Finishing: Mechanical Polishing

Polishing cnc machine working in factory

What is Polishing?

Polishing is a finishing process used to improve the surface conditions of a workpiece, usually using an abrasive which is glued to a work wheel or belt. Polishing can be used for decorational or functional purposes, such as oxidation removal or corrosion prevention.

The Polishing Process

Polishing is done in stages depending on the condition of the metal and the desired result. Rough abrasives are used to remove imperfections such as nicks and scratches from the metal, followed by stages of higher grit abrasives to smooth the metal to the desired finish. Buffing may then be used to produce a “mirror” finish. Buffing is less aggressive, using a loose abrasive or cloth which is attached to the work wheel. There are two types of buffing motions:

Polished metal  
  • The cut motion– Using medium to hard pressure, the workpiece is moved against the rotation of the buffing wheel to produce a smooth, semi-bright finish.
  • The color motion– Using medium to light pressure, the workpiece is moved with the rotation of the buffing wheel to produce a shiny, bright finish.