Laser cutting is precise, but the beam itself has a small width, and it removes a little material as it cuts. That removed width is called the kerf, and accounting for it is the secret to parts that fit together cleanly.
Kerf and fit
Because the kerf removes material along the cut line, slots come out slightly wider and tabs slightly narrower than drawn. For press-fit and interlocking designs, this gap needs to be allowed for, or parts end up loose or impossible to assemble.
Kerf varies a little with material and thickness, so test cuts help for critical fits.
Designing to fit
When you send artwork for laser cutting, tell us about any interlocking or press-fit features and we will allow for the kerf so everything slots together as intended.