Heating of thermoplastic interlayers in a preform tool for producing a preform of a composite member

Abstract

Systems and methods for producing a preform for a composite member. An exemplary method includes preparing a lay-up of reinforcement layers and thermoplastic interlayers, and transferring the lay-up to a preform tool. The method further includes inducing heat in the preform tool to a transition-temperature range that causes the thermoplastic interlayers to become tacky or viscous, and applying pressure to the lay-up with the preform tool to shape the lay-up into the preform.

1 . A method of forming a composite member, the method comprising:
 shaping a non-conductive lay-up of dry reinforcement layers and thermoplastic interlayers into a preform for the composite member by:
 inducing heat in a preform tool to a transition temperature range that causes the thermoplastic interlayers of the lay-up to become tacky without liquefying; and 
 applying pressure to the lay-up between complimentary dies of the preform tool, with the lay-up heated to the transition temperature range where the thermoplastic interlayers are tacky, to shape the lay-up into the preform. 
   
     
     
         2 . The method of  claim 1  further comprising:
 removing the pressure applied by the preform tool; and 
 cooling the preform below the transition temperature range to solidify the thermoplastic interlayers. 
 
     
     
         3 . The method of  claim 2  further comprising:
 determining whether a shape of the preform matches a near-net shape for the composite member; 
 when the shape of the preform does not match the near-net shape, the method further comprises:
 inducing heat in the preform tool again to the transition temperature range; and 
 applying pressure between the dies of the preform tool to further shape the lay-up into the preform. 
 
 
     
     
         4 . The method of  claim 2  further comprising:
 when a shape of the preform matches a near-net shape for the composite member:
 infusing the preform with a thermosetting matrix material; and 
 curing the thermosetting matrix material to produce the composite member. 
 
 
     
     
         5 . The method of  claim 1  wherein inducing heat in the preform tool comprises:
 applying a current to an induction coil that encompasses the preform tool to generate a magnetic field that induces heat in a susceptor in the preform tool to the transition temperature range. 
 
     
     
         6 . The method of  claim 5  wherein:
 a surface area of the susceptor corresponds with a surface area of the lay-up. 
 
     
     
         7 . The method of  claim 5  further comprising:
 selecting a material for the susceptor that reaches a maximum temperature within the transition temperature range in the presence of the magnetic field from the induction coil. 
 
     
     
         8 . The method of  claim 1  wherein:
 the lay-up comprises a thermoplastic interlayer disposed between each of the reinforcement layers. 
 
     
     
         9 . The method of  claim 1  wherein the composite member is formed for an aircraft. 
     
     
         10 . An apparatus configured to form a composite member, the apparatus comprising:
 a preform tool to shape a non-conductive lay-up of dry reinforcement layers and thermoplastic interlayers into a preform for the composite member; and   a controller to induce heat in the preform tool to a transition temperature range that causes the thermoplastic interlayers of the lay-up to become tacky without liquefying;   wherein the preform tool applies pressure to the lay-up between complementary dies, with the lay-up heated to the transition temperature range where the thermoplastic interlayers are tacky, to shape the lay-up into the preform.   
     
     
         11 . The apparatus of  claim 10  wherein:
 the preform tool removes the pressure applied; and 
 the controller controls a cooling device to cool the preform below the transition temperature range to solidify the thermoplastic interlayers. 
 
     
     
         12 . The apparatus of  claim 10  further comprising:
 a molding tool that infuses the preform having a near-net shape for the composite member with a thermosetting matrix material, and cures the thermosetting matrix material to produce the composite member. 
 
     
     
         13 . The apparatus of  claim 10  further comprising:
 an induction coil that encompasses the preform tool; 
 wherein the controller instructs a power supply to apply a current to the induction coil to generate a magnetic field that induces heat in a susceptor in the preform tool to the transition temperature range. 
 
     
     
         14 . The apparatus of  claim 13  wherein:
 a surface area of the susceptor corresponds with a surface area of the lay-up. 
 
     
     
         15 . The apparatus of  claim 13  wherein:
 a material selected for the susceptor reaches a maximum temperature within the transition temperature range in the presence of the magnetic field from the induction coil. 
 
     
     
         16 . The apparatus of  claim 10  wherein:
 the lay-up comprises a thermoplastic interlayer disposed between each of the reinforcement layers. 
 
     
     
         17 . The apparatus of  claim 10  wherein the composite member is formed for an aircraft. 
     
     
         18 . A system configured to form a composite member, the system comprising:
 a preform tool to shape a non-conductive lay-up of dry reinforcement layers and thermoplastic interlayers into a preform for the composite member, wherein the preform tool includes:
 complementary dies; and 
 a susceptor embedded in at least one of the dies; 
   an induction coil that encompasses the preform tool; and   a controller that instructs a power supply to apply a current to the induction coil to generate a magnetic field that induces heat in the susceptor to a transition temperature range that causes the thermoplastic interlayers of the lay-up to become tacky without liquefying;   wherein the preform tool applies pressure to the lay-up between the dies, with the lay-up heated to the transition temperature range where the thermoplastic interlayers are tacky, to shape the lay-up into the preform.   
     
     
         19 . The system of  claim 18  further comprising:
 a molding tool that infuses the preform having a near-net shape of the composite member with a thermosetting matrix material, and cures the thermosetting matrix material to produce the composite member. 
 
     
     
         20 . The system of  claim 18  wherein:
 a material selected for the susceptor reaches a maximum temperature within the transition temperature range in the presence of the magnetic field from the induction coil.