1 Topic by Morganism

  • Morganism
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Topic: Y-axis problems

I previously had a problem with my Y-axis grinding. Adjusted all the belts and things have been working for a few months.

About 3 weeks ago the noises came back again. My x-axis belt was very loose. I tightened it, and snapped it. I was able to reattached the existing belt, and it worked.

However, I still was getting some noise and also getting shifts in my print along the Y-axis. My print shifts mid-print towards the back of the machine. Even on a very thin print, like a lithopane.

I re-calibrated my y-axis belts. This improved the situation. During the process, the left side was not moving smoothly. I found that as I moved it toward the front of the machine it was rough, with almost a gritty feel to its motion. Initially, I suspected my bearing was bad. However, it runs smoothly on the back half of the rod. Since I have owned the machine, when I adjust that side it does find a sweet spot, but the gear slides back and forth as I move the y-axis. I tried to center it to get it as close as possible. It does not seem like that is how it supposed to work.

To answer my own question, I think I have a bent rod. Is that the mostly cause?

Solidoodle 4-Mostly stock running off headless Raspberry Pi with Octoprint

2 Reply by jagowilson (edited by jagowilson 2015-11-05 16:27:47)

  • jagowilson
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Re: Y-axis problems

To investigate if you have a bent rod, take all the belts off the back rod and attempt to spin it. If it spins smoothly (consistently), your problem is in alignment of the belts. You may also have a burr on the rod that is getting caught in the bushing. Hard telling.

To recap, here's how you align the belts properly...
1. Disconnect the Y motor belt entirely
2. Loosen the left and right pulley set screws.
3. Grab the carriage on the left and right ends and exercise it the entire length of the machine, back and forth, until the belts align.
4. Tighten the left and right pulley set screws without moving the pulleys.
5. Get the tensions equal
6. Loosen the set screw on the drive belt pulley (center pulley)
7. Put the Y belt on.
8. Exercise the entire carriage again, back and forth, until the motor and shaft pulleys align. You can also align it by hand if you prefer.
9. Tighten the center pulley set screw without moving it.

3 Reply by Morganism

  • Morganism
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Re: Y-axis problems

That is a good explanation of how I have been aligning the belts.   I am suspecting the left rod, not the back rod, is bent. It might be a burr on that rod that is catching, but it is more in the area of the second quarter of the rod (from the front) that I am feeling the problem. The other 3 quarters it moves smoothly. Like you said, move them until all three pulleys align. However, my left pulley never stays in the same spot. It will wobble back and forth as I run the carriage forward and backward. Up to about 1 pulley width in each direction. Is there any way to check the side rods for being bent? Nothing has happened to my printer that I know of that would have caused this rod to bend, but that seems to be the symptoms I am having.

Solidoodle 4-Mostly stock running off headless Raspberry Pi with Octoprint

4 Reply by wardjr

  • wardjr
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Re: Y-axis problems

You can simply rotate those rods and watch for side to side or up down movement in relationship to the bed or frame.

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