Numerical control device for a cam machining

摘要

A cam is machined by rotating a work (2) by a rotary axis (1) and by reciprocating an X axis mounted with a tool (3). The X axis is designed to stop at a stop position in the event of an emergency stop. At this stop position, the amount of retraction up to a position where the tool (3) does not interfere with the work (2) and any obstacles (5) is set. When an emergency stop signal is entered during a binary operation because of occurrence of an abnormality, the movement for each period corresponding to the set amount of retraction is added to the movement for each period of the binary operation and the X axis is driven by the resultant movement. The binary operation is stopped when reaching the stop position. The tool (3) is held at a position retracted by the set amount of retraction from the stop position. Thus, the tool (3) can be retracted to the predetermined position where it interfaces with neither a workpiece (2) nor an obstacle (5).