Building a Prusa i3

Hi there everyone,

I'm new to this forum and new to the world of 3D printing. I've always wanted a 3D print since I was introduced to the technology, but never had the money to buy one. Kinda lost hope on the idea of ever owning one until I started Googling and discovered there are open source plans all over the net and I could build on for a faction of the price, due to the fact that I have access to a fully equipped workshop/toolroom (lathes, milling machines, band saws, welding machines, etc)

I found some plans (.dxf files) on the internet for a frame to laser cut, and got a set cut out of 6mm aluminum. Some of the edges are rough, so I will file them smooth, then drill and tap the 3mm holes. I decided to go with a frame that has triangular supports just to give it some more strength. See the pic below. I will make my own y-corners out of square aluminum as I have all the sizes needed. I've got all the threaded rod and smooth rods already, just need to get some linear bearings and I can start assembling the frame.

Just wanted to start a build log here for people to follow. I also wanted to ask if there is anything specific I should know, any tips or tricks to help me out along the way? Any weak spots on the default Prusa i3 that I can make better? Any advice will be greatly appreciated.

http://i58.tinypic.com/64dumr.jpg

The Y axis made from threaded bar and 3d printed blocks is probably the weakest point on the prusa i3 I've never had a problem with the alloy frame moving .. The side supports are probably overkill.

I came across what I think I'd a better design it's called the p3steel you might want to look at that it fixes the problems I just mentioned.

I will replace alot of the printed parts with parts made of aluminum, such as the Y-corners and motor mounts etc.

I had a look at the P3Steel design. Looks like it would be much stronger, but would there be a HUGE difference in print quality between the 2 designs?

I wouldn't think so I'm not having any print issues related to the i3 frame.. the only issues I've had are with the heated-bed
and the spring configuration I made for leveling it, autoleveling using a sevo and microswitch needs constand fiddling. I'm doing away with all of that and using a silicone heater attached to an aluminium bed that will be permanently fixed, and will use an inductive probe for bed leveling very similar to the printbot simple.

you've got a nice frame, and I'm sure you will do a good job of making a sturdy y axis frame for it.. it should be good.

Can you send me more information regarding the leveling of the bed? It was something that I was thinking of. Here is a pic of the Y-corner blocks I made to. It's made out of 3mm aluminum square tube. the holes are drill 10/20/30/45mm from the bottom up. The top hole that the smooth 8mm rod goes into was first drilled right through using 6mm bit, the only 1 hole drilled using 8mm bit. Then I want to drill and tap the center of the smooth 8mm rod so i can put a bolt through the Y corner block and into the smooth rod, helping stabilize the smooth rods to the whole frame. Not sure if it will work out, but I'll try it.

I'll hopefully be getting the motor and idler mounts as well as some linear bearing this week then I can start assembling.

http://i61.tinypic.com/153me07.jpg

there isnt a lot of clerance above the 8mm smooth rod for the Y Carriage (unless your going to raise it up a little) here are some pics of the plastic parts you can see the smooth rod sticks out the top:

http://i898.photobucket.com/albums/a...ps9yzli1dn.jpg

you can also see the spring configuration for leveling the bed I.m going to remove that completely on the new build and just use a fixed bed (still held in place with the 3mm screws it just wont be adjustable) and I will use a inductive proximity sensor to do the auto-leveling.

Ok yes i see what you mean. I will cut my aluminum blocks shorter so that the bed doesn't touch.

I have seen guys using proximity sensors for auto leveling. I think I will use that system.

So I went to my local 3D printer supplier today, picked up some 3D printed parts, bearings, motors, and a few other bits and pieces. I will start assembling tomorrow and then share some pics.

http://i62.tinypic.com/wb6t13.jpg

So I've been busy this weekend. I ended up spray painting my frame and bed red, because the aluminum was badly scratched. I sand blasted it first, then 3 coats primer, then 5 coats paint. Everything is coming together nicely, only having a slight problem getting the bed to move smoothly from end to end. Some places move smoother than others but I guess i just need to adjust the threaded rods until I find a happy medium. I just need to get a few more bearings and a few odds and ends, then its just stuff like the electronics and heated beds and ends.

http://i57.tinypic.com/2rdgena.jpg
http://i58.tinypic.com/2i89ldk.jpg
http://i57.tinypic.com/2mcvv50.jpg
http://i59.tinypic.com/2r3xtvc.jpg

Looking good!

I'm sure you already know, but just in case: be careful when bead or sand blasting aluminum alloys. Depending on thickness and composition, they can curl rather easily/rapidly.

Also, and ya probably don't care since you painted it, if it was an alclad type alloy, the bead blasting pretty much destroys the anti-corrosion properties of the aluminum cladding.

Ok wow I didnt know any of that. Thanks for the heads up. Do you think I've messed up the frame by doing what I've done?

Heh..., I'm sorry, didn't mean to alarm ya!

1. If it hasn't warped, it won't. The warping generally occurs owing to differential heating in the material during bead blasting.
2. Wrt the corrosion..., it could only be a problem if you plan to strip the paint off it, and operate the printer in the rain, for, I dunno, a few years.
3. Finally, keep in mind, people build these dang things out of wood. Sure..., that's a bit flip and there's more to it than that..., but with the tolerances of Prusa style FDM and the various calibration strategies..., I wouldn't worry too much.

So, you're doing a fantastic job, far more detailed and in-depth than anything I would attempt.

Keep it going!

P.S.: Oh..., OK..., one more thing about bead blasting: NEVER use it on a porous material that will interface in any way with moving parts. E.g., a crank or engine case. Beads will be trapped in the porosity, slowly released into the surrounding lubricant, be transported to the nice and expensive moving stuff..., which you'll get to buy again, very quickly.

Quote:

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Originally Posted by ZorAxe

Ok wow I didnt know any of that. Thanks for the heads up. Do you think I've messed up the frame by doing what I've done?

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Ok great. Thanks for the tips. I was a bit worried for a second there. I'll hopefully get some more parts soon and do some more building!

Finally got to do some more work on my printer. The Y axis is complete. Just need to finish up the belts on the X axis and the threaded rod and mounts for the Z axis. Will hopefully get all the electronics next week, and then test all the movement of the different axis.

The left hand z axis rod is not straight because I hadn't mounted the top mounts down yet.

http://i59.tinypic.com/2ce2lu9.jpg

I went manual for levelling...
http://3dprintboard.com/showthread.p...eatec-in-Spain

Here is a quick video of my Y-axis moving. I haven't got RAMP 1.4 yet so I connected the NEMA 17 to my CNC engraver which runs from an Arduino UNO and CNC Shield. Just a some Gcode file I wrote to move the axis back and forward.
https://youtu.be/VI5nJ8D23xM

Quote:

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Originally Posted by ZorAxe

Here is a quick video of my Y-axis moving. I haven't got RAMP 1.4 yet so I connected the NEMA 17 to my CNC engraver which runs from an Arduino UNO and CNC Shield. Just a some Gcode file I wrote to move the axis back and forward.
https://youtu.be/VI5nJ8D23xM

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Very cool, the first movements are always fun to watch.

It's really coming together! What do you have left?

Thanks man! :D The next step is to get all the electronics sorted. Then extruder, hot end and heated bed. Once I have all that I can start calibrating.

Only problem is I live in South Africa and most of the stuff is imported, and with our currency being very weak, it makes everything expensive, so that's why I'm building piece by piece.

OK, so I havent had internet for the longest time due to lightning storm. In that time I've spent alot more time on the printer. Got all the parts and its up and running. See the pics below. I've added a RepRapDiscount Full Graphical LCD, and an Auto Bed Leveling Inductive Proximity Sensor which really does help with the print layers. Overall I'm getting so good prints (well I think so) The printer is printing within .05mm accurate which I'm happy with.

I'm still learning all the slicer settings. I switch between Cura and Slic3r. Both are great. I find Slic3r has alot more advanced settings which can allow for more, but also over complicate things. Cura is great simple and works straight out the box with great prints. It's generally my go to slicer. One big downside to Slic3r I have found is it makes seams, and if your object you are printing is round, the seam doesn't look so great. Maybe someone can give me advice to get rid of that.

I had a few problems with prints curling and lifting, but 99% of those are gone thanks to an AMAZING hairspray my wife uses :P Also played around with different temperatures and have go some decent settings now.

http://i59.tinypic.com/2vt5v1v.jpg
http://i61.tinypic.com/34e6s5w.jpg

That looks great! I love the red.

You can correct the seams in slic3r under the print tab.

Scroll down and see "Seam Positioning" here:
http://manual.slic3r.org/expert-mode/fighting-ooze