Hi all,
I know this is important as I hear it talked about… and I know it is not currently inplimented, but can someone eplain what this is and why it is importent… and what we need to do now to compensate for its lack?
Thanks!
1 Like
Kerf is one of the most popular topics at https://community.glowforge.com/c/glowforge-tips-and-tricks Lots of tutorials and info.
3 Likes
Kerf on any cutting machine is simply how wide of a swath is cut. On a laser this is very small but for some things it still needs to be corrected for. Now start reading all the links @dwardio gave you. 
1 Like
Think of cutting a piece of wood on a table saw. The blade is going to remove a certain width of the material. The laser does the same thing, only on a much smaller scale.
Kerf the width of the material burned away by the laser. Kerf will be different depending on several factors; beam power, focus, material, speed, etc. Kerf compensation typically applies mostly to cuts, so that’s the context I’ll talk about here.
In general, the design you send the laser has paths that are defined as zero-width vectors. We tend to have a stroke width of whatever value makes it easier to design with, but what the laser cares about is that mathematical description of the cut path.
So, if your design is a 1” square, the laser will cut four 1” lines. The result is a square hole and a square piece. But what are the dimensions of each?
The kerf will be half on each side of the line. So, let’s say the kerf in this material, speed, power, focus combination is 10/1000”, or 0.010”, and your square was cutting from (1,1), (2,1), (2,2), (1,2), (1,1).
The piece cut out will be 0.005” inside each of those lines. It will be as though an infinitely thin beam had cut along the path (1.005,1.005), (1.995,1.005), (1.995,1.995), (1.005,1.995), (1.005,1.005). Since it is inset by half the kerf, if you add the half-kerf on the left and right sides together, the square is narrower by the full kerf: 0.990”
Similarly, the effective size of the hole would be as if the imaginary zero -width beam had traveled (0.995,0.995), (0.995,2.005), (2.005,2.005), (2.005,0.995), (0.995,0.995) and would measure 1.01”.
Kerf compensation is the process of offsetting the centerline path of the cut to make either the hole or the piece the exact size you designed. Did you need the square to be 1.000” wide? Or did you need the hole to be 1.000” wide?
At this time, all kerf compensation must be directly baked into your design. In the future, the Glowforge software can apply correction, but only if it knows which side of each cut needs to have the designed dimensions.
11 Likes
And some have already mentioned, kerf has been explained at nauseam within the Forum. That’s what the great search feature is all for LOL I’m sure you will find all your answers there and more