Film adhesive bonding apparatus and process

Abstract

The invention relates to a method of bonding two members together utilizing a stack of solid film adhesive and a layer of solid film adhesive, both disposed between the members. A pressure-applying device may be utilized to apply low pressure to force the members together. The pressure may force the stack to compress and expand in varying directions in order to substantially remove air-bubbles between the layer and one of the members. A heating device may be utilized to change the layer and the stack into liquid states in order to bond the members together with a void-free bond-line.

1 . An apparatus comprising two bonded members prepared by a process comprising the steps of:
 (a) placing a layer of a first film adhesive, in a solid state, so that a first side of said layer is disposed against a first member;   (b) placing a stack of a second film adhesive, in another solid state, so that said stack is aligned against and along a second side of said layer with the layer and said stack disposed between the first member and a second member, with the stack not covering a substantial portion of said side of said layer; and   (c) applying heat to turn each of said layer and said stack into liquid states, and pressure to force said first and second members towards one another, with the second member being disposed against the stack, causing said stack to compress in a height direction, to expand in a width direction, and to spread out against said second side of said layer to substantially cover said second side of said layer while removing air-bubbles between said first side of said layer and said first member in order to bond said first and second members together with a substantially void-free bond line.   
     
     
         2 . The apparatus of  claim 1  wherein said first and second members each have length and width dimensions with each respective length dimension being at least twice as large as its respective width dimension. 
     
     
         3 . The apparatus of  claim 1  wherein said layer of said first film adhesive has a thickness in a range of 0.005 inches to 0.015 inches. 
     
     
         4 . The apparatus of  claim 1  wherein said height of said stack is substantially in a range of 0.04 inches to 0.10 inches, and said width of said stack is substantially in the range of 0.25 inches to 1 inch. 
     
     
         5 . The apparatus of  claim 1  wherein the step of applying pressure to force said first and second members towards one another utilizes at least one of a clamp, a pneumatic device, or a spring. 
     
     
         6 . The apparatus of  claim 1  wherein the step of applying pressure comprises applying pressure substantially in a range of one pound per square inch to five pounds per square inch. 
     
     
         7 . The apparatus of  claim 1  wherein the step of heating utilizes an oven. 
     
     
         8 . The apparatus of  claim 1  wherein the step of heating comprises heating at a temperature substantially in a range of 150 degrees Fahrenheit to 350 degrees Fahrenheit. 
     
     
         9 . The apparatus of  claim 1  wherein said first and second film adhesives have viscosities which are over one-million poise at room temperature, and viscosities which are substantially between nine-hundred to twenty-seven-hundred poise after being heated. 
     
     
         10 . The apparatus of  claim 1  wherein said first and second members each have length and width dimensions with each respective length dimension being substantially greater than its respective width dimension. 
     
     
         11 . The apparatus of  claim 1  wherein one of the first and second members is made of a composite and the other of the first and second members is made of a composite or a metal. 
     
     
         12 . The apparatus of  claim 1  wherein the first film adhesive and the second film adhesive are both epoxies. 
     
     
         13 . The apparatus of  claim 1  wherein the step of placing a layer of the first film adhesive further comprises placing the first side of said layer so that it substantially covers a surface of the first member. 
     
     
         14 . The apparatus of  claim 1  wherein the step of placing the stack of the second film adhesive further comprises aligning the stack against and along a length-wise section of the second side of said layer. 
     
     
         15 . The apparatus of  claim 1  wherein the step of placing the stack of the second film adhesive further comprises aligning the stack against and along a length-wise center section of the second side of said layer. 
     
     
         16 . The apparatus of  claim 1  wherein the step of placing the stack of the second film adhesive further comprises aligning the stack so that it does not cover a substantial portion of said second side of said layer. 
     
     
         17 . An aircraft comprising two bonded members prepared by a process comprising the steps of:
 (a) placing a layer of a first film adhesive, in a solid state, so that a first side of said layer is disposed against a first member;   (b) placing a stack of a second film adhesive, in another solid state, so that said stack is aligned against and along a second side of said layer with the layer and said stack disposed between the first member and a second member, with the stack not covering a substantial portion of said side of said layer; and   (c) applying heat to turn each of said layer and said stack into liquid states, and pressure to force said first and second members towards one another, with the second member being disposed against the stack, causing said stack to compress in a height direction, to expand in a width direction, and to spread out against said second side of said layer to substantially cover said second side of said layer while removing air-bubbles between said first side of said layer and said first member in order to bond said first and second members together with a substantially void-free bond line.   
     
     
         18 . A pressure-applying apparatus comprising:
 a first pressure-applying member;   a second pressure-applying member spaced-apart from and opposing the first pressure-applying member, wherein the first and second pressure-applying members are configured to move towards one another to apply pressure to items disposed between the first and second pressure-applying members;   a first member disposed against the first pressure-applying member in-between the first and second pressure-applying members;   a layer of a first film adhesive, in a solid state, with a first side of said layer disposed against the first member in-between the first and second pressure-applying members;   a stack of a second film adhesive, in another solid state, disposed against and along a second side of said layer with the layer and said stack disposed between the first member and a second member, with the stack not covering a substantial portion of said second side of said layer; and   a second member disposed in between and against both the stack and the second pressure-applying member   
     
     
         19 . The pressure-applying apparatus of  claim 18  wherein the first member is disposed above the first pressure-applying member in between and against both the first pressure-applying member and the layer, the layer is disposed above the first member in between and against both the first member and the stack, the stack is disposed above the layer in between and against both the layer and the second member; the second member is disposed above the stack in between and against both the stack and the second pressure-applying member, and the second pressure-applying member is disposed above and against the second member. 
     
     
         20 . The pressure-applying apparatus of  claim 18  further comprising a heating device for heating the layer and the stack.