Rubber sheets and rubber coatings are difficult to gauge with conventional thickness measurement techniques. With ultrasonic thickness gauges, however, any point on the entire surface of a rubber sheet - and not just the edges alone - can be measured without ever having to contact 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 rubber-steel, rubber-plastic, etc.

It is important to know the exact nature of the application -- rubber coating on certain materials may require special setups in order to maintain accuracy of thickness readings. Ultrasonic thickness measurements on rubber can be done manually or semi-automatically.

Equipment: Manual thickness measurements on rubber sheets can be done with the Models 35DL and 35. Typically, these hand-held gauges in combination with a 5MHz or 10MHz contact transducer measure rubber materials in the range of 0.010 to 0.250 in. (0.12 to 6 mm).

Thick or attenuating rubber materials may have to be measured with the HP (High Penetration) version of the 35DL.