Can plastics and rubber roll over sound?
Make a groove and put the rubber ring in it. If the ultrasonic welding is done on the outer wall of the groove, this can be done. If you have a better design, I don't think you need one more ultrasonic welding process
Ultrasonic welding can not be used, you can make a groove in the plastic parts, EPDM rubber ring into the card, and if it is more insurance, you can use adhesive EPDM rubber, very good 3M4799, or direct bonding with 3M4799
