Modern adhesive technology: a cutting-edge technology in automobile manufacture

Citation

(2007), "Modern adhesive technology: a cutting-edge technology in automobile manufacture", Assembly Automation, Vol. 27 No. 2. https://doi.org/10.1108/aa.2007.03327bab.002

Modern adhesive technology: a cutting-edge technology in automobile manufacture

Modern adhesive technology: a cutting-edge technology in automobile manufacture

Adhesive bonding has become a key technology in the automobile industry and the Bremen-based Fraunhofer Institute is helping engineers and technicians from all over Europe to meet these challenges.

The demands being made of the automobile industry are constantly increasing: the vehicles need to become ever safer and more comfortable, but must also weigh less and have economical fuel consumption.

Such constant progress would not be possible without a highly developed adhesive bonding technology. This ensures that ever lighter materials can be used in the assembly halls and that crash compatibility nonetheless increases.

Corrosion protection and insulation against vibration and noise are further factors that increase the value and life of a car. The German Fraunhofer Institute for Manufacturing Technology and Applied Materials Research (IFAM) provides engineers and technicians from all over Europe with a groundbreaking adhesive technology qualification programme with internationally recognized diplomas. IFAM in Bremen is Europe's biggest independent research and training organization in the field of adhesive bonding technology.

From cylinder head and brake linings to windows, mudguards and tailgate adhesives are being used in more and more sections of the car. A vehicle such as the current BMW 7 Series already contains around 180m of adhesive joins. A car coming off the production lines today contains up to 20kg of adhesive. Every year the entire transport resources sector in the EU uses around 250,000tons of adhesive, and Germany, with 85,000tons, accounts for over 20 per cent of the entire annual production.

Improved crash safety

In the bodywork adhesives, combined with spot welding, are already standard practice for many manufactures. “Adhesive bonding improves the crash properties of the bodywork because it brings an improvement in rigidity of up to 27%” says Eckhard Cordes, Laboratory Director for polymer materials and textiles at the DaimlerChrysler works in Bremen. This plant alone processes 2,500tons of adhesives every year. With adhesive bonding technology the forces are not focused on particular points as is the case with welds, rivets or screws, but instead spread right across the bonded surface. This results in a more even distribution of stresses. Moreover, the material is neither damaged nor deformed by the effects of heat. “Working with the same material strengths, an adhesive bonded bodywork has a significantly higher rigidity than with alternative joining techniques. This enables us to use thinner sheet metals, which in turn reduces weight and saves energy” explains an adhesive bonding technology expert at BMW in Munich who has completed the training as European Adhesive Engineer at the Fraunhofer IFAM.

And there are even more advantages: adhesives can dampen vibrations or noise, insulate heat and prevent corrosion. Moreover, they accelerate production because bodyworks can be adhesively bonded much faster than they can be welded. Because the sheet metal is delivered to the assembly halls with a coat of oil to protect it from corrosion, researchers at Fraunhofer IFAM in Bremen have helped to develop special adhesives. These absorb a large part of the oil so that they adhere reliably to the metal. If required these bonds can be dissolved again, which is a major advantage when it comes to recycling.

A question of the mix

Steel is still an important material in automobile construction, but the development of lighter and simultaneously more stable vehicles is bringing additional materials into the game. “The future lies in an optimum mix of the materials. And here adhesive bonding technology surpasses all other joining techniques because only this method allows very different materials such as aluminium, steel, magnesium, plastic, glass and modern fibre composite materials to be joined without any problems” explains Professor Dr Andreas Gross, the Head of Center Adhesive Bonding Technology at the Fraunhofer IFAM.

The use of adhesive bonding technology is not confined to vehicle bodywork: the greater safety of modern cars is due also to the fact that nowadays the windscreens and rear windows can be glued directly into place. These adhesive joints in the more modern method give the bodywork greater stability than the previously applied synthetic rubber. Moreover, the adhesive bonding technology allows a better window design and the integration of additional functions such as heating filaments and antennae.

Adhesives are also increasingly being used in the assembly of the engine components because they improve the quality of the sealing gaskets. This applies for instance to cylinder head gaskets, elements of the cooling system and the oil sump.

The experts agree that in the future adhesives will gain even more importance. “The combination of high- stability steels with other materials such as plastics or aluminium is becoming ever more important in bodywork construction, in order to make the car lighter and more stable. Adhesive bonding technology is a good method for achieving this” says the BMW adhesives expert. His colleague Eckhard Cordes at DaimlerChrysler states that up to 20 times more adhesives will be used in his company's upcoming compact series. In both companies the adhesive engineers are trained in line with the IFAM qualification concept.

“What will really determine whether adhesive bonding technology can develop its full potential in the future is the competence of the people who use it. This is because success can only be assured by proper expert application from the choice of adhesive to its proper use with the materials at hand. In our IFAM qualification programmes we enable planners, decision-makers and practicians to acquire truly up-to-date knowledge, combining research results with practical applications. In this way, the companies can profit from the latest developments in adhesive bonding technology” says Professor Dr Andreas Gross.

Further information at: www.bremen-bonding.com