A Numerical Tool to Aid Design-for-Manufacture of Injection Over-Moulded Composite Parts

Thermoplastic injection overmoulding has the potential to offer aerospace quality components at automotive production rates, but the effective combination of these two manufacturing processes makes component variability a concern. Thermoforming and injection moulding both share complex time, temperature and pressure dependencies, which make overall process optimisation difficult by trial and error. This project will create new design for manufacturing tools that will unleash the full potential of injection overmoulding for the production of composite components. Wider adoption of the injection overmoulding process will help reduce the sector’s dependency on thermosets and offer a more sustainable thermoplastic-based alternative that can be more readily recycled. In addition, injection moulding compounds readily use short fibres (<5 mm), providing a circular economy for thermoplastic composites waste.

Current thermoforming simulation tools are computationally inefficient and cannot be integrated with existing injection moulding simulation tools to model the combined process effects. The influence of the short-fibre injection phase on the integrity of the organosheet insert is commonly overlooked. This project sets to develop new numerical tools that can efficiently support the design and manufacture of overmoulded thermoplastic composites, building upon existing expertise and constitutive models available at the University of Bristol (UoB) and the University of Nottingham (UoN).

A particular emphasis of the project will be to capture the deformation of the oraganosheet throughout the process, starting with the initial thermoforming phase and including the influence of the injection overmoulding phase.

Objectives include:

• To understand the influence of tool temperature and injection pressure during overmoulding on the integrity of a UD organosheet insert
• To investigate strategies to constrain a UD organosheet insert to maintain integrity during injection overmoulding