I recently ran some engraving and cutting of royal blue acrylic on my Glowforge Basic (purchased in December, 2020).
Other than this specific outcome, the Glowforge is working fine. It engraves and cuts both acrylic and plywood without any other issues. Everything lines up as I expect it to, multiple steps run without incident and there are no registration issues. I get the cutting and engraving depths I expect, with normal variances in natural materials.
The engraving steps which produced this problematic outcome are all set to run at 1400 speed and full power.
I tried two different brands of acrylic from two different suppliers. The first time I had this issue was with somewhat suspect acrylic from a seller on Etsy. I chalked it up to a problem with the production of the acrylic.
I then ran the same job on Modfy Royal Blue acrylic. I’ve worked with a lot of Modfy’s acrylic and have never had an issue.
Not only did I have the same issue, the issue manifested itself in the exact same spots in both jobs.
That likely rules out the material and probably rules out anything location-specific in the cycle of running the Glowforge, because I cut in different locations on my print bed both times but got the same result.
Please see the attached pictures. The engraving I’m doing is to get the upper orange layer to sit in the exact center of this blue layer, but if the engraving I did in this blue layer has a bunch of high spots, that’s not going to work.
I recently did a basic cleaning on my Glowforge, but I didn’t yet pull the lens or the mirror to clean those. I did clean the windows on the print head and I also cleaned the window on the far left of the gantry, along with vacuuming out everything. This was done within two or three jobs before running this job, and I think it was the first engraving I did after cleaning.
It’s important to note that I engraved other things after this for the same job, on gray Modfy acrylic, and they engraved without issue. A large area was engraved and it engraved to a consistent depth throughout the entire engraving.
In this first picture you can see how the artwork was oriented inside the Glowforge when it engraved and then cut. You can see that the defects in the engraving depth run horizontally. The three sets on the left are the shady Etsy acrylic and the two sets on the right are the Modfy acrylic. Note how the defects appear in the same place in each letter impacted by the problem.
In this picture, you can see the same thing running across two sets of identical artwork. These came from the same sheet of acrylic (shady Etsy), both engravings run at the same time. The artwork was vertically aligned. The defect appears in the K and the S, but not in the same horizontally-aligned engravings between the K and the S (the perspective boxes underneath the lettering between the K and the S)
Here is a close-up of the defect in the Etsy acrylic.
Here is a close-up of the defect in the Modfy acrylic.
I then thought it might be the artwork - something that went wrong. Here are two screenshots of the K and the N, taken in Inkscape, selected with the Node tool, as seen in the vertically running KNICKS lettering. The nodes all appear to be as-expected. If they weren’t connected in a continuous outline as expected, I’d think the fill wouldn’t appear as it does… the fill would also be twisted. Because I’m engraving, the stroke is off. Only fill.
Anyone seen this before?
