Ultrasonic welding of thermoplastics: resonance damaging internals 1

[robyoung]

I am attempting to get my arms around an ultrasonics welding problem, whereby nodal resonance is damaging internal components of my product during welding. Any ideas?

 

[dukane]

If you are referring to damage at the nodal point of the plastics component, i.e., away from the "anti-node" where the ultra sonics is introduced (horn contact)then I would try these-

mechanical dampening (via fixture)of the effected area, clamp around the piece

lower amplitude at face of horn (of course not so low that welding quality is not adversely effected.

lower amplitude at different frequency- if you're using 20kHz, try 40 kHz if possible, or maybe 15 kHz. Part size will dictate this

make internal components more robust, i.e., add ribs, cushioning, pot in epoxy?

 

[dallascowboy]

Are all of your components made from the same material? Changing one or the other components in contact changes the degree of the effect of the ultrasonics.