energy Process Integrity Gauge (ePIG)
A host of single spindle operations are common in today's automated transfer line manufacturing. Milling, drilling, boring, grinding and sawing are all common operations that can produce either quality parts or hundreds/thousands of rejects. Even worse, visually good parts with minor imperfections can become recall liabilities after assembly into the final product. Traditional gauging is a common quality check but often proves inconvenient and expensive to add to automated lines.
Fortunately, these common machining operations share two distinct characteristics in their sound or vibration signature allowing for an online Process Integrity Gauge. There is a distinct cutting signature as the tool and work piece are actually in contact and then another as the machine idles. Using the cutting energy signature as a quality indicator provides very economical and reliable means of continuously monitoring the manufacturing process. The statistical examination of this indicator provides a nearly "false alarm free" gauge of the expected consistency of the manufacturing process.
Since these smart systems are very affordable, they can be deployed on nearly every operation for real-time quality assurance catching common problems such as tooling problems, clamping problems, part hardness, worn gibs/slides, wrong speed/feed, thermal problems, coolant issues, PLC problems, etc. The system can even use the idle signature to identify a host of machine condition health problems (traditionally monitored with CBM techniques) that can also lead to bad parts or extended line shutdown.