The trick to making large molded items like the Sunrise chassis is ensuring that the resin is distributed evenly among the layers of woven fiberglass cloth. To be practical commercially, however, large items need fast production times. Still, the quicker the resin is pumped into the mold, the greater the chances of washing glass fibers out of the mold. Air entrapment is also more likely. To avoid such problems, DE4 uses a multiple-port mold, measuring 16 feet long by 80 inches wide, which can regulate the flow of resin individually to each injection point.
Sensors monitor the flow of resin.
The injection system is at the heart of the molding process. In earlier versions, an operator monitored a light board to supervise resin flow through 11 ports. The operator could open and close individual injection ports to satisfy the demand for resin. On a later version of the injection system, DE4 gives a PLC control of the resin flow. The mold was cast from epoxy resin, and made in two mating halves.