Melamine and particle board
Melamine is a hard plastic coating on particle board. The coating chips at the cut edge, especially on the bottom face. A compression bit, a scoring pass, or a sacrificial backer all solve it. The core underneath is weak and holds fasteners poorly.
What you are cutting
Two very different materials in one sheet. The surface is a thin, hard, brittle melamine resin layer. The core is particle board: wood chips and glue, weak, with no fibre continuity. The cutter goes from one to the other and back, and both transitions are where things go wrong.
Chipping, and the three fixes
- Compression bit. Squeezes both faces toward the middle so neither chips. The correct tool, and the one the cabinet industry uses. Remember it has to cut deeper than its upcut section.
- Scoring pass. A shallow first pass, about 0.02 inches deep, that severs the coating cleanly before the main cut goes through. Works with a plain downcut bit.
- Sacrificial backer. A sheet of scrap underneath so the cutter exits into that instead of into air. Supports the bottom coating exactly where it would otherwise blow out.
Sharpness matters more here than in almost any other material, because the failure mode is brittle fracture. A slightly dull bit that still cuts wood acceptably will chip melamine every time.
The core
- Weak in the edge. Screws into the edge of particle board pull out under very little load. Use proper cabinet hardware designed for it.
- Crumbly in fine detail. Do not expect small carved features to survive.
- Water finishes it. Worse than MDF, because the chips swell and never recover.
- Heavy, and not very stiff for its weight.
Where it belongs
Cabinet carcasses, shop storage, shelving, jig bases, anything flat and painted or already surfaced. It is inexpensive and the surface is already finished, which is genuinely useful. It is not a material for carving, for detail, or for anything that will be handled by its edges.