Post on 23-Feb-2016
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FIBERGLASS DASHJames Rasmussen
Background Original dash was made from sheet metal, foam, and vinyl Was too heavy for its purpose Didn’t offer standard gauge sizes Didn’t offer any knee room Wasn’t originally fitted with a stereo The dash made the electronics on the car hard to work on
due to the original removal method of the dash piece
Design goals Lighten and stiffen the component through the
use of composites Add a single DIN slot Shorten the dash for more knee room Incorporate hard points into the core so
clamping forces can be applied to the mounts.
Designing the dash The original dash was measured at critical
locations to ensure the top edge and steering column fit correctly
Gauge holes were added in key locations so the strength of the dash was not compromised.
The single DIN slot was placed ergonomically with the front face away from the core to help keep the weight on the core.
Foam models were CNC routered and checked for fitment on the car
Manufacturing the Mold Once the dash model was correct, a female mold was
created in Solidworks, tool paths were created in Mastercam, and a mold was routered out of polyurethane foam
The mold was then coated with resin and sprayed the a polyester primer.
The primer was wet sanded, buffed, and coated with release.
Layup 7725 modified twill weave fiberglass was used
Conforms nicely around complex surfaces Strength calculations determined only two layers
were needed on each side of the core Wet layup was used
Thought the resin would set too fast for a RTM Dry fibers wouldn’t stay in place if bagging was
attempted Complex female mold used a stretch vacuum
bag to help reduce wrinkles and make bagging easier
Assembly Skins and core were CNC routered so layup and assembly time
would be reduced Material was removed from the core to allow aluminum inserts All four parts were bonded together with a glass bead and resin
mix Edges of the outside skin were trimmed
Testing Dashes were subjected to a three point bending test 30 pounds was applied to the part of the fiberglass
dash with the least amount of cross-sectional area Ten pounds was applied to the original dash The fiberglass dash deflected only .1 inches The original deflected .1 inches
Final Product Composite dash was considerably lighter Improved stiffness Ergonomic controls New mounting style eases installation
Fiberglass dash Original dash
Possible Design and Manufacturing Changes
A lighter fiberglass or carbon fiber would be used
Aramid paper or aluminum honeycomb would be used instead of blue foam
Molds would have even more draft Molds would have been sanded to a finer
grit and a different release agent would be used
Plastic hard points would be used