The K Fair, held every three years in Düsseldorf, Germany, is a giant, 19-hall extravaganza of thermoplastics technology. Two exhibits at large machinery companies at this year’s K show the emerging importance of thermoset resin transfer molding, particularly when teamed with carbon fiber.
The exhibits at K2013 echoed a theme at the SPE Automotive Composites Conference held in September in Novi, Mich. where suppliers like Dieffenbacher showed their latest advances in high-pressure RTM.
In resin transfer molding, which dates back to the 1960s, resins (historically thermosets) are injected into a closed mold, impregnating fibers. The process can be used to produce complex parts, unlike the autoclave and pressure forming processes used to make body panels. There’s renewed focus on the process because of improvements in capabilities that boost productivity and put it squarely in the automotive lightweighting game.
At K2013, KraussMaffei had a world premiere of a production cell producing carbon fiber-reinforced (CFRP) components with a polyurethane (PUR) matrix for a sports car. Interestingly, the parts come out of the mold with a paintable surface. The roof shells (0.6 square meter) for the Roding Roadster Targa contain a carbon fiber volume of 50%. The centerpiece of the machine is a new RTM mold carrier with a compact design and a clamping force of 3800 kN (381 tons). Dieffenbacher was a supply chain partner in the project. Eight finished roof parts per hour are produced—good for RTM, but not yet really good enough for series production of a mass-volume car.
Over at the Engel stand, a v-duo 700 vertical machine (first time ever shown at a trade fair) was shown automating the production of lightweight components for the KTM X-Bow sports car using the RTM process. A mix of
carbon-fiber and glass fabrics were impregnated with a new “snap-cure” polyurethane thermoset resin from BASF Polyurethanes in a liquid reactive molding process.
In the United States, Plasan Carbon Composites is now teaming with Toray to develop an advanced RTM process for making structural carbon fiber parts for automotive applications.
Future developments with thermoplastics will speed up the RTM process even more.