I don’t know the correct terminology. I hope this makes sense.
I started to do inlay by cutting the same design on 1/8 inch Basswood plywood and walnut plywood.
I would then swap the cutouts and put the walnut cut out into the basswood piece and the basswood cut out into the walnut piece.
It looks OK, but there’s a gap between the cut out and the main piece.
I would like to know how to make the cut out piece strip tightly into the base piece.
How do I deal with the size of the curve and making these pieces fit tight?
Also, how do I size the cuts when I want to inlay acrylic with wood?
The gap exists because the laser “cuts” by burning away some of the material. The amount of material removed is called the kerf, and the size of the kerf will vary with different materials and settings.
You can measure the kerf. Draw and cut a one-inch square from your material, then measure its size with calipers. It will be something less than an inch. Subtract that number from one and divide by 2, that’s your kerf for that material.
You will then have some idea how much larger to make a piece to account for the kerf. It’s not much. Rather than do math, some people just add a small number like 0.003-0.01" to the size of the pieces to get a tighter fit.
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I ppreciate it, Dan84,
I had no idea there’s a formula.
I looked up the kerf size for CO2 Laser or actually for Glowforge and it didn’t give me an exact number, but a range of like 0.003 to 0.008 or something like that, And the reason for the range is variables like material,speed and power.
I’ll start testing it out, thanks much
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Once you have the kerf, it may help to flip the piece of material being inlaid. Play around with it. Also, flipping the image horizontally or vertically. Do some test pieces and play around with it. For simple shapes the kerf should be fairly straight forward, but for complex shapes you may find you need a looser kerf than for geometric ones.
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@dan84 and @caribis2 are exactly right about how to go about it. The tip about flipping one of the kinds of pieces is important for a tight fit.
Here’s the face of an automated moon phase display device I’m working on at the moment. It inlays PG medium maple and PG medium Basswood Hardwood:
To cut it I used a kerf compensation of 0.12mm and the PG settings on my GF Pro. I flipped the design of the basswood parts so that the laser cut them from what would be the eventually be the backs of the pieces to their fronts. Since the laser beam is slightly conical, the cut edges are slightly non-vertical. By flipping one set of pieces, the cut edges that go together match up even though they’re ever so slightly non-vertical.
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Kerf can vary a lot but for common materials like plywood, MDF, and acrylic, 0.007" is in the right ballpark.
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There is a good way to adjust for kerf once you know what it is. You set the cutline width to the kerf you want, then (in Inkscape) hit Path> Stroke to Path (Cntl-Alt-C) and then Path>Break Apart (Shift-Cntl-A) and you will have two lines, one on each side of the original line (you might want to shrink their width for less confusion). Then by taking each part by the line outside the result will be exactly the same size after the cut.
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I am a novice at Inkscape and your instructions look complicated cause I don’t have a clue what I’m doing with all this path stuff. I look at a lot of tutorials that tell me how to do things, but I don’t understand the fundamentals is there a tutorial you’re aware of to learn the fundamentals
when designing for inlay, do you draw the objects with stroke only, fill only, or stroke and fill both?
I get different sizes for each of those.
And if I set the stroke width to zero, I assume that removes the stroke from cutting.
Actually not. The stroke width makes no difference in the cutting width or engraving. That is why I laid out how to have that width by having two lines instead of one.
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