To qualify and quantify:
- The formation of the interface between an injected polymer and a composite insert, and;
- The evolution of the residual stress build-up and warpage of the overmolded structure in order to implement these in commercially available numerical design tools.
Keywords: consolidation, stamp forming, overmolding, injection molding, residual stresses, warpage, interface, healing
The overmolding process combines the forming of a thermoplastic composite with an injection or compression molding process. The process allows for complex parts with high structural performance due to the continuous fibers that, in the ideal case, are positioned along the load paths in the part. Further advantages are the high level of function integration, net shape processing, edge finishing and its potential for large series production in an automated process. However, the availability of design tools for the manufacturing of complex parts using the overmolding process is limited. Here, these tools are being developed with the purpose of reducing the development time and cost of a new part.
For a precise prediction of the interface strength and the warpage, the following steps need to be taken into account simultaneously:
- The fiber reorientation and accompanying thickness change during forming are needed for a proper design of the injection mold cavity;
- Both process-induced residual stresses caused by the forming and the injection step are required for a warpage simulation and subsequent compensation of the tool geometry, placement of injection points and the thermal management;
- The formation of a good bond between the injected polymer and the composite part, which determines the ability to transfer stress between the injected structure and the composite part, needs to be known along the entire flow pattern of the injected polymer melt.
- The accumulation of the process-induced stress caused by shrinkage is needed for an accurate strength prediction.
- Interested in application of the developed knowledge? Please contact Sebastiaan Wijskamp.
- New thermoplastic composites materials
- Resin Systems
- Molding Compounds
- Fiber Placement
- Tailored Blanks
- Press Forming
- Welding Technologies
- Metal composite joints