Ultrasonic thickness gauging is a widely used nondestructive test technique for measuring the thickness of a material from one side. It's fast, reliable, and versatile, and unlike a micrometer or a caliper it requires access to only one side of the test piece. The first commercial ultrasonic gauges, using principles derived from sonar, were introduced in the late 1940s. Small, portable instruments optimized for a wide variety of test applications became common in the 1970s. Advances in microprocessor technology led to new levels of performance in today's sophisticated, easy-to-use handheld instruments.

What can be measured?

Virtually any common engineering material can be measured ultrasonically. Ultrasonic thickness gauges can be set up for metals, plastics, composites, fiberglass, ceramics, and glass. On-line or in-process measurement of extruded plastics and rolled metal is often possible, as is measurement of individual layers or coatings in multilayer fabrications. Liquid levels and biological samples can also be measured. Ultrasonic gauging is always completely nondestructive, with no cutting or sectioning required.

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