Method and tooling arrangement for diffusing braze weight pressure in brazing of aerostructure honeycomb sandwich panel

An arrangement for brazing a lightweight metallic aerostructure panel having at least two opposing metal face sheets and a central metal honeycomb core layer, which comprises:

• a tooling base having a determinable upper surface;
• an aerostructure panel having at least upper and lower facing sheets that are to be brazed to a central honeycomb core layer to provide a unitary aerostructure honeycomb sandwich panel and being positioned on said upper surface of the tooling base;
• a conformable working honeycomb core layer disposed on an upper surface of said upper facing sheet of said aerostructure panel so as to conform to the configuration of said upper facing sheet, and
• a pressure means disposed on an upper surface of said working honeycomb core layer to provide uniform downward pressure on said honeycomb core and thereby cause a uniform pressure to be exerted upon the aerostructure panel when it is subjected to a brazing cycle having an elevated temperature for brazing together the elements of the panel without wrinkling of the face sheets of such aerostructure panel.

An arrangement for brazing a lightweight metallic aerostructure panel having at least two opposing metal face sheets and a central metal honeycomb core layer, which comprises:

• a tooling base having a determinable upper surface;
• an aerostructure panel having at least upper and lower facing sheets that are to be brazed to a central honeycomb core layer to provide a unitary aerostructure honeycomb sandwich panel and being positioned on said upper surface of the tooling base;
• a conformable working honeycomb core layer disposed on an upper surface of said upper facing sheet of said aerostructure panel so as to conform to the configuration of said upper facing sheet;
• a pressure means disposed on an upper surface of said working honeycomb core layer to provide uniform downward pressure on said honeycomb core and thereby cause a uniform pressure to be exerted upon the aerostructure panel when the panel is subjected to a brazing cycle having an elevated temperature for brazing together the elements of the panel without wrinkling of the face sheets of such aerostructure panel, wherein said pressure means comprises a pan having a conformable bottom surface and quantity of metallic pellets uniformly disposed in said pan, and said conformable bottom surface of the pan is a metallic relatively thin conformable sheet that receives a uniform layer of metallic pellets to provide a pressure surface that exerts a pressure on the working honeycomb core layer to thereby apply a uniform pressure to the upper face sheet of the aerostructure panel to be brazed together;
• lubricated slip sheet means disposed between the upper face sheet of the aerostructure panel and the working honeycomb core layer and between the working honeycomb core layer and the pressure means and between the lower face sheet of the aerostructure panel and the tooling base;
• and
• an additional layer of working honeycomb core positioned between the tooling base and the lower face sheet of the aerostructure panel to be brazed, wherein a layer of conformable tooling honeycomb core having non-fixed contracting upper and lower face sheets and having a thickness that is at least equal to the thickness of an adjacent portion of the aerospace panel to be brazed is disposed around the outer perimeter of the aerostructure panel to be brazed for operable cooperation with the upper tooling honeycomb core and the tooling base.

In an arrangement for brazing a lightweight metallic honeycomb sandwich panel which includes a tooling base for receiving a metallic honeycomb core panel comprising opposing upper and lower metallic face sheets and a central layer of metallic honeycomb core to be brazed together in a brazing cycle into a unitary aerostructure panel, and a pressure means to exert a pressure on the upper face sheet of the panel to insure intimate contact of such opposing face sheets and the central layer of honeycomb core during a brazing cycle, the improvement comprising:

• a layer of flexible conformable working honeycomb core interposed between the upper face sheet of the honeycomb core panel to be brazed and the pressure means to ensure that the pressure exerted by such pressure means is uniformly applied over the upper face sheet of such panel during the brazing cycle;
• lubricated slip sheet means interposed between the working honeycomb core layer and both the aerostructure panel to be brazed and the pressure means;
• and
• an additional core layer having non-fixed contact with upper and lower face sheets and having a thickness substantially equal to the thickness of the aerostructure panel to be brazed which is disposed around the outer perimeter of such panel and in operable contact with the tooling base and deformable working honeycomb core means to provide a uniform pressure to an outer face sheet of such acrostructure panel.

In an arrangement for brazing a lightweight metallic honeycomb sandwich panel which includes a tooling base for receiving a metallic honeycomb core panel comprising opposing upper and lower metallic face sheets and a central layer of metallic honeycomb core to be brazed together in a brazing cycle into a unitary aerostructure panel, and a pressure means to exert a pressure on the upper face sheet of the panel to insure intimate contact of such opposing face sheets and the central layer of honeycomb core during a brazing cycle, the improvement comprising:

• a layer of flexible conformable working honeycomb core interposed between the upper face sheet of the honeycomb core panel to be brazed and the pressure means to ensure that the pressure exerted by such pressure means is uniformly applied over the upper face sheet of such panel during the brazing cycle;
• lubricated slip sheet means interposed between the working honeycomb core layer and both the aerostructure panel to be brazed and the pressure means;
• an additional core layer having non-fixed contact with upper and lower face sheets and having a thickness substantially equal to the thickness of the aerostructure panel to be brazed which is disposed around the outer perimeter of such panel and in operable contact with the tooling base and deformable working honeycomb core means to provide a uniform pressure to an outer face sheet of such aerostructure panel;
• and
• an additional layer of conformable working honeycomb core disposed between the tooling base and the lower face of the aerostructure panel to be brazed.

An apparatus for brazing a metallic aerostructure panel comprising:

• a tooling base having an upper surface which is capable of supporting a central honeycomb core having an upper and lower face, an upper face sheet adjacent to the upper face and a lower face sheet adjacent to the lower face;
• at least one conformable honeycomb core;
• and
• a pressure means for providing pressure on the at least one conformable honeycomb core so that the at least one conformable honeycomb core exerts uniform pressure on at least the upper face sheet during a brazing cycle for brazing the upper and lower face sheets to the central honeycomb core.