Cut & Print losing alignment between runs

This may have been covered elsewhere but I cannot find it being reported.

I have successfully used cut and print many times over the last 18 months, but have not needed to use it since upgrading to v1.7 until today.
The issue is that I am making a 400x440 panel which is too big to fit in my laser so have split it into 4 200x220 panels.
The pattern design in Lightburn is 400x440 and I used a 200x220 mask to split the pattern into the 4 quadrants.
So far so good and the real world panel blanks and the Lightburn designs all match sizewise.
So I create a jig and set up lightburn to process the lower right quadrant and it comes out OK.
I then replace that panel with the upper right quadrant and run that and then find that the panels do not line up, (although they do in Lightburn).
Furthermore if I use the laser position tool to move the laser to the centre of one of the targets I find it is no longer in alignment so I have to redo the cut and print and repeat the job. Fortunately it is no an engraving just a stencil cut, but it is still annoying as it takes 30 mins to strip the masking off, reapply and then reset and redo the cut.
Anyone come across this or have a suggestion?
The pictures show the misalignment, the laser position tool centered on the target and the real location of the laser.


locate

As an update to this I have been trying Print & Cut with another project. As secretary of a club at the end of the year I am faced with generating a large number of individual membership cards and it is a chore manually cutting these out. So I redesigned the print output to include two targets thinking I could import the PDF into Lightburn and use the Print & Cut.
The PDF imported fine and I added the necessary cut boxes but as with the job above the print and cut was useless.
I set up target 1, then target 2 then accepted the setting. (Made no difference whether I used scaling or not.)
I then did the simple test of using the position tool to reposition the laser to target 1 and it was about 10mm too high on the Y and 3mm short on the X. Similarly when I positioned it to target 2.
Any ideas?

Walk us through the entire process of using print and cut. How are you aligning the targets? Are you using the direction arrows in the move panel or the location pin or moving the laser head by hand? Do you have any laser offset enabled in Device settings?

  1. All control via move panel.
  2. Home laser
  3. Alt 0 to invoke tool
  4. Select target 1
  5. Set move distance to 100mm to get laser close to target 1.
  6. Reduce this to 5mm, 1mm then 0.5mm to set laser on target
  7. Set target 1
  8. Select target 2 and use ‘Jog to target’
  9. Set laser for target 2
  10. Select ‘Align’ option

No laser offset.

This worked for me fine some 6 months or so ago. Only over last month have I needed to use it again and now hit the problems.

Looks like you’re doing everything correctly. Is there any slop in your machine? Try running this file on cardboard at highest speed and just enough power to get a good mark, with any optimizations turned off. That will identify any mechanical slop.
BacklashTest.lbrn2 (199.0 KB)

Thanks Tim. No, no slop - and that wouldn’t account for more than a few mm error. When it starts cutting the shapes, they are spot on - just in the wrong place! Totally lost faith in P&C - will have to return to careful positioning.