How to apply kerf properly to a hole?

[limjiajun]

Hi all,

I'm trying to apply kerf to a laser-cutting pattern, but it doesn't seem to apply it properly for holes - it seems to apply it only once, when it should apply it twice to compensate for the cuts on either side of a hole.

Photos for example:

This is a sketch rect that's 3.3mm wide

Used to create this hole

This is the laser cutter tool setting, with a kerf width of 0.13mm, which is then post-processed using the Glowforge post

Which resulted in a hole width of 3.17mm, when I expect 3.04mm (3.3mm - (0.13mm * 2))

How do I get it to kerf as I expect? There's also a chance that my expectation is wrong, so I'll appreciate any help or correction!

Thanks,

Jay

[davebYYPCU · Accepted solution]

When you think about it, cutting a hole 3.3mm should leave a 3.3mm hole, expecting something else is a little odd.

A kerf 0.13 wide will give you an offcut from inside the hole 3.04 wide.

Might help....

[limjiajun]

I'm not sure why I got stuck thinking that the kerf was the radius of the laser. I was indeed expecting a 3.3mm-wide hole, but I kept thinking I had to offset the laser in by the full kerf amount to compensate, rather than half. Not my finest moment. Thanks for the response and diagram!