Laser is misaligning the cut after an engrave

So I have an issue at the moment where after a fairly detailed engraving of multiple items the vector cut after is misaligned by the time it gets to the third row.

The engraving is perfectly in line never misses a beat by the seems of it.

And I also have a 100w where I don’t have these issues with the same file.

I’m running the cut at 23 mmps 40% power, and the engrave is running at 500 mmpm 60% power.

I checked on the pvm settings, X was true Y was false, so I set them both to false, no improvement.

I took the file size down dramatically to only three rows, but it’s still seems to have the issue.

It could go either way, because eyeballs aren’t good at measuring absolute positions. Relative position errors are obvious, but tracking down which one is off takes careful measurement.

Some basics:

  • Is the picture oriented with the laser head engraving the material left-and-right?
  • Does the engraving run from bottom to top?
  • Does it engrave the entire sheet at once, then return to cut the outlines?

Lay down some cardboard (because cheap) and run only the engraving layer. When it’s done, don’t move the cardboard.

  • Use the Click to Move tool to position the laser at the dot directly under the heart in the lower left pattern
  • Fire a manual pulse to mark that location on the cardboard

If the laser pulse doesn’t hit dead center in the dot under the heart, then the error happened while engraving.

Check other patterns across the layout to verify the dot-vs-pulse position. If the engraving starts at the bottom of the layout (front of the laser platform), then those patterns should be closer to the ideal position, with the error getting worse toward the top (rear of the platform).

The error may come from a mechanical problem, in which case both the engraving position and the Click-to-Move positions can be wrong. In either case, you know the machine is not moving to the commanded position because the engraving and the pulse positions don’t match.

Then check the cut layer:

  • Turn the engraving layer off
  • Turn the cutting layer on
  • Reduce the power so the “cut” layer will mark, not cut
  • Run the layer

Repeat the Click-to-Move exercise with the point of the heart (which looks like it’s supposed to be cut out of the disk), checking a bunch of them across the platform. If they all match up, then the cut layer is properly aligned. If not, then the cut layer has problems.

Then you can start tracking down the real problem.

I assume you mean the PWM Rising Edge Valid signal and they’re now both False. That matches the settings for my OMTech 60 W, so it seems reasonable.

You’d think the machine would ship with a correct configuration, but the initial values seem almost random.

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