1 Topic by reidbaker

  • reidbaker
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Topic: Y-Belt jittery (not smooth in one direction)

Just noticed that my y belt isn't pulling smoothly in 1 direction on my SD4.

Any tips? Basically when the nozzle is moving towards the front/glass it has a slight shake an I notice that the belt on the left side that's responsible for the Y direction is having a hard time moving forward. It does but it stutters.

Any thoughts?

Thanks!

2 Reply by grob

  • grob
  • grob
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Re: Y-Belt jittery (not smooth in one direction)

Does it look like the idler pulley at the front left is jammed?
If you turn the printer off, how does it feel to move the carriage back and forwards by hand?
Have you adjusted the belt tension at all?

It could be the sliding bushings are binding a bit causing the stuttering, not necessarily the belt itself.

* I'd start by adjusting the y axis belt tension as per the solidoodle video.
* After this, make sure all the grub screws on the y driveshaft pulleys were appropriately tightened (caught me out on occasion!)
* If still stuttering, try applying a small amount of lithium grease to the rails.
* Then if is was still shaking, and definitely the belt not the slide rails, finally I'd pull apart the y idler pulley, clean it up, check for scoring / wear / damage, regrease it and reassemble.

SD3. Mk2b + glass, heated enclosure, GT2 belts, direct drive y shaft, linear bearings, bowden-feed E3D v5 w/ 0.9° stepper
Smoothieboard via Octoprint on RPi

3 Reply by reidbaker

  • reidbaker
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Re: Y-Belt jittery (not smooth in one direction)

What seems to be a problem is on the left side (facing the machine) the two ends of the belt are slightly out of alignment so as it slights towards the edge of the gear it starts to grind then slip. When looking at the machine dead on, I notice that the assembly on the front left angles down slightly, particularly when compared to the same assembly on the right for the Y axis.

I'm not sure if this is warping on the 3D printed house or what, because it seems like the screws are all in the right places and tightened.

4 Reply by grob (edited by grob 2014-09-27 12:38:39)

  • grob
  • grob
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Re: Y-Belt jittery (not smooth in one direction)

Hmm, from your description it does indeed sound like something is broken - if you could post a good clear picture of the parts of which you are suspicious (e.g. "the assembly on the front left [that] angles down slightly"), it will me much easier to confirm what is wrong and perhaps suggest a quick fix to get going again...

(Note: you can either upload and attach images, or link to them from an image sharing site such as imgur)

SD3. Mk2b + glass, heated enclosure, GT2 belts, direct drive y shaft, linear bearings, bowden-feed E3D v5 w/ 0.9° stepper
Smoothieboard via Octoprint on RPi