BMW car body made of
For a manufacturer that’s built its reputation on racing, BMW is well-versed in the importance of lightweight construction. The company’s mass-production i3 electric vehicle has the distinction of being the first car ever to use a carbon fiber plastic composite, or CFRP, in its body panels. This ultra-light material, which is also used in add-on M Performance Parts and whole carbon chassis components for high-performance sports cars, saves about a ton of weight, enabling the four door family car to do the century sprint in 7 seconds with a mass of only 1.2 tons.
A Buy BMW full carbon fiber body kits composite is made from a bundle of individual carbon fibers held together by thermosetting polymers known as a matrix. For the i3, the carbon is sourced from German supplier SGL Carbon (Wiesbaden, Germany), with the matrix supplied by a Japanese partner named Teijin Automotive Interiors (Tokyo, Japan). The process involves heat and pressure to melt the synthetic resins, which are then injected into the fiber bundles using a special nozzle. The assembly is then cured in a heated vacuum chamber. Once cured, the component is cut to size and prepared for molding.
The i3 body is produced by the automaker’s Leipzig, Germany plant. CW recently visited the facility, which is also where the automaker builds its all-electric i3 and i8 vehicles. Both production sites rely on a hybrid body-in-white design that marries carbon fiber with aluminum and steel in what BMW calls its Intelligent Composite concept. The result is a sedan body that’s 137 lbs lighter than the previous generation, with improved body strength and torsional rigidity.
What is BMW car body made of
Aluminum, which is produced at BMW’s Moses Lake, Washington, plant and the i3’s exterior side frames, accounts for about half of the sedan’s weight savings. The other half is saved by the use of CFRP and a redesigned front and rear suspension.
BMW’s iX electric vehicle also uses CFRP, and the manufacturer claims that its body-in-white is 176 lbs lighter than the i3’s. This is thanks to a mix of aluminum and high-strength steel, which are bonded with CFRP and welded at the Dingolfing, Germany, plant. The multi-material construction results in a lower center of gravity and an even distribution of front-to-back weight for optimal handling.
Shops servicing these cars will need to review OEM procedures to preserve the integrated structural safety features of the BMW’s multi-material bodies. This includes ensuring that all welding is performed at the correct temperature to prevent premature failure and cracking.
Shops will also need to be aware of the different manufacturing processes used for each of these different materials. For instance, BMW utilizes wet compression molding and resin transfer molded (RTM) for some of its CFRP components, while others are produced via pultrusion, which produces long strips of composite that can be shaped by cutting tools. These different manufacturing techniques will have a definite effect on repair methods and cycle times, as well as on the availability of repair parts and materials.