A sphere forming and polishing machine

A simple system for the production of spheres for magnetic measurement is described. The sphere grinder and polisher produces highly accurate spheres by grinding a rough sphere between three rotating grinding heads using a variety of grinding and polishing media. The system can produce highly accurate spheres with variations of less than 5 mu m from the mean diameter of 5 µm from almost any material, including hard anisotropic materials such as die-upset NdFeB (MQIII). The domain pattern at the pole and equator of a polished sphere of NdFeB is then revealed by Kerr microscopy.