Rtm molding method and device

Abstract

An RTM molding method and device includes disposing a reinforcing fiber substrate in a cavity of a mold consisting of a plurality of dies, clamping the mold, and injecting resin to complete molding, wherein divided areas with respect to the surface direction of the reinforcing fiber substrate are assumed, each divided area is one in which injected resin expands over the entire surface in the area and can be substantially uniformly impregnated in the thickness direction of the substrate, and resin introducing paths are formed for respective assumed divided areas to introduce injected resin into the respective divided areas. When a relatively large molded product is molded, a molding step from resin injection to impregnating/curing can be implemented at high speed without generating a non-resin-flowing area, thereby producing a high-quality molded product with a shortened molding time and increased production speed and volume.

1 . An RTM molding method comprising the steps of disposing a reinforcing fiber substrate in a cavity of a mold consisting of a plurality of dies, clamping said mold, and thereafter injecting resin to complete molding, characterized in that divided areas with respect to a surface direction of said reinforcing fiber substrate are assumed, each divided area is one in which injected resin expands over the entire surface in said each divided area and can be substantially uniformly impregnated in a thickness direction of said substrate, and resin introducing paths are formed for respective assumed divided areas for introducing the injected resin into said respective divided areas, and wherein, after resin is impregnated into said reinforcing fiber substrate by injecting the resin from a resin injection line toward a resin discharge line, which are disposed on an outer circumference of said cavity, the resin is heated and cured, and said resin injection line is divided into a plurality of parts. 
     
     
         2 . The RTM molding method according to  claim 1 , wherein said resin injection line and resin discharge line are formed substantially over the entire range of said outer circumference of said cavity. 
     
     
         3 . The RTM molding method according to  claim 1 , wherein the length of said resin injection line is two times or more the length of said resin discharge line. 
     
     
         4 . The RTM molding method according to  claim 1 , wherein said resin injection line and/or said resin discharge line is formed from a groove processed on said mold. 
     
     
         5 . The RTM molding method according to  claim 4 , wherein said mold comprises an upper die and a lower die, and said groove is all processed on said lower die. 
     
     
         6 . The RTM molding method according to  claim 1 , wherein said resin discharge line is also divided into a plurality of parts. 
     
     
         7 . The RTM molding method according to  claim 1 , wherein resin injection from said resin injection line divided into a plurality of parts is carried out in order from a resin injection line part which is substantially more distant from said resin discharge line. 
     
     
         8 . The RTM molding method according to  claim 1 , wherein resin injection is carried out also from said resin discharge line by switching said resin discharge line to a resin injection line after a predetermined period of time. 
     
     
         9 . The RTM molding method according to  claim 1 , wherein a core material is laminated to said reinforcing fiber substrate. 
     
     
         10 . The RTM molding method according to  claim 1 , wherein a tube for resin injection and/or a tube for resin discharge is provided being nipped between parting surfaces of dies, and portions between said tube and said dies are sealed with an elastic material. 
     
     
         11 . The RTM molding method according to  claim 10 , wherein an end portion of an O-ring for sealing said cavity of said mold at positions of parting surfaces of dies is incorporated into said elastic material for seal. 
     
     
         12 . The RTM molding method according to  claim 1 , wherein, while resin is injected into said mold at a pressurized condition, gas and excessive resin in said mold are discharged intermittently. 
     
     
         13 . The RTM molding method according to  claim 12 , wherein, when a resin pressure in said mold of resin pressurized and injected is referred to as Pm and a resin discharge pressure at an injection port for injecting resin is referred to as Pi, a flow rate of resin flowing into said mold is controlled by selective control between conditions of Pm=Pi and Pm<Pi. 
     
     
         14 . The RTM molding method according to  claim 12 , wherein a flow rate of resin flowing into said mold is controlled by adjustment of a diameter of a discharge port for discharging resin. 
     
     
         15 . The RTM molding method according to  claim 14 , wherein said adjustment of said diameter of said discharge port and a timing for said adjustment are stored in memory, and based on the stored information, said flow rate of resin flowing into said mold is automatically controlled. 
     
     
         16 . The RTM molding method according to  claim 1 , wherein, when resin is injected into said cavity of said mold at a pressurized condition, a ratio of a flow rate of resin per a unit time (Q:cc/min.) to a projected area of said cavity (S: m 2 ) (Q/S:cc/min.·m 2 ) is in a range of 50<Q/S<600. 
     
     
         17 . The RTM molding method according to  claim 16 , wherein the product of said ratio (Q/S:cc/min.·m 2 ) and a pressurizing force of resin (P:MPa) ((Q/S)×P:ccMPa/min.·m 2 ) is in a range of 20≦(Q/S)×P≦400. 
     
     
         18 . The RTM molding method according to  claim 16 , wherein a pressurizing force of resin is in a range of 0.2 to 0.8 MPa. 
     
     
         19 . The RTM molding method according to  claim 16 , wherein said resin is cured for 3 to 30 minutes at a constant heating temperature in a range of 60 to 160° C. 
     
     
         20 . An RTM molding method comprising the steps of disposing a reinforcing fiber substrate in a cavity of a mold consisting of a plurality of dies, clamping said mold, and thereafter injecting resin to complete molding, characterized in that divided areas with respect to a surface direction of said reinforcing fiber substrate are assumed, each divided area is one in which injected resin expands over the entire surface in said each divided area and can be substantially uniformly impregnated in a thickness direction of said substrate, and resin introducing paths are formed for respective assumed divided areas for introducing the injected resin into said respective divided areas, wherein at least one surface layer of said reinforcing fiber substrate comprises a continuous fiber layer, and a layer positioned immediately under said surface layer comprises a random mat layer. 
     
     
         21 . The RTM molding method according to  claim 20 , wherein said surface layer is formed from three or less continuous fiber layers. 
     
     
         22 . The RTM molding method according to  claim 20 , wherein the total weight of said continuous fiber layer forming said surface layer is 700 g/m 2  or less. 
     
     
         23 . The RTM molding method according to  claim 20 , wherein reinforcing fibers of said surface layer are formed as a carbon fiber woven fabric. 
     
     
         24 . The RTM molding method according to  claim 20 , wherein the total weight of said random mat layer is 150 g/m 2  or less. 
     
     
         25 . The RTM molding method according to  claim 20 , wherein said random mat layer comprises glass fibers. 
     
     
         26 . The RTM molding method according to  claim 20 , wherein a core material is laminated to said reinforcing fiber substrate. 
     
     
         27 . An RTM molding device for disposing a reinforcing fiber substrate in a cavity of a mold consisting of a plurality of dies, clamping said mold, and thereafter injecting resin to complete molding, characterized in that divided areas with respect to a surface direction of said reinforcing fiber substrate are assumed, each divided area is one in which injected resin expands over the entire surface in said each divided area and can be substantially uniformly impregnated in a thickness direction of said substrate, and resin introducing paths are formed for respective assumed divided areas for introducing the injected resin into said respective divided areas and wherein, after resin is impregnated into said reinforcing fiber substrate by injecting the resin from a resin injection line toward a resin discharge line, which are disposed on an outer circumference of said cavity, the resin is heated and cured, and said resin injection line is divided into a plurality of parts. 
     
     
         28 . The RTM molding device according to  claim 27 , wherein said resin injection line and resin discharge line are formed substantially over the entire range of said outer circumference of said cavity. 
     
     
         29 . The RTM molding device according to  claim 27 , wherein the length of said resin injection line is two times or more the length of said resin discharge line. 
     
     
         30 . The RTM molding device according to  claim 27 , wherein said resin injection line and/or said resin discharge line is formed from a groove processed on said mold. 
     
     
         31 . The RTM molding device according to  claim 30 , wherein said mold comprises an upper die and a lower die, and said groove is all processed on said lower die. 
     
     
         32 . The RTM molding device according to  claim 27 , wherein said resin discharge line is also divided into a plurality of parts. 
     
     
         33 . The RTM molding device according to  claim 27 , wherein resin injection from said resin injection line divided into a plurality of parts is carried out in order from a resin injection line part which is substantially more distant from said resin discharge line. 
     
     
         34 . The RTM molding device according to  claim 27 , wherein resin injection is carried out also from said resin discharge line by switching said resin discharge line to a resin injection line after a predetermined period of time. 
     
     
         35 . The RTM molding device according to  claim 27 , wherein a core material is laminated to said reinforcing fiber substrate. 
     
     
         36 . The RTM molding device according to  claim 27 , wherein a tube for resin injection and/or a tube for resin discharge is provided being nipped between parting surfaces of dies, and an elastic material for seal is interposed between said tube and said dies. 
     
     
         37 . The RTM molding device according to  claim 36 , wherein an end portion of an O-ring for sealing said cavity of said mold at positions of parting surfaces of dies is incorporated into said elastic material for seal. 
     
     
         38 . The RTM molding device according to  claim 27 , wherein means for, while injecting resin into said mold at a pressurized condition, discharging gas and excessive resin in said mold intermittently is provided. 
     
     
         39 . The RTM molding device according to  claim 38 , wherein, when a resin pressure in said mold of resin pressurized and injected is referred to as Pm and a resin discharge pressure at an injection port for injecting resin is referred to as Pi, means for controlling a flow rate of resin flowing into said mold by selective control between conditions of Pm=Pi and Pm<Pi is provided. 
     
     
         40 . The RTM molding device according to  claim 38 , wherein means for controlling a flow rate of resin flowing into said mold by adjusting a diameter of a discharge port for discharging resin is provided. 
     
     
         41 . The RTM molding device according to  claim 40 , wherein means for storing in memory said adjustment of said diameter of said discharge port and a timing for said adjustment, and based on the stored information, automatically controlling said flow rate of resin flowing into said mold, is provided. 
     
     
         42 . The RTM molding device according to  claim 40 , wherein said means for adjusting said diameter of said discharge port comprises a valve opening/closing device.