Micropolishing is done to achieve a better Ra finish, that will reduce oil drag and increase bearing life.
Micropolishing consists of rotating a workpiece at relatively slow speeds. An abrasive cutting media, is then applied to the part while oscillating at lower amplitudes and higher frequencies. The cutting medium can be traditional vitrified abrasive stones or Mylar-backed coated abrasive tape. The tape can be either be supported by a hard backing that is designed to mirror the ideal part geometry, or a semi hard contact roll that conforms to the part being finished. Unlike stones, where fresh abrasive crystals are exposed as stones wear, the tape approach always introduces fresh abrasive crystals either indexing between each workpiece or through continuous tape feed. The rotational speed of the workpiece, amplitude and frequency of the oscillation, micropolishing time, grit size of the cutting medium, pressure applied on the workpiece and type of coolant are all used as process control parameters.