Moving workpiece parts on machine tools

摘要

Machine tools for processing plate-like workpieces by punching include a punching tool including a punch and a punching die, a drive unit for moving the punch and the punching die relative to each other along a stroke axis for cutting a workpiece part free from a plate-like workpiece, a hold-down device that is movable along the stroke axis and that includes a stripper that contacts an upper surface of the plate-like workpiece while the plate-like workpiece is punched through by the punch, a detection device for detecting a reference position of the hold-down device along the stroke axis, wherein the stripper contacts the upper surface of the workpiece at the reference position, and a numerical control unit for positioning the stripper at a particular distance from the reference position such that a workpiece part that has been cut off can be moved away from a processing region.

主权项

1. A machine tool for processing plate-like workpieces by punching, comprising:
a punching tool comprising a punch and a punching die; a drive unit for moving the punch and the punching die relative to each other along a stroke axis for cutting a workpiece part free from a plate-like workpiece; a hold-down device that is movable along the stroke axis and that comprises a stripper that contacts an upper surface of the plate-like workpiece while the plate-like workpiece is punched through by the punch; a detection device for detecting a reference position of the hold-down device along the stroke axis, wherein the stripper contacts the upper surface of the plate-like workpiece at the reference position; a numerical control unit for positioning the stripper, after the plate-like workpiece is punched through by the punch, at a particular distance from the reference position above the plate-like workpiece such that a workpiece part that has been cut off from the plate-like workpiece during the punching process can be moved away from a processing region of the machine tool; and a driver arrangement that rigidly couples a motion of the hold-down device with 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 plate-like workpiece, wherein the numerical control unit is configured to detect that a motion coupling between the hold-down device and the punch has begun by comparing the position of the hold-down device and a position of the punch along the stroke axis.