Abstract: In an automated apparatus and method for resin transfer molding, a resin pot defining a resin chamber for receiving liquid resin is coupled in fluid communication with a mold cavity. A pump unit in the form of a piston member driven by a hydraulic cylinder, is received within the resin chamber, and pumps the resin from the resin chamber into the mold cavity upon stroking the piston member. A control unit is coupled to the pump unit, and to a pressure sensor which transmits signals to the control unit indicative of the pressure of the resin flowing between the resin chamber and the mold cavity. The control unit is responsive to the signals from the pressure sensor to control the pump unit, and maintain the resin flowing between the resin chamber and the mold cavity at a substantially constant pressure.

Abstract: In an apparatus for resin transfer molding, the resin is introduced into a heated resin pot, and a piston member is driven through the resin pot to displace the resin into a heated resin line. The temperature of the resin in the resin pot is substantially constant, and is above room temperature but below the catalyzing temperature of the resin. The preheated resin flows from the resin line into a preheater, which heats the resin to molding temperature and catalyzes the resin, and the catalyzed resin is then introduced into the mold cavity of a resin transfer mold containing a structural preform. The resin is maintained at a substantially constant pressure within the heated resin line, and the movement of the piston member is continuously monitored during the resin transfer process. The resin transfer process is terminated when the rate of movement of the piston member decreases below a predetermined minimum value approaching zero.