Layup Mandrel Rib Structure for Composite Molding

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Solution Overview

Problem

Conventional methods for manufacturing layup mandrels are inefficient due to the need for complex assembly, extensive machining, and high material usage, particularly in creating metal face sheets, which require significant raw material removal to achieve the desired shape.

Innovation Solution

A layup mandrel system comprising a rib structure with a lofted surface and a non-porous skin, where the ribs shape the curvature of the part during curing, and a modular base with handles for easy transportation, using composite materials for the ribs and skin, and vacuum integrity to press the part against the skin for molding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a metal face sheet is used for the layup mandrel, then the structural strength and durability are improved, but the manufacturing complexity and material waste increase significantly due to extensive machining operations required to achieve the final shape

Engineering Contradiction:
Improvestructural strengthVSAvoidmanufacturing complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent applies composite materials by constructing the face sheet from a modular assembly of separate structural components (ribs, skin, and optional stiffeners) rather than using solid metal. This composite approach maintains the required structural strength while eliminating the need for extensive machining operations, as the components are assembled in their final configurations using adhesives and fasteners

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The face sheet is segmented into discrete components including ribs, skin panels, and stiffeners that can be manufactured separately and assembled modularly. This segmentation allows each component to be optimized independently and assembled without complex machining, reducing both manufacturing complexity and material waste while maintaining overall structural integrity

Inventive Principle:
Principle #1Segmentation

2Manufacturing precision

If a dedicated substructure is designed for the layup mandrel, then the molding precision is improved, but the manufacturing time and resource consumption increase due to complex assembly processes

Engineering Contradiction:
Improvemolding precisionVSAvoidmanufacturing time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The rib structures, skin panels, and other components are pre-formed to their final shapes and configurations before assembly. The ribs are pre-bent to match the desired curvature, and the skin is pre-cut to exact dimensions, eliminating the need for time-consuming on-site machining and adjustment during mandrel assembly

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent employs a modular and adaptable mandrel design where components can be easily assembled, disassembled, and reconfigured. The use of removable fasteners and adhesive bonding allows for quick assembly changes without permanent modifications, reducing manufacturing time while maintaining molding precision through consistent modular interfaces

Inventive Principle:
Principle #15Dynamics

3Manufacturing precision

If extensive machining operations are performed on the face sheet, then the surface accuracy is improved, but the material waste and production cost increase

Engineering Contradiction:
Improvesurface accuracyVSAvoidmaterial waste
Core Design Contradiction:
Manufacturing precisionVSLoss of substance

Solution Approach 1:

The skin component is designed as a thin-walled structure that is pre-formed to the required surface accuracy through forming processes rather than machining. This thin-film approach achieves the necessary surface quality for molding while minimizing material consumption and eliminating the need for subtractive machining operations that would generate significant waste

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The surface accuracy is achieved through pre-forming the skin and rib components to their final shapes before assembly. The components are manufactured with precise dimensions and surface finishes in advance, eliminating the need for subsequent machining operations and the associated material waste

Inventive Principle:
Principle #10Preliminary action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach simplifies the manufacturing process by reducing material waste, enabling efficient shaping of composite parts with a single machining step and allowing for the reuse of the base, while ensuring compatibility with high-temperature curing and reducing the need for extensive machining operations.

Implementation Method 1

the skin is non-porous so that the skin has vacuum integrity when the skin is sealed to a bagging film so as to form a bag containing the part, the vacuum integrity maintaining a vacuum in the bag used for pressing the part against the skin during curing of the composite material

Methodology Applied
Scientific EffectVacuum: Vacuum

Implementation Method 2

the ribs are disposed to at least partially shape the curvature molding a part pressed against the skin during curing of the part

Methodology Applied
Scientific EffectMechanical constraint: Mechanical Force

Data Source

PatentEP4163076B1Rapid tooling layup mandrel and method of moulding a part
Publication Date: 2024.11.27 THE BOEING CO
  • EP4163076B1 patent drawingFigure 1
  • EP4163076B1 patent drawingFigure 2
  • EP4163076B1 patent drawingFigure 3A~3B

AI summary

A layup mandrel (100), comprising: a rib structure (102) comprising ribs (104) defining a lofted surface (106); and a skin (108) attached to and supported by the rib structure (102), wherein: the skin (108) has a surface (301) having a curvature (112) of the lofted surface (106); the ribs (104) are disposed to at least partially shape the curvature (112) molding a part (300) pressed against the skin (108) during curing of the part (300); and the part (300) comprises or consists essentially of a composite material.