| Summary: |
A composite sheet material is used to produce an underbody
panel with variable stiffness and density values within the panel, where
needed, without added mass or material volume.
Weight savings: 4 kg per vehicle or 30% when compared to a similar
glass reinforced PP compression or injection molded composite part. |
| Most Innovative Feature: |
SymaLITE composite sheet material produces an underbody
panel with variable stiffness and density values within the panel, where
needed, without added mass or material volume. |
| Other Innovative Features: |
The panels made with this composite sheet material have
variable wall thicknesses and densities which provides good acoustics and
high fracture resistance. |
| What Forming Process? |
Sheet thermoforming. |
| First Time Process Used: |
Yes. |
| Previous Process: |
Sheet metal, Aluminum, SMC, GMT, LFT (compression &
injection molded). |
| Tooling Innovations: |
Multiple parts are thermoformed, at low pressure (50 psi),
in a single matched metal mold which has internal delay activated pierce
punches that cut all draw direction holes during the forming operation. |
| New Material Developments: |
This composite sheet, developed for the BMW underfloor
system panels, is a mixed fiber fleece product designed to have high loft,
plus it is laminated with PP films on the outside surfaces to meet highway
abrasion requirements and resist absorbing moisture. |
| Weight Savings: |
Weight savings versus a similar glass reinforced PP
compression or injection molded composite part is 30%, in this case a
savings of (4) kg per vehicle on the BMW Series 5. |
| Cost Savings: |
Panels are cost competitive with compression/injection
molded parts--weight is driver. |
| Cost Avoidance: |
Addition of these panels eliminates the addition of PVC
underfloor coating to the vehicle. |
| Direct Consumer Benefit: |
Use of these panels reduces interior vehicle noise,
especially on wet roads and reduces fuel consumption due to a reduced
vehicle drag coefficient. |
| Translates to Other Vehicles?: |
Yes, it can be translated. |
| Safety Benefits: |
Good response to impact--no brittle failure.
Part does not break up such that pieces fall off the car; the
failure mode is soft, it creases and folds. |
| Environmental Benefits: |
PVC is eliminated from vehicle underfloor and damaged parts
and off all from molding process are recycled into an injection molding
process. |
| Additional Comments: |
Prototype parts made with SymaLITE Light Weight Reinforced
Thermoplastic sheet can be produced fast and inexpensively using wood
tools. Relative stiffness of
a part can be varied without adding/subtracting material mass or altering
the tool. |
