Patent US 4,150,327

Automatic control of the machining process of a series of workpieces is effected by a computer-controlled machine tool in which the feed speed of a cutting tool is controlled automatically according to a program determined in a preliminary teaching mode in which a sample workpiece is machined by a cutting tool advancing at a constant spaced speed and in which signals representing working torque on the tool for different positions of the tool relative to the workpiece, modified to take into account cutting characteristics, are stored in a memory. During a subsequent adaptive cutting mode the tool feed speed for machining successive workpieces of a series is determined by processing reference signals extracted from the memory with signals representing the actual thickness of the stock to be machined to generate a signal controlling the instantaneous rate of tool advance, taking into account tool wear parameters.