Designing 'Custom-Fit' products
Few technologies have impacted product development as much as layer manufacturing techniques (LMT). Using this method, manufacturers are able to form a product by adding material in layers rather than removing it, for example through milling. The EU-funded project Custom-Fit is seeking to create a fully integrated system for the design, production and supply of individualised products using 'rapid manufacturing technologies'. Within such a system, products made with graded materials could be put together during a single manufacturing process. The products resulting from LMT can be distinguished by their multi-material and graded structure, which improve mechanical structure. As with most manufacturing technologies, the process is highly automated, drawing upon computer-aided design (CAD). The Custom-Fit team has designed three different systems for producing products with graded structure, using three different types of software. According to Lieve Boeykens from the company Materialise, who is leading software development in the project, each of these systems is very unique: 'These are very strong products. They may be lighter in terms of data size, but they are able to define the graded structure and deposit the material properly. It is not just our partners in the project who will benefit from these developments; eventually other market players will be able to use the same software too.' The three different software designs are as follows: - InnerSpace, designed by TNO (the Netherlands), allows the designer to define material property distributions as well as the distribution profile. The software can be used to define the material distribution for the whole object or just part of the object. - MultiPhase Topology Optimisation, designed by IFAM (France) is a numerical simulation technique that is able to determine the optimum distribution of two or more different materials in components under thermal and mechanical loads. It seeks the optimal spatial distribution of several different materials in order to achieve maximum stiffness. - Finite Element Analysis (FEA), designed by Materialise (Belgium), is able to define a geometric model that comprises a large number of small scale volumetric elements. Each element can carry as many properties as the designer wishes to define. It also enables the designer to define the material deposition within the object. Together, the Custom-Fit team is using the software to design a range of products, including implants, prostheses, helmets and seats. The next step is to manufacture such products, and to interface the new software with existing manufacturing machines.