Novel thick laminate fabrication method

Abstract

The invention is a processing technique which allows Fiber Reinforced Polymer laminates of any arbitrary thickness to be manufactured. Thick laminates processed in this fashion will not exhibit adverse process induced residual stresses which serve to reduce or limit laminate operability, performance and service life. This invention provides a means by which conventional processing problems associated with very thick laminate construction can be avoided, thereby ensuring a high degree of thick laminate part quality and performance

1 . A method of producing a thick laminate assembly of Fiber Reinforced Polymer (FRP) panels comprising; 
 placing an electric heating element on a surface of a first panel such that the heating element can be controlled external to the laminate assembly,    covering the surface of the first panel and electric heating element with thermoset resin; and    placing a second panel on top of the first panel, wherein the electric heating element is used as the heat source to cure the thermoset resin, thereby bonding the two panels together into a laminate assembly.    
     
     
         2 . The method of  claim 1  further comprising the step of bonding additional panels, sequentially or simultaneously, to the laminate assembly until an assembly of desired total thickness is achieved, using electric heating elements as the heat sources for curing the thermoset resin used to bond additional panels to the assembly.  
     
     
         3 . The method of  claim 1  wherein the electrical resistance element is at least one heating wire laid over a surface area of the panel in a serpentine pattern, such that both ends of the wire can be accessed external to the panels.  
     
     
         4 . The method of  claim 3  wherein the turns of the pattern are within the surface area of the panel.  
     
     
         5 . The method of  claim 3  wherein the turns are around pins external to the surface area of the panel.  
     
     
         6 . The method of  claim 1  further comprising a step of sealing the joint line between panel when the resin is heated to a point of minimum viscosity.  
     
     
         7 . The method of  claim 1  wherein the assembly is vacuum bagged during the curing process.  
     
     
         8 . The method of  claim 1  wherein at least one thermocouple is also placed between the panels to monitor temperature during the cure cycle.  
     
     
         9 . The method of  claim 8  wherein two thermocouples are installed at opposite diagonal corners of the panel.  
     
     
         10 . A method of producing a thick laminate assembly of Fiber Reinforced Polymer (FRP) panels comprising; 
 placing an electric heating element on a surface of a first panel such that the heating element can be controlled external to the laminate assembly,    placing a film adhesive with the heating element; and    placing a second panel on top of the first panel, wherein the electric heating element is used as the heat source to heat the film adhesive, thereby bonding the two panels together into a laminate assembly.    
     
     
         11 . The method of  claim 10  wherein the film adhesive is a single layer woven fabric, pre-impregnated with thermoset resin and partially cured.  
     
     
         12 . The method of  claim 10  further comprising the step of bonding additional panels to the laminate assembly, either sequentially or simultaneously, until an assembly of the desired total thickness is achieved, using electric heating elements as the heat sources for heating the film adhesive used to bond additional panels to the assembly.  
     
     
         13 . The method of  claim 10  wherein the electrical resistance element is at least one heating wire, such that the wire is laid over a surface area of the panel in a serpentine pattern and both ends of the wire can be accessed external to the panels.  
     
     
         14 . The method of  claim 13  wherein the turns of the heating wire pattern are within the surface area of the panel.  
     
     
         15 . The method of  claim 13  wherein the turns of the heating wire are around pins external to the surface area of the panel.  
     
     
         16 . The method of  claim 10  further comprising a step of sealing the joint line between panel when the film is heated to a point of minimum viscosity.  
     
     
         17 . The method of  claim 10  wherein the assembly is vacuum bagged during the heating process.  
     
     
         18 . The method of  claim 10  wherein at least one thermocouple is also placed between the panels to monitor temperature during the heating cycle.  
     
     
         19 . The method of  claim 10  wherein two thermocouples are installed at opposite diagonal corners of the panel.  
     
     
         20 . An adhesive film for joining panels together comprising; 
 a single layer woven fabric, pre-impregnated with thermoset resin and partially cured; and,    at least one heating wire, wherein the wire is woven into the fabric in a serpentine pattern, such that the wire can be accessed on both ends external to the fabric, and the wire resin and fabric are packaged as one unit which can be placed between panels to be joined.    
     
     
         21 . The adhesive film of  claim 20  further comprising at least one thermocouple mounted on the fabric with connections external to the film.