25.09.jpg?dl=0
https://www.dropbox.com/s/0q9ukgh8b6...24.43.jpg?dl=0
https://www.dropbox.com/s/faz0n9ecsm...24.29.jpg?dl=0
https://www.dropbox.com/s/fg88hzgrw9...23.56.jpg?dl=0
https://www.dropbox.com/s/hnxtgugqyz...21.16.jpg?dl=0

----------


## spegelius

Got the first working prototype of the Z-axis screw-mechanism. It works, but turning the screw requires a bit of force. But there's no slack so that's probably a good thing. Probably need to smooth out the threads with a file bit, because it seems that the seam is also causing a bit of unevenness.


https://www.dropbox.com/s/b70qxbx19z...52.38.jpg?dl=0


The screw itself is a V-shaped thread with a pitch of 3 mm, diameter 25mm. I didn't want to use simple nut, because of the wear that will happen. Wear in intself wouldn't be that big of a problem if it would happen evenly on the length of the screw, but unfortunately fost prints won't use the full z-length.
So the nut uses side rollers matched to the screw shape and hopefully the wear will happen in the axles of the rollers and not in the screw.
Side rollers are printed in PETG, other parts PLA. Again hoping that the different materials reduce wear. Also using some silicone grease inside the rollers.


https://www.dropbox.com/s/jfoo0uhhnq...53.28.jpg?dl=0


Also improved the mechanism for joining screw parts together using a keyed center part, same as I use for the z-rails. Keying makes sure that the screw parts are joined in proper way.
https://www.dropbox.com/s/pn1jp7dbtd...52.58.jpg?dl=0
https://www.dropbox.com/s/i69e4xfeg3...53.00.jpg?dl=0


Source code for the screw thing: https://github.com/spegelius/Dollo/b...s/z_screw.scad


Next, create motor screw coupler, integrate this thing to the bed carriage parts and try to print the whole thing. Who knows, maybe even get it working...

----------


## spegelius

Oh Prusa Slic3r, why you do this to me... over-extrusion and blobs and stuff. Started print the parts for the Z-rails and having a hard time to get the parts to print with decent quality. For most part Prusa Slic3r has been working ok, quality has been decent and consistent. But for some reason the rail parts are hard for the slicer. Switched to KISSlicer to see if the problems persist and lo and behold, pristine quality (Slic3r on the left, KISS on the right):

https://www.dropbox.com/s/iuqovg1dds...20.42.jpg?dl=0
https://www.dropbox.com/s/r89p7yanfu...21.18.jpg?dl=0
https://www.dropbox.com/s/duyaqt57me...21.36.jpg?dl=0

I guess the slope on the rail is the problematic are, as Slic3r tries to ensure vertical shell thickness and does it over somewhat. I haven't seen this problem this strong even though there have been some hints about Slic3r extruding more material than S3D and KISS. Also I've upgraded my Prusa MK2 with E3D Titan, which is a geared extruder (it's calibrated properly).

Switching slicing sw mid project isn't something I like to do because it's yet another variable and might cause problems when fitting parts together. But slicer starts to misbehave, alternative is to spend extra time with post processing, which I'd like to do without as much as possible. So KISS it is, at least for these rail parts.

Other progress: I have the z-screw - bed carriage part somewhat finished. But I'd really like to make the rail sliders replaceable, so one doesn't have to reprint the whole z-screw part when replacing them so going to do some more tweaking. Onto OpenSCAD ->

----------


## spegelius

Z-axis is progressing, models are finalizing, parts are printing et cetera.

In the meantime, X and Y endstops holders. There are two varieties to choose from, both clip on the rack. Choice is yours.
Top of rail, good if you want to have some flexibility in choosing the endstop position. Using one on my first Dollo:
- https://github.com/spegelius/Dollo/b...op_racktop.stl

End of rack. To adjust endstop position, whole rack needs to move:
- https://github.com/spegelius/Dollo/b...op_rackend.stl

Print settings:
- material: PLA or other.
- 2x perimeters
- 10% infill
- perimeter first
- no supports

Assembly is easy, just slide the switch in the slot and slide the whole thing either on the dovetails on the end of the rack or on top of the rack. 
https://www.dropbox.com/s/99oxk2w85f...23.26.jpg?dl=0
https://www.dropbox.com/s/1wev33yxiq...24.30.jpg?dl=0
https://www.dropbox.com/s/uajlvyt9jx...24.58.jpg?dl=0
https://www.dropbox.com/s/itnjdpmg5c...51.01.jpg?dl=0

----------


## jiaoguanxiu

Hello! Thank you a lot for the submission of this post! Once I had the same problem, and could not figure out what was the issue with!
https://www.oyostepper.com/

----------


## spegelius

Finally got some Z-axis assembly done and it's actually looking like the damn thing could work even. Only one side done, other side will see some iterative updates.

Rail holders top and bottom:
https://www.dropbox.com/s/gwk1kdnkff...32.19.jpg?dl=0

Frame rail/slide setup. Also supports the Y-beam. Rail slides are replaceable, printed from PETG. Used PTFE spray on the rails to improve the movement, still bit siff:
https://www.dropbox.com/s/i6j2e5o8au...25.27.jpg?dl=0
https://www.dropbox.com/s/7jpn0lxaxu...51.12.jpg?dl=0
https://www.dropbox.com/s/e292po68uz...51.36.mp4?dl=0

Motor coupler, Z-screw and motor mount/leg:
https://www.dropbox.com/s/dihvkjfkyd...07.23.jpg?dl=0
https://www.dropbox.com/s/0rqnvq8r0r...01.41.jpg?dl=0
https://www.dropbox.com/s/zac7e1regd...07.37.jpg?dl=0
https://www.dropbox.com/s/ytivc70i4b...07.52.jpg?dl=0

Assembled on the frame:
https://www.dropbox.com/s/mcikaqyjnw...18.02.jpg?dl=0
https://www.dropbox.com/s/xnab5e5kmy...18.07.jpg?dl=0

Rest of the legs on the frame:
https://www.dropbox.com/s/ihju3xijtc...29.40.jpg?dl=0
https://www.dropbox.com/s/6vhhh7jfzf...48.22.jpg?dl=0
https://www.dropbox.com/s/3idy1yzqzc...48.31.jpg?dl=0

Not detailing the print settings etc. yet, because there will some adjustments.
Things to improve:
- all z-screw side rolls aren't turning, which is bad thing in long term: the roll will wear unevenly and probably cause problems at some point. So to force the rolls to roll, I'll add some teeth on the rolls and z-screw.
- z-screw sections joining: currently using glue to glue the center part, but maybe think something mechanical
- z-endstop placement; probably add a dovetail slot on the z-screw carriage where the endstop or endstop arm can be mounted
- not perfectly happy with the rail frame mount pieces, frame needs some disassembly when installing the rails. Probably good for now though...

I might connect some electronics to see how things work.

----------


## spegelius

Slow progress for few weeks, but progress nevertheless. Got things wired up and another side of the z-axis printed with even z-endstop made. New z-screw has gearing so side rolls are definitely turning. Had some hard time with OpenSCAD as rendering took few hours for the new z-screw. Actually did some optimization using render() and looping rendered pieces to get the full height which sped things up quite a lot.
And everything seems to more or less work. A short video of homing and moving z-axis:

https://www.dropbox.com/s/ykfw4axmky...37.19.mp4?dl=0

Still, even though things seem to move ok, there's small wobble going on. This is caused by the rigid stepper motor coupler and a slight curve on the first s-screw, due to gluing the pieces without putting them in a jig. I already designed a screw jig and redesigned the coupler to use similar flexible system I use on the first Dollo, but haven't installed it yet. I think I'll finish this version just to see how bad the wobble is and upgrade the z-screws after that.
I have more parts printed so assembly is needed: bed frame and couplers for attaching the bed frame to z-axis and hot end mount. Need to design parts for mounting the actual bed and decide about what kind of extruder to use. Actually not that much to go before printing can be attempted.

----------


## spegelius

Long time since last update, been busy with other things. But now it's my vacation and been finalizing stuff like extruder and bed attachment and doing cable management (which I don't like that much for some reason).

Springy things for attaching bed. Not pictured here, but bed level adjustment is built in with screws.

https://www.dropbox.com/s/woe22jzxff...26.33.jpg?dl=0
https://www.dropbox.com/s/w4og5d38px...26.39.jpg?dl=0

Did not take pictures of the extruder, but it's a remix of this: https://www.thingiverse.com/thing:2243325. Modified to work with E3D Hob Goblin.

Other pictures:
https://www.dropbox.com/s/vae3yywead...26.26.jpg?dl=0
https://www.dropbox.com/s/2awbx1j8h5...26.49.jpg?dl=0
https://www.dropbox.com/s/wthpr7h9ex...26.53.jpg?dl=0

And it does print, even though I had some problems with bed leveling. Currently don't have heated bed, only a glass so bed adhesion isn't the best possible.
https://www.dropbox.com/s/93vma6n5dd...42.45.mp4?dl=0

First prints. Need some tuning but the cable clips are very usable (https://www.thingiverse.com/thing:585580).
https://www.dropbox.com/s/fb8pr6tep0...36.47.jpg?dl=0

Currently printing a bit larger box: https://www.dropbox.com/s/ikk0vk5soc...36.53.jpg?dl=0. Uneven bed and Dollo's bit wobbly movement shows a bit here. X and Y axis need some time to get honed in so just need to print more stuff.

----------


## spegelius

Enabled mesh bed leveling which does help with the bed adhesion. As I have no sensors, I use the manual leveling, which actually works very well, just takes bit more time.
Using Marlin's linear advance, currently testing value K150 (~60cm bowden tube). Does reduce the need for retraction, usually with this long bowden I need to use something like 5mm retraction. With LA enabled, even 2.5mm is enough.
Replaced A4988 stepper drivers with DRV8825 for X and extruder. Does make the printer bit quieter. Will swap Y driver to DRV8825 later, need to test it properly because in past I have had some bad experience with driving to parallel motors with DRV8825.

Some prints that I got done today on the new Dollo:

Stackable box, looks like crap for a couple of reasons: retractions for PETG and linear advance not tuned in, warping and inconsistent bed movement (bed does not stay level in Y-axis due to bent z-screws). I actually printed this the see how much effect the last problem has and it can be seen that on 3mm intervals (z-screw pitch) there's some banding happening. Other than that, z seems to work fine and the dimensions are very good.
https://www.dropbox.com/s/ihoysq5yej...21.34.jpg?dl=0
https://www.dropbox.com/s/ihl0e1l26o...21.44.jpg?dl=0
https://www.dropbox.com/s/6f0emx127p...21.55.jpg?dl=0

Of course 3DBenchy is one test model that just needs to be printed. PETG and 0.2mm layers, S3D. Turned out quite good actually. The z-banding can be seen here too, and again retractions need a bit of tuning. Also no part cooling yet, even though PETG isn't that dependent of it.
https://www.dropbox.com/s/j3duq4flso...39.13.jpg?dl=0
https://www.dropbox.com/s/fy2v3o0jeg...39.23.jpg?dl=0
https://www.dropbox.com/s/bl45m8jeir...39.34.jpg?dl=0
https://www.dropbox.com/s/o53t6btgxk...39.45.jpg?dl=0
https://www.dropbox.com/s/xgmrev0mak...57.40.mp4?dl=0

Printing parts for the cable shroud. Most of the parts were printed on Prusa MK2, but now I can use Dollo to print them. PLA, KISSlicer, 0.25 layers (KISS dynamic layers). Also tuned linear advance from 125 to 150 for these parts.
Also when positioning the models in line with the z-screws, the bed rocking motion is minimal.
https://www.dropbox.com/s/61o1tyvt4y...33.15.jpg?dl=0
https://www.dropbox.com/s/jcy8o5edm2...33.26.jpg?dl=0
https://www.dropbox.com/s/h3zb8qno5h...58.48.jpg?dl=0

To fix the bed rocking motion, I'm printing new z-screws that use flexible coupling to the motors. Also because the z-screw consist of multiple parts, connecting them together is prone to result in bend screws. I designed a jig to keep the parts straight when the glue sets:
https://www.dropbox.com/s/srcf56s4bj...04.19.jpg?dl=0
https://www.dropbox.com/s/qvdz1sxgry...04.34.jpg?dl=0
https://www.dropbox.com/s/6qpp88pce8...04.38.jpg?dl=0
https://www.dropbox.com/s/6rck3jrbsxba5h9/2018-07-05%2012.12.58.jpg?dl=0

Next:
- install new z-screws
- order a heated bed
- mounts for RAMPS and Raspi
- mount for ATX power supply
- design some parts for cable management
- part cooling

----------


## spegelius

So got the new z-screws installed, after some reprinting of the z-screw parts. Didn't get the parts glued in at perfectly, there was a bit too large gap between the parts and motor doesn't have enough power to move through that without skipping steps. Newest parts work well as long as I don't print parts over 90mm in height.
Changing the screws was quite easy, luckily I designed the whole bed carriage to be detachable. Also the z-motor mounts are quite easy to detach.
https://www.dropbox.com/s/toqsp6n5ds...45.39.jpg?dl=0
https://www.dropbox.com/s/1t6tr260ce...15.10.jpg?dl=0

The new flex coupler works quite nicely, although the Filaflex tube is maybe even bit too flexible.
https://www.dropbox.com/s/gc0zejm6f9...15.21.jpg?dl=0
https://www.dropbox.com/s/81lchfvkyd...16.07.jpg?dl=0
https://www.dropbox.com/s/1fj4uf4rft...18.23.jpg?dl=0

Also printed part cooling fan using Taulman Nylon. Nylon had absorbed some moisture, which lead to stringing, but after cleaning the part it seems to work ok.
https://www.dropbox.com/s/t1tkh0p50l...06.26.jpg?dl=0
https://www.dropbox.com/s/vyxeiahun0...06.30.jpg?dl=0

Anyways, now the bed moves more or less straight. Another stackable box, green PETG. Again, having trouble with retraction, even though I upped the retraction length from 2.5 to 3.6. Starting to think that maybe the linear advance might be doing something nasty...
https://www.dropbox.com/s/s4vptji4l7...46.33.jpg?dl=0
https://www.dropbox.com/s/koi9dqru4p...46.40.jpg?dl=0
https://www.dropbox.com/s/7q3frm3hqb...46.52.jpg?dl=0

To fix the retraction problems, I ran KISSlicer destring wizard. To get a good baseline, I disabled linear advance for this. For string-free results, 5.3mm of retraction is needed. Next I'll run the same print, but this time I replace the increasing retraction length with increasing linear advance. Once the LA is tuned in, I'll run the retraction calibration again to get the hopefully optimal retraction settings...
https://www.dropbox.com/s/gz8as6q77e...06.13.jpg?dl=0

One thing Dollo has problems with is printing circles. I suspect that the friction of the axis mount causes very small stalls in the movement that lead to small imperfections. Loosening the motor mount screws should ease the movement, but I think this type of rail setup will never be perfect.
https://www.dropbox.com/s/vy2gh92k90...06.21.jpg?dl=0

----------


## spegelius

Ok update time. Been working on few things on the new Dollo build and I guess the build could soon be said that it's "finished". As if any printer build project is ever truly finished...

First, I made some adjustable feet for the frame. The feet are adjusted with the screw in them. There's also dampening parts under the feet, printed with Filaflex. Don't mind the gap in the top surface, using linear advance with KISSlicer seems to require upping the infill-perimeter overlap quite a lot and I haven't tuned it in yet.




For electronics, I designed some mounts that attach the frame. The PCBs are held in place with notches on the side and for example RAMPS/Arduino can be just slid in the mount. For RAMPS, designed a 60mm fan mount that clips on the RAMPS PCB (blatantly copied this design: https://www.thingiverse.com/thing:145946). With 5V, the fan is practically silent, yet has some airflow.
Also as I need some extra 12V and 5V outputs and a way to connect ATX PSU with PCI-E connector, I designed and connector mount and fan connector board with 12V and 5V outputs. There's also a connector with 5VSB,PS_ON and GND so I might use 5VSB line in future to power Raspi and RAMPS and control the ATX PSU from Octopi. This would get rid of the USB changer for the Raspi. For now, PSU main on/off will do fine.







Also mounted ATX PSU under the frame, which you might just see here. There's new cable shroud, previous version was too flimsy and sagged too much. This version uses PTFE tbe as the spine, which seems to work much better.
I need to get longer cables for the display, it's now on the back left corner of the printer.



Printed this vase to test the ~full z-height. The result is ok-ish considering the whole z-axis uses only plastic, but the inconsistencies get worse when going higher. Not sure what's the cause, but two possibilities come to mind: the z-rail slides seemed too loose last time I checked them (PETG probably wasn't the best material for those) or the glass plate I use moves around slightly, due to how it's mounted. I'm revising the rail slide design a bit so that should tell me more.




So to finalize this build:
- try to improve the z-quality. Not mandatory, the quality is still passable
- design parts for mounting the heated bed I bought
- raise Z height with one set (12cm) so total print height would be ~24cm
- maybe design a mount for the display (and get longer cables...)

----------


## spegelius

For printing parts for Dollo, I mostly use my trusty Prusa MK2 (now upgraded to MK2.5). It produces quality parts with good tolerances and does it reliably. My other printers are bowden setups and although they can produce quality prints, they are more prone to filament jams with certain PLA brands. I've noticed that even the Prusa suffers from this in extreme cases, but the direct drive extruder setup minimises the problems caused by filament not moving freely. With bowden, the pressure builds in the long tube and causes quality problems.

Since the Prusa is the only printer capable of printing all the parts for Dollo and other projects that require certain level of quality, it is quite busy and tied up most of the time. Getting another printer that can print with the same quality and reliability has been on my mind for a while. Since I upgraded the MK2 to MK2.5, I ended with some extra parts:
- bed
- extruder
- smooth rods for X,Y and Z
- bearings
- other bits and bobs

So I got the idea to put the parts in good use and build another Prusa. For frame, I'm going to use Dollo extension parts, I think it'll be robust enough. If not, I can always make it stronger with metal rods inside the extension parts.
As I have the MK2 heated bed (MK42), I'm planning on using Prusa fw so I have full MK2 calibration features. As I don't have the Minirambo board, I'm going to try to port the fw to RAMPS. If that doesn't work, then just buy the Minirambo. Also I'm planning to use DRV8825 or Trinamics stepper drivers, so that should improve on the already great printer.

I started the design work on the frame parts, I forked the Prusa repository. Thankfully the parts are designed with OpenSCAD, so modifications are easy to do: https://github.com/spegelius/Origina...tree/MK2_Dollo. Did a mockup of the original frame so I can re-create the part positioning accurately. Frame design is progressing quite nicely.
prusadollo.jpg

----------


## spegelius

Ok I got bit carried away with the Dollo Z-axis upgrade, it will be 2x120mm which means that the max z height is about 35cm. one z-screw and z-rail glued together, other z-screw in jig waiting for the glue to cure. I'm pleased how straight those parts are, seems that the jigs help a lot.
More parts to be printed and assembled. Also need to redesign the z-motor mount, current solution is not very stable.



Prusa/Dollo hybrid design is also progressing well. Most of the frame parts are designed and started printing them. Using grey and white PolyMax PLA for most of the parts, along with black PETG for the motor mounts and X-carriage parts. Quality filament does have it's good points; it's easy to print, no jams even on all-metal hotends. With same exact gcode, cheap PLA's cause problems.

Screenshot_2018-08-31_17-39-34.jpg

----------


## spegelius

Got the Dollo3D.2 z-axis upgrade done and printing. Full z-height is now ~36cm and the bed moves that full range seemingly without too much fuss. Designed new z motor mounts, which are much more stable than the previous solution.
Also found out few things that I need to tweak:
- bed carriage needs to be properly tightened to the z screw parts. Noticed that it's not level because it can tilt a bit. Used some screws to fasten it properly for now
- the larger frame is now bit wobbly, as was expected. So need to design some parts to make the frame more rigid.
- the z screws aren't perfectly straight, which might cause problems. Need to do couple test prints with ~full height to see how it goes
- there's no top support for the z screws and when bed lowers down, the screws wobble around a bit, maybe causing problems. Probably need to design something to keep the screws in check






Printed benchy and the same vase as before, this time with white PLA as I had it loaded. There's some inconsistencies in layers, not sure how much of it is due to the current z-setup or the filament (which is bit uneven on other printers also). Z wobble maybe, but seems that there isn't a consistent pattern...








And Prusa/Dollo hybrid is partly in assembly stage. Most of the parts are designed and being printed out. RAMPS enclosure, PSU cover and display cover need to be modified and need to redesign the bed carriage a bit.
Also modified the y-idler to be adjustable, fixed a small Prusa z-rod positioning error and planing to modify the x-idler to adjustable too. If my calculations aren't off, total usable z-height for this build would be around 23cm so 3cm extra compared to default Prusa MK2

----------


## spegelius

Tried printing something taller, a vase from here: https://www.thingiverse.com/thing:570288. Scaled 2x so 30cm total height. Print time ~24h. Filament ran out @24.7cm so I edited the file to continue from ~correct layer with blue PLA. Sadly the blue part came off, not sure why because the rest of the blue part holds together fine, even though the print quality is quite bad at the top.
Also seem to having some problems with the extruder, had to disable linear advance because the motor was skipping steps with low print speeds... again not sure what is going on, the motor is a quite beefy thing and driven by DRV8825 driver. Maybe try switching to A4988 as the other Dollo runs fine with one, with same motor and extruder design.

File is sliced with KISS, which leaves ugly gaps in the print. Probably didn't have proper settings for hollow print or something...

It's obvious that the frame wobbling around starts to cause visible problems when the parts get taller. So need to get the frame rigid.

----------


## spegelius

Ok two things:
- the blue filament is not PLA, its PETG  :Roll Eyes (Sarcastic): . Explains why it didn't bond to the white... note to self, next time actually check the filament instead of 'remembering' where I left certain rolls....
- swapped the DRV8825 driver to A4988 and no more skipped steps. I think the problem is this: http://cabristor.blogspot.com/2015/0...steps.html?m=1. Missing steps with low speeds... and the problems were evident with low perimeter speeds. Wonder how much this affects the surface quality... must print another benchy.

This DRV8825 problem might affect my plans about PrusaDollo if I can't trust the drivers. I have those diodes mentioned in above blog so maybe I'll try if that works.

----------


## spegelius

Reprinted the vase and benchy after changing the stepper driver. Results do seem bit smoother, although the material is different color and brand PLA. 

Had a look at Aliexpress, tl smoothers that are attached between the board and stepper driver look like what I want. But first I'm going to build one myself to see if it works. BTW, buying stuff from Aliexpress is almost too easy with the mobile app.

----------


## curious aardvark

okay - wow ! 
you've made your own extrusion and screws :-) 
Damned impressive.

Discounting your time and the print time - what sort of cost would you say the two printers will come to - individually ? 
filament, plus electronics.

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## spegelius

Well the original Dollo design and extrusions are by @benengel94, I've just gotten into this hobby of trying to make good enough 3D printed 3D printer  :Smile: . The z-screw idea has been forming in my mind slowly and still mutating to perhaps something actually useful. Well see. Current version works but might wear out quite fast.

For the first Dollo, I'd say ~2 rolls of PLA + some odd bits of PETG, ABS, Filaflex and small amount of Nylon for the part cooling fan thingy. So depending how cheap you can get the filament, something like 40 euros.
Bit less for the new build since it's not finished yet, doesn't have those frame stabilizer parts which I need to redesign somewhat.

For the electronics (had a quick look at Aliexpress):
- RAMPS + display ~25 eur
- 6 motors ~35eur
- 12V PSU ~20 eur
- some ?3Dv6 clone hotend ~10 eur
- PTFE tube ~60cm few euros
- endstop switches, extruder gear, few M3 screws and grub screws, M3 nuts, wire... ~10 eur?

So something like 100 eur. With the filament, not the cheapest printer out there, but I'd say much more fun  :Smile: .
Personally I have bad experience with clone E3D hotends so I would opt for genuine part.
Of course the design doesn't demand RAMPS or need a display. That's just what I've been using and configure Marlin for. I'm planning to install Megatronics 3.1 to the 1st Dollo, bought a DuetWifi for one of my other printers and Megatronics is without printer now. It has option for 3 extruder motors, so my plasn for IDEX setup on Dollo should work with that board (probably).

For the discarded Dollo parts, I think something like 15 rolls, mostly PLA. That's prototyping... I still have most of the old parts, maybe someday I can recycle them somehow.

Also, PrusaDolloMK2 build is progressing, bottom of the frame is mostly assembled. Printing some bow ties so I can get the Z frame parts assembled. Modified the X parts so that they accept the brass tr nut and added possibility for belt tension adjustment, need to print these.




Box of parts waiting for assembly:

----------


## spegelius

Prusadollo progress: as I don't have the original aluminum bed carriage, I designed printable version based on the original. Of course it should be quite stiff so I printed it with ColorFabb XT-CF20 carbon fibre filament. Result is quite stiff, especially since I used 0.8mm nozzle, 3 perimeters (2.4mm), 1.5mm top and bottom surfaces and 25% infill. XT is bit finicky to print since it likes to stick to the nozzle and leaves blobs in random positions, so I had to babysit the print somewhat. Also had a fail when trying to print with 0.15mm layer, the material just wouldn't stick to the previous layer. Ended up printing with 0.25mm layers (KISSlicer synamic layers 0.25-0.3) and the result is more than good enough.
XT's glass transition temp is ~80C so I printed the corners with ABS, so that the heat from the bed should be ok even when heating the bed up to 100C. I do have insulation under the bed PCB, so XT should survive fine.

----------


## spegelius

Received some stuff I ordered from Aliexpress (stepper motors) and decided to do some assembly on PrusaDollo. Got the Y-axis, X-axis, Z-axis and LCD mount mostly done. Bed carriage moves properly on Igus dryling bearings. The smooth rods could be bit tighter, but shouldn't be a problem. Belt installed and tensioner solution seems to work nicely. Also the frame seems to handle the belt tension without problems. The knob for the LCD needs bit  of redesign, it seems that this particular LCD assembly has a bit longer shaft on the encoder so the knob is quite high.
Z-axis needed some ad hoc remodeling, couldn't move the X-carriage all the way up and had to saw some material off of the top z mounts.
For X-axis and lower z mount parts I needed to use some painters tape to make the bearings and rods fit tightly. It seems that the Prusa parts are meant to be printed with Slic3r PE; KISSlicer does more accurate parts IMO, so couple of things are bit too loose.

The Z screws have 7cm of unused length. Might buy longer smooth rods and print more extensions to get full use of them.

----------


## Roberts_Clif

I too made a  Prusa Dollo would like to see your STL enhancements are you going to release to the forum.

IMG_1811.jpg

IMG_1812.jpg

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## spegelius

Nice, looking at your build makes me think I could have gone a bit different way like the corners and rod holders. Have you got it running yet?

All files are here: https://github.com/spegelius/Origina...tree/MK2_Dollo. I'll be doing some fine tuning and PSU cover and RAMPS enclosure need to be done too.

Still missing few pieces: GT2 pulley for the X-axis and some M2x12 bolts for the endstops (probably could get something hacked together, but I'll do this properly). Also RAMPS fw needs to be modded from Prusa sources, which should mean basically just adding RAMPS pin assignments and tuning the steps. Found this: https://www.thingiverse.com/thing:2607463, there's the pins_ramps.h file I need.

----------


## spegelius

Got the PSU cover redesigned and printed for bigger PSU (not wattage, but physical size). Mount and wiring also done. PSU seems to work, adjusted it to 14V for little extra performance.




Modified the Prusa firmware for RAMPS and so far so good: display works, temperatures seem ok and the fan extender I bought a year ago also works after configuring the correct pins for it (pins 6 and 11, normally meant for servos). So now I can have 3 fans that are controlled by the FW: hot end, part cooling and electrinics cooling.
Took the RAMPS from my first Dollo build, going to put Megatronics in it someday.



Also modified the RAMBo cover for RAMPS. As my other printers are occupied currently, decided to try printing the parts with the new Dollo. And the results are good enough, even though they aren't top quality. What's important is that they are dimensionally correct.



Currently assembling the extruder and hot end. Getting close to actually testing this thing. Wiring won't be finished yet, nee to design some clips for wire routing.

----------


## spegelius

Got things wired up for some testing. Everything seems to work after fixing few things in FW, like steps for 0.9 degree motors, z-height and display button rotation direction.
Went through the Prusa printer selftest, which was pass. One thing the Prusa selftest is missing, though, is a smoke detectio; heatbed mosfet shorted and smoke ensued. My bad, didn't check the MK42 bed resistance which apparently is low enough to cause too much current to be pulled through RAMPS mosfet. Luckily I have spares so new one is soldered in and I'll just limit the max power in FW so everything should be good... hopefully.

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## spegelius

Finally got the damn thing printing. Took some effort, electronics was really the thing that caused some problems:
- as mentioned previously, fet was blown due to bed drawing too much juice. The bed resistance is 1.1 ohms, so @14V that is ~180W, with is bit too much for the fets that are rated for 10amps I think? Replaced the fet and tuned the bed max power from full power to ~115W (duty cycle from 255 to 160). I think there's bit room to go higer, but I'll see how this works. Bed seems to heats up reasonably fast.
- the electronics cover I printed was too small. The display connector cables were too high, so had to redesign the model 10cm taller and reprint it. Dollo3D.2 to the rescue again, new cover done and works fine
- while assembling the RAMPS to the new cover, some of the pins didn't go the the Arduino connectors and obviously caused problems with endstops and display. Common problem with RAMPS, you need to align the boards correctly and check that the pins aren't bent.
- while debugging this problem, I accidentally nudged stepper driver heatsink off and it caused a short on top of the driver. Result: z-axis is dead. Depression ensued. But resolved this problem by switching the E1 and Z driver pins in Marlin and now Z is driven by E1 socket driver. No big loss since won't be using E1 on this printer.

After I got all things sorted out, ran the selftests, XYZ, Z and first layer calibrations. Everything checks out, my frame is 100% correct if Prusa's algorithms are to bebelieved. Awesome.

Still, couple of things to sort out:
- Trinamics and the 0.9 degree motors doen't seem to like each other. Ugly coil whining, even though everything moves properly. Probably switch A4988 drivers in for now. Sad, was really hoping to have the Trinamics interpolation. 
- X-endstop mounting screw head hits the left z-coupler at minimum z-height just enough to cause skipped steps. Need to file some stuff off of the screw head or the coupler.
- top frame isn't stable. Not a surprise since it's printed. Need to design clamps to tighten it. Wont affect print quality with small z-heights, but taller prints will suffer.

Classy Marvin scaled to 50%. Some PLA I purchased from Amazon. Seems to need bit more retraction and maybe cooling. Also first layer is a mess due to the z-skipping, lucky that print even stuck to the bed. I'll try Benchy tomorrow.

----------


## Roberts_Clif

> As mentioned previously, Mosfet was blown due to bed drawing too much juice. The bed resistance is 1.1 ohms, so @14V that is ~180W, with is bit too much for the fets that are rated for 10amps 
> 
> - while debugging this problem, I accidentally nudged stepper driver heat-sink off and it caused a short on top of the driver.


No, I had other problems with my secound 3D Printer, after fixing never got back to My 3D Printed System...

On my Controller I made heat sinks with an Aluminum Bar for a heat sink. As they were overheating did not need a large heat sink, no space for a good Heat sink.
With an adequate Cooling fan the Straight Bar Aluminum provides sufficient heat dissipation.  

Controller 2.jpg




> As mentioned previously, Mosfet was blown due to bed drawing too much  juice. The bed resistance is 1.1 ohms, so @14V that is ~180W, with is  bit too much for the fets that are rated for 10amps 
> 
> Question is a separate supply for the bed that you are using or is this power controlling everything.


If you have a single power supply powering everything you may have many problems.
By using your supply powered at 12 volts power P in watts (W) is equal to the squared voltage V in volts (V) divided by the resistance R in ohms (Ω)

Equals 130.9090 Watts




> I am not sure how it came to be that we started adjusting our 12 volt power supplies to 14 volts.
> This must be from the movie "Tool Time" an "Tim the Tool man Taylor", if you remember the movie everything Tim made had to have more power.
> 
> PROBLEM : The Power supply was designed for 12V and a specific current draw. When we exceed this rating the supplies cause problems.
> will take my Power supply because I know it.
> 
> My Supply 12volts at 30 amps = 360 watts
> If I was to turn the voltage up to 14 volts
> Then 14volts at 30 amps = 420 watts this supply was designed for 360 watts.
> ...

----------


## spegelius

I adjusted the PSU to 14V because that's what Prusa did with MK2 when it was launched and it was suffering from temp faults when using the part cooling fan. Their fix was to tune the PSU to 14V. I haven't checked the PSU on my original MK2 (now MK2.5), but I assume it's running at ~14V.

You might be correct about lowering the voltage back to 12V, though. It's obvious that 14V is overkill for the MK42 bed, especially with RAMPS. Also I'm using a silicone sock on the hotend so lower voltage shouldn't cause problems with it. Also as I bought the E3Dv6 directly from E3D, it might be that it has a more powerful heater cartridge than what MK2 was shipped with.

Still, the printer has been working fine so far, no blown fets since I restricted the bed power in firmware.

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## Roberts_Clif

They Did What !!!!!

Then do a happy medium 13v.

OR

Add a Smaller dedicated supply for the Controller. Then using external high power mosfets drivers with the Larger 14 V Power Supply. thereby protecting the Controller from over current and noise.

https://www.ebay.com/itm/2pcs-ANET-A...LG5Q:rk:2:pf:0

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## spegelius

Actually it seems Prusa didn't mess with PSUs, they upgraded the heater cartridge to a more powerful. I remembered watching a clip about it in youtube, the PSU 14V mod was Tom's doing: https://www.youtube.com/watch?v=pRX_uvG9Z-w.

----------


## dirtyknightsdolls

Being new to this, I feel overwhelmed by the choices.... I'm going to need help, that's for sure

----------


## Roberts_Clif

> Being new to this, I feel overwhelmed by the choices.... I'm going to need help, that's for sure


Choices are easy, 
They are dependent on what you can spend?
How much space you have for a 3D Printer?
What materials you want to 3D Print?

When these choices are made then a list of choices can be derived to suit your needs.
The more money the better the 3D Printer.

Now some will say that the less expensive 3D Printers are no good. However I have two such Aluminum frame 3D Printers that have more than paid for themselves.
Both cost around $200 US Dollars
Now I went a little overboard with a Heat Chamber for 3D Printers, Spare Parts, Tools, air tight Storage containers with disentent moisture removal for filament and Filament $600 US Dollars.
For a grand total of well over $1000 US Dollars invested. 

Not bad considering I have TWO 3D Printers, Enough variation of Filament as to print most anything and spare part to make repairs without any downtime.

----------


## spegelius

Got the frame stabilization done for the Dollo.2 build. It's quite rigid now. Printing all the screws, beams and center parts took quite a lot of time and material, so not sure if it's worth to do the stabilization with plastic when same thing could be done with threaded rods. But for science!
For the models, I also did some experimental internal infill magic by adding 0.1mm holes through the bolts, beams and center parts. The idea is that slicer has to add extra parimeters around those holes, thus making the parts stronger. I have no comparison to parts without the extra infill features, so how much it helps is just a guess.

To test the stabilized frame, I printed yet another vase, 330mm in height. 0.6mm nozzle, 0.35mm layers, 2 perimeters. The quality is quite good almost all the way, but at the top there's slight banding, which I think comes from the z-screws that aren't secured at the top and move around somewhat. But marked improvement to the previous vase, that showed quite bad artifacts due to the frame shaking around.

----------


## spegelius

So here's whats happened with Prusadollo:
- the original 240W PSU started acting up, I had lowered the voltage to ~12.3V and now PSU cannot keep the voltage stable during load. So the overvolting might've caused some damage. Swapped in a 360W PSU from the old Dollo that I've been planning on upgrading for a while now. Had the design a slightly bigger PSU cover for it.
- redesigned some of the corner pieces and added some 8mm threaded rods inside the frame parts, now it's quite a lot more stable. Probably still lacking a bit in stiffness, butt good enough for now. Need to test a tall print the see if there's any artifacts...

2019-01-05 17.37.11-1.jpg2019-01-05 18.06.48-1.jpg2019-01-17 20.05.49.jpg

- changed stepper drivers to DRV8825 with 1/32 microstepping. They are  quite quiet, especially after the Trinamic drivers coil whine. But It  seems that there's some problems with slow speeds, probably this  problem:  http://cabristor.blogspot.com/2015/0...steps.html?m=1. To  fix that, I tried the diode hack shown on that page (TL smoother I  guess) and lo and behold, it seems to work. At least partially, slow  speeds are smooth now. But when the printer slows down from fast moves,  it sounds like there's a sudden skipped step, even though the prints are  fine. That doesn't happen with A4988 drivers, so not sure if I'm going  to continue using DRV8825. The increased resolution (400steps/mm x and  y) is tempting... made a box for the diodes, they get somewhat hot.

2019-01-17 20.18.10.jpg2019-01-17 20.18.03.jpg

-  also tried printing ABS with 100C bed temp. Result = the bed belt  holder came loose, because the bolts underside the bed heated enough to  make the PETG bit soft. Shows in print quality quite drastically when  belt position can shift ~1mm. So I need to reprint that part with ABS  and also attach the belt holder to bed carriage with extra bolts other  than those that are in contact with the bed.

Todo is Raspberry pi box and powering it from 12V. Thinking about using 7V 5W zener diodes in parallel so the power draw won't be an issue...

----------


## spegelius

Wanted to test how MK2Dollo handles a tall print and started, admittedly bit optimistically a 24h 23cm tall Nefertiti print. Progress after 13 hours of printing:

2019-01-19 12.28.49.jpg

You'll probably notice a quite prominent ringing artifact on the left cheek that I think might be caused extempore filament routing from the spool:
2019-01-19 12.29.08-1.jpg

It's chafing against the plastic and probably causes enough friction to affect the print quality. The point where the artifacts are, is just the point when the head yanks more filament from the roll when printing the perimeter. Need to figure something better for that...

Other than that, the print is going along fine. 0.3mm nozzle, 0.17mm layers, 3 perimeters, gyroid infill 5%, Slic3r PE.

----------


## spegelius

Changed the filament feed mid print and no more chafing. I normally use that kind of spool container for all printers, but was lazy. Lesson to be learned: don't be lazy.

2019-01-20 12.32.26.jpg

Print finished fine, took ~27 hours. So the full 23cm is usable on the MK2Dollo build and seems no drastic problems with quality. There's the quite prominent ringin on the left cheek, but not quite sure if it's due to the filament chafing or just regular ringing... Also there's some small differences in layer coloration, which is probably the filament (Amazon basics Gold PLA).
All in all, happy with the result.

2019-01-20 12.32.34-1.jpg2019-01-20 12.33.04-1.jpg2019-01-20 12.32.43-1.jpg

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## spegelius

Finally got the heated bed installed on Dollo3D.2. It's a MK2B from Aliexpress, not the best option, but with a glass on top of it good enough. Added some insulation to the underside of the bed so it should heat bit better. Printed adjustment screw mounts that attach to the bed carriage and used long M3 bolts. Seems to be working fine so far, although the PCB does warp bit when heated and it's not fully in contact with the glass.
2019-01-26 15.12.14.jpg2019-01-26 15.13.47-1.jpg2019-01-27 15.08.06.jpg2019-01-27 15.08.14-1.jpg

MK2Dollo has now Octopi mounted on the frame. Also it's powered from the same PSU as the printer, so no need for the usb charger. Used buck coverter to get 12V->5V for the Raspi. The converter I had is bit overpowered, ordered some smaller ones and maybe swap it later.
2019-01-27 15.08.55-1.jpg

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## spegelius

Now that both Dollo3D.2 and MK2Dollo are more or less finished products, I can finally star working on the first Dollo expansion. Step 1, take it apart:
2019-01-27 18.13.07-1.jpg2019-01-27 19.06.05.jpg2019-01-27 19.06.07.jpg

Step 2 is to sort out what I can reuse and what needs to be printed. The orange extension parts will go to trash can as will the corners and maybe some of the black extensions. Those are the very first parts I printed and they are bit too small on X and Y (printer wasn't calibrated) and they are also fragile and mostly broken, apparently printed with too much heat. Not sure how much off the breakage is because they  are couple of years old...
Probably going to use the metal z-screws for this build.

----------


## spegelius

Found the actual reason why MK2Dollo made that artifact on the Nefertiti bust: the bed carriage was bumping on the ziptie that holds the smooth rod in place. Not sure why, might be that I've slightly mispositioned the bearings too deep on the carriage.
Fixed this by rising the bearings 2mm on the bed carriage model. For the already printed parts, I made spacers. Also fixed the y belt holder more firmly on the bed carriage so printing ABS should be possible again.
2019-01-30 18.42.25.jpg2019-01-30 18.42.33-1.jpg

For the Dollo rebuild, need to print quite a lot of extension parts and 4 corners. Bed carriage needs 8 and there's pieces missing from the frame. Also as I'm planning on using the full length of the 505mm threaded rods, I need to replace 4 60mm pieces from the corners. Ran out of black filament, now waiting for my order to arrive.
Also as I'm going to reuse the z-rails, I need to modify some of the bed carriage/z parts. And there's also some bugs that I need to fix so some modeling work to do.

Currently the max viable print dimensions should something like this: 320x320x450mm. Which means I need to get a bigger bed. I have some 3mm aluminum, just need to get heater for it. Or multiple heaters, I wonder how hard it would be to make a sectioned bed...

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## spegelius

Received some filament and printed lots of parts in addition to previously printed parts so that the Dollo rebuild can continue. Some of the extensios were quite brittle and I had to scrap them. I think the reason is the printer I printed them with, a Tronxy X5S with E3D lite v6 clone that has quite powerfule part cooling fan. I'm running the cooler at ~30% for PLA at the moment. @ 100% the hot end heater can't keep the hot end heated and filament just doen't stick to previous layer. Probably need to lower the speed bit more...
2019-02-09 16.44.54.jpg

Got the frame built during weekend. Ran out of long ties and bow ties, so printing them now so I can get the bed carriage assembled. The frame is actually quite rigid, at least compared to previous builds; the extra stiff versions of the corner parts seem to help. Also probably going to use 8mm metal rods on the beams that hold the rails.
2019-02-10 20.37.19.jpg 2019-02-10 20.37.31.jpg

Updated the rail holder parts a bit, now the slider is threaded and it is fixed to holder with two nuts that also center it. I'm reusing the 520mm rails from the old build so the sliders are bit larger than usual, just for this build:
2019-02-10 20.40.37.jpg 2019-02-10 20.40.58-1.jpg

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## spegelius

Installed the z-rails, sliders and bed carriage. Carriage moves about somewhat sluggishly but the slides take bit time to wear in, after that they work fine:

2019-02-13 21.01.26.jpg 2019-02-13 21.31.19.jpg 2019-02-13 21.47.05-1.jpg2019-02-13 21.47.09.jpg

Started printing the X and Y rails. The old ones are ok, but too short and not quite the lastes versions so it would be too much hassle to print pieces that match them so I'm reprinting them all.

For electronics I'm going to go with MKS Sbase for now. Installed Smoothieware yesterday and did basic config, but of course cannot validate it yet since the printer isn't assembled yet. But TFT works and motor turns.

On wiring side I have plans for some custom connectors that I'd like to use to make the wiring cleaner and modular. I did something similar on my Tronxy X5S where all hot-end wiring is terminated near the hot-end, so swapping hot-ends is lot less hassle because all wires have connectors near the hot-end. Currently swapping Volcano end E3D6 on that printer as needed, so I'll be trying to build on that idea.

----------


## klimbo

> Installed the z-rails, sliders and bed carriage. Carriage moves about somewhat sluggishly but the slides take bit time to wear in, after that they work fine:2019-02-13 21.01.26.jpg 2019-02-13 21.31.19.jpg 2019-02-13 21.47.05-1.jpg2019-02-13 21.47.09.jpgStarted printing the X and Y rails. The old ones are ok, but too short and not quite the lastes versions so it would be too much hassle to print pieces that match them so I'm reprinting them all.Tutuapp 9apps ShowboxFor electronics I'm going to go with MKS Sbase for now. Installed Smoothieware yesterday and did basic config, but of course cannot validate it yet since the printer isn't assembled yet. But TFT works and motor turns.On wiring side I have plans for some custom connectors that I'd like to use to make the wiring cleaner and modular. I did something similar on my Tronxy X5S where all hot-end wiring is terminated near the hot-end, so swapping hot-ends is lot less hassle because all wires have connectors near the hot-end. Currently swapping Volcano end E3D6 on that printer as needed, so I'll be trying to build on that idea.


wwhere is  your plans

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## spegelius

Ain't got time to make any plans... but here are models: https://github.com/spegelius/Dollo

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## spegelius

X and Y racks printed and assembled. Yellow REAL PETG, printed with Prusa MK2.5. Turned out quite nice.
2019-02-24 13.20.51.jpg 2019-02-24 11.59.53.jpg

Started assembling Z-axis.

2019-02-24 11.35.22.jpg2019-02-24 11.38.45.jpg

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## spegelius

All axes are now assembled. I took some extra time with X and Y mounts, now the motor is positioned very tightly towards the rack. Even so that the movement feels quite rough when the gear moves on the rack. Probably shows as artifacts on prints, at least at first, probably wears during use.
Reinforced X and Y axes with 8mm threaded rods so no drooping should happen, although Dollo.2 build has been quite rigid.
2019-02-24 18.10.34-1.jpg 2019-02-24 18.10.40.jpg 2019-02-27 21.18.08.jpg

Made an enclosure for the MKS Sbase. Used the model that comes with the Sbase github files as starting point, modified it to take 80mm fan and other changes. Also made adapters so it attaches to Dollo frame with snap clips.
2019-02-27 19.11.25.jpg 2019-02-27 19.11.40.jpg

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## spegelius

Mounted the Sbase on the frame and tried Z-axis motor and Z endstop. Working fine, however I need to wire Z-motors in series so the movement is smooth on slow speeds. See: https://www.instructables.com/id/Wir...ors-in-Series/. DRV8825 again...

2019-02-27 21.18.16-1.jpg2019-02-27 21.30.19.jpg

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## spegelius

Got the motor wires cut to proper length and made connection boxes for the Z and Y wires. To boxes connect the two motors in series and are mounted on the frame. 

2019-03-05 20.06.56.jpg 2019-03-05 20.06.59.jpg 2019-03-11 14.25.24.jpg

Also installed X and Y endstops and everything seems to work correctly. For X I probably need to use TL-smoother so the DRV8825 jerkiness won't show on slow speeds. For Y and Z that isn't a problem because they are wired in series.

2019-03-11 14.25.43.jpg

There's also hotend mounted, but I need to reprint the part cooler shroud and the mount. Not sure what PSU to use, I have 24V brick that I could use for all other except the bed as it's only ~100W. but all fans and hot end is 12V so I'd need to either replace those or use diodes or something to lower the voltage. Hot end should be usable as long as Smoothieware allows for limiting the heating power.

For I'm going to use the old 21cm bed for now. Need to print mounts for it.

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## andrewpiana

all my prob solved

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## maria002

This is a good option.

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## smithclarkson01

The Engels also plan to offer an optional CNC router to their Kickstarter backers, which will allow the 3D printer to become a CNC machine. They are also considering making a laser cutter/engraver attachment available as well. 9AppsVidMateVLC

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## spegelius

Sadly the Kickstarter wasn't successful. But I guess it was inevitable, Dollo isn't the best option commercially... rather a 

So the Dollo rebuild: I took a 360W 12V PSU from my Tronxy X5S (going to convert that to 24V with DuetWifi at later time) and things are moving. I wired most things and running some movement gcode the wear the X and Y parts in a bit: https://www.dropbox.com/s/1r8aazwvh8...54.31.mp4?dl=0. Some 50000 movement lines, seems to work fine, no skipped steps and moving quite smoothly after few hours.
Wiring is a mess, but I'll clean it up once I figure how...

Got the hotend wiring PCB printed and mounted. It has connectors for the wiring so swapping hotends is easier, no need to rewire whole thing. I have similar connector on my Tronxy, been working fine for a while: 
2019-03-29 19.54.41.jpg

Going with the old 21cm bed for now. Printed some adapters for the bed carriage to allow mounting the smaller bed on it. Need longer bolts to get the bed mounted on it:
2019-03-29 19.55.04-1.jpg

Tomorrow maybe try some printing...

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## spegelius

Mounted the bed properly, added part cooling fan and wired them properly. After leveling the bed and a couple of test prints I got this benchy printed:

2019-03-31 16.58.55.jpg2019-03-31 16.59.00.jpg2019-03-31 16.59.18-1.jpg

Looking quite good.

Had some jamming problems on the first try, reduced retraction a bit and added filament oiler, no more jams. Also other Z-motor was binding occasionally due to the coupler being just a bit too tight fit, fixed that by wrinting some g-code to move the bed up and down and using a file to smooth out the coupler while moving.

Need todo something about the wiring next and also mount the PSU to the frame.

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## spegelius

MKS Sbase is a nice board and Smoothieware seems to work fine. However, Smoothie lacks one feature that I consider a must with Dollo: mesh bed leveling i.e. the manual leveling. Smoothie only supports leveling with a sensor, but Marlin has that so I compiled Marlin 2 bugfix for MKS Sbase. Everything went better than expected and after leveling the bed, I tried to print some easter eggs. Suprisingly the result was quite bad, seemed like layer shifting.
2019-04-15 22.12.32.jpg

After tuning the accelerations, jerk/junction deviation etc. for few nights I started fiddling with the stepper parameters, like minimum pulse width etc. Finally changing minimum pulse width from  2ns to 3ns fixed the problems and the result are as good as they should be.
2019-04-15 22.13.05.jpg2019-04-15 22.12.38.jpg

Mesh bed leveling is a nice feature, but it's bit tedious if you need to do it often as you have to manually jog the z-axis. So I started thinking about a removable sensor that's basically a limit switch that you can attach to the X-carriage for the duration of the leveling sequence. Bltouch would be even easier, but it takes some space around the hotend permanently so removable sensor is a good compromise.

----------


## umarsami

Goood One Thanks

----------


## JenniferT

very interesting.

----------


## scottsen11

If you are new to 3D printing this is not yet a good place to start. I am still working on the documentation and will be making assumably videos in the future. If you already have an idea of how 3D printing works then just know to use the most up to date files on the github repo and do you best. Use the pictures to guide you! yes it is a cube shape.

----------


## spegelius

Been a while since last update on Dollo builds. Progress has been slow, but there's progress.
For the Dollo rebuild and Dollo.2 I did some cable management, actually had a failed print due to loose cable yanking X-endstop free during print and causing X-axis to stop moving (a safety feature I guess?).
Also for Dollo rebuild I got the frame stabilized; I used parts from the old build as much as possible, creating adapter parts as needed.
2019-08-12 18.19.09.jpg 2019-08-12 18.19.13.jpg

For Dollo rebuild, I went bit off the original plan because I was redesigning the extruder I use with Dollo for use with Bondtech gears and the Dollo build was the easiest to test the extruders with. So now the Dollo rebuild has two of these extruders: https://www.thingiverse.com/thing:3813628, with these to add more torque: https://www.thingiverse.com/thing:3091980.
Since I'm using only one hotend, I use this 4x-feeder part: https://www.thingiverse.com/thing:3807101. As the Sbase-board only supports 2 extruders, I can only print with two colors. Filament changes are handled with this post-processing tool: https://github.com/spegelius/filaswitch
The setup seems to work reliably. I'll eventually move the extruders (4 in total) to my Tronxy X5S once I get it updated to 24V.


2019-08-12 18.19.24.jpg2019-08-12 18.20.21.jpg 2019-09-01 15.07.10.jpg

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## scottsen11

If you are new to 3D printing this is not yet a good place to start. I am still working on the documentation and will be making assumably videos in the future. If you already have an idea of how 3D printing works then just know to use the most up to date files on the github repo and do you best. Use the pictures to guide you! yes it is a cube shape. shareit apk

----------


## spegelius

Been a while since last time I updated this thread so here goes. I haven't abandoned my Dollo journey, both of the machines are alive and kicking. Been doing some printing on both of them and also some upgrades along the way now and then, tweaking them is just do interesting.

Dollo rebuild in it's current state:
IMG_20200704_110203.jpg

Cable management has been on my todo list for a long time and I finally got around to doing something to it. It's not the prettiest by any means but a big improvement to the wires hanging freely. I printed some cable chains and designed some parts to mount them onto. I use a mount that goes onto the stepper motors on X and Y where the cable chains mount to. This seems to wek very well. I took the chain design from Snappy reprap files with some modifications for extra rigidity. Seem to work reasonably well even though the long X-axis chain droops quite a lot. Probably need to tweak the chain design more.
Also got the mainboard cover on. There's still room for improvement in wire cleanup, but so far much better.
IMG_20200704_110911.jpgIMG_20200704_110237.jpgIMG_20200704_111552.jpg

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## spegelius

On Dollo rebuild I've been experimenting with the extruder positioning. Some while ago I designed an extruder riser for my Tronxy X5S (https://www.thingiverse.com/thing:3271808) and originaly I used it on Dollo too, but then I wanted something more adjustable, so I designed this arm that is built on parts that can be rotated to get the desired position. Works ok, but it's bit wobbly so I'm going to print another arm on the other side to support the extruder better.
Using an extruder riser allows for sorter bowden tube. I haven't measured the difference but it's about 20cm compared to the original position without riser. Currently I have 2.5mm retraction with linear advance value 0.3. The bowden tube is about 45cm.
IMG_20200704_112250.jpgIMG_20200704_112345.jpg

I swapped a Volcano on the Dollo rebuild as I needed the E3Dv6 on another printer. I tried some 1.2mm nozzle printing. It's a kinda new area because the amount of material moving through the nozzle is quite a lot more than normally. Tuning the retraction is hard to get perfect, on my test I didn't get it completely nailed down and it's not just about the retraction amount.
I printed a couple of pieces to test out full print height and Volcano. Both are ~40cm tall and have only one 1.2mm perimeter. This sows on the owl since some areas aren't properly supported and there's gaps and artifacts.
Material used was PLA, about half a 1kg roll I think.
The vase print was supprisingly fast, only about 7 hours.
IMG_20200704_112840.jpgIMG_20200704_112820.jpg

Other small thing on Dollo rebuild:
- swapped X and Y motor gears, they were getting a bit of backlash due to the printed gears starting to get loose on the motor shafts. Did some refactoring on the desing too.
- currently running Marlin 2.0.5.3 on the SBase and no problems
- Z accuracy is a bit of problem when using mesh bed leveling, which is expected due to the printed 'bearings' that do bind a bit. With mesh bed leveling, the bed just doesn't do those very small movements. Also the printed Z-rod nut has bit of backlash.
To combat this I made a poor-mans lock nut from TPU which acts as a kind of psring and takes the slack off, which helps a bit.
IMG_20200704_114127.jpg

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## spegelius

On both Dollos I did some Z-axis refactoring by moving the Z-screw to the middle of the Z-rods. I saw some parts tilting slightly caused by the Z-rod being some 30mm invards and the friction of the printed Z-slides and rods. The change in print quality wasn't very noticeable asfter all, I've noticed that using Z-hop seems to kind of hide some inconsistencies in Z-movement, it kind of resets the Z-position.
IMG_20200704_110228.jpgIMG_20200704_110015.jpg

I'll be adding a support leg beside the Z-motor, I suspect that the beam holding the motor bends enough to cause some small errors in Z. Not sure if it really matters, but I want to see if there's any difference.

The fully printed Dollo.2 Z parts are holding together supprisingly well, I've done at least 500h of printing on the Dollo.2 and the parts are still in good working order. I checked them during the Z-screw position change when replacing some parts and there's no noticeable slack yet. Happy to see it's working and there's no need to do maintenance on it all the time.

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## spegelius

On Dollo.2, I also did some cable management. Same cable chain setup. I also designed a new RAMPS case and redid some wiring from the ATX-psu. I was having some issues with temperatures fluctuating and the problem turned out to be insufficient wires for the 12V input. The problem manifested when the bed was heating, which caused to 12V level on RAMPS to drop and also affected the temp readings. As with it's bigger brother, the wiring is still a bit of a work in progress, I'll need to cut them to correct length and get some cable sleeves done.
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I've been using a printed planetary geared extruder setup for a while (https://www.thingiverse.com/thing:775636) and it's been working quite well. However, due to motor heat, the sun gear started to slip on the motor so I swapped in a Titan I had laying around. For Dollo.2 I haven't seen the need to go fo rised extruder, might explore that later...
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Both Dollo's seem to be quite reliable printers, even though the print quality isn't perfect. They get the job done as long as you don't expect pristine quality. And they are fun to tinker with.

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## spegelius

As seen on ReprapFirmware thread, I started using RRF in my Dollo rework. After some tuning it seems to be working quite nicely. Time will tell if it's going to be my main driver. Luckily switching back and forth between Marlin and RRF is easy, just copy the firmware.bin to sdcard and boot the board. When going from RRF to Marlin, mesh bed leveling needs to be redone though as EEPROM is lost in RRF flash. Such problems don't exist with RRF as all configuration is in files on sdcard.
Tuning the RRF exposed a problem on the printer, though. The part cooling is inadequate so redesing is needed, along with changing the 40mm axial fan to radial if possible. Mor on that later.

I added a Z-motor support for both of my Dollo's. The design is quite simple, the leg just clips on to the Z-motor. The leg is adjustable. It does seem to help, at least on the Dollo rework, mesh bed leveling seems to have much better resolution now. So apparently the beam supporting the Z-stuff was having some slack after all. Haven't tested this on Dollo.2 yet, just finished installing the parts.
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## spegelius

So I did some tuning on the fan shroud, moved the nozzles closer to the hot end and aimed the outputs towards the nozzle. I printed the axial version since getting the radial version to work might impose some limitations to printer's max Y size. Currently the fan sits under the X-beam, the axial version has plenty of room to be there. Radial on the other hand is a bit harder to get positioned properly. I looked at some fang-type shrouds in Thingiverse for inspiration, for example this: https://www.thingiverse.com/thing:2175956. But something like that will require some intensive modeling and reusing available models probably won't work.
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Anyhow, I printed couple of benchies and there seems to be a bit of improvement, but still has issues. First one is sliced with KISS, variable layer height 0.15-0.35, 0.6mm nozzle, fan 100%. I also reduced perimeter/solid overlap and retuned my extruder e-steps since it seems there's a bit of over-extrusion in some points, causing the inconsistencies of the extrusion.
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Next one is sliced with PrusaSlicer as I wanted to see if the slicer has an effect. 0.2mm layer height, 0.6mm nozzle, 100% fan. The default print speed of the profile I modified was bit faster than on KISS an that shows on the ships prow. Also PrusaSlicer has adaptive layers now it seems, I haven't tested that yet.
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I'll need to design a fan shroud that uses a radial fan, axial just seems to be too inefficient. Designing those ducts similar to the fang-design will be an interesting challenge with OpenSCAD, doable, but not sure if looking forward to it...  :Smile: 

For this printer, I'd say the quality is good enough as it is since I mostly print mechanical parts that doen't need very high level of quality. Also with 0.6mm nozzle the layer heights usually are around 0.3mm or more so the small deviations probably just fade away. Still, would be nice to get this sorted out.

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## spegelius

Got a shroud modeled for radial fan. Positioned it below the X-beam, seems I can get away with it without reducing Y-movement much. Printed in ABS, with a load of supports. PrusaSlicers supports are quite good, but with ABS I had to design in some custom supports without gaps, because some parts of the prints weren't bonding enough to the supports and were lifted off due to curling. OTOH, the supports were quite easy to remove. Win some, lose some.
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It does seem to help, the radial fan I have are quite powerfull. Currently running one @ max 45%, could maybe go bit more higher. Defining max speed for fan in RRF happens with M106 X122 (122 being the speed 0-255). The prow on the benchy is now definitely better. Other parts, the same. Is suspect that the layer issues are due to the Dollo itself, there might be some backlash or some other mechanical inconsistency going on. Also some small zits, can't seem to get rid of them with Volcano. Maybe a really long wipe would do it. Well, not going to pursue better quality, the machine works well on more coarse prints and that's enough for me (for now).

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## spegelius

Having a weird problem with Dollo rework: most prints come out fine, but there's this one box I've been printing and it has what seems to be a layer shift that keeps repeating on the same layer on each print. If I rotate the model 90 degrees, the problem goes away.
The model: https://www.thingiverse.com/thing:647425. By default the model is oriented so that the open side faces left so the shift happens on Y-axis. This could be mechanical as Dollo is what it is, but the MKS Sbase uses DRV8825 stepper drivers and those are known to have issues with missed steps in some scenarios. I do have tl-smoothers on X and E axes and Y-motors are connected in series so there shouldn't be a problem. But I'd like to be sure so I'll probably hook another board just to eliminate this. My SKR v1.4 Pro arrived some time ago, might as well use that for testing.

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## spegelius

Well I swapped the SKR v1.4 Pro in for a test print. The swap wasn't too much hassle, the RRF config from Sbase worked quite nicely as a base for the LPC RRF online configurator. The Trinamic drivers are quiet, the Sbase isn't bad but the DRV8825 tend to have some random low noise coil whine is noticeable.
Anyhow, the print result was exactly as with Sase, so it's not a problem with the DRV8825 drivers. Just Dollo doing it's thing I guess.
Will be going back to Sbase.
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## spegelius

After taking a closer look at the slop on the axes, I went back to Marlin + Octoprint. RRF doesn't have backlash compensation feature so Marlin it is for now.
When the motors are locked in position, moving the axes they do have some slop which shows as artifacts in prints in certain cases, for example holes are kinda skewed and as shown with the box, can result in a noticeable shift.
Need to tune the backlash properly. Still the things I usually print with my Dollos aren't too bothered about small errors in movement...

Received some goodies, a 340x310 PrintBite and FlexDrive G5 HW kit. I have some 3mm aluminum plate I've already cut, just need to drill the holes, order a heater pad for it and reprint some bed carriage parts to get full size bed.
The G5 Flex was a bit of a last minute purchase decision, I want to see how well this kind of extruder works. If it works as advertised, you'll kinda get the best of bwden and direct drive - very light etruder, but still direct drive.
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## spegelius

Alas, another Dollo thread update. Not much changes about the printers, but thought about sharing an general update about how the printers are behaving. Been using both of the Dollos, maybe few hundred printing hours for both and no major problems, but still some smaller issues.

On the bigger Dollo:
- a scrub screw fell of from the left Y-axis gear. This jammed the left side of the Y-axis, which of course caused a big layer shift. Re-applied the screw and hopefully tightened it well enough this time, although this could be an issue about PLA strecthing over time and eventually the screws just get loose...
- had a couple of min temp errors on the hotend, turned out the hotend heater wire had a spot that was getting warm, apparently there had been a kink on that spot and it started failing. Fixed the wire and works so far.
- small quality issues (the layer shift mentioned above), seems to be related to the X- and Y-axes sleds rocking back and forth a tiny amount when changing direction... maybe yet another redesign coming. I do have few ideas to try

On Dollo3D.2:
- current RAMPS setup has some issues, USB connection from Octoprint might take lot of tries before getting a connection. After connection is established, it works stable though
- having undervoltage issues with Raspi, apparently the 5V I'm feeding to it from the ATX PSU isn't good enough. Might be a reason for the USB issue...
- In general the power from ATX PSU seems to be bit on the low side, the voltages seem to dip a bit every time bed heater is turned on and this affects even the temp readouts, I get a rare mintemp error when hotend and bed heaters turn on and off and the temps jump few degrees up and down.
- might be a good idea to replace the ATX PSU with proper 12V PSU, I'm not even using the ATX standby option
- print quality over 150mm height seems the degrade a bit, apparently the Z-axis needs to be improved

Even with few hickups here and there, both of the printers still print quite solidly. Currently been printing these table legs with assorted PETGs. Each segment is 210mm tall and has 5mm holes for 5mm threaded rods. Also they are accurate enough that they fit each other, with 0.5mm tolerances modeled in. I do have some improvements planned, but not in a hurry as the Dollos are doing their thing well eough at the moment.

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