Scanning the Horizon — Post-Process Closed-Loop Automatic Feedback Gaging

One of the notable trends in quality control for machine tool users is post-process closed-loop feedback gaging. Post-process feedback gaging is a method of effectively controlling the quality of parts by controlling the size of the parts. It is a measurement technique that enhances part quality by automatically regulating machine tool cutter positioning.

At the exit end of the machining cycle, the workpiece is located for measurement, away from the environment in which it was machined. The gaging system measures the part, calculates corrective data statistically, and feeds the information to the machine controller prior to the next machining cycle. In a truly closed-loop system, the gage is the brain. Every part is measured for conformance while the process is controlled to produce similar target or nominal-sized parts — preprogrammed from within the gage.

A gage of this type was recently engineered to measure tappet rollers, combining a Micro CAG microprocessor with air tooling. The gage automatically checks five dimensions of each part as it exits from the lathe: ID at three planes, bellmouth, and taper. A flip gate directs good and bad parts. The system includes an SPC package and software to conduct repeatability and reproducibility studies.

Reprinted from Modern Machine Shop.