The customer was using standard O-rings as static face seals. The problem was infrequent but expensive when it occurred. A low percentage of the time, one of the O-rings would fall out of its groove during assembly. It could only be detected when the transmission was completely assembled and tested. At this point, the unit had to be disassembled and reworked. Their goal was to come up with a seal that would retain itself 100% of the time and eliminate rework.
We presented a solution to use interference fit, press in place seals to ensure that the seals maintained their position during assembly. There were five different seals but one of them was difficult because there was retention only on the OD. We worked with our supplier to provide a style that had not been proven in an OD retention application but we were confident it would perform well.
The customer was completely satisfied after pre-production builds and testing for all five seals. They have ordered additional parts to run their second pre-production build. They are planning to implement these parts into production 3Q-4Q 2020.