x-axis "squished" sometimes?

Assembly questions and answers for the Shapeoko 3 CNC Mill
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loneboat
Posts: 8
Joined: Fri Aug 26, 2016 2:56 pm

x-axis "squished" sometimes?

Post by loneboat » Sun Aug 28, 2016 3:47 am

This is a brand-new Shapeoko 3. As my first project I decided to drill a grid of holes in the wasteboard to affix clamps to. When I started it, I noticed that some of the holes were "squished" in the x-axis. My gut says this means the x-axis belt is skipping sometimes. I have tried tightening the x-axis belt, but that doesn't seem to help. (As a sidenote - How do I know HOW tight to make the belts? I've read warnings about over-tightening, that it can bend the motor axis). I am using the endmill which came with it (#201), and I have tried changing the feed rate from 60" (the default) to 30" - just in case it was skipping because it was feeding to hard (although I've ALSO read warnings about feeding too SLOW). That also did not help.

Here are some pics of the holes I drilled: http://imgur.com/a/rLlP1

Note that SOME of the holes are just fine!

loneboat
Posts: 8
Joined: Fri Aug 26, 2016 2:56 pm

Re: x-axis "squished" sometimes?

Post by loneboat » Sun Aug 28, 2016 4:17 am

In trying to figure it out, one thing I noticed is that when the machine is ON, there is a bit of play in the x-axis, about equal to the amount of squishing in the x-axis features. The y and z axes don't seem to have any play at all. How can I troubleshoot the source of this play? The belt seems tight, and the area of play is REALLY loose (like it slops back and forth about 1/5", but when it hits the end of the play, it resists very strongly.

The movement is smooth, and the belt is looping smoothly through the pulleys when it moves. The x-axis motor turns when it moves, and hits a hard limit at either end of the play. It seems like there is no "flexing" anywhere causing the play - all the parts seem rigid. All gears seem engaged with the teeth in the belts, and I see no missing teeth on either the motor or the belt. The play exists regardless of where along the x-axis I am (i.e. if I have jogged the machine to the middle of the x-axis, I get the same play as if I am at either end, or anywhere along it).

loneboat
Posts: 8
Joined: Fri Aug 26, 2016 2:56 pm

Re: x-axis "squished" sometimes?

Post by loneboat » Sun Aug 28, 2016 4:34 am

Edit: I think I've found the issue! The little grub screws in the x-axis motor on the gear were very loose. Tightning those seems to have eliminated all play. I haven't yet run another job yet, but this seems to have fixed the play issue.

WillAdams
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Re: x-axis "squished" sometimes?

Post by WillAdams » Sun Aug 28, 2016 1:06 pm

Shapeoko 3XL #0006 w/ Carbide Compact Router w/0.125″ and ¼″ Carbide 3D precision collets

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