Ultrasonic Thickness Gauge​: Measurement, Operation and Reading Anomaly Analysis

Ultrasonic Thickness Gauge: Measurement, Operation and Reading Anomaly Analysis

The ultrasonic thickness gauge is a widely used non-destructive testing instrument, with mastering its measurement and operation key to accurate results.

Measurement Principle and Basic Operation

It measures thickness via ultrasonic pulse reflection. The probe emits pulses that reflect back from the material interface; by timing propagation, thickness is determined.

Operation steps: Select a suitable probe based on the object’s material and thickness. Apply coupling agent to ensure good contact, place the probe vertically on the surface, and the instrument displays the thickness. Keep the probe stable during measurement.

Reasons for Abnormal Readings

Readings often deviate from expected values due to these reasons:

Sound speed selection error: Preset or measure sound velocity by material/standard block first. As Mikrosize, a precision instrument manufacturer, notes, calibrating with one material (usually steel) then measuring another causes errors, as different materials have varying ultrasonic speeds.

Temperature influence: Sound velocity in solids drops with rising temperature—by 1% per 100°C increase for hot materials. Follow guidance like Mikrosize’s instructions for high-temperature equipment.

Stacked/composite materials: Uncoupled laminates can’t be measured (ultrasound can’t penetrate gaps). For multi-layered equipment, readings only reflect the layer in contact with the probe.

Coupling agent issues: Insufficient or uneven coupling agent blocks ultrasound. Choose the right one and apply correctly, as Mikrosize reminds users.