Parts Cutting Different Sizes Across Bed

[jordan matthai]

When cutting across my entire laser bed (30" x 48") Parts on the right side of the bed are 1/16" Shorter in the X Axis Direction.

I have fully aligned the mirrors. Squared up the X and Y axis. Tightened Belts, Checked and tightened Pulleys and have tried changing the microstep pulse count. After all this the parts are still smaller on the right side of the bed. Any Ideas?

There may be a simple solution but I can't seem to track it down.

[Rich Harman]

Could be a stretched (or damaged) belt. I think most people tend to over-tighten belts. As long as the belt engages the pulleys properly and is not flopping around when under use (or sagging under their own weight) - I don't see a reason to tighten them further.

Other than that, is the kerf consistent? If the shorter pieces also have wider kerfs, then that would explain the difference.

Also make absolutely certain that the parts in the drawing are correct, maybe rotate the whole job 180 degrees and see if that changes anything.

[Kev Williams]

Concur with Rich, my guess is belt wear.

No matter the laser, users tend to use the machine most often in one general vicinity, usually that would be near 'home position'. So the first few inches of the belt's teeth get worn narrower, and the belt itself tends to stretch. This occurs on both ends of the gantry. So what can happen is when the 'fresher' ends of the belt get closer to the opposite cogs, the tooth spacing and belt itself can be shorter. A 1/16" shorter? Anything's possible I guess- My LS900 (24x24" table) had a spot around the 16 to 18" area where it was running off .040" in spots. I flipped over the belt, and that took care of it- at least in THAT area, after the flip I started getting backlash issues between 1-3" from the left edge.

Short version, flip the belt, see if things improve, or change. If either happens, get a new belt :)

[AL Ursich]

New Belt....

[jordan matthai]

Thanks for the tips! I'll give a new belt a try and see if it clears it up. Cheers!