PSA: Nylon is not the printing material you want, contrary to what people say

General Discussion
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I’m interested mainly in a printed motor pulley, i can do a wheel one easily as i use a 6" tyre with a 60+ tooth pulley there, the stresses and heat are spread over a wide area. I haven’t yet seen a printed motor pulley (at least not one that survives very long). I’ve also never seen anyone mention a motor mount printed in PC, however that’s not exactly easy to print with. PC-Max is probably the right stuff for that, but I’m only just beginning the 3d printing journey, and regardless the best way of testing would be to just print it and see if it disintegrates :slight_smile: …

Thinking about it i suppose the motor gear is small enough to 1st print to test, then get shapeways to make it in metal…

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I desperately tried at the beginning (end 2016) to print motor pulleys, with a m4 set screw. The best worked for 100 meter :joy:

14-15 teeth are too small diameter and the print could be not strong as needed , i did not try with 16-18T that would be great and more feisable, with keyway.

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yup. screws wont last unless its going all the way through the motor shaft. learned that the hard way as well. now, i filed a D shape into the motor shaft and just glue the pulley onto it.

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I was also thinking about printed spur gears with keyway and a filed spot. What kind of glue do you use? Printed gears would maybe allow for helical gear setups.

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hmm, your typical soft drink bottle is made out of PETG. It deforms rather than shatters/explodes, which is also my experience when using it for motor mounts. It flexes way more than PLA does (in fact, to such a degree where it no longer returns to its original shape), but less so than nylon.

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I had similar experiences with PETG, the motor mount flex more under the weight of the motor and my threaded inserts cracked the part open from within (should have screwed them in hitter but still). Both not as present when using PLA.

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Threaded inserts are a no-go for PETG & PLA, unless the screws are relatively large and you are using loads of perimeters. I tend to go with clamped designs. Now switched to CNC alu…sadly, 3d prints don’t compare :slight_smile:

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I’m using inserts originally made for wood applications so the thread itself is really big and chunky, then i print the part with a hole 2mm smaller than the insert and heat it up to gently screw it in. When all is cooled down the insert is surrounded by plastic that melted into every nook and cranny of the thread and it holds beautifully, didn’t manage to break an insert free when screwing in the grub screw. A clamped design sounds good too, maybe i’ll try next revision.

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maybe one day. For now i use Shapeways. We couldn’t be happier with the wheel pulleys’s performance. The price is kind of terrible per unit, but if you want a functional, long lasting part on demand in any color with decent tolerances you have little choice. Its either a bunch of money for the part with access to 26 other variations in tooth count and all the primary colors, or a bunch of money for the mold fees and only one variation in tooth count in one color.

didn’t seem like much of a choice really.

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Good approach. The small threading is usually what causes the issues (even when working with softer alu types).

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if its thin its flexible, but the more solid i gets, the more unstable it becomes. thats at least my experience. ps: bottles are made from PET. the Glycol is missing there

i was using the luctide 910?. cant remember its name but technicaly its for glueing metal and not nylon. took ages to cure but i did it during the winter time. probably not the best glue you could use. normal supoerglue would be enough i think but i havent had that at hand at the time.

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