Building a Prusa (build log)

I just ordered the plastic parts for a SAE Prusa off of ebay.

I will post my build log here as I get my parts.

I already have
threaded rods / hardware
Stepper motors
SAE Prusa plastic parts
Some hot end parts (heater barrel, makerbot nozzle, PTFE bushing)
smooth rod
gen 6 electronics
upper and lower build platforms
Nophead style heater block
Belts for x and y axis
brass bushings for the abs bushing holders

I need to buy

Edited 4 time(s). Last edit at 02/09/2011 08:35PM by jolijar.

Edited 3 time(s). Last edit at 02/09/2011 08:27PM by jolijar.

I have built the frame. I cut the rods according to the SAE Prusa wiki but have been following the instructions on the Metric page (as there are no instructions on the SAE page.) I have there is alot of extra material at the end is that normal? Should I cut it to match?

I am waiting on my order from Mendel-parts.com and Makergear.com for the electronics, belts and heater parts.

So far assembly has been somewhat easy. I had a few issues gluing the Z axis bearings and I think I should have gone with PLA bushings instead of Brass ones (its a very tight fit). I dont really like the way that the x rods are connected to the x-idler and x-mount the screws keep falling out of the nuts and I cant tighten them more because its pulling the nuts through the abs. Any ideas how to solve this?

Solved the issue with the x-idler and x-mount
Zip ties... It holds the part way better then the screws did.



There is absolutely no play at all.

Looks good, I have s few questions.

What size motors does the Prusa require?

Can standard Mendel hardware kits be used to build the Prusa Mendel?

Can the bushing be printed from PLA or does ABS work better?

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-John, San Diego, CA

www.youtube.com/user/GeoDroidJohn

MrJohnEcker on Twitter, Gmail

1) It takes 5 NEMA 17 motors.

2) Yes, but you would have many nuts, bolts and bearings left over. There are Prusa kits on emakershop.

3) PLA gives lower friction. I don't know if ABS would work. If it does, it will take more torque to move the axis and possibly lead to early failure and lower print quality.

Bushings can be printed in ABS only if you are going to use a brass bushing insert. ABS directly on the metal rods would wear out very quickly.

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I am using the bronze bushings with abs holders. it is a tight fit on the rods if there are any imperfections on the rods it will bind. however if you get it running smoothly it should be very precise.

I've heard some chatter that the Prusa Mendel does not print as well as the orginal Mendel. True/False? Opinions?

I believe the Prusa will print better simply because there are less moving parts.

As long as you have the bushings set up properly with no binding, there's no reason it shouldn't print just as well as the original Mendel.

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Help improve the RepRap wiki! Just click "Edit" in the top-right corner of the page and start typing. Anyone can edit the wiki!

i'm certain that the bushings will be an issue for some users. if your rods aren't perfectly straight, you might get binding in a particular place, so you will only be able to print reliably in a small area. I'm sure as more and more people build it there will be some people with that issue. However, as long as you can print, you can print upgrades. if you do have binding issues, there are bearing-based replacement parts that won't bind

the only other thing is that the frame pieces are smaller/thinner, which might lead to some vibration/resonance issues with lots of small, rapid x/y moves, or at certain feed rates. Sells mendel parts are beefier, which might suppress this more.