Laser Step Calibrations Issues - Different Across Bed!

Community Laser Talk
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1

So I’m running my step calibration process in order to get very precise measurements on some parts I’m working on. Got my 100x100mm squares, and multiplying my step length by the resulting ratios, etc. No issues there. However, I’m finding that I’m getting different measurements across my bed. So while I can get my calibration to produce a perfect 100mm square (+/- .02mm) near the home position, I’m getting a 100.5x100.7mm square near the center of the bed. I’m absolutely stuck on what to do next. These parts are done in batches from large sheets, so I would ideally have a tolerance within 0.1 mm across the bed.

Is there another calibration step I can take? Some sort of scaling ratio? Or do my motors just suck and I’m stuck with them?

Unit is a 100W HL-Yeah 1060L running a Ruida G644XG.

2

My assumption would be that this isn’t a stepper issue. Could be something physical like something out of square or an alignment issue.

Can i suggest you run a grid of the squares across the entire bed surface and get a map of dimension deviation for the whole laser? Based on the outcome could give you an idea of the scale of the problem and clues as to the source of the deviation.

3

Thats a good idea. It’s a step in the right direction, one might say! I’ll give that a try and follow up.

4

@BossWood did you ever solve this issue? I’m running into a similar one.

5

Typically, folks measure cut dimensions without taking the kerf width into consideration.

The doc explains how to measure the length of marks on the surface:

Measuring a simple square on cardboard will get you most of the way toward the goal.

6

This totally makes sense, but my issue is my cuts are not consistent across the bed. I think if it were a kerf issue I would still say the same size square across the bed but my 150mm x 150mm squares appear to be off by up to 0.4mm depending on where it is. I imagine it’s a hardware issue and I need to work through it.

7

AFAICT:

  • If they’re consistently larger toward the far end of each axis, then it’s a calibration problem.
  • If they’re irregularly sized, then it’s a mechanical problem.
8

Ahh. This makes sense. It seems to be consistent further away from the origin along the y axis. Thank you I will work on calibrating tonight!