Attaching Transducers with Adhesive

Question:

We have an ultrasonic cleaning machine with several tanks with 18 piezoelectric transducers attached in each one. The transducers are two piezoelectric stacks screwed to an aluminum radiating bar. After 10 years, the transducers wore off. We have attached new transducers to a tank, but the activity is near null. We have used an adhesive to attach them, but I think the solution was no good. What kind of glue or material must I use to fix the transducers? Some people suggested that I try epoxy, but it is a generic name. Can you suggest a product? J.M.

Answer:

Using epoxy to attach the transducer is considered common in some applications. You may want to try a standard epoxy (can be found in a hardware store and may be called "5 minute epoxy"). If you try this and it is not effective, you may have to consider that something else is wrong with the system. Since these are 10 years old, the stacks could be losing performance. The crystals that make up the piezoelectric transducers can, over time, become depolarized such that the frequency applied to them is no longer as effective. There are probably several other things that can go wrong with the transducers that I am not aware of. I would suggest you contact the original manufacturer to see what they would suggest. They may be able to recondition them better than anybody, if it is even possible.