Additive manufacturing for replacement parts for Volvo cars equipment

Sammanfattning: During this master thesis project, various polymer materials have been studied in relation to additive manufacturing. Additive manufacturing is a 3D printing process that has facilitated the productivity of the company, Volvo Cars. The printing process is based on a design conceived from CAD software. The final design is sent in digital form to the printer from which the prototype is built, layer by layer, until the finished product is finished. This thesis project analyzed which polymers would work the best in Volvo’s car industry as to durability and sustainability. A limited number of polymers were chosen for investigation, some also with various additives to change the microstructure and properties. The tensile strength of the polymers was tested, yielding their Young´s modulus. Tests were also performed to measure the wear resistance of the samples. The design of the samples was decided to be a circular disk. The reason behind was that the samples should not be too thin or have a too complicated shape, the inner structure being solid. The primary data were the possible changes in thickness. These samples were afterwards examined under a stereo microscope in order to obtain a 2D image of how the surface had changed. From all the polymers investigated, the tensile tests showed that PA12 CF(polyamide 12 carbon fiber) had the best strength as it contains carbon fibres which stabilizes the material. However, as for wear resistance the polymers PC (polycarbonate) and TPU( thermoplastic polyurethane) could handle more punches before they fractured. PC has the advantages of being very strong, due to very strong bonds between the atoms within the polymers chains, and at the same time constituting a very flexible material. TPU is also a very strong and flexible material, and it has the extra advantage of being suitable for large components. Considering these aspects, these three materials are selected as efficient and suitable for making mechanical components. As a result from this very investigation, they are recommended for making prototypes or components that have good strength and wear resistance.