Rapid manufacturing of woven comingled flax/polypropylene composite structures

Abstract

The use of natural fibre reinforced composites such as flax fibre / polypropylene is in a constant expansion particularly in automotive and marine industries due to their good mechanical properties, low density and thus, lightness, low environmental impact, low cost, recyclability, renewable properties of flax fibres and a minimum energy intake during their process. One of the major challenges of thermoplastic composites for the automotive industry is to manufacture finished parts in a single processing step within a minimum amount of time. For this purpose, a stamping airflow device was specifically developed. It is designed to produce woven comingled composite parts from comingled woven fabrics such as flax/polypropylene in only 200 s. Firstly, preliminary tests and the optimization of processing parameters were performed. Then, a quasi-static mechanical characterization of the formed parts was realized. By using criteria based on mechanical properties, the optimal process parameters such as the level of pressure, temperature, holding time and cooling rate so that to obtain the lowest voids rate were determined. Finally, a comparison of the mechanical properties of parts obtained from using the new manufacturing process and a conventional thermocompression process is presented to demonstrate the interest and the level of performance achieved by this original and fast manufacturing device.