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Optimization of joining processes for new automotive metal-composite hybrid parts

Final Report Summary - METALMORPHOSIS (Optimization of joining processes for new automotive metal-composite hybrid parts)

Executive Summary:
MetalMorphosis aims to develop a new range of novel metal-composite hybrid products for the automotive industry, based on the knowledge transfer from the Electromagnetic Forming (EMF) usage in joining dissimilar metal products and taking advantage of new developed composites and its capability to be bonded to metal.
MetalMorphosis approach is to combine and involve all the main players – Top-down and bottom-up in the value chain – from the automotive industry in the development of the next generation of metal-composites hybrid materials, ensuring a strong contribution from industrial drivers (towards those which are industry’s main needs in what concerns to automotive parts), an active involvement of SMEs (in the manufacturing of pilots / demonstrators), a valuable participation from RTD’s (performing research activities in multidisciplinary key knowledge areas and defining the drive beyond the state-of-the-art) and – last, but not the least – a major role to be played by multipliers organizations who will ensure the exploitation of projects’ main results towards the automotive market and other linked sectors.
MetalMorphosis gathered a wide – but simultaneously specialized and multidisciplinary – consortium composed by 9 European partners, according to their expertise areas – Welding and joining technologies, Composites, Industrial Manufacturing and Automotive OEM – which have strong interest in developing new joining processes for metal-composites and lightweight materials addressing the challenges for the automotive industry for the following 10 years.

Project Context and Objectives:
The overall aim of the project “MetalMorphosis” is to develop a range of novel metal-composite hybrid products for the automotive industry, using the new and innovative new electromagnetic pulse technology, which is highly suitable for joining dissimilar metal products. Its application range will be extended towards joining of composites and metals.
The joining technology uses pulsed electromagnetic forces to contactless deform and/or join workpieces. This process also offers the possibility to join material combinations, which are difficult or impossible to join using conventional processes. Electromagnetic pulse joining is an automatic process and is already used in the automotive industry for joining metals, due to its specific technical advantages; among which its high repeatability and the fact that it’s a cold joining process (it does not use heat but pressure to create a joint). Moreover, the process is also much more environmentally friendly compared to conventional joining processes.
Composites offer the possibility to achieve impressive weight reductions for the next generation products. Composite production processes and materials evolve quickly to fulfil the needs of a diverse range of industries, from established markets such as sports and aerospace, over fast growing markets such as wind energy, to markets such as infrastructure, consumer products and automotive, where composites now increasingly penetrate, replacing traditional construction materials.
However, an often overlooked design and production problem of composites is getting the load into the composite structure. Mechanical joints (bolting, riveting) are reliable and widely accepted, but they create local stress concentrations which reduce the strength of the composites by as much as 50%, enough to eliminate the envisaged weight gains in many designs. Bonded joints are effective, but require very secure engineering, clean production environments and well-trained personnel to ensure reliable joints. Moreover, companies, and especially SME’s, lack the skills to design and produce reliable bonded structures.
The project goals can be described as follows:
• Development of new joining processes for composites and metals, for sheet and tubular applications.
• Knowledge about the properties of the joined materials and workpieces (strength, ductility, microstructure, ...) and concerning the applicability.
• Demonstration that the electromagnetic pulse technology is a valuable alternative for realising high-performance joints.
• Increased productivity and cost reduction for hybrid components by using these advanced techniques: joining operations are performed faster and more efficient and robust, so more economic, due to a less expensive production process and a better guarantee of the quality.
• Coping with the requirements of environmental compatibility: it will be possible to produce in a more environmental-friendly way.
Considering the technology assumptions and composite’s identified potentials, all conditions have been brought together to research new joining methods for composites with metals in order to develop specific automotive parts that match automotive market challenges.

Project Results:
By the end of the project more than 800 experiments were performed in order to obtain the best geometries, joint designs and process parameters to produce hybrid parts. From each of these experiments, several composite parts from different materials with different fibers were produced, each of those parts was characterized by different approaches, namely active thermography. Then the parts were tested in EMJ process with different parameters and finally the hybrid parts were characterized by non-destructive and destructive analysis.
The demonstrators’ were concluded successfully with the developments of new hybrid shock absorber, brake pedal and bumper.
Joints experiments were investigated using different joining concepts to acquire generic knowledge regarding the feasibility of the joining concepts. Several crimping experiments and subsequent characterization of the joints, were realised and the most successful joints for each joining concept and each composite material were investigated providing the definition of the most successful joints.
The optimal parameter settings and the parameter windows to obtain the most successful joints for each joining concept and each composite material were found.
The feasibility proof of magnetic pulse welding (MPW) and EMR high velocity electromagnetic accelerated self-piercing riveting (EMR) for joining composite- metal hybrid sheets was an important achievement because the processes extend the limited number of joining processes for such parts. For the EMR, no equipment exists, which delivers 1 kJ at 1 Hz repetition rate and this created the motivation and the theoretical basis for a new EMR equipment development.
Knowledge was gathered to integrate the individual process steps into one manufacturing process chain. The specifications for an efficient process chain were identified, including the required innovative process steps enabling production of demonstrators through EMJ/EMF.
It was demonstrated that the MetalMorphosis approach has lower impacts on each of the analysed indicators. The LCCA (Life Cycle Cost Analysis) highlighted the innovative method performs very well specially for the brake pedal demonstrator, mainly due to the labour consumption for steel processing operations.
Three selected demonstrators were developed and manufactured according to function, requirements and design. A comparison between the conventional components and the manufactured demonstrators was made in terms of component properties, joint quality, performance and productivity (cost). All three demonstrators achieved important weight decrease when compared with traditional components. The performance results achieved were quite good and can still be further improved. A cost-benefit analysis was also made for the demonstrator parts and for all three demonstrators a significant cost reduction per part was achieved.

Potential Impact:
The project proved through demonstration that the electromagnetic pulse technology is a valuable alternative for realising high-performance joints.
A performance improvement on joints of the specified material combinations, compared to the reference technology was achieved through the development of new joining processes for composites and metals, for sheet and tubular applications.
Advanced knowledge about the properties of the joined materials and workpieces and concerning the applicability was achieved through finite-element simulation models of the considered electromagnetic joining processes, with sufficient accuracy.
The manufacturing of hybrid components without degradation of the composite material can be achieved. Final metal-composite hybrid products with no impureness or imprint on the workpieces’ surface are possible to be obtained, as no mechanical contact between the tool coil and workpiece takes place.
An increased productivity and a reduced Life Cycle Cost of the products and cost reduction for hybrid components by using these advanced techniques can be attained due to a less expensive production process and a better guarantee of the quality and this was demonstrated.
The developments of the technology within the project cope with the requirements of environmental compatibility: it is possible to produce in a more environmental-friendly way.
The project can enable companies to manufacture new or complex products based on metals and composites, with an increased productivity and cost reduction by using these highly innovative joining techniques. Joining operations will be performed faster and more efficient, so more economic, due to a less expensive production process and a better guarantee of the quality. Finally, the project will make the process specific advantages directly exploitable in industrial manufacturing for metal-composite components.
MetalMorphosis project was designed to match automotive market new trends and demands. Its development and implementation will allow reinforcing European competitiveness in this industry, regarding the fierce competition from emergent markets.
A broader use of composites will be possible using the electromagnetic pulse processes, on the condition that the necessary requirements concerning strength, fatigue, or other aspect can be achieved. Based on the scientific results, the application field of the joining technology, especially in the field of lightweight products, can be extended, because it will be possible to join them more effectively to other materials and components. This will help the targeted SME’s to broaden their market and to develop new innovative products.
The project will, therefore, open a new window of opportunities for European enterprises for the design and manufacturing of new lightweight hybrid components, by validating the electromagnetic pulse joining technology application for joining metals to composites and by developing a repeatable, trustable and affordable process which will allow SMEs to face new challenges related to the automotive demands for lightweight materials.
The need for products composed of dissimilar materials with different properties is a big market trend and these materials must be joined in effective ways. International trend reports in several important industrial sectors such as Automotive and Aeronautics show the importance of this new range of products. The continuous need for weight reduction and fuel economy are great inducers for the combination of the best properties from different materials (metals and plastics) into single hybrid parts/components raising a huge market opportunity that the major suppliers are craving for.
Regarding dissemination activities there were published several references to Metalmorphosis in newsletters and magazines, in several countries. A project website was also developed being the primary support for dissemination and promotion.
The consortium published five newsletters along the project promoting the project results. The newsletters are available through the Metalmorphosis website. A project brochure was also produced with information about the project. The brochure was distributed in public events promoted by the partners, for instance in the demonstration workshops.
The consortium also produced a promotional video illustrating EMF technology applied to hybrid parts in order to disseminate the technology and addressing to the project results and the consortium capabilities. This video is available in the website and was showed in public presentations.
A collaborative platform was also developed to support project management being also an important tool for internal promotion and a Linkedin Metalmorphosis Group was created providing opportunity for social dissemination and interaction among interested in the project areas.
As exploitable results, the complementarity of competences and capabilities of each partner allow to offer an integrated offer to the potential partners, users or customers as an integrated service. The three demonstrators developed in the project are also exploitable results and a new Electro Magnetic Riveting – EMR equipment.
As the first exploitable result, the consortium decided to present to the market an integrated service that covers all the value chain from design to hybrid metal-composite products. Currently there are no available services supported on the use of composite/metal materials joined by EMJ Technology.
The second exploitatable result is a Monotube Shock Absorber, mainly developed by the end-user Tenneco. The advantage sought was to reduce the shock absorber weight and simplify the production process. The innovation of the hybrid shock absorber is the use of multiple materials in order to reduce weight.
The third exploitable result is a Hybrid Brake Pedal, led by TOOLPRESSE, a Portuguese SME, consisted in the development of a hybrid brake pedal, composed by two composite parts connected by an aluminum tube. The combination of material allows to comply with the bending requirements of the part. The use of new materials allowed to rework the pedal geometry obtaining a safer parts without sharp edges.
The fourth Exploitation Result is a Hybrid Crash Absorber (bumper) led by Regeneracija. The bumper is a safety system used to observe the low speed collision and is traditionally made in steel. The new hybrid crash absorber combines composites with aluminium that allows joining all the composite parts, making it easy to replace and maintain all the features of the traditional crash absorber. By using different composite parts is possible to have simple geometries that make the production process much easier.
The fifth Exploitation Result is a new EMR equipment. This key exploitable result competitive advantage is based not only in the equipment but also in a deep knowledge of the process namely in aspects such as the identification of process parameters to be optimized. For the EMR up to now, no equipment exists, which delivers 1 kJ at 1 Hz repetition rate. This was the particular motivation and the theoretical basis for the new EMR equipment development.

List of Websites:

Metalmorphosis Management Bureau
Zona Industrial, Rua da Espanha Lote 8
2430-028 Marinha Grande
Phone: +351 244 545 600
Fax: +351 244 545 601