Welding Technologies: Hot Plate

Hot plate welders can accommodate a wide range of part sizes and configurations. These machines offer high-reliability hermetic seals and strong mechanical bonds on complex part geometries.

Hot plate or heated tool welding is probably the simplest yet most versatile plastic joining technique. Its applications vary from small components to large pipelines. The technique involves:

1. Pressing the parts to be joined against either side of a heated plate
2. Removing the plate when the parts are sufficiently molten
3. Pressing the components together and holding them until they are cooled

The heated plates are usually flat, but more complex shapes can be used to weld a three-dimensional joint profile. Welding equipment may be portable for on-site use or fixed for factory use. In either case the heat is usually applied electrically by resistance heaters. The surface of the plate is usually coated with PTFE to prevent the adherence of molten plastic. The main welding parameters are the temperature of the plate, the heating time, the welding pressure and the welding time.

Most thermoplastic materials can be joined using hot plate welding. If the correct procedures are followed, welds with tensile strengths equal to that of the parent material can be obtained.

Hot plate welding is a relatively slow process with weld times ranging from 10 seconds for small components up to 60 minutes for parts with a large joint area.

Typical applications