Use of adhesives in automotive require in-depth material, design, manufacturing & engineering knowledge. It is also necessary to understand functional requirements. For perfect and flawless adhesive joinery, the exact quantity of adhesive, its material composition, thickness of adhesive layer, substrate preparation methods for adhesive bonding, handling and curing time of the adhesive have to be studied & optimized.
This paper attempts to describe different aspects of adhesive bonding in automotive industry to include: Selection of adhesives based on application and design of the components, surface preparation of adherend, designing of adhesive joint, curing conditions of adhesives, testing and validation of adhesive joints. Emphasis was given to study & verify the performance of different adhesive joints to meet end product requirements.
Samples were prepared with a variety of adhesive and adherend combinations. These combinations were tested for tensile, single lap shear, T-peel, flexural & fatigue tests according to standard testing methods. Since the performance of the adhesive depends upon weathering parameters, the test samples were also subjected to mechanical testing after conditioning them under extreme temperatures, exposing samples to fuels (diesel, petrol) & oils (gear oil, axle oil) to develop the confidence on performance of the part and to simulate actual field conditions. This material level data generated in lab is used for 1) Selection of adhesive 2) Optimize the adhesive curing parameters, based on manufacturing practice 3) Carrying out design modification to get desired level of adhesive strength 4) Inputs for carrying out crash / NVH CAE on vehicle level.