Monitoring machine tool conditions by measuring a force component and a vibration component at a fundamental natural frequency

Abstract

Methods and apparatus for monitoring, during machining of a workpiece (30,30'), the wear condition of a cutting tool (31,31') having its cutting portion in a structure (32,32') that is held by substantially more massive means (33,33'). A dynamometer (35,35') and filter (36) measure the component of the dynamic force exerted between the tool (31,31') and the workpiece (30,30') approximately in the direction (A,A') normal to the primary cutting edge (34,34') of the tool (31,31') and to the main cutting velocity (V,V') at approximately the fundamental natural frequency of the held structure (32,32') in the same normal direction (A,A'). An accelerometer (37,37'), filter (38), and integrators (39) measure the component of vibration in the tool (31,31') approximately in the same normal direction (A,A') at approximately the same frequency. Data processing equipment (41,42,43) computes the value of a wear indicative function of the ratio of the measured force component to the measured vibration component, and provides a display, adjustment, or other selected type of response (44) thereto. The computed value of the function typically indicates the amount of wear (FW) on the flank of the primary and secondary cutting edges (34,34') of the tool (31,31') during turning, milling, or drilling.

Dependencies are inferred from the claim text.