Importance

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Abstract

During machining of workpieces, particularly crankshafts, in a central ren of the workpiece, both tips at opposite unmachined ends are axially retracted from the workpiece; both machined ends of the workpiece are clamped centered with the radial clamping members. During the machining of one workpiece end, the workpiece is clamped equalized at the oppositely located end and during the machining of the central region is clamped centered at this end. A workpiece after end machining and before machining of the central region is relieved for elimination of existing axial tensile-strength pressure stresses. Before the machining of the central region there is applied an axial tensile-strength stress upon the workpiece. Apparatus for carrying-out the method includes two oppositely located main spindles and chucks, which have radially and axially adjustable clamping elements and having two oppositely located centering tips, which are adjustable axially relative to the clamping elements respectively the chucks. One chuck has centering-clamping clamp elements and equalizing-clamping clamp elements which are radially adjustable independently of each other. The centering and the equalizing-clamping clamp elements are adjustable axially in common. One chuck is provided with a load-relief device which is provided with a piston-cylinder-unit. The one chuck for axial stress loading of the clamped workpiece is adjustable by engagement of the piston. The one chuck is a clamping-tong chuck arrangement.

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First Claim