Tuesday, December 08, 2009

Got it!

I'd heard that people printing Mendel were having trouble printing the largest pieces of Mendel in anything but PLA. Since PLA filament is hard to acquire in the US at this point I thought it would be nice if those hard-to-print parts could be printed in some other plastic. Since I am working with HDPE right now, I decided to have a go with HDPE.

The trial part I've begun with is x-carriage-lower_1off. I've discovered that a segmented apron positioned 0.5 mm away from the perimeter of the part does the job of successfully suppressing warping. Here you can see the spacing between apron and part.

Here is the completed print.

I've cleaned off a bit of the strings.  I understand that the newest Rapman firmware release pretty much gets rid of strings.  I haven't taken time to install it yet, though.  There was only one instance of corner curling.

I've circled the corner in red.  The curl amounted to about 1 mm.  Belt sanding leaves you with a flat bottom to your part.  The fill was raft material.  I got the part out of the the apron and off the raft with my belt sander.

If you want to print this on your on machine you can download the STL for the part combined with the segmented apron here.  I made no changes to the part save adding the segmented apron.

I had to rotate the original part to work on my Rapman 3.0.  You many have to rotate it again to get it to work on other Reprap machines.  I would appreciate hearing if this approach works for ABS.  I have ABS here and could try it, but I want to see if I can apply the same technique to do what I understand to be the other big Mendel part, viz, z-leadscrew-base-bar-clamp_2off.


nophead said...

Great work!

Prober said...

I agree with Nophead..Great work!

I'm keeping a keen eye on both of you...hheheh

Give me a few weeks to get my system up and running and I'll give this part a go on ABS.

timo said...

Have you tried this apron method with ABS?

Forrest Higgs said...

Maybe this afternoon. I'll have to switch my machine over to ABS, replace the polypropylene printing surface with the acrylic one and recalibrate it. That will take a little while.

Zaggo said...

I print this part in ABS on my MakerBot in this very moment :) See my comment on the RepRap blog (http://blog.reprap.org/2009/12/got-it_08.html) for more information.

Jeff Keegan said...

I'm sure there's a tool that I could use to measure that .stl file's dimensions, but I haven't made it to the point where I've scheduled myself time to enjoy learning about those tools yet (must.. print.. parts.. before.. loaner.. RepStrap.. goes.. away!). Any chance you could measure the height width and depth of that object with and without the apron?

My loaner RepStrap is a MakerBot and I'm increasingly concerned that not all of the parts fit on that 4x4 build platform (based on nothing other than random fear).

Keep up the good work!