Francis Arthur discusses a novel manufacturing process to produce lightweight composite components at higher throughput to support sustainable transport initiatives
Composite materials can have huge benefits for the development of new products, offering unique physical and chemical properties that can be tailored to specific applications. The use of composites has significant potential in the transportation industry, making it possible to create a lighter and more durable car, train and aircraft components, such as body panels, doors and battery enclosures. However, the cost of traditional manufacturing methods for these materials, together with the long curing process that they typically involve, has been a key hurdle to the wider adoption of these materials. This article discusses a novel manufacturing process that makes it possible to produce lightweight components at higher throughput to support sustainable transport initiatives.
A Lighter, More Sustainable Future
The manufacturing of lightweight structures in transportation has historically centred around aluminium, mainly due to its strength, weight and recyclability, and also because its widespread availability has made it a cost-effective solution. However, composites can often meet the same technical requirements and provide significant further weight savings – up to 40 % in many cases – due to their low density and high strength and stiffness. Composites are not only volumetrically lighter, but also allow more intelligent design and shaping that result in even lighter, streamlined structures. For example, in traditional pressed or stamped metal parts, the thickness of the sheet is uniform throughout – engineered to the requirements of the highest stress point – but can add unnecessary weight in low-stress areas and may require lightweighting through machining. In contrast, composites allow the thickness and performance of the material to be varied between low- and high-stress zones, moulding components to exactly match the requirements of the application to save unnecessary weight.
Together with excellent chemical resistance and low maintenance, these properties make composites extremely attractive in transport applications, especially electric vehicles, where there is high demand for lighter materials to help meet the growing popularity of this sector. A major contributing factor to the increased weight of electric vehicles is the batteries, which has driven engineers to explore lighter materials in parts such as battery casings. This is an application where composites can offer game-changing solutions over metallic alternatives. As well as reducing weight, composites also provide the opportunity for multifunctional designs in a single component, for example, with the addition of embedded insulation and/or EMI shielding.
Historical Pain Points
Unfortunately, the laborious and costly manufacturing process for composites has been a significant barrier to many companies looking to adopt these materials. The challenge now is to be able to make them more cost effective, and at a rate suitable for more widespread use. Until now, the most common advanced composites manufacturing process has been hand lay-up and autoclave curing, which entails a significant level of highly skilled labour, and results in high quality parts but low throughput. Single parts often take hours or days to manufacture, including lengthy and energy-intensive curing steps. However, recent developments in production processes and automation, as well as the introduction of optimised resin chemistries, mean that this largely manual process has now been transformed into an automated workflow, helping to make high volume composite production a reality.
In The Driving Seat With Innovation
A novel manufacturing technique, which combines snap-cure resins and prepreg materials with press curing, is now allowing composite parts to be formed in just minutes. The process begins with in-house, high speed prepreg manufacture and automated ply cutting. This is followed by moulding using an innovative system called Fast Press Cure, which stamps and cures the material in a fraction of the time previously required for thermosetting materials. The material is then automatically de-moulded, removed and passed onto the final machining and post-moulding processes. This system enables the manufacture of composite components at speed and is cost competitive compared to metallic alternatives. In addition, with an in-house prepreg line, materials can be tailored to each project specification, optimising the material and resin chemistries to provide the required fire, impact, electrical or insulative properties.
Supporting Sustainable Transportation
This innovative process can operate at a cycle time suitable for medium to high volume manufacturing, as well as offering significantly more energy-efficient production than previous methods. This results in decreased production costs with a lower environmental impact. With this streamlined, efficient and cost-effective manufacturing process, composites can reach their full potential in high volume applications and help to support the world’s transition to sustainable transport.
Francis Arthur is the engineering manager at TRB Lightweight Structures