24 January 2009
24 January 2009
Personal watercraft (PWC) hulls have traditionally been manufactured from glass fibre reinforced polyester resin using the robotic shell moulding (RSM) process or sheet moulding compound (SMC) process.
When searching for an alternative, Camoplast researched many technologies and materials, ultimately determining that LFI – if modified – could meet its customer’s goal of producing a PWC hull that was strong and lightweight with a superior Class A finish, yet less expensive.
In LFI, long glass fibres are injected along with polyurethane resin in a one-step process: A fiberglass chopper is attached to the polyurethane dispensing mixhead, which is attached to a robot. The robot is programmed to move over the open mould cavity while simultaneously dispensing both the long glass fibers and the polyurethane resin in an open-pour method. At the end of the pour, the mould is closed to form the part.
Due to the quick cure time of polyurethane resin, it was not possible to fabricate a part the size of the PWC hull. However, Camoplast collaborated with material supplier Bayer MaterialScience and plastics processing equipment manufacturer KraussMaffei to devise Camoplast Long Fiber (CLF) technology.
To bring the process from concept to reality, Bayer MaterialScience developed a proprietary grade of its Baydur® STR 814 polyurethane system. This new grade features a 60-second open time (compared with a traditional open time of roughly 10 seconds), enabling the flow of the material and reinforcing glass into tight spaces, previously impossible, thereby making it possible to design-in strengthening ribs, etc. At the same time, KraussMaffei enhanced its proven LFI processing technology by nearly doubling the glass output capability from 180 grams/second to 300 grams/second, enabling the production of the highly reinforced structural parts.
The custom polyurethane formulation, along with specially designed KraussMaffei processing machinery and additional Camoplast innovations, makes it possible to produce large parts, such as the PWC hull.
“The hull of a PWC is the largest and most vulnerable part of the vehicle. As it breaks over waves there is the chance that it could crack,” said Yves Carbonneau, engineering director, Camoplast. “The part must have the best structural and mechanical characteristics while remaining lightweight for high performance. By using a light material, the Baydur STR 814 system, reinforced with molded-in ribs, we achieved the necessary strength to withstand big waves and other safety issues that are inherent with a PWC.”
“The innovative solution Camoplast developed, CLF, is the most efficient way to achieve the company’s high performance and aesthetic goals for the PWC hull,” said Craig Snyder, market channel representative, Bayer MaterialScience LLC. “Because innovation is a key focus area for Bayer MaterialScience, naturally we’re pleased to play a role in a project that is the first of its kind in the industry.”