Adhesives in the automotive industry

Thanks to innovations in adhesives, “adhesive-bonded cars” are safer and more economical than their forerunners. Adhesives have taken over many of the functions of traditional welding in the automotive industry.

For instance, in 2001, around 10 metres of adhesive bond-line were used for the body of the BMW 7 model; today about 15 times that amount is used. Modern adhesives have enabled automotive engineers to reduce spot welding by about 50%. Today about 9% of total annual adhesive production worldwide is used in vehicle construction.

Today a car contains up to 18kg of adhesives – and for good reason; crash tests have demonstrated that “adhesive-bonded cars“ do better than “welded“ designs. One important factor is that adhesives do not affect the substrates used in assembly, whereas other mechanical fastening techniques including welding, riveting or bolting can affect the rigidity of assembly materials.

Automotive engineers design car bodies to ensure that as much impact energy as possible is transformed into deformation energy, rendering it harmless. In the event of an accident, adhesives behave like a “buffer“ and “crash resistant” adhesives contribute towards ensuring maximum protection for passengers.

However, enhanced safety is not the only benefit of adhesives in vehicle production. When doors are welded, the outside is laboriously reworked to ensure a good finish. Glue-bonded doors, however, do not need reworking, resulting in lower production costs.

The windscreen must withstand powerful stresses (imagine the head wind when driving down a motorway at high speed) and advanced high performance adhesives ensure that it not only remains perfectly in place in the frame but also adds to the rigidity of the car body. And in case of a crash the windshield supports the passenger airbag thus significantly contributing to the safety of the passengers. These adhesives guarantee perfect “hold” in all extreme weather conditions - wind, rain or hailstorm, blistering summer heat or bitter frost in the winter. Directly bonded front and rear screens deliver lower air resistance too, providing a further bonus of reduced fuel consumption.

For modern cars, manufacturers use a range of materials including sheet metal, glass, rubber and plastics. Adhesives are the ideal solution for bonding this composite mix of materials.

Adhesive use is not limited to automobile production but is widely used in other vehicles too. A typical railway carriage, for example, built between 1981 and 1993 used 10kg of adhesive; today some modern carriages weigh in with up to 500kg of adhesive – an increase of 5000%! While modern airliners such as the Airbus and Boeings use adhesives to bond up to 50% of the assembly.

With kind permission of: www.feica.com