Preface: I have already solved this problem, but the behavior of the Glowforge rasterizer was unexpected. Looks like a bug to me, so letting you know.
One of the things I was looking forward to printing after my Glowforge arrived this week was a mylar PCB stencil for printed circuit boards (used to apply solder paste to surface mount PCBs). I’ll post a separate how-to in this topic also, but here’s the issue I ran into.
Eagle (the PCB design tool I use) will output an SVG of the images I need. When I print the output file (detail: using eagle2svg ULP in Eagle) untouched, it prints fine. However, if I add anything to the SVG file, like cutlines or text, then the file is rasterized and the print head goes through all of the right movements but the laser never fires. No fluorescing, nothing.
Simple example SVG:
After some trial and error, I determined that the SVG file Eagle outputs has all of the stencil holes grouped together as well as dotted line around the group that was a very light grey and impossible to see without zooming in. If I delete the dotted line and ungroup all the stencil holes (just filled squares) then it prints correctly with the additions such as text etc. (Note: I’m not sure if one or the other or both are required, as I changed them both at the same time and it worked.)
The issue IMHO is that the SVG file (with additions) was accepted and processed without errors, but would not print. For a while, I was concerned that I had a bad laser unit, but after I determined that other files printed OK, I dug into it and found the cause. This is an issue that could lead someone to believe they have a hardware issue, as the rasterizing software should give you an error message if the laser is not going to fire. Failing silently by moving the head over the material without firing the laser is not the proper action.
I blew my afternoon chasing this down, so hopefully this saves someone else from the same fate.
But … happy now as I can produce terrific PCB stencils that will same me a lot of time!