Patent ID: 8420002

Claim:
A method of RTM molding comprising: forming a reinforcing fiber substrate, where reinforcing fiber layers are bonded to each other, as a preform having a first fiber volume content in a range of 45 to 60%, which is a volume of reinforcing fibers in the bulk volume of the reinforcing fiber substrate, that is lower than a target fiber volume content of an FRP molded material to be molded; placing the reinforcing fiber substrate in a mold; providing resin injection lines and evacuation lines each communicating with an inside of said mold; reducing pressure in said mold by evacuation; injecting a resin into said mold and impregnating the resin into said reinforcing fiber substrate to form said FRP molded material to achieve a fiber volume content lower than the target fiber volume content of said FRP molded material; stopping injection of the resin; and thereafter, starting evacuation of the resin after the resin reaches the evacuation lines and continuing evacuation until said target fiber volume content is obtained, wherein, after said injection of resin is stopped, at least one line of resin injection lines is changed to an evacuation line, and said evacuation of resin is continued until reaching said target fiber volume content and, upon reaching the target fiber volume content, said evacuation of resin is stopped and then said reinforcing fiber substrate is heated up to a resin curing temperature, wherein an injection amount of resin corresponding to the first fiber volume content is preset as an injection amount preset, and said injection of resin is stopped at the time said injection amount preset is reached, and wherein an evacuation amount for reaching said target fiber volume content is preset, relative to an injection amount of resin as an evacuation amount preset and said evacuation of resin is stopped at the time said evacuation amount preset is reached.