Tool and method for bonding layers of a metallic axisymmetric structure having complex curvatures

Patent metadata

Field	Value
Publication number	US-10232463-B2
Application number	US-201615347624-A
Country	US
Kind code	B2
Filing date	Nov 9, 2016
Priority date	Feb 11, 2008
Publication date	Mar 19, 2019
Grant date	Mar 19, 2019

Abstract

A tool and method for bonding layers of a shell by the differential pressure bonding process. The tool and method includes a plurality of separable mandrel segments that combine to form a mandrel having a longitudinal axis, an outer surface, an upper end, and at least one substantially continuous inner surface. The inner surface has a substantially axisymmetric shape having complex curvature. In this embodiment, the tool further includes a retort configured to at least partially shroud the outer surface and upper end of the hollow body. The retort includes at least one vacuum port. The tool is configured to facilitate the compression of a plurality of layers of a multi-layer shell having complex curvature as the shell layers and an interdisposed bonding material are heated to an elevated bonding temperature.

First claim

What is claimed is:

1. A method of bonding a plurality of layered materials by differential pressure bonding to produce an axisymmetric shell having an exterior surface with at least one convex or concave curvature, the method comprising:
(a) assembling a segmented mandrel comprising a plurality of separable mandrel segments, the assembled mandrel having a longitudinal axis, an outer surface, an upper end, and a substantially continuous inner surface having a substantially axisymmetric shape;
(b) placing a retort to at least partially shroud the outer surface and the upper end of the assembled mandrel, the retort including a vacuum port;
(c) placing an impermeable flexible membrane about the substantially continuous inner surface of the assembled mandrel;
(d) assembling the impermeable flexible membrane and assembled mandrel to receive there between layers of the axisymmetric shell to be bonded together, wherein the axisymmetric shell is continuous along an entirety of the exterior surface;
(e) applying a vacuum to the vacuum port of the retort during a differential pressure bonding process that forces the impermeable flexible membrane in a radially outward direction and towards the substantially continuous inner surface of the assembled mandrel, thereby forcing the impermeable flexible membrane against the layers of the axisymmetric shell to be bonded together;
(f) bonding the layers of the axisymmetric shell by forcing the impermeable flexible membrane against the layers of the axisymmetric shell during a differential bonding process resulting in an axisymmetric bonded shell;
(g) removing the impermeable flexible membrane from the substantially continuous inner surface of the assembled mandrel, wherein the impermeable flexible membrane is flexible when removed from the assembled mandrel.

2. The method of claim 1 , further comprising:
(a) cooling the assembled mandrel and the axisymmetric bonded shell;
(b) removing at least a first mandrel segment from the plurality of separable mandrel segments; and
(c) separating the axisymmetric bonded shell from the remaining mandrel segment or segments of the assembled mandrel.

3. The method of claim 1 , further comprising positioning a thermal shield concentrically inside the layers of the axisymmetric shell prior to heating and bonding.

4. The method of claim 1 , wherein the plurality of separable mandrel segments comprises a lower mandrel segment and an upper mandrel segment atop the lower mandrel segment, and wherein the upper and the lower mandrel segment are separable at a joint that substantially coincides with a highlight of the exterior surface of the axisymmetric shell.

5. A method of bonding a plurality of layered materials by differential pressure bonding, the method comprising:
(a) assembling the plurality of layered materials into a pre-bond shell assembly, the pre-bond shell assembly having an axisymmetric shape and an exterior surface with at least one convex or concave curvature, wherein the pre-bond shell assembly is continuous along the entirety of an exterior surface;
(b) positioning the pre-bond shell assembly into a first mandrel segment having a first axisymmetric contoured inner surface;
(c) assembling a second mandrel segment having a second axisymmetric contoured inner surface onto the first mandrel segment creating an assembled mandrel, the second axisymmetric contoured inner surface and the first axisymmetric contoured inner surface configured to define a mandrel inner surface that substantially conforms to the axisymmetric shape of the pre-bond shell assembly;
(d) positioning a thermal shield assembly, comprising a frame, an outer skin surrounding the frame, an inner skin that lines the interior of the frame, and a thermal insulation that is disposed in between the inner skin and the outer skin, concentrically inside the pre-bond shell assembly; and
(e) heating the pre-bond shell assembly, the first mandrel segment, and the second mandrel segment to an elevated bonding temperature while establishing a pressure differential that presses the pre-bond shell assembly against the mandrel inner surface as the plurality of layered materials are bonded together.

6. The method of claim 5 , further comprising:
positioning the first mandrel segment and the pre-bond shell assembly on a base plate after positioning the pre-bond shell assembly into the first mandrel segment;
positioning a retort assembly that covers a top surface and a cylindrical outer surface of the assembled mandrel, the retort assembly including a vacuum port after assembling the second mandrel segment;
sealing an impermeable flexible membrane along a bottom edge to the base plate and along a top edge to the retort assembly.

Assignees

• Rohr Inc

Inventors

• Sommer Thomas Edward
• Ramsey Mark Alan
• Rishel David Dwain

Classifications

• B32B37/10

  characterised by the pressing technique, e.g. using action of vacuum or fluid pressure · CPC title

• B32B37/0046

  characterised by constructional aspects of the apparatus · CPC title

• B23K2101/02

  Honeycomb structures · CPC title

• Y10T156/10

  Methods of surface bonding and/or assembly therefor · CPC title

• B23K20/023 Primary

  Thermo-compression bonding · CPC title