Carbon Core, aluminum, and multi-material joining
BMW's Carbon Core construction bonds carbon-fibre-reinforced plastic into the passenger cell alongside steel and aluminum, and the i3 and i8 went further with full CFRP passenger structures. The point of those materials is stiffness at low weight, and the consequence is that they cannot be treated like sheet metal: BMW specifies where a CFRP component may be repaired, where it must be replaced, and which bonded joints may be separated at all.
Aluminum panels get their own separated area and their own tooling, for the same reason they do on every mixed-material car — steel particles embedded in aluminum start galvanic corrosion that surfaces under the paint long after the repair. Structural joints are riveted and bonded to specification, rivets are single-use, and adhesive cure times are respected rather than rushed to hit a delivery date.
- —Separated aluminum work area with dedicated tooling
- —CFRP components evaluated against BMW's repair-or-replace criteria
- —Riveted and bonded structural joints per the factory procedure
- —Three-dimensional structural measuring, before and after
- —High-voltage shutdown procedure on i models
- —Corrosion protection, seam sealer, and cavity wax restored
