I have a design that consists of a 5" circle of plexiglass, with an inset circle, 1mm width, that I want to engrave to make space for a small gasket. I created a circle, changed it’s color, make sure it was not filled. when I upload it to the flowforge, it shows up as a cut. when I change it to an engrave, it recolors the interior of the circle as though it plans to engrave the fill.
Can someone suggest what I might be doing wrong in inkscape?
Yes, engrave works for filled shapes only. So it wants to engrave that entire inset circle. What you need to do instead is convert that 1mm width circle to a filled donut shape that has a width of 1 mm. I think the tutorial you want is this one: Inkscape - Converting Objects and Strokes to Paths
Why not set the inner circle to score?
Actually, that could work quite well as long as you run a bunch of tests to determine what level of defocussing you need to get exactly a 1mm line width. Otherwise, the default score will be the width of the laser beam and will probably be too narrow. I found a focus height of about 0.25” above the material height gave a nice wide line on acrylic but I don’t remember the exact width.
0.4 inches FP on 1/8 draftboard. (Just discovered it like five minutes ago.)
Bad news is, if you are running a defocused Score, you get absolutely no depth cut into the wood, it’s mainly for marking the wood. If you want to run a gasket in it, you’d want the depth that a regular deep engrave would give you.
I think the OP was talking about acrylic, which maybe works better with this technique.
Got it to work using first method mentioned.
Yay! Thanks to @jules, who wrote that tutorial.
I’m doing another cut of that pattern (two actually), and it occurs me to me that the bulk of the time to do the item is that engrave of the circle, mostly because it’s doing a scanline rendering.
It seems like this is something that could be done with a set of concentric circles if the firmware was a little smarter, but I imagine there is a good reason for not doing it this way.
Any thoughts about this?
A set of concentric circles will give you an over-burn at the start point for each circle, which will add up to a noticeable mark, I think.
How about trying a tight spiral ? One start and finish, but you might not be able to spot it was a spiral rather than circles ?
EDIT …or combine to two - outer and inner circle, with a spiral ‘fill’.
@johnbrooker is right about hotspots. I did a series of experiments in this vein and posted here:
I think this same type of issue plagues 3d printers, in the sense that it results in a vertical imperfection that runs up the side of a printed object, if the printer always starts a layer at the same place. IIRC, some slicers deal with this by shifting the start point. I imagine that the glowforge could do something similar.
I wonder if simply rotating the circle each time you copy/paste a smaller one would do the trick ?
I’d break the path at the top, then rotate if I were going to try it again.