Tapping apparatus and method

摘要

A CNC tapping machine includes a spindle to which a tap is attached and a spindle motor for rotating the spindle. The load torque acting on the spindle motor that is detected when performing a tapping procedure without a workpiece is stored in a memory as referential, torque data. During a tapping procedure, a detection device detects the load torque acting on the spindle motor. A computer computes the difference between the load torque defected by the detection device and the referential load torque and uses the difference as the cutting load acting on the tap. As a result, the cutting load torque acting on the tap is accurately detected.