Vibration characteristics of the Mk II Fokker Bond Tester probe

The vibration characteristics of three Fokker Bond Tester probes (3814, 3412 and 3414), with different length to diameter ratios, have been investigated. The resonant frequencies of each of the three probes have been predicted and measured, there being good agreement between the two sets of results. The mode shapes of a large model of a Fokker Bond Tester crystal have also been predicted and measured, with excellent agreement between theory and practice being obtained. This indicates that the predicted mode shapes for the crystals, obtained using a similar analysis to that used for the model, are also accurate. The frequency response of each of the Fokker Bond Tester probes tested is quite complex, there being many more major modes of vibration of the crystal in the frequency range of interest than is suggested by the manufacturers. The corresponding mode shapes of the crystal are also more complex than other reports indicate.