New Prusa snap fit x-ends not fit for PLA?

I just printed the new snap fit Prusa x ends, and ran into a few problems.

The red highlights are where the part cracked under stress. First from inserting the smooth rods, then along the holes for the zip tie, when I pushed in the top lm8uu bearing.

Print settings

This is printed in white PLA from Ultimachine @200 deg C. Nozzle is 0.5mm, layer height is 0.35mm, it has 2 extra shells (thus 3 in total) and infill of 30%. I believe the problem is the flexible part of the push fit design, which doesn't flex at all. I don't know whether it's because of the brittle PLA, or if it can be avoided by using either fewer or more outer shells. Heating the part before inserting the smooth rod will probably help, but

If this is a problem with PLA, I hope there will be an option to switch out the push fit with m3 nut and bolt. Looking forward to having a look at the OpenSCAD files!

Blame the user
The crack along the lm8uu holders is most probably my own fault, it was a tight fit, and I did manhandle the bearing quite a bit. There are some small lips to hold the bearing in place (in the z direction) and the bridge did sag a tad so the bearings didn't fit very well under the top ones. You can sort of see it in the second picture. Using 100% infill might solve this, as moving the holes up would just move the weak spot.

Edit 2011.07.11 :
I just printed the x-end idler, and the bearing holder snapped when I pushed in the bearing (had to use a wood clamp, it was that tight). This trouble might be my printer drawing outside of the lines, instead of on the inside. I'll be back with more info.

Difference in PLA?
This is the first object I have printed in this white PLA, and it might need a little skeinforge tweaking to get perfect. It seems to flow more, and thus pushes out more plastic than with the other Ultimachine PLA I have. (Silver, transulent blue, natural and black).

For this print I tried to drop the speed from 60 to 55mm/s, and on the x ends, it didn't loose enough y-steps to ruin the results. I have a theory it might be the weight of the plastic spool keeping the maching from rattling, anyone else experienced this? I still can't print gregs lm8uu x-carriage properly though.

New hot end review on the way


While I'm blogging, I might as well drop in a picture of a nice little puzzle I got in the mail:

It's an Arcol 0.35mm hot end, which I'm looking forward to try out. One thing I'm a sceptical about is the hot end relying on threaded PEEK to hold the pressure. People have a lot of good of things to say about this design, but to me a push-fit version just seems a the "safe" way to go. Also, it's a bit large to fit on gregs lm8uu x-carriage, so I have to figure out which printer to put it on, as it won't fit on Adesina now.

My biggest print yet, and it's creepier than I thought it would be.

I've always wanted to print one of these, and when a simple straight-to-skeinforge-version with non-broken stl files was posted by RoTorIT - http://www.thingiverse.com/thing:9321 - I had no excuses any more. Thanks a lot. :)

The body piece is 22cm across, and printed diagonally it took every single mm of bed space I have available, which turns out to be 170x185mm. I even had to turn off skirt to make it fit, and it came dangerously close to the bolt heads on the bed. But it was totally worth it. the spider is HUGE.

Total print time was close to 24 hours @55mm/s. I had to print one piece at a time, because for some bizarre unknown reason I lose y steps if I print several objects at the same time. Some of the pieces are the same, and I'll post them here for your enjoyment:

• Part 6 & 7
• Part 8 & 9
• Part 20, 22, 24, 26 (small leg)
• Part 21, 23, 25, 27 (large leg)

The pieces doesn't fit together that well, and could have been 0.5mm fatter. Though both the mouth parts and tail parts sits tight amongst each piece and locks itself in place, the legs sit quite loose. I sort of solved it by squeezing / bending the print a bit while hot off the printer, which made most of it sit pretty nice.

In case you didn't notice already, it's printed in transculent blue PLA from Ultimachine, which is UV reactive. It looked far less scary when I took the pictures last night.

Imagine this scenario: You place the spider in a dark corner of the basement, with the room lit only by a single bulb. Then you hook up a motion detector which turns off the bulb and turns on several UV leds pointed at the spider. I'd do it, but it'll probably be smashed to pieces in blind arachnophobia fear, and I really don't feel like printing another one (before I have a giant bot farm).

A coalition of obsessions.

You like?

First blog, first post, first print!

So, how do one start out one of these blog things? How about a historical event?

I hereby present Aida - my RepRap Mendel - and the first output she produced that did something else than not stick to the platform.

 We have low stiction levels.

And it stayed put the whole time, oh joy!

RepSnapper even predicted the strings.

Hi to everyone on #reprap. Thanks a lot guys, wouldn't and couldn't have reached this RepRap milestone without you!

So, why am I starting up this blog thing anyway? I have a fever, and the only cure is MORE REPRAP. So I went to my doctor and told him, and he gave me a RepRap Prescription. How's that for a blog intro? *insert wacky smiley face*

A proper introduction to Aida is appropriate, and is in the works, meaning I have not even started writing it.

Have fun, all my fellow reprappers, and everyone else.

-Nudel