Hi everyone! I’m struggling with a little project of mine and was hoping I could get some help. I’m cutting squares out of 3mm MDF from A file I created in Inkscape. So I make The square in Inkscape, make sure the measurements are correct and save the file. I load the file into the glow Forge press print the size is off by a minimal amount but still off.
The 3 mm MDF that I’m using isn’t proof grade and I’ve gotten it to cut through, but it’s scorched the MDF. I tried looking for topics and help on the situation, but if anybody would be willing to give me any tips I’d greatly appreciate it.
There is a setting in Inkscape where you have two options, visual or geometric bounding boxes. You want geometric. Otherwise it counts your stroke width as part of the size of the box.
You must also take kerf into account when cutting (true of blades as well as lasers). Kerf is the amount the laser obliterates.
If you make your stroke width the kerf of your laser (I default to .007") it removes the issue with the bounding box, but make the change in your settings anyway
As for the MDF, it’s possible the glue they’re using isn’t terribly laser capable. I presume you started with the PG Draftboard setting and then lowered the speed when that didn’t work? If yes, the addition of medium tack masking on both sides may be all you need. If you started with a random setting, see how it compares to the PG setting and go from there.
When you say the size is off, albeit by a minimal amount, do you understand that burning/cutting any material results in destroyed material so a one inch square will not be exactly one inch when it is cut out. The material burned in the process of cutting is the kerf. If you want an exact square after cutting, you will need to make the file slightly bigger to allow for the kerf.
Your scorch is flashback - the laser hitting the metal crumb tray. It looks like your cuts are a bit overpowered. Paper masking on the back is the easiest way to keep your project clean.
When I bring any file into the Glowforge, when the piece is selected there is a pop-up that can give you the size to 3 decimal points. Sometimes I size it there, sometimes I just need to check the size. I quit swearing at MDF by swearing to never use it again. I saw recently that someone called it termite carp and I have not heard a better description.
