25th September 2017
Hexcel’s HexMC®-i molding compound and HexPly® carbon fiber prepregs have been selected for an innovative high-rate manufacturing process demonstrator produced through a collaboration with Cranfield University and Metisse Motorcycles. The project displays a new rapid production process for the high-rate manufacturing of structural components with the demonstrator part being produced in under three minutes.
Cranfield University’s Aurele Bras and Andrew Mills developed the process for the rapid production of lightweight carbon fiber parts as part of an EPSRC funded project run by CIMComp. Hexcel, Cranfield and Metisse Motorcycles then collaborated on a composite demonstrator to validate this unique process and its benefits within high-rate manufacturing applications such as Automotive.
An aluminum footrest bracket was chosen as the component with all parties working together to optimize the part design for composite production. A detailed stress analysis, steel tooling design and fabrication were carried out before arriving at a finished prototype that was over 50% lighter than the original component. Hexcel’s HexMC®-i molding compound with HexPly® carbon fiber UD prepregs were specifically selected for the project.
All mounting holes and attachment points were molded in their final shape and position, with the demolded part ready to use with no secondary machining steps. As a result, overall production time for the composite bracket was just under three minutes in a lab environment, with a complete cycle time of less than two minutes being deliverable with an automated production cell.
The finished part, made from combined prepreg and HexMC®-i (which is made from chopped fiber), weighs just a small percentage more than a fully continuous fiber prepreg solution. The Cranfield team has also shown that this Hexcel material combination delivers a significant performance and weight improvement over traditional SMC solutions that may be considered too heavy for key composite structural parts. Hexcel’s snap-cure HexPly® M77 resin, used in both the HexMC®-i and HexPly® UD prepreg, delivers reliable and consistent rapid curing with a common resin matrix throughout the part.
Claude Despierres, Sales & Marketing Director – Automotive at Hexcel, said, “Our collaboration with Cranfield and Metisse Motorcycles has validated the use of a HexMC®-i and HexPly® UD hybrid part design in replacing complex cast or forged metallic parts that could not previously be formed with composites in a cost-effective high-rate production process. This demonstrates the effectiveness of the technology for components such as battery boxes, brackets, enclosures and even steering or suspension parts, that all could be made lighter and more rapidly with this new production process.”