What is Metal Polishing | CRATEX Abrasives

Mechanical material removal process has numerous phases and each phase is characterized by the extent to which the material is removed. The first phase with the highest metal removal rate would be grinding . It usually comes after various cutting operations and it is a process of removing deformed or damaged surface material. The goal is to prepare the surface for finer finishing operations with minimal damage that can be removed in the shortest possible time.

Other material removal phases are deburring, sanding, lapping, smoothing, cleaning and finally – polishing. Same as other operations, polishing is used to remove the damage that was reduced but not completely removed by the preceding step.

The purpose of the polishing operation is to create a smooth and shiny surface, which is not necessarily mirror-like as many people seem to believe. If we were to point out the difference between different polishing processes, we would have to say that mirror-like polish is rather achieved by buffing, a polishing operation that uses loose abrasive applied to the work wheel. Polishing is used to enhance an object’s appearance, to create a visible difference in color and cleanliness and to create a reflective surface.

Abrasives used the most in the finishing phases are diamond, aluminum oxide and silicon carbide. Polishing process normally includes different progressively finer abrasive grit textures. If the material is unfinished, the process starts with a coarse abrasive (usually 60-80 grits), continues with various finer abrasives, so that each following abrasive has a finer grit than the preceding one until the desired look is achieved. A craftsman will go from coarse to 120 to 180, 220 or 240, 320, 400 and even above 1,000 depending on the kind of work that’s being done and the material that’s being polished.

The purpose of coarse grits is to remove highly visible imperfections on the metal surface, such as deep lines and scratches, pits and nicks. Progressively finer abrasives reduce these imperfections more and more, making them less visible until they are no longer visible with the naked eye. Achieving a mirror finish usually includes some sort of polishing or buffing compound, polishing tools and a high-speed polishing machine or tool.

This article will present different How-to metal polishing projects and various CRATEX finishing tools.