Adhesive Problems with Vibration Motors

We recently received an enquiry from one of our customers who was experiencing some failures with their motors, a fairly low percentage (about 30 from 5,000) but still enough to cause concern. After some investigation, we concluded that the source of the problem was vapour from adhesives settling on the motor’s commutator.

Certain glues and adhesives are subject to ‘blooming’. This is where the vapour of the adhesive can condense or other parts of the system. For DC motors, if this occurs on the commutator or precious metal brushes it has the potential to break the connection and cause an open circuit in the motor – thereby failing.

Blooming is particularly prevalent in certain types of adhesive, such as cyanoacrylates. A common example of cyanoacrylate is the brand The Original Super Glue. This is particularly popular with hobbyists as it is easy to source and use, however, many other versions are widely used across the industry.

In the case of our customer, the glue was used to secure the enclosure and PCB together – the vibration motor did not come into contact with it. It is for this reason we recommend using low-blooming and high viscous adhesives. For more information, we have some tips in Application Bulletin 007: Mechanical Mounting for Vibration Motors: To Bulkheads.

Or you can always contact us!

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