Toyota Uses Semiconductor Laser in New Resin Welding Method

TOKYO ― TOYOTA MOTOR CORPORATION (TMC) announced today that it has developed a more efficient and highly reliable method of welding together resin automobile components. The method, which employs an energy- and space-saving compact semiconductor laser, substantially reduces the use of fasteners, contributing to resource conservation, vehicle-weight reduction and improved recyclability. Commercial application is scheduled to start later this year.

The new process bonds together two types of resin material―one colored with dye that allows the passage of light, and the other colored 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 significantly improving the preciseness of resin component molding and to fully applying the latest measuring technologies.

Moreover, since only modest laser output is required to weld resin materials, a semiconductor laser, with its higher energy-conversion rate and smaller size, is used, instead of a gas or solid-state laser.

Currently, it is common to hold resin parts together using fasteners (bolts, small screws, clips, etc.), adhesives, vibration welding, ultrasound welding and other methods. Compared to these, laser welding provides equal or superior bonding strength and has the added plus of minimal effect from unnecessary vibration or heat. This makes laser welding ideal for bonding electronic and other parts that are vibration- and/or heat-sensitive, as well as for bonding resin parts with complex shapes.

From this fall, 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 introduce this cutting-edge technology to affiliated companies, gradually expanding its use for engine and body parts.