Surface Finishing for medical devices

In medical technology the surface decides more than appearance: corrosion resistance, cleanability, sliding behaviour and — for implants — whether tissue attaches or not. The field is correspondingly broad: grinding and polishing, vibratory finishing, blasting, electropolishing, passivation, pickling, anodising, plus the various coating methods.

With stainless steel it is essentially about the passive layer. Every mechanical operation damages it and introduces foreign iron; passivation rebuilds it chemically, while electropolishing additionally removes a thin layer, smooths micro-peaks and removes embedded particles. This improves not only corrosion resistance but cleanability — the smoother the surface, the less adheres to it.

With implants the direction is often reversed: surfaces are deliberately roughened, blasted or etched so that bone can grow on. For buyers this means the surface specification must match the application and should be measured, not described — roughness values such as Ra or Rz are comparable, "mirror polished" is not.