Adhesive bonding technology Adhesive bonding in transportation construction Intelligent solutions for transportation construction
Content New opportunities in 1 transportation construction Reliable bonding in 3 transportation construction Customised development 4 stages for optimal solutions Customised systems for 5 production! Figures on title page: (from left to right) Sealing an airbag control unit: The robot moves the component under a fixed adhesive nozzle (Photo: Reinhardt Technik GmbH & Co., Kierspe) Thick-film bonding: Bonding polycarbonate and aluminium Structurally bonded polycarbonate windows and rows of seats in a high-speed single-hulled ferry (Photo: Henkel-Teroson GmbH, Heidelberg. Shipbuilder: Fr. Lürssen Werft, Bremen) Fraunhofer-Gesellschaft (FhG) Research partner for industry The Fraunhofer-Gesellschaft is the leading organization for institutes of applied research in Europe. It currently operates 56 research institutes and employs about 11,000 people at various locations throughout Germany. Most of the annual research budget of about 900 million euros is directed at contract research for both private industry and public sector. The results of this research make a key contribution of safeguarding the position of industry in Germany. IFAM expertise and know-how Adhesive Bonding Technology and Surfaces Expertise and know-how The Fraunhofer Institute for Manufacturing Technology and Applied Materials Research Adhesive Bonding Technology and Surfaces (IFAM) is the largest independent research organisation in Europe in the area of industrial bonding technology. More than 90 employees are actively engaged in research and development work, with their goal being to develop applicationorientated bonding system solutions for industry. Multifunctional products, lightweight construction and miniaturization realised by intelligent combination of materials offer new opportunities and IFAM has the knowhow to bring these to fruition. The work of the institute extends from fundamental research through to manufacturing and on to the market introduction of new products. Industrial fields of application are in plant engineering, vehicle manufacture and micro-assembly and in the packaging, textile and electronics industries. The business field Adhesive Bonding Technology is principally concerned with the development and characterization of adhesives, with the constructional design of adhesive bonds and with their realization and qualification. Another key area of work is the provision of certified training courses and follow-up courses in the area of bonding technology. This is so because appropriate, timely and competent staff training is becoming ever more important for technology transfer. The business field Surfaces is divided into plasma technology and coatings technology. These areas are concerned with the pretreatment of the surfaces of the materials which are used. As a result, additional properties are conferred on the materials which enables them to be used in other areas of application. A field being worked in by both areas is Surface and Interfacial Analysis. The fundamental knowledge being obtained here guarantees the reliability of adhesive bonds and coatings.
New opportunities in transportation construction The properties of the most suitable materials are optimally benefited from in the light-weight design. The combination of these materials results in significant advantages for both manufacturers and users at many levels. When different materials are combined with each other their different expansion properties can cause problems. The elasticity of bonded joints is an invaluable asset here. Greater efficency, lower costs Modern light-weight design has revolutionised transportation construction over recent years. Regardless of whether we are talking about ships, aircraft, cars or rolling stock, the use of the best available materials has resulted in significant improvements to weight, safety and comfort. At the same time, cost-savings have been realised. This has been possible due to the intelligent application of modern bonding technology. This has allowed the bonding of hitherto unrealisable combinations of materials in transportation construction, for example, the bonding of glass with steel, aluminium with magnesium and the bonding of fibre-reinforced composite materials with metal. Additional functions can also be incorporated via the adhesive, for example vibration damping, electrical insulation and corrosion protection. These extremely flexible bonding techniques have also resulted in a significant increase in vehicle rigidity. Today, adhesive bonds are able to meet the highest requirements and can be excellently combined with mechanical joining techniques such as clinching, riveting, screwing and also spot welding. (top) Lightweight construction of a rail vehicle: Strengthening a steel framework construction using elastically-bonded prefabricated GRP lightweight structures and bonded window elements (Photo: ADtranz) (bottom) High-speed single-hulled ferry (Photo: Fr. Lürssen Werft, Bremen) Optimal solutions IFAM develops suitable solutions for bonding applications in transportation construction based on the individual requirements of customers. The reliability and long-term behaviour of the bonded joint are central aspects of the development work. Taking into consideration all boundary conditions, the bonded joints are designed following an intensive process such that in addition to providing improvements for the production and for the use of the vehicle there are also clear cost-saving benefits. Adhesive bonding technology Adhesive bonding in transportation construction 1
Reliable adhesive bonding in transportation construction Rubber-elastic adhesives are used in the construction of ships, rolling stock, utility vehicles and cars. In shipbuilding, for example, panes of polycarbonate are bonded to the aluminium outer structure. Elastic-plastic adhesives are used in chassis construction and in aircraft construction. Efficient joints Bonded joints must comply with strict requirements in transportation construction. They have to bear loads over a long period of time and must be able to withstand strain and motion. Bonds should also be as resistant as possible to changes caused for example by humidity or operating media. In addition, they must be designed to be resistant to fatigue caused by alternating mechanical stresses. In order to create a highly effective joint, appropriate pretreatment of the surface, optimal engineering calculations and design of the joint and correct application of the adhesive are hence vital, in addition to selection of the right adhesive. (top) The material testing laboratory tests bonded joints developed for special applications. The shear tension resistance samples show an elastic thick-film bond that joins polycarbonate and aluminium and is used in shipbuilding. The pretreatment of the surfaces is carried out with the industrial applications in mind. The pretreatment processes can be automated for series production without problems. Contact person Surfaces: Dr. Guido Ellinghorst Telephone +49 (0) 421 / 22 46-4 99 E-mail eh@ifam.fraunhofer.de! Investigation of new construction methods for rail vehicle construction. The sample component was affixed using rubber-elastic and elastic-plastic adhesives. Project realization in cooperation with Siemens AG (Transportation Systems, Train Engineering). The project was funded by the Bundesministerium für Bildung und Forschung BMBF (Germany Federal Ministry for Education and Research) under 03N3084. Surface pretreatment The surfaces play an important role in the bonding process. Appropriate pretreatment can sometimes confer additional properties on the surfaces. They can for example be cleaned and activated so that there is improved adhesion for lacquers, paints or adhesives. An example is the wet chemical treatment of aluminium for aircraft construction. This considerably improves the long-term behaviour of bonded joints. A key aspect in the design of bonded joints is the behaviour of the adhesive to coatings, plastics, metals, glass or ceramic materials. The IFAM Business Field»PLATO Plasma Technology and Surfaces«has extensive know-how on these matters. (bottom) Nozzle assemblies of an atmospheric pressure plasma unit for cleaning, activating and coating surfaces in continuous in-line operation. Adhesive bonding technology Adhesive bonding in transportation construction 3
Customised development stages for optimal solutions The trains of today contain far less iron than they once did. Aluminium, glass and fibre-reinforced composite materials are bonded onto the framework structures of local trains. Bonding technology is also used in key areas on Intercity Express trains (ICE) and Transrapid trains. The interplay of simulation work and verification by load testing is based on proven methodology. Engineering calculations and design The central feature of the services offered by the Fraunhofer IFAM for adhesive bonding in transportation construction is optimum design of the bonded joint in accordance with the specific needs of the customer. If the requirements are known, the best possible joint is identified following a series of harmonised development stages. The design starts with a decision: whether to select a highly flexible, rubber-elastic adhesive or opt for a more rigid, elastic-plastic adhesive. The strength of the bonded joint is determined in tests: What forces have to be applied to destroy the bond? The nature of the bond break yields further information for the design. With a»cohesive break«the damage occurs in the bond layer, meaning that the strength of the adhesive is decisive for the strength of the joint. With a»boundary layer break«, the failure occurs in the thin boundary layer between the bonded component and adhesive, which is only a few thousands of a millimetre thick. Numerous tests are carried out to determine the failure behaviour under different conditions, for example at different temperatures. The so obtained information defines various failure criteria and allows computer simulations to be carried out which identify critical zones socalled hot-spots. (top and bottom) Bonded joint of a steel-sandwich base plate used in shipbuilding (Bondship- Project Jos. Meyer-Werft, Papenburg) Contact person Design: Dr. Markus Brede Telephone +49 (0) 421 / 22 46-4 76 E-mail mb@ifam.fraunhofer.de The combination of simulation work and the verification by load testing allows the limits of a joint to be ascertained. This methodology results in the design of a bonded joint that is tailored to withstand the required strains and stresses and fully meets the requirements of the application. The composition and geometry of the joint components and the production conditions are also taken into account here. 4 Adhesive bonding technology Adhesive bonding in transportation construction
Customised systems for production Airbags are vital for personal safety. In order to prevent malfunctioning for example late activation the sensitive electronics must be efficiently and lastingly protected against external influences. The hermetic seal on the housing, that consists of three different materials, is realised using an adhesive the bonding of these seals is carried out several thousand times a day in the series production. Contact person Production Planning: Dipl.-Ing. Stephan Kim Telephone +49 (0) 421 / 22 46-5 25 E-mail kim@ifam.fraunhofer.de Contact person Manufacturing Technology: Dipl.-Ing. Manfred Peschka Telephone +49 (0) 421 / 22 46-5 24 E-mail pe@ifam.fraunhofer.de Production and application Besides optimum calculation and design work, the development of an efficient bonded joint also requires diligent production planning involving reliable pretreatment and application technologies. As a provider of a full range of services for bonding in transportation construction, IFAM is also able to offer extensive know-how in these areas. The stages of the production process are simulated with the help of Computer-Aided-Production- Engineering (CAPE). Taking into account all relevant parameters such as working space considerations, accessibility, cycle times, etc. and the ease of changing these in the simulation gives early feedback for the real processes. These advance investigations allow economic decisions to be made about the degree of automation for the subsequent production process. The individual, customer-specific designing of this process as a result of the detailed production planning carried out at IFAM leads to customised solutions and avoids flawed development work. This also applies for the application of the adhesive. The unique physical properties of each adhesive necessitate appropriate treatment and processing. Based on the key parameters elucidated from the process and adhesive development work, IFAM identifies a selection of the most suitable plant components from the large range on offer for example mixing systems, pumps or drives. These are then tested under industrially relevant conditions. Here, IFAM offers individual, modular structured concepts that yield an optimal result. (top and centre) Digital Engineering IFAM development»adhesive Analysis V1.0«for computer-aided gap-size determination using as an example the landing flaps in aircraft construction (here: optically measured CFRP - panel and reinforcing rib). The relevant data from the system is used for off-line programming of the robots so that the application of the material can be carried out in an automated way. (bottom) Manufacture of hatchbacks for compact cars: controlled, speed-proportional adhesive application (Photo: Reinhardt Technik GmbH & Co., Kierspe) Adhesive bonding technology Adhesive bonding in transportation construction 5
Further information is available on the business fields: Adhesive Bonding Technology Plasma Technology and Surfaces. IFAM Fraunhofer-Institute for Manufacturing Technology and Applied Materials Research Adhesive Bonding Technology and Surfaces Institute director: Prof. Dr. Otto-Diedrich Hennemann Wiener Straße 12 D-28359 Bremen Telephone +49 (0) 421 / 22 46-0 Telefax +49 (0) 421 / 22 46-4 30 E-mail ktinfo@ifam.fraunhofer.de Materials Science and Engineering Head: Dr. rer. nat. Markus Brede Telephone +49 (0) 421 / 22 46-4 76 E-mail mb@ifam.fraunhofer.de Further information: http://www.ifam.fraunhofer.de