Plastics assembly processes

When manufacturing plastic parts, the aim is usually to produce a complex, multi-functional component in a single operation. However, in order to reduce tooling costs, or to join elements of long extruded products, or to create new functions, assembly is required.

This can be done permanently by bonding or welding, the latter involving a variety of processes: thermal, high-frequency, ultrasonic and laser. For sufficiently thick components, riveting can also be used, as with metals.

Removability can also be ensured by screwing directly or using inserts, and above all by flexible snap-fitting, or even the use of a thin hinge.

Naturally, operational practices differ significantly from those used in metal assemblies.

A priori, several assembly techniques can be distinguished on the basis of whether or not they can be disassembled (table 1 ).