Ultrasonic Welding

Ultrasonic assembly is often used to assemble two injection molded thermoplastic parts.  This method offers many advantages such as speed, reduced costs, and ease of automation. Ultrasonic systems are also used to insert and stake various types of inserts, for spot welding, and for swaging.  Although the parts are typically of the same resin, in some cases dissimilar resins can also be bonded together.  For specifics on this method and for equipment and processing recommendations, we recommend contacting one of the major suppliers of ultrasonic welding equipment.

In designing parts to be joined via ultrasonic welding, extra consideration should be given to the material selection and the joint design to fully exploit the advantages offered by this welding technique.

• Crystalline resins tend to melt and solidify quickly and are thus more difficult to weld than amorphous resins.  Fillers,moisture, many additives, mold release agents, and regrind may all affect the welding process.  
• Although there are several types of joint designs, we often recommend a shear or scarf joint for our resins to achieve a strong seal.  To obtain reproducibility on a production basis, a holding fixture should be used to position the parts.