Piston machining

A machining center for machining a piston for a positive displacement machine, said piston being presented to said machining center in the form of a work piece of a rough casting having an inner cavity, said machining center comprising:

• a fixture for gripping said piston along said inner cavity of said piston;
• a spindle for rotating said piston about a vertical longitudinal axis of said piston, said spindle being translatable along a first axis;
• a slide table positioned underneath said spindle for moving a plurality of cutting tools into contact with said piston;
• said plurality of cutting tools comprising:
• a first cutting tool for milling said piston when said piston is rotated by said spindle;
• an ovality unit for moving a cutting tool toward and away from a center line of said piston in synchronization with the rotation of said piston to give said piston a non-circular cross-section;
• at least one non-rotating tool for cutting a groove in the outer diameter of said piston while said piston is being rotated by said spindle;
• and a second rotating cutting tool for cutting a cross bore through said piston orthogonal to the longitudinal piston axis to facilitate insertion of a connecting pin to said piston, said spindle holding said piston stationary during the cutting of said cross bore.