KraussMaffei is focusing on innovative lightweight components for its appearance at the Composites Europe trade show in Düsseldorf, Germany and presenting its cross-process expertise in machine and process engineering. The company offers customers competent support from a single source throughout the entire project phase, from component development, pre-batch production, and component testing all the way to series production and post-mold processing.
The HP-RTM (high pressure RTM) method has already proven itself in many applications for manufacturing composites with carbon fibers in pre-batch production and is now finding its way into large series. "With our expertise and high-quality machine technology, we are setting new standards in the automotive market," explains Erich Fries, Manager of the Composites/Surfaces Business Unit, in which KraussMaffei has combined its expertise over all lightweight construction technologies across the entire process chain and material systems.
"Our systems are now in use by numerous major producers in the automotive and commercial vehicle industries, and we are brought into new developments very early on, since we can contribute to solutions at every step of the process chain." Use of the HP-RTM (high pressure RTM) method keeps gaining importance for series production in high-technology industries. Development of the method, however, is still long from being completed. The very complex requirements springing from required numbers of pieces, automated processes, affordable material costs, and the greatest possible weight savings for a component lead to many variants.
As of recently, two methods known as compression RTM and wet molding, each offering its own specific advantages, are available for high-pressure resin transfer molding (HP-RTM). With wet molding, for example, carbon fibers can also be recycled as piece goods (scrap from the preform manufacturing). Reliable partnerships are the prerequisite for efficient implementation in this respect. For example, as part of its cooperation with Dieffenbacher GmbH, KraussMaffei supplies complete systems which cover the entire production process from processing of the carbon fibers through to the ready-to-install, post-mold finished part.
KraussMaffei recently received a particularly interesting order from an Asian OEM for a complete HP-RTM (high pressure RTM) manufacturing cell for manufacturing carbon-fiber-reinforced composites. KraussMaffei supplies the metering technology, including mixing head, mold technology, and solutions for cutting the finished part. Components for fiber preforming and pressure molding come from cooperation partner Dieffenbacher. This shows that resin transfer molding is becoming a global trend and is not just limited to the European market.
Even today, many people still think of composites as carbon-fiber-reinforced components in an epoxy resin matrix, the classic carbon-fiber-reinforced plastic components. For KraussMaffei, however, this field is far broader. "Among reactive materials we also see polyurethane and cast polyamides as alternative matrix materials; among thermoplastic materials, polyamide and polypropylene have proven themselves," says Fries. "In this dynamic environment of development there is still no clear trend to be identified, but it is certain that the developments still have not been completed." Depending on the requirement for mechanical strength or the component cost, all more or less common fiber types come into question as reinforcement material.
Step by step, fiber-reinforced components are being integrated into production vehicles today to build up the knowledge about composites systematically. Thermoplastics perform well here thanks to their short cycle times, weldability, and potential functional integrations, with which multiple additional functions can be brought into a component. Not only are thermoplastics getting better all the time as matrix materials, new production methods and even design principles are also opening up.
"The transformation happening in the automotive industry as well as in aircraft construction and other industries could not be more thrilling," states Martin Würtele, Manager of Technology Development at KraussMaffei. The designers have to search for opportunities to achieve functional improvements using high-performance composites and designs appropriate to the materials." For example, a load-carrying thermoplastic carbon-fiber-reinforced part— manufactured from a composite sheet—can have ribbing added to it in the injection molding process, along with other integration and function elements.
