Checkline TI-MINIMAX - Manual (Page 44)

Dakota Ultrasonics
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Chapter 7 Transducer Selection
7.1 Selecting the Transducer
Transducer selection is a very import part of getting the best results from the
MINI-MAX. The frequency and diameter of transducer should be carefully
selected using the following information:
•
Select the largest diameter transducer that will seat completely on the end of
the bolt. If there are multiple applications and diameters to consider, select a
diameter that will work for as many applications as possible, thus reducing the
overall number of transducers needed.
•
When selecting the proper frequency, the following items should be taken into
consideration:
Higher frequencies are typically a better choice when measuring smaller
diameter bolts as the sound is better focused resulting in less beam
spread and more directivity.
Lower frequencies are more forgiving of potential bending and attenuative
materials. This is primarily due to the longer wavelength avoiding
smearing or distortion of the waveform. Longer wavelengths require
more of a phase shift before distortion will occur. Lower frequencies offer
an increased amount of dispersion and a reduced amount of directivity. As
this may seem to go against what may typically be considered a good
choice, in the case of bending it’s actually the best choice overall.