When two
plastic parts are bonded together a heating, melting and resolidification process - the
conventional way we understand welding - we refer to the process as Welding.
Generally this is achieved when two similar plastics are bonded together, such as PS to
PS, Nylon to Nylon, to PP to PP, or when compatible plastics are bonded together, such as
ABS to PS or SAN to ABS etc.,
In ultrasonic welding, the Horn and Fixture are designed according to to part geometry. The Horn may
need to incorporate reliefs, or match the contours of the part it is to weld.
In Utrasonic Welding, one component is held rigidly in a fixture, the other placed over
it, so it aligns itself, without external support.
The horn contacts the upper part, couples to it and transmits ultrasonic energy, thereby
vibrating it relative to the rigidly held lower part and creates friction heat, melt and
flow at the joint interface.
When the ultrasonic is switched off, the melt resolidfies and a weld bond is formed.
Each step, the application of pressure, the trigger and timing of ultrasonic energy
holding the assembly under pressure until resolidification is complete, is programmable
and controlled by electronic circuit.
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