Double side grinding apparatus and double side polishing apparatus

摘要

A double side grinding apparatus and a double side polishing apparatus, with a narrow tolerance range, reduces pitching errors, and ensures a sufficient level of rigidity against the force of reaction to machining, while enhancing positioning accuracy. The double side grinding apparatus or a double side polishing apparatus includes a plurality of guideways for supporting and shifting main spindles, and these plural guideways on end define a geometric center matched with the center of gravity of the main spindles. The number of the guideways is preferably three in order not to obstruct the mounting and removal of a workpiece.