On-CMM core temperature measurement using ultrasonic phase-shift method

Activity: Talk or presentation typesOral presentation


Temperature variation in manufactured workpieces can affect that workpiece’s accuracy. In large workpieces, the core temperature can vary significantly from the part’s surface temperature. This temperature gradient can result in an inaccurate representation of the part’s temperature. Conventional sensors used in CMM temperature measurements can only measure the surface temperature of the workpiece. The temperature of a material affects the velocity of sound travelling through it, when an ultrasonic wave travels through a material, its average velocity can be known if the transit time and the length of travel are known. This average velocity can in turn be used to estimate the core temperature of the part. However, the main limitation is the required acquisition electronics for obtaining high resolution measurements required in precision manufacturing. Using an ultrasonic phase-shift method, simulations as well as in-process experiments were carried out on the CMM for core temperature measurement. The created ultrasonic phase-shift system which makes use of a dual element piezoelectric transducer achieves higher resolution than the traditional pulse-echo method which is more expensive and more complicated to use. The results show that the estimated temperature using the ultrasonic method predicts material expansion with higher accuracy than the surface temperature probe, with the error from the surface predicted expansion being 1.1 µm while the error from the ultrasonic thermometry is 0.58 µm. The results also show a high level of repeatability.
Period17 Sep 2021
Event title41st International MATADOR Conference
Event typeConference
Conference number41
LocationManchester, United Kingdom
Degree of RecognitionInternational