Rubber sheets and coatings can be difficult to gauge with conventional mechanical thickness measurement techniques. However, ultrasonic thickness gauging enables measurements on any point on the surface of a rubber sheet—not just the edges—without contacting the opposite side. Ultrasound waves travel through the rubber coating and reflect from the acoustic interface of the rubber and the substrate. This acoustic interface can be air, rubber steel, rubber composite, or other materials as long as the outside surface of the rubber is available for probe coupling.
It is important to fully understand the application before taking thickness measurements. Rubber coating on certain materials may require special setups to maintain accurate thickness readings.
Ultrasonic Equipment Used for Thickness Measurements on Rubber Sheets
Ultrasonic thickness measurements on rubber sheets can be performed using precision thickness gauges, such as the 39DL PLUS™ gauge and the 45MG gauge with Single Element software. When combined with the appropriate transducers between 2.25 MHz and 20 MHz, these handheld gauges can typically measure rubber materials in the range of 0.008 to 0.250 in. (0.2 to 6 mm). This range will vary depending on the transducer and setup being used. Thick or attenuating rubber materials will require the High Penetration software option for the 39DL PLUS and 45MG gauges.
The 72DL PLUS™ gauge offers a larger touch-screen display and a higher measurement update rate (up to 2 KHz). This gauge is available in a high-frequency version (up to 125 MHz) for measuring very thin rubber coatings. It can measure much thinner materials than conventional ultrasonic thickness gauges.
