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High Volume Joining of Composites to Metal for Automotive


TWI, along with 8 companies (Nissan, Jaguar, Gestamp, Stadco, Warwich Manufacturing Group, Scott Bader, Granta Design and Far Composites) took part in the Innovate UK funded ‘Lightjoin’ project. The aim of the project was to develop methods to allow the joining of composites to metal in a high-volume manufacturing environment. Nissan’s production process involves this type of high-volume environment, in which one car comes off the production line every minute. A fast production process is essential for companies to maximise profit. This requires each part of the production process to operate as efficiently as possible in order to minimise assembly times. Reliable processes are also imperative to prevent expensive and wasteful rework or part rejection.

Investigation and Findings

TWI investigated techniques to insert carbon fibre floors into Nissan cars, with two specific methods being explored. The first method involved adding the floor after the car body was made by using blind riveting to join the two different materials together using a cold curing polyurethane adhesive. The second method consisted of integrating the floor at the same time as the making of the body, through punching in a steel element before direct resistance spot welding.

Another aspect of the project involved Carbon Fibre sheet, high strength steel and aluminium being validated for high volume production at Gestamp. The advantage of using this combination of materials for the sub-frame is that it results in a significant weight saving while maintaining a very high level of performance.

Production Software Development

An additional part of the project was the production of software by Granta Design, who developed a joining design tool, which permits engineers to select any combination of materials (material type, sheets thickness and orientation of the joint stack). After this, it generates data on the feasibility of the materials for joining in a production line, the predicted cost of the production process and valuable joint performance data.



This project allowed TWI to display and apply their expertise and knowledge on joining technology, while contributing to advances in the car manufacturing process and developing capabilities for future schemes.

Avatar Sullivan Smith Automotive Programme Manager

Sullivan Smith joined TWI Ltd in 2011 where he holds the position of Automotive Programme Manager. Prior to that he was employed by Tata Steel from 1998 through to 2011, working in resistance welding R&D and support for the automotive industry.

Sullivan’s specialization is in resistance welding and mechanical fastening processes. His main tasks have been to provide technical support to the European automotive and general manufacturing sectors. In recent years Sullivan has worked on the joining of dissimilar metal alloys and metal to composite joining, and the joining of electrical connections for EV applications. He is also the UK expert on the ISO standard committees for resistance welding and mechanical fastening.