Maintenance options: polish, repolish, weld repair, re-nitride, re-coat, scrap

Polish is the right call when the wear mode is light surface pickup, fine adhesive smearing, or a scuffed compound layer that has not yet cracked through. Diamond-paste progressions (45 µm to 14 µm to 3 µm, the Kemet sequence) restore surface finish without removing meaningful substrate. The die goes back into production with the same case it had before, minus the top few microns of compound layer.

Polish works on three wear modes. Light adhesive pickup in a low-flow region, where a thin smear of billet metal is sitting on top of an otherwise sound surface. A first-stage flash-land scuff at 10,000 to 20,000 hits, where break-in is producing a slightly rough finish on a still-hard case. A localized burnish from a misaligned lube cycle that left a dry spot for a few hundred hits before someone caught it. In each case the surface treatment underneath is intact, the dimensions are still in tolerance, and the operator is removing a cosmetic or near-cosmetic layer.

Polish is the wrong call, and actively dangerous, on three patterns. A heat-check network that has matured into single propagating cracks, where polishing the surface erases the visual evidence of the cracks while leaving the cracks themselves untouched at depth. A washout region where dimensional drift is the real failure, because polishing removes more material in the same direction the wear was already going. A corner with a hairline crack that runs into the substrate. Polish does not arrest crack growth. It removes the surface that was telling you the crack was there.

The rule on the floor: polish restores finish. It does not restore a case, it does not heal a crack, and it does not recover dimension. If the dye-pen at the next inspection shows the crack returning in the same spot at 5,000 hits, the polish was hiding it, not fixing it.