Fundamentals of Ultrasonics - PLASTICS

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Variations of Joint Designs or Energy Directors

For the design of plastic parts for assembly with ultrasonic energy, many recommendations exist to save time, energy and tooling modifications. The first step for a designer is to determine the most suitable joining technique. The following variations are possible:


  • Ultrasonic Welding
  • Ultrasonic Swaging, Staking, Spot-Welding
  • Ultrasonic Insertion

Ultrasonic Welding

The molten material builds at the contact area of the energy director between the to be welded parts. The ultrasonic waves are transferred through the part to the joint area. Common "standard" joint designs include:


The recommended process examples listed above can be varied with inserted gaskets or in-molded 2K injection molded gaskets.


Ultrasonic Swaging, Staking, Spot-Welding

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In addition to conventional types of joint design for bonding injection molded plastic parts, ultrasonic welding can be used in a verity of forms to accomplish a mechanical bond when only one part is of thermoplastic material. Common applications include:


Ultrasonic Insertion

Ultrasonic Insertion is a very common technique in Ultrasonic Welding in which metal threaded inserts are embedded into plastic parts. Components that can be ultrasonically inserted include:


The Weld Horn couples directly with either the insert or the thermoplastic part.