What to cut with a laser, and at what thickness

Plyjoin does not know what material you will use: it works out the joints from the thickness you tell it. But the choice of material changes the result more than any setting, and it is worth knowing where to start.

Materials that work well

Poplar plywood, 3–4 mm. The cheapest and the easiest to cut. The grain is irregular, so thin tabs snap more readily. The right material for learning and for prototypes.

Birch plywood, 3–6 mm. More expensive, far more uniform, clean edges. Tabs hold. This is the material for work that will be seen.

MDF, 3–6 mm. Uniform, no grain, cuts beautifully and costs little. But it is dusty, it drinks moisture and the cut edge stays black. Excellent for templates, jigs and interiors.

Acrylic (PMMA), 3–5 mm. A mirror-polished edge, no scorching. Brittle with thin tabs: be generous with the tab count. The kerf is smaller than on wood.

Cardboard and greyboard, 1–3 mm. The cheapest way to test a design before cutting it in wood. A cardboard prototype costs twenty cents and tells you whether the sizes work.

What must never be cut

PVC and anything containing chlorine (vinyl, synthetic leather, some faux leathers) releases hydrochloric acid as it burns: it destroys the machine irreversibly and harms anyone breathing near it. There is no safe way to cut it on a CO₂ laser.

Polycarbonate and PTFE are also to be avoided: the first burns instead of cutting, the second releases toxic fumes.

If in doubt, ask your supplier for the safety data sheet.

Thickness, where the truth is

None of these materials is the thickness on the label. “3 mm” plywood measures between 2.7 and 3.1; “3 mm” acrylic is often 2.8, because extrusion tolerances are wide.

Always measure with a caliper and type that number into the “Material” panel. If the sheet is uneven, measure at four points and use the average. See the thickness and clearance guide.

The kerf changes with the material

The same laser, at the same power, burns a different groove in plywood and in acrylic. Change material without re-measuring the kerf and your joints change with it. It takes ten minutes: how to measure it.

Try it now

Open the app, type the thickness of the material on your bench and draw something: the rest adapts by itself.