(Mahr Federal: Providence, Rhode Island) --­ Tapers play an important role in orthopaedic devices. Most hip and knee implants use tapers because they provide good alignment and can be "locked" into position. In manufacturing these devices, the control of taper and size determines how well an implant performs over its lifetime. Increasingly, air gauging has become the inspection tool of choice for controlling these critical parameters.

"Air gauging was the breakthrough gauging technology of the '40s and '50s" says George Schuetz, director of precision gauges for Mahr Federal. "Introduced decades before electronic gauging, it provided the first high performance 50 µin. or better gauging on the shop floor. Despite its age, air gauging today is actually growing in popularity, especially in high precision areas like orthopedic devices. It is fast, easy to use, provides high precision results even under the toughest shop conditions, and can last for years measuring literally millions of parts."

For years the taper design of choice for orthopaedic devices was the simple round taper, Schuetz says. It functioned well, but with demands for better performance, new designs have been developed. Innovations such as special surface finishes and complex taper forms employing oblong tapers have improved orthopedic device performance.

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