Effect of processing parameters on quality and strength in thermoplastic composite injection overmoulded components

Traditional manufacturing processes for pre-consolidated continuous fibre thermoplastic laminates (organosheets) offer excellent mechanical properties but are limited by geometrical design. The integration of an injection moulding stage to an organosheet thermoforming operation allows for the manufacture of combined short and continuous fibre reinforced composites that benefit from high intrinsic mechanical properties, geometric complexity and low production cycle times. This study aims to understand the effects of the processing parameters, specifically, the organosheet pre-heating temperature, holding pressure and clamp force on the yarn deformation, fibre orientation, void content and organosheet matrix displacement in carbon fibre - Polyphenylene Sulphide (CF-PPS) ribbed plates manufactured via injection overmoulding. The bonding of the ribs to the woven fabric organosheet is evaluated by rib pull-off tests using a custom-designed clamping fixture. The holding pressure profile and clamp force predominantly affect the yarn deformation, whilst the pre-heating temperature influences the bonding between the overmoulded ribs and the organosheet plate. The results also suggest that for pressed organosheets (with no overmoulded short-fibre material) the quantity of matrix material displaced from the organosheet increases with clamp force and pre-heating temperature.