I have a file I am trying to use kerf offset on and no matter what I do, nothing happens. The file is an svg and I have no “open” shapes. When I put in a number (.155) it says “outwards”, I hit OK and then process the cut with difference in size. No difference in the preview as well. I restarted LB and tried again, with no-joy. Am I missing something?
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If that’s in inches, it’s a very large kerf.
If it’s in millimeters, then it’s small enough to not make a visible change in the Preview unless it’s on a tiny feature.
How are you measuring the difference?
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I cut several 10mm x 40mm rectangles and measured 9.73 mm with calipers after cutting. I am trying to do an inlay. After I put in the offset, I cut and measured and there is no difference in size.
I duplicated the design and put the duplicate on a separate layer then added the kerf offset to one of the layers only. Opened the preview window and this is what I got. The preview window won’t show the kerf offset by itself, you need a copy to compare it to. I put the non offset copy into perforation mode to help verify which direction the offset actually goes. Once you verify the offset in preview, you can delete the perforated copy.
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Assuming the machine axes are correctly calibrated, then the total cut width is 2*0.27 = 0.54 mm and the Kerf Offset would be 0.27 mm for a snug fit.
You should also measure the hole those came out of, because it should be 10.27 mm. If not, then:
- The axis calibration is incorrect or
- The laser beam isn’t cutting perpendicular to the surface or
- Something else has gone awry
Where did the 0.155 mm kerf offset come from? As @thelmuth shows, it will be difficult to see any of those offsets at the scale of the “Detrott” letters.
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I tried that as well, with negative results.
When I cut the 10mm rectangles, the Final Cut width was 9.74, .25 being the kerf (.125 x 2). The .155 was me being generous with my offset for the design. I don’t know how LB not outputting the offset would be the lasers fault as LB is not sending the file to the machine. It only cuts the original file size.
Try this:
- Set the kerf offset to +5 mm outward, which should be easily visible in the
Preview - Set it to -5 mm (inward) and take another look at the
Preview
If it’s not visible in both of those, then upload the lbrn2 file so we can take a look at the situation.
Detroit.lbrn2 (750.7 KB)
When I do this SVG in XCS for my Xtool P2, it has no problem doing the offset.
Loading the file, selecting the “DETROTT” shapes (because I have Cut Selected Graphics turned On), and running Preview produces this:
Setting the layer’s Kerf offset to -5 mm (inward):
Setting the speed & power to mark cardboard produced these results:
So the Kerf offset behaves as expected on my machine for the “DETROTT” shapes in that file.
The file contains other shapes far off the workspace grid, which is why I used Cut selected graphics, but their presence doesn’t affect the outcome.
Nor does LightBurn, at least here, so the question now becomes what’s different between the setups.
What happens in a New file with a simple 20 mm square and 10 mm inward / outward Kerf offset values on the Mira and P2? If the results are different for the same file (albeit with different speed & power settings), upload it so I can test it, too.
I tried your suggestions, and it seems to be working, at least on preview. The whole situation is weird because I did a totally different design yesterday and it seems like LB set its own offset and ballooned out the tabs I was cutting. I restarted LB and it cut the file as instructed (correctly). When I tried the Detroit file this morning with a 5 mm offset, it looks ballooned out as it should. I will actually cut the file later to see if it’s working correctly and report back to you. This is definitely a LB problem and not my machine.