Patent ID: 9446442
Filing Date: 2016-09-20
CPC Classification: B21D,Y10T

Claim Text:
1. A method of moving a workpiece part away from a processing region of a machine tool for processing plate-like workpieces by punching, comprising: moving a punch and a punching die relative to each other along a stroke axis for punching a workpiece through with the punch to cut the workpiece part free from the workpiece; while the workpiece is being punched through with the punch, contacting an upper surface of the workpiece with a stripper mounted on a hold-down device of the machine tool; determining a reference position of the hold-down device along the stroke axis, at which the stripper contacts the upper surface of the workpiece; after the workpiece is punched through with the punch, positioning the stripper at a particular distance from the reference position above the workpiece according to a rigid motion coupling between a motion of the hold-down device and a motion of the punch such that a position of the hold-down device relative to the punch remains constant while the stripper is lifted from the upper surface of the workpiece, wherein a beginning of the rigid motion coupling between the hold-down device and the punch is detected by comparing positions of the hold-down device and the punch along the stroke axis; and moving the workpiece part that has been cut free from the workpiece with the punch away from the processing region of the machine tool.