plastics joining

We are surrounded by products that are assembled using plastics joining techniques. Tamper proof packages are most often sealed using polymer welding techniques. Almost all pre-packaged food is sealed with a welding process. Synthetic fabrics are seamlessly "sewn" with a polymer welding process and automobile assemblies include many plastic parts -- everything from fuel tanks and taillight housings, to instrument panels and intake manifolds that are assembled by welding. Wherever a thermoplastic item is assembled from a series of molded parts, you can be certain that polymer welding was involved in its assembly.

Creating the Plastics Bond
Fusion bonding or welding of plastics requires the melting of a thin layer of material at the joint interface. Bringing two melt layers into contact allows polymer chains to diffuse across the boundary creating a bond when the two parts are made of the same material. The strength of the weld can approach that of the parent material and avoids the stress concentrations created by mechanical fasteners.

The heat required to melt the thermoplastic for welding can be supplied in a number of ways. Heat can be introduced into the joint area by frictional processes, by electromagnetic excitation, or by direct heating. While some of these heating processes such as dielectric (RF), hot plate, ultrasonic, and vibration welding have been available for many years, new techniques such as laser and friction stir welding are now being developed. Each technique has different advantages and limitations.

EWI's Plastics Welding Capabilities
EWI has equipment on site to evaluate all of the common plastics welding processes. Our staff of engineers and technicians has more than 20 years experience in developing and troubleshooting plastics welding processes for our industrial clients.

Learn more about the strengths and limitations of the most prevalent polymer welding approaches: heated tool, ultrasonic, and laser welding. For help in selecting the best joining option for your plastics assembly challenge, contact EWI.

• Ultrasonic welding
• Heated tool welding of plastics
• Laser welding of polymers