Touch Probing with a Feather's Touch

Multisensor measurement systems combine the strengths of two or more sensor technologies on a single inspection platform so that all critical features of a complex part can be measured. These systems often include non-contact sensors—video and/or laser—for surface and edge measurements, and touch-trigger probes to reach part features that the non-contact devices can't access, such as cross holes.

In some cases, the size of a typical touch-trigger probe may prohibit the measurement of very small slots, holes, grooves or bore draft angles, for example. The touch-trigger measurement technique may also prevent such measurements. Because the probe must deflect in order to register a position, it is possible that the probe's shank could contact the part before completing this deflection (this is known as shanking error).

SmartScope multisensor measurement systems from Optical Gaging Products (Rochester, New York) offer touch probing technology that requires no stylus deflection. The technique uses a miniature probe that is in constant micro motion. As the probe's small stylus ball approaches the object to be measured, its micro motion is damped by the part being measured. When the system detects this change in micro motion, it registers the measurement. The probe does not deflect at all, which allows its diameter to be so small and also enables measurement of very flexible of materials in X, Y and Z axes.

To guard against damage when not in use, the probe retracts into a protective housing and deploys only when very fine touch probing routines are required. The probe and housing can be stored in a probe change rack as any other probe could.