Consider giving this material to laser registration/alignment method a try… Method for cutting jobs that are > CNC workarea
At the very least it should help you diagnose the problem.
bLouChip Thanks, will give it a shot. Have to try cut an acrylic P&C sheet today.
Just for clarification, when using this method:
Are you cutting just the two referenced shapes, or several other shapes?
Stinger77 Thanks, will check out the video, need to cut another sheet today.
Good info on the video, but doesn’t really apply to the job at hand. I’m printing graphics onto a sheet and then cutting the shapes around the graphics. The cuts need to be pretty accurate in relation to the graphics. In the job that inspired this thread, I used the laser positioning tool to locate the corner of the shape to cut, then the laser cut in a different spot.
I will however, make better jigs after watching the video.
Thanks again, Matt
Good question. Unlike Print and Cut tool which I believe registers the entire LB pallet area to the laser XY and allows you to select any subsequent shape and cut it registered to P&C output, the method I describe with Two-Point Rotate/Scale tool only registers the selection at the time of using the tool. So, the ‘selection’ can be one or many shapes, including groups. I usually select everything on the LB pallet at once, make a super group, and align the whole thing; this of course preserves the overall design on the pallet. After alignment, you can ungroup and cut any shape or selections of shapes.
Again, the benefit of the Two-Point Rotate method is that you can see the accuracy of the registration in real time, on the LB pallet as you do it, and hence re-do it if you don’t like the accuracy, all of this done before the cut. In my case of plasma cutting, just by definition of the process I have to use since plasma process is not native to LB, I then get another step of accuracy check in that I save the gcode to post process it to convert to plasma process, and then I use a different CNC gcode sender to run it (UGS), I don’t use LB’s RunGcode feature due to needing more finite control (macros mainly) and feedback (monitoring) while the job runs. In running the gcode via UGS, I usually do at least 1 dry run with plasma jet disabled, and once happy with how the toolpath behaves then I arm the plasma jet and cut it.
I hope this helps.
I figured out the issue for the print & cut on the acrylic. After heat pressing, the acrylic shrinks in spots while cooling. I had a severe one today, it shrank in the middle of the 12"x12" square by nearly a quarter inch, but was almost original dimensions at the top & bottom of the sheet. I will just have to fight them for graphics with an outline, can build in wiggle room for photos that are cut out.
As to the laser cutting in a different position than expected. I had left the print & cut active, I think this affects the cut location, even if you move the shape in the program. I turned off the p&c today and positioned the laser around the graphics, it was slow, but I didn’t lose any product.
Thank you all for your help and suggestions! I did learn some tricks and y’all got me looking in the right directions!
Glad you were able to get to closure on this. Sounds like the expected culprit ended up being the actual culprit.
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