TWI Industrial Member Report Summary 85/1979
By S A Westgate
The joining of aluminium alloy sheet has received an increasing amount of attention in recent years particularly in the motor industry. This stems from the desire to reduce vehicle weight and obtain improved fuel economy. Weldbonding is a combination of resistance welding and adhesive bonding which offers the potential for improved static and dynamic joint strength, joint sealing and vibration damping compared to resistance welding alone. Emphasis is therefore placed on the use of this technique for commercial quality work in mass production industry.
The various aspects of the technique which have been reviewed are: material surface preparation, adhesives, weldbonding procedures, mechanical properties, quality control and nondestructive testing. The types of adhesive which are considered are mainly heat cured vinyl plastisols and epoxy resins. The viscosity of the adhesive determines the ability to weld through the glue line and a long pot life is an advantage. Although surface preparation is critical for optimum adhesive bond properties, some of these adhesives produce reasonably strong and durable joints even with lightly oiled material.