High-Accuracy High-Response Touch Trigger Probe for Coordinate Measuring Machine

摘要

This paper presents the development of a fast and accurate touch trigger probe for Coordinate Measuring Machine (CMM), which has five to ten times better performance than conventional one. The probe consists of a sensing module and a reseat module. The sensing module detects impulsive force at precise moment of contacting the spherical stylus tip with a work piece surface and generates a touch trigger signal. The reseat module absorbs contact force for safety and repositions in the fixture with high repeatability. The pre-travel variation (lobing error) is decreased by a signal processing of output from 4 piezo-elements mounted on a stylus bottom and control of a transmitting time difference between longitudinal wave and bending wave. The reseat positioning error is decreased by resetting elastic deformation of the contact points in the reseat module. As the results of the above new ideas, a measurement error of the probe is expected to be approximately 210nm (6□) under 30mm/s measuring speed.