VW Explores Thermoplastic RTM
Another German automaker pursues liquid reaction molding of structural composites.
I recently posted news that BMW in Germany had installed a large vertical press from Engel to mold composite parts with liquid reactive thermoset resins. Now, it appears that Volkswagen in Germany is also pursuing liquid reactive molding of composites, but in this case with thermoplastics.
KraussMaffei (U.S. office in Florence, Ky.) is developing equipment systems for thermoplastic RTM, involving conversion of liquid caprolactam monomer into nylon 6. Because of the low-viscosity of molten caprolactam, it can impregnate dry fabric reinforcements in a mold, which would be impossible with viscous nylon in its polymerized state. KM has pursued what it has dubbed “T-RTM” using one of its own PUR metering machines paired with a vertical-clamp, tilting mold carrier (introduced at K 2013). This equipment comes from the Composites/Surfaces Business Unit of the Reaction Process Machinery Div. at KM.
The first products made with KM’s T-RTM process are B-pillar reinforcement prototypes made at the FRP TechCenter of the Volkswagen Group Research Center in Wolfsburg, Germany. The project utilized caprolactam supplied by BASF SE (U.S. office in Wyandotte, Mich.). A special RimStar series metering machine was adapted specifically to the extremely low viscosity of caprolactam and was fitted with a special mixhead, high-performance axial pumps, and a fully electric temperature-control system.