# Specific 3D Printers, Scanners, & Hardware > RepRap Format Printer Forum > MakerFarm Forum >  New i3V owner: A few beginner questions

## DanSilov

Hello everyone. I've just finished assembling my i3V, and while I had a lot fun building it, I'm yet to achieve reliable printing results. And since this is my first 3D-printing experience, I've would like to ask a few (maybe) stupid questions.

- I've started with PLA, and I'm using configs for Slic3r provided my Makerfarm, and they set temperature for PLA 225 for hot end and 70 for bed. Isn't this a bit higher than most PLA guides recommend?

- My first layer almost always looses a few first lines, because extruder can't seem to start extruding in time. Is there anything I can do to make this better?
IMG_7997.jpg

- Also, first layer always has these thick lines with visible gaps between them. For example, large extruder gear which I was trying to print, is really different in that regard from the one supplied in the kit. Is this a matter of Slic3r settings or something else?
IMG_8002.jpg

- The main problem I currently have is with extruder, which stops extruding after about 5mm printed. At first I figured out that it was the small gear that didn't have a bolt inside. Even though in the guide video Colin says it is optional, turned out after motor gets hotter, gear just slips. I've fixes this, but now I see there's another issue. After some time the large gear kinda tightens itself to the point that I can't even move it by hand (after disabling steppers of course), and I have to use pliers to loosen the front large bolt. But it then just goes and tightens itself again. Any advice, what can be done there?

- Also, I can't seem to understand how to change filament. I also have ABS which I wanted to try, but the last piece of PLA inside the hot end is not possible to extrude all the way. 

- The hot end I have (hexagon) is somehow always takes too long to get to 225 degrees, and when it reaches 210 or so it starts going up and down for quite some time until it finally climbs to 225. Is it something with thermistor? I've made sure it is inserted all the way, but I din't cover it with kapton tape or anything.

----------


## DanSilov

Looks like I figured out the problem with extruder large gear self tightening. I've disassembled it again and apparently I haven't tightened the second nut well enough. Hopefully this will fix this.

I've also wrapped the hot end in kapton tape, and temperature looks much more stable now.

----------


## printbus

Welcome to the i3v club!

I've been using 225 degrees without issue. I've read on other forums that the uncalibrated thermistors tend to read high, so setting for a temperature of 225 might actually turn out to be lower in terms of a real temperature.  Just a thought.  Some people have described disabling the stepper motors, and then manually rotating the large gear on the extruder to get a feel for how the filament is extruding at different temperatures as a way to figure out the optimum temp setting.  I tried that, but I found it hard to notice much difference. 

On your first layer, it could also be that you have too much space between the nozzle tip and the glass.  I adjust mine so that a piece of paper is fairly snug between the two. If you haven't already, by all means calibrate the feed rate of your extruder. Mine was low by about 5%. That'd be another reason for not enough coverage on the first layers.  I've been tweaking the Slic3r settings recently, but used the MakerFarm configurations for a number of things successfully. Google on extruder calibration for info - look for calibration videos my Zennmaster. Finally, if you try to move around the cold extruder tip manually, does it feel loose?  Mine did, and I went back through the extruder assembly to eliminate mechanical play wherever I found any.  See Post #17 in the Printbus build log for details on what it took to eliminate that play.  I felt that having a solidly mounted extruder tip was important to especially the first layer.  

On the extruder, check to make sure the two bolts on the upper rail wheels don't rub against the large gear. Mine were rubbing.  I didn't work through whether the rotation direction fits, but maybe that could be part of the reason why the gear tightens up on you.  

Swap out the filament by cutting off the filament with a length extending from the top.   Using pronterface, turn on the nozzle heater and wait for it to get to temperature.  Then using the "reverse" button on Pronterface, back the filament stub out of the extruder while gently pulling on it.  I usually set Pronterface up for a long value like 50mm, and then gently pull on the stub while also releasing the spring mechanism. I don't like using the 0.1mm steps available on the LCD to control the extruder. I cut my filament with an anvil cutter that makes a very clean cut, and cut at an angle to make it easier to feed the new filament into the extruder.   

Following a hint I found elsewhere, I used a dab of automotive muffler cement to affix the thermistor to the hot end.  That seems to have worked pretty well.

----------


## DanSilov

Thank you, makes sense that thermistor might show lower values. I've tried to print with anything between 180 and 225 and it worked well with PLA every time.

I've checked the hot end, and it's all tight. Also, leveled the bed with the sheet of slightly thicker paper. Should I use something really thin?

Haven't yet calibrated the extruder, will probably get to it later, after I finally finish printing spare parts for the extruder  :Smile:

----------


## printbus

> ...leveled the bed with the sheet of slightly thicker paper. Should I use something really thin?


That gap is just one of the tweaks you get to figure out.  When everything else is right and coverage doesn't seem to be pretty solid on the first layer, adjust it thinner.  I've read how some people eye-ball the skirt while it is being extruded and manually adjust the Z-rods as necessary to get the "squish" they want.  Since they may jump in with it later, I'll point out that there are also some proponents here that recommend incorporating an autoleveling approach that turns the whole leveling and gap issue into a matter handled by firmware.

----------


## DanSilov

Well, extruder and printer works reliably for hours now, but results are somewhat mixed. I've printed extruder and a knob from Thingiverse, and every time the top layer has this visible mesh and the lines are very thin. I've tried to adjust Flow Rate via printer display during the print and set it to 110, but it looks like there's no difference.

IMG_8003.jpgIMG_8004.jpgIMG_8005.jpg

I've also checked bed level before printing the knob yesterday, and in all four corners I could barely slide a piece of paper under the hot end.

----------


## gmay3

Hmm, what speed and temperature settings did you print this knob with? 

Could be two issues I can thing of. It looks like the top layers are either not sticking well to the previous layer which could be a temperature, speed kind of thing. Also make sure that the two screws on your greg's extruder that have springs to tighten the filament to the hobbed bolt are fairly tight. Maybe just try an additional turn or so. Maybe the hobbed bolt isn't gripping your filament as tightly as it might need to.

In slic3r try increasing your Extrusion Multiplier, it's probably set to 1 by default, I would try changing it to 1.1 or 1.2 and seeing if the thickness of the top layers improves a bit.

If you haven't already check out the calibration thread first!  :Big Grin:

----------


## printbus

I'd also like to know what nozzle size you have on the hex hot end.  

Your issues look almost like, but not as bad, as when I forgot to load Slic3r with a configuration file and it ran with the defaults.  It was trying to print my 1.75 filament with settings assuming I was feeding 3mm.  The entire print came out very "stringy" like your top layers look.  

I know gmay3 is pointing at another print for flow test, but I'd maybe find a single-wall calibration test to try.  That would help identify whether all layers are light on the extrusion or there's something going on with just the solid fill on the top layers.  As to a source for one, Gmay3 links to a zennmaster youtube video for the feed rate calibration; zennmaster also has another video where he fine tunes the extruder settings using a single wall print test.  You'll need a set of digital calipers to measure the wall thickness.

----------


## DanSilov

I have hex 40mm hot end for 3mm filament, and I definitely loaded respective settings in Slic3r before generating G-code. 

If this is related to temperature (duh, everything is probably related to temperature  :Smile: ), I might try to reverse the fan that is always on. It's flowing full speed inside the wooden box, and most of air eventually gets down to the print.

Haven't yet checked two screws on the extruder, but I remember not tightening those too tight, as it looked that filament grips there well enough.

Currently still at work, but will start with some calibration as I get home.

----------


## DanSilov

I print always at 100%, not trying to go faster at the moment, need to get some good results with normal speed first  :Smile:  The knob was printed at 210/70 with PLA. Interestingly enough middle layers stick very well to each other, I have some good-looking results with extruder gears, both small and large. But with large it's the same story – top layers look like a mesh.

----------


## printbus

I've only got about a month more experience than you, so bear that in mind.  Note that while the overall print speed may be 100%, Slic3r applies about 10 different speeds factored off that, depending on what is being printed (perimeter, infill, etc.).  If you haven't seen them, these Slic3r settings are visible in the Speed section of the Print Settings screen.  

One thing that was enlightening for me was to feed the gcode through a viewer like gcode.ws. You probably can with other viewers too, but with gcode.ws, you can click on layer info and then walk through the print layer by layer, observing how different speeds will be applied to different parts of the print.  I would compare the print speed being applied to the top solid layers with what is being used elsewhere, since that seems to be printing OK for you.

Reducing 3mm filament to the 0.40 mm tip is a pretty good reduction (3mm has almost 3x the surface area as 1.75mm filament) and it could be you're just not melting enough fast enough.  You might need a higher temp (210 could be low anyway) and/or a slower "top solid infill" speed in Slic3r. Or maybe even a higher drive adjustment for the extruder stepper motor driver to maintain the pressure at the nozzle during high flow volumes.

EDIT: Unless it has changed since I archived the config files, the MakerFarm config file for 3mm PLA on the 0.4mm hex hot end will have Slic3r print the top solid layers at 100 mm/sec.  It'll print perimeters at 75 mm/sec, and the external perimeter wall at 70% of the other perimeters, or 52.5mm/sec. So, the external perimeter walls you can see are printed at about half the speed of the top solid layers.   That could be part of the reason why the rest of the print looks OK, at least on the outside.

EDIT #2: Well, there is a another filament cooling setting in Slic3r that will slow the print down if the time spent on a layer is less than a default of 30 seconds. That should be the case for at least the knob, so the above numbers may not apply.  Just another reason why I like to look in a gcode viewer before I print to see what the printer will actually be doing.  Regardless, the config file will still have the top solid infill printed faster than the perimeter shells.

----------


## printbus

gmay3, how did your knob in http://3dprintboard.com/showthread.p...umbwheel-Model print?  Looking at mine, my top side has the same mesh look that DanSilov is battling here. You can even see it in the picture I posted.

EDIT: Looking at the gcode, that was the last item I printed with a bridge speed of 150mm/Sec as set in the Makerfarm Slic3r config files. That seems awfully fast to my inexperienced judgement. For my knob, slic3r has a bridge layer under the top layers, and perhaps the bridge didn't work very well and the top layers aren't properly supported. My recent prints are coming out solid top (now I'm using a bridge speed of 70mm/sec), but I've also been dinking around with ABS since that knob.

----------


## Roxy

> EDIT: Looking at the gcode, that was the last item I printed with a bridge speed of 150mm/Sec. That seems awfully fast


Agreed.   I know my printer could not run at that speed doing bridges.

----------


## DanSilov

Well, I had an interesting evening last night. First I stumbled upon this post (http://3dprintboard.com/showthread.p...inter-Extruder), where the video describes exactly the symptoms I was having with my prints. So I immediately decided to calibrate my extruder using that video and gmay3's post a reference. 

I quickly found out that my extruder was a bit uderextruding (94mm instead of 100mm requested), and I used LCD menu to adjust E-steps. I decided to use the same G-code I printed before – a 24mm 20% infill cube. The result, well, dreadful.

Original settings (mesh at the top, not watertight, but very neat print otherwise):
IMG_8008.jpg

After calibration (a mess all around):
IMG_8011.jpg

I then reuploaded firmware using link provided in MakerFarm guide (BTW, should I try vanilla Marlin firmware, will it make any difference?), enabled EEPROM access just in case. Then I decided to try printing 20mm 100% infill cube, as per gmay3's post. I used adjusted E-steps, which I saved to EEPROP and I also set Extruder Multiplier in Slic3r to 1.1 just to see what will be the result. 

Here's the result:
IMG_8013.jpgIMG_8015.jpg

I've tried two times, and both times the print started bending around corners, and then it lost adhesion (the first time this happened for me). At this point I gave up. 

Looks like something is definitely off with extruder, since even Extruder Multiplier doesn't force it to extrude more material. I'm not really sure what to try now.

----------


## gmay3

printbus, I don't think I had the same problem with my knob but will take a look tonight and post a picture.

DanSilov, sorry you've been having a frustrating time with this. Sometimes this is how it goes with 3d printing  :Mad: . I would double check your calculation of the Esteps. It seems like your 24mm cube with 20% infill has less plastic (hence the caving in corner) after your changed the Esteps. Your initial commanded 94mm instead of 100mm for the Esteps cal should have had more plastic come through.

Ok so as far as the 20mm 100% infill box goes, like you said we need to get your print to stick before anything else because if the corners are bent up the print will not be accurate enough to show if your 20mm 100% infill is flat on top.

I'm assuming you are using the good ol' glass bed with hairspray method. I have had really good success with this so far as far as sticking to the bed goes. I found that in the beginning I was putting too little hairspray so try just a little more to see if this helps. (I'd recommend taking your glass off and spraying it on top of an old tee shirt, then let it dry for 5 mins or so) 

I would recommend trying two things next.

1. Twist your Y bed gently clockwise and counterclockwise to see if the delrin idlers on the Y bed have loosened up. This happens for me every 20 prints or so and can mess up your bed leveling. Then re-level your bed so that the nozzle hits the z endstop at a height of about 70 to 80% of your desired layer thickness away from the glass at each corner of the bed. So for 0.2mm about .16mm.

2. I think I read that your were printing PLA at 220 or and 70 for the bed. I'm not a PLA master as I usually print in ABS but when I've printed PLA at 185 and and 60 for the bed temp I've had success.  

Any way, I hope some of this helps but keep us posted with how its coming along!

----------


## DanSilov

gmay3, thank you for all the advice. I understood the 3D printing is not easy from day one, in fact I welcome the challenge  :Smile: 

The problem with sticking to the glass is that it's something entirely new. I've printed quite a few things with PLA (bad quality, but still), and never ever I had any problems with adhesion even without using hairspray. In this case it looks like the print is shrinking into the center when it cools down. Maybe it's because it is 100% infill. Will be tinkering around some more today.

----------


## printbus

Bed adhesion suggestions beyond gmay3's points - 

You might post a bottom view of one of the prints so we can see how your first layer is coming out.  Have they improved from your initial post?

I learned to let the heat bed soak at temperature for a while - maybe 5 minutes before enabling a print. That likely helps the heat soak through the glass. My adhesion failures with PLA have frequently been when I've skipped this soak time.

Did you reverse the hot end fan like you thought you might? I face the fan airflow forward too, but I found the MakerFarm fan does create a draft over the forward side of the heat bed that was creating problems on least large prints. The forward side of the print would tend to lift and curl up.  I initially just added a piece of painters tape along the bottom side of the fan to help deflect the airflow off the heat bed.  I've also ditched the strong and overly loud fan Makerfarm provided for a slower, quieter one. It puts through less air, but it's till cooling the hot end while not creating as much draft over the heat bed.  Finally, I also now let the heat bed soak with the Y-bed pushed all the way back. That allows any draft from the hot end fan to clear the heat bed.

----------


## printbus

For grins, and since I've seen the open mesh top on a print as well, I ran some comparison prints of that knob.  These may not provide any firm answers for you, but there might be some info of value.  I assume this is the knob you started with - http://www.thingiverse.com/thing:221920.

I ran three prints of the knob. The first on the left used Slic3r 0.9.9 and the unmodified MakerFarm config file for 0.4mm hexagon hot end, 1.75mm PLA.  White doesn't photo well, but it's the only PLA I currently have.  Although not as extensive as on  your print, the top layers definitely show the mesh and are not "closed".  Watching the print layer by layer, substantial droop was observed when printing bridges at 150mm/Sec as specified by the config file. One such layer is where the knob transitions from being open on the bottom to closed, and the other is just under the logo on the top.  For the lower layer where bridge was used, it took several additional layers before the newly applied honeycomb infill seemed to not suffer from it.  For the upper layer where bridge was applied, the drooping was substantial enough that the next solid layer also sagged, and the top and final layer therefore didn't have a substantial subsurface to extrude against - hence the stringy and open appearance. More extensive infill or a print cooling fan would probably help here. 

The second in the middle used Slic3r 1.1.6 and a custom config file for 0.4mm hexagon hot end, 1.75mm ABS.  Version 1.1.6 adds some config parameters beyond v0.9.9. I didn't know what would happen if I used the 0.9.9 config file with it, so when I started using it I recreated new config files for v1.1.6, initially leveraging settings MakerFarm had in the 0.9.9 files.  Over time, I've been tweaking many of the print speeds. Right now most more closely follow what is suggested starting here - http://richrap.blogspot.com/2012/01/...tings-and.html than the MakerFarm values. Most significantly, the bridge print speed is considerably slower than 150mm/Sec.  Beyond those changes, I now also typically use rectilinear infill at 25% (just works better for me than 20% honeycomb), first layer extrusion width of 250% (my ABS seems to do better with this), and top solid infill extrusion width of 125%.  A crosshatch pattern is noticeable on the top layers, but the top is solid.  

The third knob on the right also used Slic3r 1.1.6 and a config file identical to that for the ABS knob except that the bed and nozzle temps were set for PLA (70/225 per the MakerFarm suggested settings).   The same crosshatch pattern shows up as on the ABS knob, but it is solid.  

The underside of the knobs is interesting.  I had previously noticed that v1.1.6 either extrudes a bit more and/or does better at going back and filling small missed areas.  For the v0.9.9 print, you can see numerous gaps that carry up into the knob.  In the v1.1.6 knobs, the printer was diligent at going back and touching up numerous spots on each layer. I can't speak to whether the difference is in v1.1.6 itself or in the config file differences.  Likely because of these touchups, v1.1.6 takes longer to generate a gcode file, and prints take longer. I'm not implying that v1.1.6 is better - I think I have work to do in tweaking retraction, acceleration, and who knows what else related to all these touch up spots. Right now I tend to end up with a slightly excessive amount of plastic in areas where the touchups occur.  I wanted to experiment with a 1.x.x version since support capability was revamped in 1.0.0, and 1.1.6 was the latest available.  

All knobs printed with calibrated esteps/mm based on feeding 100mm filament length, but not fine tuned for single wall print thickness or variation in filament diameter.

----------


## DanSilov

printbus, thank you for such extensive comparison! I really hope to achieve something similar to the last one you printed, which looks quite solid. Also, thank you for the link to settings blog-post, will definitely help. Maybe you can also share your 1.1.6 config, the one you used for printing last knob?

Yesterday I've printed 4 different 20mm blocks with 100% infill with all kinds of settings, and results are still really bad. I didn't have any problems with adhesion, but that might be because I've flipped the fan again (yesterday I tried to print with the fan blowing air out of hot end). I've increased flow rate, reduced speed settings (pretty randomly, but to much lower values), all to no avail. Below are some results. Bottom of every block looks like the one one picture.

IMG_8020.jpgIMG_8021.jpg

I've even sliced and printed one block using Cura, which is a nice enough tool, but results were still bad (one side of block was 9mm, the other – 10mm). 

It looks though I might have some problem with the extruder. I've gone through calibration procedure about 5 times yesterday, and I couldn't get the extruder to reliably extrude 100mm. Before it was underextruding, then after I adjusted E-steps it was overextruding by* a lot*. Then again underextruding and so on. When I assembled the extruder, it had some issues with guidler fitting correctly, it looked a bit overprinted, so I had to use a knife to take off some plastic. Also, my hobbed bolt doesn't that many teeth as the one on this picture. I managed to print all the parts for the extruder earlier. Although they have the same open mesh on top, they look good enough. I will try to reassemble the extruder with my parts and then run the calibration process to see if I get reliable results this time. 

Also, did anyone measure and adjust stepper voltage? I checked my extruder stepper voltage after printer assembly, and it was 0.36v. It doesn't skip and turns quite nicely, so not sure if this might be a problem.

----------


## printbus

My extruder stepper driver is set to 0.35v.  

The MakerFarm hobbed bolts don't have as many teeth as the one you linked to.  I don't have a picture, but looking down into the hobbed bolt area I can see about five teeth.  Regardless, as long as the teeth are consistent around the bolt I don't think the number of teeth shouldn't matter much. 

Just trying to help with ideas, I would scrutinize everything from the filament spool to the print surface. These come to mind - 
Make sure the filament spool isn't catching on whatever is holding itPart of the guidler bearing is exposed on the left side.  Mark it with a Sharpie or something and verify it seems to always rotate when the hobbed bolt does.Retract a section of filament and observe how the hobbed bolt teeth are digging into the filament. I don't have a picture to offer, but mine leaves a pretty rough serrated feel on the filament.  Spacing between marks should be consistent. If the marks aren't very substantial, try increasing the tension screws more.ADDED: Looking down into the hobbed bolt area, do the channels between teeth on the bolt look clean?  Does the cut area of the hobbed bolt appear to line up with the filament guide above it? (I futzed with finding the right spacers under the head of the hobbed bolt to improve the alignment; maybe on 3mm filament that's even more important)Check all the extruder hardware for tightness.  I've had the motor start to get loose and the two extruder mounting bolts get loose.  As mentioned earlier, make sure that (with the hot end cold), you get no mechanical play when you manually try to manipulate the hot end tip around.I used longer bolts on the motor so I could put large flat washers on the backside of the mounting plate.   I have to be careful that the large gear is clearing the motor bolt heads on one side and also the delrin wheel bolts on the other. Rubbing on either side would lead to erratic extrusion.If you haven't already, consider tearing down the hot end to clean it.Do you have any other filament to try? Is the diameter of the filament you're using consistent? Unroll a length of it and run your fingers over it.  Feel any bumps on it? I had a roll with small bumps that I just happened to notice one day by doing that. Some of the bumps were large enough to jam up at the top of the hex hot end, but others could have been sized right to struggle in passing through the body of the hot end.

----------


## printbus

Here's my Slic3r v1.1.6 ini file used for that print.  This is provided for your diagnostic purposes, not as a decree for the best possible settings. I'm changing parameters daily.  You'll have to rename the file as .ini, and remember this is set up for 1.75mm filament.  

BTW - you could also bring the hot end up to temp, disable stepper motors, and manually rotate the large gear to get a feel for the extrusion.  The stepper motor will still have a cogging effect, but the feel should at least be consistent as you rotate the large gear. 

Also, I think I was seeing similar results from the steps/mm calibration where the first correction would lead to too much filament being fed.  What seemed to have helped me get more consistent results is to always ignore the first long extrusion after I've warmed up the hot end.  So, I run an extrusion and ignore it. Then I mark the filament and run another extrusion for the measurement.  It could be this helps normalize the temperature throughout the hot end or helps "wash out" any filament that might have cooked a bit in the nozzle as it cooled after the last time I used the printer.

----------


## DanSilov

Ok, another update. Yesterday I've disassembled my extruder to build new one with parts I've printed before. Turned out small gear was badly deformed, so that might've been the reason for some of my problems. I've assembled new extruder, and when I put new small gear on the motor, I had to knock it hard a few time to fit, and I was worried, that I broke it (when I turn the gear by hand, something inside catches a little on every turn). Other than that, new extruder fit perfectly, even though print quality it baaad. At least everything fits together much better than the original I had in the kit.

I've also decided to switch to ABS, which I also have a roll of, but haven't yet tried. After putting everything together I've calibrated extrusion, and it was perfect 100mm every time! At least that was a small win.

Then I printed the small extruder gear and then the dreaded knob. The knob turned out much better than the last one on the top – no mesh, everything looks watertight. But the sides are awful, as you can see on the pictures. I've used settings that *printbus* uploaded here, with adjustments for ABS and 3mm. 

IMG_8022.jpgIMG_8025.jpgIMG_8023.jpg

The small gear turned out much nicer, but the top had the same issues as my PLA version – it's not closed properly. It might be because of some Slic3r settings, which I set incorrectly. The gear I printed with MakerFarm config and 100% infill. 

IMG_8024.jpg

----------


## printbus

Your issues appear to be beyond what I can help with. If no one else jumps in, perhaps posting in the Tips Tricks and Tech Help forum would get more visibility than the few of us watching the MakerFarm subforum. Maybe using 3mm filament on a 0.4mm nozzle tip requires something special.  

What do you think happened to the original small gear? Did it start to fall apart, or does it seem like it got hot and warped out of shape?  Just wondering if that could be indicating something.

Do you use a print cooling fan at all? I think small prints like the small gear can be tough to print.  Slic3r will default to slowing down the print to ensure 30 seconds per layer, but that's still a lot of heat being applied to a small surface area.  Go 100% infill to boot and you could be dragging around in soft material that never gets a good chance to cool down.  

Good luck, man.

----------


## gmay3

DanSilov, I would not recommend printing extruder parts with 100% infill however that print does look like it came out pretty good. I usually print them with 30% infill at a max and this could cut down on some over extrusion errors that could lead to a misshapen gear tooth.

As far as the knob goes, I can't see how your extruder would draw plastic in between the outer grooves in the knob unless something is mechanically wrong with your axes.

Try these and let us know that you have checked them:

1. Check all your belts and make sure they are tensioned pretty tightly (should ring out quietly when plucked)

2. Check for any wiggle in you x and y idlers by verifying that all delrin idlers are tight enough to the aluminum extrusions. You should have no play in any direction other than the axis is intended to move. Make sure the delrin idlers are not too tight where they limit rotation of the bearings.

3. Check the bottom of the x axis where the captive nuts meet the z threaded rods. Sometimes mine have come out of their holes underneath the x idler.

4. Try these prints again at 30% of your normal printing speed, just to rule this out.

Good luck and let us know how it goes!

----------


## DanSilov

*printbus*, *gmay3*, thank you for your help and advice. This all definitely helps as I slowly progress with this whole 3D-printing thing  :Smile: 

Will check the axis and idlers, but so far everything looks pretty tight. Just to be sure, how do I set the speed to 30%, is it just by turning the knob on LCD main screen, or is there a general setting in Slic3r I need to set?

----------


## gmay3

No problem at all!

Yeah you've got it, its just as simple as turning the knob during printing down to 30% on the main LCD. Definitely keep the slic3r settings the same (as far as print speed goes) for this test so we have a control in this experiment  :Big Grin:

----------


## printbus

While you're checking over the axis mechanics, you might as well also make sure the belts aren't rubbing on the wood bracket sides at either the x-ider or the y-idler.  I don't think issues there could explain your problems but any catching of the belt on the wood could cause things to twitch and affect print quality.

----------


## clough42

Yow.  I just stumbled across this thread.  I'll read back through it and see if I can come up with anything else to try.

If you could post a video showing it printing, that would be helpful.  To help, I would need to be able to see the X and Y axis movement as well as the turning of the extruder gear.  Do you already upload something?  Did I miss it?

----------


## clough42

BTW, a great way to calibrate your Z axis is to print a single layer and measure it.  Set Slic3r to print three loops around the next object you print, then peel the loops off after printing and measure the thickness with calipers.  It should match your first layer height exactly.  Measure at several points around the loop.  This will help distinguish first layer height issues from extruder flow issues.

----------


## clough42

I've read through everything again, and I don't see anything obvious.  It definitely looks like you were having trouble originally with your z height, and that was killing your adhesion.  Personally, I've never gotten PLA to stick to glass.  Cold glass with blue painters tape works great for me.  For ABS, the glass and hair spray works best.

The blobby prints you posted recently look to me like a couple of possible problems.  If the nozzle is crossing between islands in the print, your retract might not be working right.  Try reducing it to 10mm/s if you haven't already.

I don't know how your calibration went, but way too much plastic could cause that look.

If you're printing small parts without a print cooling fan, the hot end just sits above the same area for a long time, radiating heat that re-melts the print.  This can cause that look.  Of course, if you're using a heated bed, the print coolingfan will make the print curl.  No problem with a cold bed and painters tape.

Make sure slic3r is set to print loops around the part to clear the nozzle before printing.  This avoids the sparse first layer you mentioned early in the thread.  You can also peel up the loops and measure them with calipers to check your bed level and z height.  The thickness should match your first layer thickness exactly.

A video of it printing would be very helpful.  We may notice something that you don't realize is abnormal.

One other question: where do you live?  Do you have high humidity there right now?  Is the printer in an air conditioned space?

----------


## DanSilov

Ok, it's time to return to my so far not so great 3D-printing efforts. Thanks again to everyone for their advice. Let me try to go one by one with answers and then also share some findings of my own.

1. I've checked the assembly of pretty much everything, and the one problem I found was that extruder block tilted slightly to the right (side with the motor). I could even tilt the block with my hand a little, so it was definitely something to improve. After I tightened eccentric bolt, the block now seems nice and tight, although it does look a small portion of degree out of perpendicular state. 

2. I'm not sure how to check belts tightness. They seem rather tight to me, and there's no skipping or anything of sorts. Y-idler belt is not rubbing the wood bracket, but X-idler belt does stick to one side and touches the wood there. I'm not sure how to adjust that.

X-idler belt rubbing the bracket
IMG_8248.jpg

3. It seems to me that I have a problem with the heat from extruder motor. It gets so hot during the 1-2 hour print, that I literally can't hold my finger on it longer than 0.5 second. The voltage is set to 0.37v. My original gear small deformed badly (see the picture below), and that was probably one of the reasons I couldn't get proper results after calibration. But the main extruder part was also a bit blobbed out of the box, I couldn't fit the guilder on it, so I had to use a knife to take some plastic off. As I've printed extruder myself, although the print was very bad quality, it was of a correct size, and after calibration it gave me correct extrusion results.

Original deformed gear
IMG_8244.jpg

4. But after some time (maybe 3-4 small prints), new extruder started to deform as well. Not sure, whether it's because it is related to bad print quality, heat from the motor, PLA as the chosen material or something else. Despite this deformation (see below), it does continue to produce a much better results than the original extruder. I've printed another set of extruder parts, and some smaller things, and most of those look good enough. Although visible mesh on top layer is still present at places and some side blobbing occurs.

Deformation of the new extruder
IMG_8247.jpg

New printed knob
IMG_8249.jpgIMG_8250.jpg

5. I figured out that problems with PLA adhesion only occur when I reverse the fan air flow to blow air out of extruder. If airs blows into extruder, most of it also cools the print a little, and I never have any issues with prints sticking to the glass, even without using any spray or blue tape. I can't even remove finished prints from the glass unless it cools down. What also helped, is the settings that *printbus* uploaded. I use "brim" setting there to add a nice 2-3mm brim around every print.  

6. I've checked the voltage of my ATX power block, and it is exactly 12v.

7. Humidity in the room I print in is around 40%, and since it's quite hot these days here, I turn AC on as well.

8. If my nozzle it hot and waiting, plastic continues to extrude a little for some time. Not sure if everyone has this, or maybe it's one the problems I'm having.

9. I do feel there's an issue with slicing. If I compare bottom pattern of the original extruder parts and the one I printed (plus a couple of just first layers), it is apparent, that my lines are much thicker and there are fewer of them. If it's the case it might explain some mesh issues I'm having – where top lines are expected to be thicker than they are, so they are extruded with a greater distance from one another, producing the mesh. (photos are in the next reply)

----------


## DanSilov

Some latest printed results with currently *deformed extruder*

IMG_8251.jpgIMG_8252.jpgIMG_8253.jpgIMG_8254.jpg

----------


## DanSilov

Here's the comparison of the original extruder bottom layer to my results.

Original guidler vs the one I printed (first layer and full part):
IMG_8256.jpgIMG_8261.jpgIMG_8262.jpg

Notice that original part has only 2 thin perimeters, which leaves enough space between perimeter and the hole to add some "cross-stitching". I've tried setting prints to 2 perimeters instead of default 3, result is the same, there's never enough space between hole and perimeter to add extra material. This is even more apparent in the next example.

Close-up of the main extruder part:
IMG_8257.jpgIMG_8258.jpg

Again, original part has 2 very thin perimeters, which allows for 2 perimeters for both hole and overall print. In my case perimeters can't even close properly.

----------


## clough42

This is good detail.  Thanks.

The extruder sitting slightly out of level is because the weight of the motor is hanging on the right side of the carriage.  You need to have the eccentric tight enough that both top wheels stay fully in contact with the extrusion, but there will always be a little flex and it will always be tilted a tiny bit.  As long as it stays at the same angle, you'll be fine.

The hot motor melting the extruder is exactly what I experienced.  The top screw got hot enough to pull through the extruder block, just as in your photos.  This has to be solved for the printer to run consistently.  I think your options are to add a fan, turn down the current or replace the motor.  I guess it could also be binding, but my large gear and hobbed bolt turned freely without the motor or filament and it still melted just like yours.

I had a lot of trouble with gaps in my prints early on.  They looked a lot like what you're posting.  Too little plastic around the sides of tabs with holes in them.  Thin walls with gaps between them, etc.  I don't know exactly what fixed that issue, but it gradually got better and I'm not seeing it any more.  I can tell you what I changed that got me to where I am, though.

1.  Reduced retract rate to 10mm/s.  Reduced blobbing and other issues related to gaps when restarting.

2.  Upgraded to newer versions of slic3r.  It's pretty buggy from version to version.  I'm a couple of revs back, but I'm running one of the 1.0.x stable versions.  Be sure to turn on variable width extrusion.  This helps with tapered edges and other situations where the gap to fill doesn't match the extrusion width exactly.

3. Switched to a 3mm/.4mm Hexagon hot end.

4.  Lowered my first layer height to .2mm, like all the other layers.  I think the wider bottom layer extrusions were because of the increased layer height.  Of course, the lower layer height makes the leveling and z height adjustment more critical.  I added auto bed leveling soon after this, and I will never own another printer without it.

5.  Added a print cooling fan for PLA.  I always get blobby, melty results without it on small parts.  What I see in your photos of the knob look similar.

----------


## DanSilov

> The extruder sitting slightly out of level is because the weight of the motor is hanging on the right side of the carriage.  You need to have the eccentric tight enough that both top wheels stay fully in contact with the extrusion, but there will always be a little flex and it will always be tilted a tiny bit.  As long as it stays at the same angle, you'll be fine.


It is rather tight right now, so I believe it shouldn't affect the print quality. I will be assembling new extruder today and will try an idea I have with the motor. 




> 1.  Reduced retract rate to 10mm/s.  Reduced blobbing and other issues related to gaps when restarting.
> 
> 2.  Upgraded to newer versions of slic3r.  It's pretty buggy from version to version.  I'm a couple of revs back, but I'm running one of the 1.0.x stable versions.  Be sure to turn on variable width extrusion.  This helps with tapered edges and other situations where the gap to fill doesn't match the extrusion width exactly.
> 
> 3. Switched to a 3mm/.4mm Hexagon hot end.
> 
> 4.  Lowered my first layer height to .2mm, like all the other layers.  I think the wider bottom layer extrusions were because of the increased layer height.  Of course, the lower layer height makes the leveling and z height adjustment more critical.  I added auto bed leveling soon after this, and I will never own another printer without it.
> 
> 5.  Added a print cooling fan for PLA.  I always get blobby, melty results without it on small parts.  What I see in your photos of the knob look similar.


1. Done

2. Downloaded the latest version from the beginning. It's 1.0.6, I believe. But I've also tried using Cura, which, in my opinion, produces much nicer gcode for smoother movements, but has less settings to play around with. Not sure where to find this "variable width extrusion" setting.

3. I've bought the kit with .4mm hexagon hot end. 

4. Will try this, and will continue playing around with settings like that.

5. Interesting, will definitely try to print something with and without a separate fan to see if it makes a difference.

----------


## printbus

I wondered about that variable extrusion width setting too, but I think what clough was getting at is leaving the default extrusion width under print settings/advanced set to a value of zero.  That tells slic3r to automatically adjust the extrusion width.  

I think part of the trick with the print cooling fan is to get it as localized as possible on just the print. My playing around with a fan just pointed in the general area of the print usually led to problems keeping the top of the heat bed at temperature and/or the hot end tip at temperature.  That's why people come up with various fan shroud schemes that focus the airflow.  After incorporating clough42's version, my print quality definitely went up.  There's a pressure related loss with the shrouds though, so you'll want a pretty strong fan on it.  If the fan is connected to D9 on RAMPS, the slicers can be set to lower the fan speed if the fan turns out too strong or loud.  

Personally, I'd stick with Cura.  I tried it this week in part because I was frustrated with the way the newest Slic3r version (1.1.6) would spend so much time doing things "bits at a time" rather than in long passes.  Once I got the first layer adjusted right, Cura along with the print cooler and retraction set to 10mm/sec started cranking out impressive quality.  Well, impressive in comparison to what I was getting out of Slic3r without the cooler and retraction at the MakerFarm default speed.  

Why not experiment with a lower driver setting for at least the extruder motor? As clough has pointed out in other threads, the MakerFarm setting for the drivers is questionable with the motors being used.

----------


## DanSilov

Just finished making a couple of mods. Installed this belt guide on both Y and X idlers. Then I assembled new extruder and before attaching the motor, I've covered the top part of it with kapton tape.

IMG_8268.jpg

Haven't yet tested this on long prints, but I can definitely feel that top part that touches plastic is not that hot anymore. I can't touch the rest of the motor, but I can hold a finger on the taped part without any problems.


I have fan running 100% of the time, as it's connected directly to power, as per original assembly instructions. It also came with the fan shroud, which focuses airflow on the hot end cooling area, but then air moves further back, where it finds the wooden wall, and flow downwards. I think, that partially helps to cool the print as well, as I never have any adhesion problems, unless I reverse the airflow.

----------


## clough42

I'll be interested to see how the tape works out.  It doesn't seem like adding insulation to the motor is the way to go.  I was told by a mechanical engineer at work that the motor is designed to dump most of its heat through the machined front face.  You really need to get rid of heat--not hold it in.  The screw will still be conducting heat into the extruder block.  I think the hot screw is primarily what causes the extrusion to yield and let it through.  Maybe I'm wrong.  Let us know.

I have been doing some test prints with the Makerfarm knob.  I'll upload some videos when I'm done.  I noticed that the design of the knob requires the printer to make a last pass around each layer, filling in a small gap at the tip of each ridge on the knob.  This requires an retract/advance cycle as it moves over each gap in the knob perimeter.  If your retraction is having any trouble at all, you'll get gobs of plastic built up around the sides of the knob.

----------


## printbus

> ...I noticed that the design of the knob requires the printer to make a last pass around each layer, filling in a small gap at the tip of each ridge on the knob.  This requires an retract/advance cycle as it moves over each gap in the knob perimeter.  If your retraction is having any trouble at all, you'll get gobs of plastic built up around the sides of the knob.


You're likely using a newer version of Slic3r.  v0.9.9 just left the gaps.  Newer versions fill in those gaps. I don't remember which version it was, but this "fix" is described in the release notes for one of the versions between 0.9.9 and 1.1.6. Something to the effect of improving fill between perimeter and infill.  Generate some gcode from Cura for comparison.

EDIT: v1.0.1 and v1.1.1 mention improving gap fill

----------


## clough42

I managed to replicate the mesh top by printing on glass at 70C with no print cooling fan:

2014-08-03 18.52.23.jpg

Then I re-ran the print on cold painter's tape, with a cooling fan, and the holes in the mesh are gone:

2014-08-03 18.52.38.jpg

With the hot bed and no cooling fan, the first layer of bridging drooped down into the cavities in the knob, so it didn't provide any support to the top layers.  Without any support, the top layers didn't squish, and they didn't spread out wide enough to touch, leaving gaps:

2014-08-03 18.54.31.jpg

Otherwise, there doesn't appear to be too much difference between the two prints:

2014-08-03 18.53.01.jpg2014-08-03 18.53.07.jpg

----------


## printbus

But what you see from the bottom of the knob isn't directly supporting the top layers.  The knob design fills in the layers at about 10mm high, and then adds low density infill for a ways before adding on the top layers.   It still could be that the upper structure doesn't recover from the bridging issue - I'm just pointing out that there's more to the knob structure than you're thinking.  

Was the extruder height recalibrated when you went from printing on glass to printing on tape?  How do your two knob heights compare? I noticed that with the three knobs I printed previously, the one sliced in 0.9.9 came out about 0.3mm shorter.    

I'm not sure what magic pixie dust did the trick, but the knob I just printed in new MakerFarm black PLA, with print cooling fan, cold bed with painters tape, 10mm/Sec retraction and sliced in Cura is at an entirely different level of quality than any of the three test prints I did before.

----------


## clough42

If you're interested (and who wouldn't be?) here are videos of the above prints.

First on glass, with a 70C bed, no fan:



And on cold painter's tape, with a print cooling fan:

----------


## clough42

> But what you see from the bottom of the knob isn't directly supporting the top layers.  The knob design fills in the layers at about 10mm high, and then adds low density infill for a ways before adding on the top layers.   It still could be that the upper structure doesn't recover from the bridging issue - I'm just pointing out that there's more to the knob structure than you're thinking.  
> 
> Was the extruder height recalibrated when you went from printing on glass to printing on tape?  How do your two knob heights compare? I'm curious whether the cooling fan makes a difference on the height result. FWIW, I noticed on my earlier diagnostic prints of the knob that the Slic3r 0.9.9 knob came out about 0.3mm short.  The two I did with v1.1.6 were OK.


Yes, you're right.  There is additional structure, but even if the honeycomb ends up at the correct height, I've seen the mesh sink into the holes in the honeycomb with uncooled PLA.  ABS seems to be a little more forgiving, but still benefits from a cooling fan.

Both knobs measure 15.01mm with calipers.  I'm slicing with Slic3r 1.1.1.  I'm using auto bed leveling, so it calibrates the Z axis for every print.

----------


## DanSilov

> Then I re-ran the print on cold painter's tape, with a cooling fan, and the holes in the mesh are gone


This is really interesting. I will try to play with heat bed temperature to see, if my results change. I do feel that the problem with blobbing I have is related to retraction, but need to play with parameters more, to understand, what helps in my case.

----------


## DanSilov

> I'm not sure what magic pixie dust did the trick, but the knob I just printed in new MakerFarm black PLA, with print cooling fan, cold bed with painters tape, 10mm/Sec retraction and sliced in Cura is at an entirely different level of quality than any of the three test prints I did before.


I've printed small robot (http://www.thingiverse.com/thing:40212) with 0.1 layer height using Cura and Slic3r to compare. I haven't made photos yet, but results are really interesting. Will post later, but definitely shows that there are some things to improve in Slic3r settings, most probably related to retraction.

----------

