RENSHAPE® SOLUTIONS GIVES NASCAR TEAM ANOTHER FIRST
30 July 2004 - Huntsman Advanced Materials

RenCast polyurethanes from RenShape Solutions are specially designed for rapid
production of metalforming die sets.

RenCast 5146 polyurethane – already used by leading automotive manufacturers - is utilised to make complete die sets from which Hendrick technicians form up to 300 replacement car body parts. These range from relatively small “A” posts and bumpers to large “C” posts comprising the main support and full side of the racecar.

The filled RenCast 5146 system is an easy process using simple mixing and pouring
techniques. Once cured, it exhibits the right properties to form metal - a Shore Hardness of 91D, compressive strength of 96MPa and tensile strength of 32.4MPa.

“We used to have to handform each replacement panel for our cars,” explained Ralph Brawley, manager in Hendrick’s Metal Shaping Department. “So the ability to quickly cast durable, short-run metal forming dies with RenCast polyurethane has been great in saving time and streamlining the manufacture of multiple car panels.'

“Body panel designs continually change too,” he added,” and we have to be ready to change with them. If Kirksite metal dies were used, we’d have to melt down the tooling and start again with every alteration. RenCast polyurethanes enable us to simply mill out the die section being modified, recast the surfaces and we’re back in production.”

Die Building
First a master pattern is built to the new dimensions. Surfaces are prepared to give a super-smooth pattern for forming high quality steel panels. The master is then placed in a box and released with paste wax to prepare for polyurethane casting. RenCast polyurethane is then mixed, de-gassed and poured into the box over the pattern. Hendrick engineers typically cast between 150kg to 500kg of material for each die.

After the die has been cast and cured overnight at room temperature, it is removed from the box and the back surface is machined flat. The die is then placed in a new box and sheet wax added to the surface to represent the thickness of the 22-gauge AK drawquality steel used to form the car panels.

When waxing is finishing, the punch is poured and finished in the same way as the die. A die ring is then cast to complete the tool set. To do this a new box is built around the RenCast die and all surfaces are coated with release agent, and 6mm thick sheet wax is added to the sides of the die to allow for movement of the draw ring during forming. The ring is then cast to a minimum of 15cm thickness. Total time for building the complete die set is about seven days.

Part Forming
To prepare the stamp panels, the die set is installed in Hendrick’s press and oil applied to the surfaces as to act as a lubricant in the forming process. A steel blank is placed on the punch, which is then pushed up into the die to form the part.

“Our RenCast dies are strong enough to withstand the 440 tons of pressure used to form large panels such as C posts, and are suitable for deep 8cm draws,” said Ralph Brawley. “In-house production of metal- stamping dies provides us with a new opportunity to reduce turn around time on replacement panels for our fleet of award-winning race cars.”

More News:
  • For July 2004
  • From Huntsman Advanced Materials
  • For General