When designing plastic parts to be assembled by ultrasonic welding, engineers have several options: a butt joint, a step joint, a tongue-and-groove joint, and a shear joint. Which to choose depends on many factors, including the materials; the size and rigidity of the parts; and performance requirements, such as joint strength, cosmetics and leak-tightness.
“It all depends on what the end-product needs to be,” says Stephen Potpan, product manager for Rinco Ultrasonics USA. “Does it need to be hermetically sealed? Or does it just need to be strong and not come apart?