Probing for Part Inspection and Crash Avoidance

A reader uses “Ask an Expert” to explore various potential uses of the machining center’s probe.


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I am interested in using our machining center’s Renishaw probe both for inspecting parts, as well as for crash prevention by locating bolts or clamps. Do you have any advice?

Response from Dave Bozich, machine tool business manager with Renishaw

Using a probe for post process inspection is possible, but it’s a challenging issue. We generally suggest that customers keep their machines calibrated and properly aligned by using a laser interferometer, telescoping ballbar and other alignment equipment. We also suggest using strain gauge probes (such as Renishaw’s RMP600) vs. conventional kinematic probes. Strain gauge probes provide sub-micron repeatability. In addition, the use of a machine-resident artifact allows for correlation between the actual measurements taken from the part and the known dimensions of the artifact. PC-based data analysis software (Renishaw has OMV-Pro and CNC Reporter) may also be part of the solution.

Regarding using a probe for crash prevention, that is much simpler. You will first need to determine if you are using Renishaw macro software or something provided by the machine tool builder. Renishaw’s Inspection+ software provides a "Protected Positioning" cycle. This is a canned cycle used when positioning from feature to feature within a probing cycle. If the probe is inadvertently tripped as a result of interference with a clamp, machine motion is stopped and an error is raised. If you are not using this software, see if the machine tool builder’s software offers a similar routine.