Tech Briefs
Lamination saves weight

Current laminate dash panel system retains the engine side dash insulator.

MSC Laminates and Composites Inc. has teamed with National Steel Corp. to develop a laminated dash panel that is said to save between 4 to 5.5 kg (9 to 12 lb) as compared to the standard steel dash pan with associated sound deadening materials. The resulting panel has fewer parts, less overall complexity, and lower manufacturing costs. The dash panel is located at the front of the cabin behind the instrument panel. It can include the lower portion of the cowl and toe pan. Ford Motor Co. is looking to employ such a panel for its sport utility vehicle (SUV), Explorer.

Laminated steels have been used for valve covers, disk brake dampers, oil pans, heat shields, and other powertrain applications. They are now being looked at for body applications. At the recent SAE International 1999 International Body Engineering Conference (IBEC) a dash panel and extension, roof, doors, and floor pans were displayed.

Laminated steel has been shown to produce improvements in NVH (noise, vibration, and harshness) characteristics due to its design, according to James Schwaegler, Technical Development Manager. A viscoelastic polymer is sandwiched between two steel sheets, which not only absorbs vibration but also lowers the resonant frequency of the laminate. The vibrational energy is converted into thermal energy, which is dissipated within the structure. The laminate chosen for the new applications is known as PCX-1 Quiet Steel. Two versions are being examined, one with a 0.5-mm (0.020-in) thick steel sheet and one with 0.65-mm (0.0255-in).

The dash panel system currently used includes engine side dash insulator, dash panel, deadener, dash doubler, and insulator.

According to James W. Carlen, Vice President of Sales, the laminate is produced on a modified coil-coating line. The line is fitted with a laminating section, which produces the multilayer composites in a continuous operation. The two coils of sheet steel are uncoiled, cleaned, and pretreated. Various coatings and adhesives are added and cured in the ovens (a basic coil coating line). The added lamination line adds an adhesive coating line, an oven, and an area to bring the two sheets together. The laminated coils are rewound.

On the manufacturing side, the laminated steels can be resistance welded. Slitting, roll forming, brake forming, stamping, drawing, and punching pose no particular problems although tight radii can result in slight distortions. Tooling used on conventional steels requires little or no change when using a steel laminate.

To aid in the design process MSC Laminates and Composites has DAMP software that performs computer-generated material excitation and modal analysis.

Future uses of laminated steel include wheel wells, closure panels, and floor pans. Their use may prove valuable in areas where NVH needs to be controlled.

Dan Holt