Surface finish influences coating quality
Component or tool surface finish has a decisive influence on coating performance.
The prerequisites for perfect coating quality are:
For tools and components
- Surfaces must be bright. They must not be chrome-plated, burnished, steam-tempered or bath-nitrided.
- Ground surfaces must be free of microcracks, oxide layers and rehardening zones, and not produced using a blunt grinding wheel.
- Cutting edges should be burr-free to achieve full performance after coating.
- For electric-discharge machining (EDM), multiple trim-cuts are recommended to reduce the formation of the "white layer". In general, good coating adhesion to surfaces machined by electric discharge is possible if the surfaces are pretreated by micro-blasting.
- Polished surfaces must be free of residual polishing compound.
- Photo-etched surfaces can be coated without pre-treatment if they are residue and spot-free. Surfaces must be free of rust, swarf, wax, adhesive tape, paint, plastic melting residues, mould deposits etc.
- Parts must be free of abrasion dust, cleaning agent residues and fingerprints.
- Parts should be demagnetized.
We recommend for plastic parts
- to insert the parts into the coating process directly after the injection molding process.
- a well-designed gate area to reduce internal stress.