For decades, the composite materials suppliers have worked separately to develop products they think will meet the market demands. In order to sell their products they had to conform to the expectations of their customers. Glass customers used mostly polyester and vinyl ester resins, so the fiberglass suppliers all coated their products with a sizing that was tailored to the chemistry of polyesters.
Carbon fiber was used mostly in aerospace or other applications that tended to use epoxy, so the chemistry of the sizing used on Carbon Fiber was designed to work with epoxy. Now, if you happened to want to use polyurethane resin, an excellent alternative, then you had to hope that the binders designed for bonding chemically to polyester and epoxy would just happen to work well enough, because no one put a sizing on their fibers that was designed for PU.
Equipment suppliers and process developers also had to work with the materials that may have been designed for other processes. For instance, fabrics were woven for pre-preg applications, but this left no good pathway to infuse resin using RTM when using these tightly woven structures. Then, if you wanted to pre-form your fabrics into a net shape, in order to use them in an RTM process, the pre-forming binder had to be applied to the fabrics after weaving, and stacking, which added a difficult extra step, and created a new set of challenges. If a stack of many layers was to be coated with a binder then the binder would never reach the inner layers.
Finally, this is all being addressed. Over the past year, inspired by BMW’s ambitious carbon fiber BIW program, four different companies that were all in some way involved with BMW have gotten together to develop materials and processes that are designed to make it easier for automotive engineers to think of composites. Zoltek has begun putting a sizing on their carbon fiber that is designed for bonding to Polyurethane. Loctite (Henkel) has developed an internal release agent for its Max 2 resin to make it not stick to the mold tools, but bond very well to the fibers. Chomarat has combined these materials into a multi-axial NCF fabric stack for easier tool loading. Finally, Krauss-Maffei have taken their high pressure meter-mixing equipment developed for BMW’s process, and done extensive experiments using these new materials to help perfect the synergy of the materials technologies into a cohesive automotive process.
The fact that these companies are working together to make the whole system work is an industry first, but also, the fact that these companies are finally looking at Automotive OEMs as the likely users of this tailored system is especially new. In the past, automotive companies gave lip-service to wanting to use composites for their industry, but they never seemed to really take it seriously. So that is how the composite materials companies treated the Automotive Market: not seriously. The commitment that BMW has shown to developing this new approach to composites for the Auto Industry has literally changed the landscape of the composite materials market. Now, large composite materials companies like Toray, and SGL, actually see the Automotive Market as their fastest growing segment. Finally, composite materials are being developed specifically for automotive applications, and this should make a significant difference in how easily they can be adopted.
Last fall, these four companies, Zoltek, Chomarat, Loctite, and Krauss-Maffei all pitched in together to demonstrate the new system of processing technologies at the K-Show in Dusseldorf. They set up the whole manufacturing process on the floor of the show, and ran parts, in 6 minutes each, with a class-A surface. The process is 90 seconds faster without the Class-A surface, but that feature is probably the most important element to the Automotive OEMs who came to watch. During the show, some 400 parts were made. Unfortunately for North American OEMs, they don’t attend the K-Show, so almost no one from this side of the Atlantic has seen it.
The good news is that the four companies involved will be taking the show on the road, and will be coming to North America, visiting the OEMs directly and showing off this unique combination of technologies. Their plan is to set up a central website so prospective OEM engineers can visit the site for all the information they need.
At this writing, I have some links to content that comes from Europe, and some brochures, but more information will surely be included when the new website goes on line.