METHOD AND APPARATUS FOR GRINDING COMPOSITE WORKPIECES

摘要

A method is described for grinding a composite workpiece (18) to form a component having concentric (31) and eccentric cylindrical regions (30). The method comprises mounting the workpiece (18) in a computer controlled grinding machine (10) having a grinding wheel (12) the advance and withdrawal of which is controllable by a programme entered into the controlling computer (32), loading a wheelfeed controlling programme into the computer, relatively positioning the grinding wheel and the workpiece to align the wheel with a first selected region of the workpiece, advancing the grinding wheel towards the selected region so as to grind the surface thereof, controlling the wheelfeed so as to maintain grinding contact between the grinding wheel and the workpiece so as either to grind a concentric cylindrical region thereon or an eccentric (offset) cylindrical region thereon as required, information about each selected region of the workpiece being stored in the computer and addressed as appropriate so that the wheelfeed can be cotrolled appropriately depending on whether a selected workpiece region is to be ground as a concentric or an eccentric (offset) cylindrical region. The method allows a workpiece havi ng both concentric and eccentric (offset) cylindrical regions thereon to be ground using a singlegrinding machine under computer control without demounting the workpiece from the machine. The method also envisages introducing small advance and retract movements in the wheelfeed whilst the grinding wheel is engaged in grinding a concentric cylindrical workpiece region so as to introduce into t he ground region an eccentricity which is equal and opposite to any eccentricity which grinding process forces introduce into the ground region, so that the two eccentricities cancel out. A computer controlled grinding machine is described as are programmes for controlling the machine.