Wednesday, June 27, 2012

Ultrasonic Staking 101

QUESTION: In a staking operation, I want the stud to melt at the face of the horn to form a rivet head. Instead, it's melting at the base of the stud. What's going on?

ANSWER: A couple of things. First, energy is transmitting through the stud to the base. Try pre-triggering the system so that the horn starts vibrating before it contacts the stud. This will help maintain an out-of-phase relationship between the stud and horn which, in turn, will prevent the coupling that's occurring. You should also try altering the velocity, or descent of the horn. Consider a servo welder with patented melt-match technology which will allow you to match the velocity with the flow of molten plastic. Another problem might be at the base of the stud, where you probably have a 90° angle. That's acting as a stress riser, and energy tends to migrate there. That's bad--radius the base of the stud. 



For additional joint design guides, please see our downloads page.
For more information or help with operating your machines, think about attending one of our ultrasonic training sessions! The next session is October 16th-17th at Dukane. There are seats available but they tend to fill up quickly as the time gets closer, so be sure to sign up ASAP to guarantee your seat. 

Sign up here:

http://dukane-store.stores.yahoo.net/intoulplasas.html



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