FAQ: How to measure the temperature of horns and ultrasonic parts?
Thermal image of a 20 kHz ultrasonic welding acoustic stack in operation.
One of the best alternatives to measure the temperature of ultrasonic parts is a non-contact infrared thermometer (pyrometer). For accurate results, the emissivity setting must be adjusted because it varies greatly with the material and surface finishing. To avoid this adjustment issue, one may stick a piece of insulating black tape (emissivity equal to 0.95) over the part before taking readings. Shining surfaces of polished aluminum have emissivity as low as 0.07, which will lead to poor results if not properly compensated.
Infrared cameras can also be used and provide valuable insights for troubleshooting, especially for developments and optimizations. The image above shows the thermal image of an ultrasonic stack used to manufacture masks. It is possible to see that the piezoceramics, slots top surfaces and booster grips are at higher temperature than the surroundings.
Learn more about testing converters and acoustic stacks.