Finished size does not match design size

Hello, all. Lately (because this didn’t use to be a problem), I’m seeing the dimensions on the finished cut are off by a small amount. I’ve been using a 24mm x 18mm test reactangle, and it’s been coming out about smaller by about 0.8mm.

I’m using Affinity designer, with a very thin (0.2pt) line defining my object. From what I understand, the glowforge is supposed to ignore line width, etc. I’ve tried both PDF and SVG output, and the work piece is consistently different in dimensions.

Does anyone know if something has changed with the Glowforge software or Affinity software that would make an impact?

It does.

What material and settings are you using? Kerf can vary between materials but .4mm would be excessive.

If you’d like to share the SVG we can take a look at it.

Sure. Attached is the file, and some screenies/pics.

Interesting note… when I add an outside stroke to the rectangle, the Glowforge interprets that as an engrave and does not cut. I made 3 measurements of the finished work pieces, and they are fairly consistent to the width shown.

test1

Settings are: Medium Basswood Hardwood. Exported as SVG using settings I gleaned here from the community a couple years ago: Use DPI: 96, Allow JPEG Compression: Quality 85, Export Text as Curves, Add Line Breaks.

I meant your simple test rectangle. The file you attached is way to complex for me to make sense of (contains dozens of complex paths).

… although I will add, when I open that in Inkscape, the two right rectangles are exactly 15x15mm, and appear to load into the GF UI as such as well.

Before I dive in too deep, can you try make a PDF and see if you still have the problem importing into the GFUI?

AD gives me fits with exporting SVG, although there are several people that are successful.

When I opened your file in AI, the 8 PT outside square had a fill for the stroke area, that is why it interpreted as an engrave.

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0.2mm (or .007") total kerf per your photos is absolutely normal.

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Agreed. I get .1 (which as you are measuring, would be 14.8) for all the PG ply and draftboard.

Thanks for the answer @mpipes! That’s correct.

The X/Y axis motors can position the beam to within 0.001", which allows the laser to engrave with 1,000 DPI resolution. The laser beam removes material in a circular pattern. The diameter of the circle (the dot size) depends on what the material is, but ranges from 0.008" - 0.025" (0.20mm - 0.63mm).

I’m going to go ahead and close this thread - if you run into any further issues, go ahead and post a new topic. Thanks for letting us know about this!