Cutting both sides help please

With Lightburn and an Xtool D1Pro I am trying to cut the same shape through from both sides of the wood but can’t get it to align. I’m using a squared piece of wood placed accurately in a jig to make the first partial cut but when I flip the workpiece and the image in lightburn the cut is about 8mm out and not cutting as shown on the screen. Am I doing something fundamentally wrong?

With a jig it should be doable. It’s basically the same when I flip my name tag and engrave the back.
But, when the items are not symmetrical, things go wrong. In this case, I make 2 templates, for the front and the back.

Is this two separate layers mirrored and overlayed? The two layer outlines should overlap perfectly. Simply mirroring without a reference for alignment may not get you there.

Also need to be sure nothing moves AT ALL during workpiece repositioning. I suggest setting $1=255 to keep the steppers energized and using finish position to a far corner to get everything out of the way. The hard stops should also be fixed to the frame and (if used between jobs) homing needs to be very repeatable.

Yes the shape is not symmetrical but did test on a square and it too was about 5mm out on the x axis and the same if flipped vertically. Just cant get my head around it. I have an outline exactly the size of my wood thats sits firmly against a fixed two sided jig at exactly X96mm Y19mm so it goes back in the same place but when both the wood and lightburn image are flipped it is still out. yet on the screen its exactly in the correct place.
If I’m just working on one side the cuts are accurate even if I take the piece out and rehome the laser.
I’ll keep experimenting!

can you send the file, or another file with the same problem?

If I flip the wood over then the shape cant be overlayed as its mirrored and just flipping it seems to move it out of sync. I just cant workout why this would happen.
The piece of wood is exact a against a fixed two sided jig and i leave the steppers untouched and energized.
I think when I did a square of 20x20mm the second cut on the opposite side was 4mm further along on the x axis.:+1:

Heres what im doing, dont know if this will shed any light on the problem?

Ahhh, it helps me to understand. But I can’t reproduce your problem.

I use a jig for some parts I have to do once in a while. The file I have saved with jig positioned in x, y 0: 0. The parts are delivered and must be processed on both side with different things. It doesn’t matter here with me, which side I start with, one of the holes I cut have the same distance from x, y in a corner, just mirror. It works properly.

Do you have the same problem If you place your item in 0:0?

Thanks for your help but i think i’ve got bigger issues! i cut a 100x100 piece of wood and positioned it against my fixed jig and in lightburn inserted a 100x100 square at the jig coordinates and then centered a smaller square. it all aligned on the screen but didn’t center on the wood so I must have some sort of alignment issues. Strange bc ive been producing loads of pieces up till now, must just not have noticed everything was not completely corresponding with the screen position.
Dont know where to begin with resetting the alignment, I thought the limit switches would set the position everytime.
Thanks again!

Start by finding out if your 100x100 square actually measures 100x100.
If you have had a working machine, I would start by checking all moving parts. Especially the small pulleys, it is a known problem that the small pinion screws can become loose.

The 100x100 piece measures 99.70x99.73 not sure if that within tolerance.
Yes will give it a once over but I was quite methodical with tightening things up from new but you never know.

Not in my world. If you draw a square with your max X and Y the error are added. But, I am not saying that it is the problem itself that you are experiencing, it is either a result of the problem or an independent other problem. If your mechanics are in order, however, it can be easily fixed.

1 Like

Turns out the issue was the crosshair was out and had to be offset in the settings. Hadn’t noticed it until I was trying to centre a shape and my original mirroring alignment issue.
Both now are spot on and the slight measurement anomaly also seems to have gone.
Thanks for the help, I think I learned a few things from this👍

This topic was automatically closed 30 days after the last reply. New replies are no longer allowed.