Bumper Beams – case study

TowFlex fabric products provide performance and manufacturing benefits for BMW M3 Bumper Beams.
BMW set an objective to increase energy absorption and reduce weight for the front and rear bumper systems of the new M3. The new bumper systems had to fit within the same space and have the same attachment points as the previous metal bumpers. A consortium of three companies – Jacob Composites GmbH, Advanced Composite Systems GmbH (AC.S), and com_posite consultants – worked with BMW designers to develop a bumper system using continuous fibre reinforced thermoplastic materials (CFRTP) to meet the challenge.
CFRTP materials were seen as the best solution due to the advantages of high-volume manufacturing (thermoforming from consolidated sheet), automated assembly (thermoplastic welding), and recycleability.
Hexcel developed specific TowFlex E-glass/nylon 6 fabric products to meet the bumper performance and manufacturing requirements. The new CFRTP bumper design provides improved crash performance at a 60% weight savings over the previous system, and replaces the metal bumper beam as well as the shock absorbing components.
AC.S converts TowFlex fabrics into multi-layer consolidated flat sheets and tubular crush columns using a unique continuous compression moulding process. The consolidated sheets are provided to Jacob Composites for high-speed matched mould thermoforming of the bumper beams and crush column boxes. Jacob then assembles the thermoformed components and crush columns tubes using a high-frequency welding process. Completed bumper systems are provided directly to the BMW assembly line.