BMW Presses New Carbon-Fiber Production Technologies

BMW AG's Dingolfing, Germany, factory will use two new manufacturing processes wet and "hybrid" pressing to produce the carbon fiber-reinforced body of its next-generation 7 Series luxury sedan. Production is due to start July 1.

The 7 Series body uses carbon fiber in combination with ultra-high-strength steel and aluminum. BMW will employ carbon fiber, which is about 30% lighter than aluminum, in the car's roof, B and C pillars, rear shelf and center transmission tunnel.

BMW says the two processing technologies enable large-scale production of several thousand carbon-fiber components per day. The new presses have short cycle times and compact manufacturing footprints, according to the carmaker.

In wet pressing, carbon-fiber fabrics impregnated with resin are pressed wet and hardened in a molding die. This eliminates the need for dry pre-shaping that is required in the resin-transfer-molding process typically used for low-volume carbon-fiber manufacturing.

So-called hybrid presses are used to bond steel and carbon fiber parts. In the process, carbon-fiber fabrics impregnated with resin, also still wet, are placed in a molding die with sheet steel, then pressed and hardened. Combining the materials helps improve rigidity and crash protection, BMW notes.

The lightweight materials shave as much as 190 lbs off the 7 Series. BMW uses a similar "carbon-core" structure for the low-volume i8 plug-in hybrid supercar it launched last year.