Incomplete Burn

Created a plan and executed without incident a week ago.
debbies box.lbrn2 (30.5 KB)

Setup a repeat burn today but no all burnt, see the top edge.

What did I do wrong.


How does your alignment look?, have you tested it recently?
I haven’t looked at your file, I assume you checked it in the preview window.

No, I didn’t check.

I will check tomorrow. Preview and play.

845-270-1478 cell

This also looks like this could be a different material but that could be the lighting playing tricks. If this is even the same labeled wood but from different batches you could get some variation.

Both work-pieces came form the same 4x8 sheet of plywood.

The complete burn was last week, the incomplete burn was this morning. Notice the top of the work-piece.

I used the same plan, no changes except:
1 - 1st (good) burn was set to imperial
2 - 2nd (incomplete) was set to metric
3 - positioned the work-piece lower on the bed as the 1st burn was at the top edge

LightBurn works internally in metric with imperial measurements only for display so this won’t be a factor.

This would definitely imply more of an alignment or bed level issue so definitely reinforces that theory.

oops, I’ve been a little too quick with your post, sorry. Actually I thought it was an incomplete cut from the underside…
Did your laser just stop cutting the material at the top or what exactly is going on? There is no trace of a laser…

I’ve gone through your file and haven’t found anything in the preview window to indicate a problem.

Maybe I’m also misunderstanding. Are you saying the laser doesn’t fire at all during those missed spots? I had thought you stopped the laser and the issue was that you weren’t cutting through.

Everything cut as expected except the top (upper portion - 2" or so) of my plan.

I didn’t stop the laser, it was a continuous cut, all cut as expected except for the inch or 2.

Since I didn’t watch the laser as I expected it to to do it’s job I don’t know if it didn’t fire or didn’t go there.

…as it appears, it has no fire at all in the upper part. If I haven’t seen your file I would claim that there was an error in the project, but there isn’t.
Find some scrap wood or cardboard and turn the project upside down and test it to see if the error can be reproduced.

Good suggestion, will try later. Thanks.

My first impression was that something is interfering the beam, l assume it has to get there in order to continue down the other side.

If you ‘Send’ the project to your controller before starting and look at it on the controller display, do you see the gaps in your design there? If so, try clearing your controller’s memory - Ruida controllers have been known to do some strange things if there are too many files on the machine.

If you have

  1. properly working tube
  2. aligned and clean optics
  3. proper focus

They work…

I would think if you lost anything from the cut, it would be the bottom…

Does Lightburn produce any warnings when uploading?

Are you using absolute coordinates?

It does appear as if the laser is just off…

You’ve probably got a demon in the other head doing this :rofl:


I think we figured it out.

My work piece was 24", burn area was 22". Machine max is 24". Origin was lower left about 1/2",1/2".

My burn last week went as expected.

I tested earlier by repositioning my image lower and the top burned properly.

Through some additional testing it seems that sometime between then and now the machine max became 20". Therefore it would not fire & burn the top few inches.

Thank you for all your help.

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