---

General Motors Uses New Composite For GMT 800 Sportside Fenders

12 April 1999

Automotive Composites Alliance: General Motors Uses New Composite For GMT 800 Sportside Fenders

    DETROIT, April 12 -- The following was released by the
Automotive Composites Alliance:
    David Rock, staff project engineer for General Motors Truck
Group today announced the company will use a new class of reinforced reaction
injection molded (RRIM) polyurea polymer for the rear fenders of its 1999
Sportside trucks, the GMT 800 Chevrolet Silverado and GMC Sierra.  The new
composite was chosen because of cost and weight savings and styling
flexibility.  The announcement was made at a press briefing co-sponsored by
the Automotive Composites Alliance (ACA) and the Society of Plastic Engineers
(SPE) Detroit section.
    "This application is the first RRIM polymer designed to withstand the
temperatures experienced in GM's ELPO and paint line ovens," says Rock.  "It's
also the first polyurea body panel processed through an entire assembly plant
paint system at line rate.  The one-piece design wouldn't have been possible
in steel."
    An optimized fastening system allows for thermal growth at high
temperatures.  All fastening holes and slots are molded into the fender,
eliminating the need for secondary operations, such as drilling or punching.
"We were able to reduce the number of fasteners by over 50 percent and the new
fender offers easy disassembly and aftermarket repair," says Rock.
    The innovative one-piece design of the new Sportside fender reduces mass,
piece cost, investment and assembly time.  According to Rock, the new material
is molded in existing low pressure molding equipment which provides a 20
percent reduction in investment cost.  Rock says he expects this new
technology to lead future programs at GM.
    The Automotive Composites Alliance (ACA - formerly the SMC Automotive
Alliance), established in 1998, is a trade association of 26 molders and raw
materials and tool suppliers that provide the automotive industry with
reinforced thermoset composite exterior panels, interior trim and engine and
structural components.  The ACA is headquartered in Troy, MI., and is
structured as a business unit of the Composite Fabricators Association,
located in Arlington, VA.