PLA Gears VS ABS Gears

aduy, what kind of rods were the igus bearings running on? Hardened and polished rods should be very slick with those. Even the chromed rods which mayb not be the best with ball type bearings should be very good with any kind of good plastic bushing/bearing.

Maybe they were very tight to start with, or even picked up an abrasive debris?

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Yvan

Singularity Machine

they were run on the rods sold by ultimachine, im using openrail now and that stuff is amazing, the wheels are a bit expensive but they are quiet smooth low friction and durable. also these were not standard igus bearings they were a specialty kind, they have no grooves and are smooth on the inside, i think the price was over $120 but since i run the 3d printing club at my school we got them donated as samples. RJZM-01-08 [www.igus.com]

Edited 1 time(s). Last edit at 01/09/2014 04:51PM by aduy.

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waitaki
Been using PLA bearings for almost a year - still not worn.

Waitaki, could you tell me what kind of bushings you had printed, and what kind of rods?

I am using supersmooth rods, the best I could get in my country, and they are smoovvvvvvvv, smoovvvver than anything I've ever seen. Even smoother than the rods you will get from scanners/printers.



Edit: Got a reply from another Dutch seller, they can deliver this bushing:
8 / 10 x 10 mm
With the tolerance of: G7/s7 or E7/r7

Would these tolerances work for a reprap machine and which one would be better? I Have found some charts online that explain the tolerances, but the ones mentioned are not in there!

Edited 1 time(s). Last edit at 01/10/2014 04:50AM by Ohmarinus.

I use silver steel rods. Bushes as below...

[www.thingiverse.com]

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Waitaki 3D Printer

Seems like they are worth a try.

Do you use when without lubrication and do you notice any loss in how tight they are?

Do you have a movie maybe?

No lube used - I just rely on the 'slipperyness" of PLA. When you print them, they are usually tight at first but when you run them back and forth on a piece of shaft, they free off in seconds. They are a cheap solution that won't wear the shafts. I don't have them fitted to the X carriage yet but will do so when I get time - I want to see if radiated heat from the hot end up will affect them. I have also used graphite impregnated nylon bushes successfully.
Not sure what movie you mean?

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Waitaki 3D Printer

@Ohmarinus: G7 bushings should work well with g6 shafts. If I understand you correctly, you have precision shafts? I think the tolerances are 10-30 microns, or 1/100th to 3/100th mm, but I don't have my tolerances lists with me right now. I can have a look at them when I get home, though.

@waitaki: I think Ohmarinus meant to ask you whether you have a video of your PLA bushings. I would be interested, too.
Furthermore, I don't know anything about stick-slip properties of PLA; did you notice any irregular movement of the bushings when being pushed very lightly and slowly? Of course, it would be awesome if stock PLA has very low stick-slip, but maybe one can even engineer a specific blend specially made for bushings use?

As i already said, i printed some PLA bushings.
You can't feel any stick slip effect by hand on uncoated, unpolished, stainless steel rods.

Nophead uses ABS in his Mendel90 kits, including the gears, with the caveat to use white lithium grease on the gears to minimize wear.