Laser welding rids cars of nuts

The Toyota Motor Corporation claims to have developed a reliable method of welding together resin automobile components using a semiconductor laser.

The new process bonds together two types of resin material – one coloured with a dye that allows the passage of light, and the other coloured with carbon black that absorbs light.

A semiconductor laser is applied to the dye-pigmented material. Light from the laser permeates this material and then sinks into the underlying light-absorbing resin, heating and melting its surface. Heat transfer also melts the forward material, allowing for an exceptionally strong bond, once natural cooling has taken place.

Because this technology involves bonds induced by heat transfer, the two components to be joined must be virtually gap-free when aligned. To achieve this, great efforts were devoted to improving the preciseness of resin component moulding.

From the autumn, Toyota plans to use this semiconductor laser welding technology to make resin intake manifolds, for which strong and airtight bonds are essential, eliminating 13 out of the 14 bolts, nuts and gaskets conventionally used in fastening together a manifold’s structural components.

Toyota will also introduce the technology to affiliated companies, gradually expanding its use for engine and body parts.