Tapping machining method

Abstract

A tapping machining method for moving a tapping tool to a commanded position in synchronism with rotation of a spindle, to subject a workpiece to threading, and thereafter rotating the spindle in the reverse direction and withdrawing the tapping tool from the workpiece in synchronism with rotation of the spindle. The steps of the tapping machining method include moving and positioning a spindle, namely the tapping tool (4), from an initial point (Pi) to an approach point (Pr) in the depth direction (along the Z axis) while being rotated at a constant velocity. Then a pulse distribution calculation is started by using the pitch of a screw and pulses of a frequency proportional to the rotational velocity of the spindle, and threading is performed while the tapping tool is moved toward a target position (Pe) by the distributed pulses. Next, a spindle reverse rotation command is produced for rotating the spindle in the reverse direction without halting the pulse distribution calculation, even when the tapping tool arrives at the target position (Pe). Thereafter, the tapping tool is moved in the depth direction in synchronism with rotation of the spindle during forward due to inertial rotation. The tapping tool (4) is raised up to the approach point (Pr) by the distributed pulses after the spindle rotates in the reverse direction at a point (Pm), and the pulse distribution operation is ended after the tapping tool arrives at the approach point (Pr).

Dependencies are inferred from the claim text.