what tolerance can laser cutting hold?

Kerf is the width of material the beam removes as it cuts - the slot left behind, like the width of a saw blade. At OneLaser the kerf is from 0.15 mm, and it is compensated for automatically when the job is programmed, so the finished part matches the drawing, not the drawing minus a beam width.

Kerf matters most on small holes, narrow slots and fine tabs, where a tenth or two of a millimetre is a real fraction of the feature. You do not need to allow for it in your file - draw the part at its finished size and the compensation is handled at our end.

In general, three things: the material, its thickness and heat. Thicker sections carry more heat into the sheet, different materials conduct and expand differently, and long thin parts or dense clusters of features are more prone to thermal movement than compact ones.

These are general engineering facts rather than reasons to worry - a well set-up machine manages them with cutting order, speed and nesting decisions. It is why the same tolerance question is best answered per job: geometry, material and thickness together decide how hard a given dimension is to hold.

Edge finish is related but separate. A laser cut edge is clean and square enough for most fabrication work straight off the machine, and parts are deburred in house where the job calls for it.

Put the tolerance on the drawing against the dimension that matters - a note is fine - and we confirm it before cutting. That way the critical feature is checked against the machine and the material before any metal is cut, not discovered at inspection.

If a dimension is critical to an assembly - a bearing bore, a slot that mates with a tab, a hole pattern that has to line up with another part - say so. It is far easier to confirm a feature up front than to argue with a finished part.