Mesh height maps

A program assumes your material is flat. Material frequently is not — plywood cups, a spoilboard wears, a sheet sits on a chip.

A mesh height map is a grid of probed heights across the work area. With one, the program's Z moves are adjusted point by point so a cut that should be 0.2 mm deep is 0.2 mm deep everywhere, not 0.05 mm at one end and 0.4 mm at the other.

When it is worth doing

• Shallow cuts over a wide area — engraving, V-carving, PCB isolation, surface detail. The shallower the cut, the more a small height variation matters.
• Material you know is not flat — reclaimed timber, thin sheet, anything warped.
• A spoilboard that has seen work.

It is not worth doing for deep cuts through thick stock, where a few tenths of a millimetre make no difference to the result.

How it works

The map is probed with your touch plate, one point at a time, with you carrying it. With a program loaded, turn Mesh on in the Run screen's action row and press Probe Mesh. The grid is a fixed 3 × 3 over the stock — the corners, the middle of each edge, and the centre, nine points in all.

At each point the machine parks above the position and waits for you to place the touch plate. Confirm, and the probe stroke fires; the machine retracts, moves to the next point, and waits again. Abort is available at every point. The plate's configured thickness — from Settings → Probing — is what turns the probed contact into a surface height, so it must match the plate you actually own.

When the job runs, each move's Z is corrected by the height at that point, interpolated between probed positions. Probed points are drawn in the 3D view so you can see the coverage you got, and once a map exists the same button reads Re-Probe Mesh — re-probing replaces the old map.

Which surface the map describes

The setup asks which datum the map references, and the two answer different problems:

Related

• Probing
• The Run screen