Two Dimensional Tracing and Measurement Using Touch Trigger Probes

Abstract

Summary The coordinate measuring machine (CMM) has been an important advance in automating the inspection process. Future cost reductions in metrology and operating flexibility require that CMM's be operated using extensive software packages and direct computer control. A new level of automatic measurement has been developed using commercially available touch trigger probes as self-guiding feedback control sensors for part search and measurement data collection. In the scheme developed, a touch trigger probe provides sensory input into a microprocessor based, multi-axis control system that guides the probe along the contour of an unknown part. The microprocessor detects the instant when contact between the probe and the part is made, reads the coordinates of the probe, and calculates guidance commands and the point of contact in real time. This paper presents a discussion of the tracing control and measurement theory for determining points of contact on two-dimensional part geometries using a touch trigger probe.