Twisting the belt to use all toothless idlers.

I know this is an old idea, but in order to use all toothless idlers, I have twisted belt between the motor and the first outer idler.

I did this on the large printer (600x450) which uses 10mm belts. It did improve print quality by getting rid of repeating artifacts on the surface.

At the same time twist in the belt have increased the elasticity of the belt and added to ringing/ghosting especially on X.

I tried twisting belts a couple times. The twist forced the belts to ride on the pulley flanges and I never saw any improvements in prints, so I removed the twist. I tend to use largish pulleys (608 bearings- 22 mm dia), so maybe there would be some improvement for smaller pulleys.

If you think about it, the twist is supposed to allow the smooth back side of the belt to contact the pulley instead of the teeth. But the belt isn't uniformly flexible- it flexes between the teeth. So when the smooth side of the belt wraps around the pulley, it's still going to flex between the teeth and form a polygon on the pulley, not a smooth curve.

This is one of those 3D printing mysteries that seems to have no definitive answer...

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

I can see how larger diameter idler pulleys may help. On smaller printers (with 6mm belt) I do not see artifacts caused by belt's/pulley's teeth, I did see it with a wider belt. I have designed my printer to fit 20 teeth pulley diameters so it was easier for me to twist the belt instead of redesign and use large pulleys.

My corexy has similar artifacts, I didn't realize it could be due to toothed idlers. I thought it was due to my nema23 steppers. Thanks for bringing this up!

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Kind regards
Imqqmi

NFAN CoreXY printer:
[reprap.org]

I use these flanged bearings:
[www.robotdigg.com]

They have never let me down, no artifacts and no ringing. Using them since 2015 now! Just replaced them btw, but not because they ran out, just because I replaced the Y-axis idler on my MendelMax with a beefier one.

Edited 1 time(s). Last edit at 05/19/2019 02:43PM by Ohmarinus.

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http://www.marinusdebeer.nl/