Current research on additive manufacturing at the University of Surrey includes fabrication at a range of length-scales, from the micrometre and millimetre scales for printed devices, to more than a metre for metallic aerospace components.
The range of materials being explored includes nanomaterials, polymers, ceramics and metals, often used in conjunction with each other.
Additive manufacture (AM) is a disruptive technology; it offers unique opportunities for producing new components, structures and products. These products potentially offer better properties, novel design opportunities (via topological optimisation), shorter lead-time and reduced environmental impact.
Additive Manufacture includes a broad range of methods that are currently undergoing rapid development. The term is arguably preferable to the popular term ‘3D printing’ in that many conventional manufacturing processes are ‘subtractive’ in nature.
The term is therefore a reminder that additive processes, as opposed to subtractive ones, can enable more complex and structurally efficient shapes to be manufactured.
Large-scale metallic additive manufacture
The current focus of large-scale AM research at the University of Surrey is on the manufacture of metallic alloys by additive processes includes a variety of laser and arc-based processes. In the former case, a fine powder is the pre-cursor, and in the latter, a wire is normally used. We are exploring the metallurgical issues encountered in both areas, with a view to improving structural integrity and establishing appropriate structural certification.
In one project, the Department of Mechanical Engineering Sciences is working with the Surrey Space Centre and Frazer-Nash with the goal of space certifying additive manufactured satellite components. The process used in this project is Selective Laser Melting (SLM) as it offers good tolerance and reasonable surface finish. SLM is a relatively slow process as a component is created, or built, by adding layers of a few tens of micrometres at a time.
Other work is underway with other industrial partners, including Lockheed Martin UK, to produce very large components for aerospace applications. For large components (metres by tens of centimetres), a wire and arc process is used. This process is closely related to MIG welding but requires robotic automation. With this approach up to around 10 kg of material can be deposited per hour. Such a process brings a range of issues centred on stress build-up and metallurgical issues. These aspects form a major part of the current research work at Surrey.
Direct write of structural devices
Additive manufacture of functional materials at micrometre length scales is leading to the creation of novel microscale functional devices for sensing and energy harvesting. This work forms a pivotal part of Surrey's research on functional materials and devices.