Compression moulding of LFT components with increased quality by variothermal mould technology

For the production of composite components made of long-fibre reinforced thermoplastics (LFT) the economic compression moulding process is well established. However, the low temperature of the compression mould during processing leads to a significant increase in both the material viscosity and in the compression force in particular for thin-walled components. In addition, low surface qualities result which prevent the application of such components in visible areas. To overcome these disadvantages, a variothermal compression moulding process has been developed at the Institute of Plastics Processing (IKV) at RWTH Aachen University. With the variothermal mould technology a reduction of the viscosity of the moulding compound during processing is achieved. This results in a reduction of compression force by about 60 %. Additionally, moulding compounds with higher fibre contents (up to 60 % by weight) can be processed and the surface quality of LFT compression moulding components can be significantly increased for the application in visible areas. This paper describes the functionality of the variothermal mould technology and its efficiency for the process of LFT compression moulding. Results of investigations regarding the influence of the mould temperature on the process properties and the component properties are presented and discussed.