Modular Tooling for Stiffened Composite Panels

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Solution Overview

Problem

Existing tooling for curing stiffened composite panels, such as aircraft wing skins, is large, heavy, and expensive, leading to increased capital costs, floor space requirements, and long work-in-process flow times, with bagging processes often causing delays and requiring multiple tool sets.

Innovation Solution

The use of modular tooling with co-linearly arranged segments that can be reconfigured to form and cure parts of varying sizes and geometries, allowing for parallel layup, forming, bonding, and bagging processes, reducing tooling costs and assembly space while enabling quicker engineering changes and reduced cure times.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If existing large-scale tooling is used to cure stiffened composite panels, then the panels can be manufactured with required structural integrity, but the tooling becomes heavy, expensive, and requires large factory floor space

Engineering Contradiction:
Improvestructural integrity of cured panelsVSAvoidtooling weight
Core Design Contradiction:
StrengthVSWeight of stationary object

Solution Approach 1:

The tooling system is divided into multiple modular segments that can be assembled together to form the complete curing tool. Each segment is a manageable, lighter component that can be transported and stored separately, then assembled into the full tooling configuration when needed. This segmentation reduces the weight and handling difficulty of individual tooling components while maintaining the structural integrity required for panel curing.

Inventive Principle:
Principle #1Segmentation

2Strength

If existing large-scale tooling is used to cure stiffened composite panels, then the panels can be manufactured with required structural integrity, but the tooling cost increases significantly

Engineering Contradiction:
Improvestructural integrity of cured panelsVSAvoidtooling fabrication cost
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

By segmenting the tooling into standardized modular units, the fabrication cost is reduced through economies of scale. Multiple identical or similar segments can be manufactured using the same processes and materials, reducing tooling development and fabrication expenses compared to building a single large custom tool.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The modular segments are designed to be universal components that can be used across multiple different panel curing applications. Each segment can be reconfigured and combined with other segments to accommodate various panel sizes and geometries, eliminating the need for separate specialized tooling for each product variant.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Manufacturing precision

If existing tooling is used with serial assembly processes, then each component can be assembled with proper quality control, but the work-in-process flow time becomes excessively long

Engineering Contradiction:
Improveassembly quality controlVSAvoidwork-in-process flow time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The tooling segments are designed to allow parallel assembly operations. Multiple workstations can simultaneously perform different assembly tasks on different segments or on different portions of the same panel, rather than requiring sequential completion of each step. This parallel processing maintains quality control through standardized segment interfaces while dramatically reducing overall flow time.

Inventive Principle:
Principle #1Segmentation

4Productivity

If multiple identical tool sets are acquired to achieve desired production rates, then production capacity is sufficient, but both capital costs and factory floor space requirements increase

Engineering Contradiction:
Improveproduction rateVSAvoidfactory floor space
Core Design Contradiction:
ProductivityVSArea of stationary object

Solution Approach 1:

Instead of acquiring multiple complete tool sets, the system uses a library of modular segments that can be assembled into multiple complete tools as needed. The same physical segments can be disassembled from one tool configuration and reassembled into another, allowing a single set of segments to serve multiple production lines or tooling requirements over time.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The tooling system is designed to be dynamic and reconfigurable rather than static. Segments can be moved, repositioned, and reconfigured between different production runs and tooling applications, allowing the same physical infrastructure to support varying production rates and product mixes without requiring dedicated space for multiple fixed tool sets.

Inventive Principle:
Principle #15Dynamics

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 decreases tooling costs and assembly space requirements, enhances production flexibility, and reduces work-in-process flow times by enabling the simultaneous execution of layup, forming, bonding, and bagging processes, thereby improving overall production efficiency and reducing capital expenditures.

Implementation Method 1

Air in the space between the vacuum bag segments and the cure tool modules may be evacuated. This may be done before the composite parts are transferred to the cure tool modules.

Methodology Applied
Scientific EffectVacuum: Vacuum

Data Source

PatentEP3023234B1Fabrication of stiffened composite panels
Publication Date: 2020.01.08 THE BOEING CO
  • EP3023234B1 patent drawingFigure 1~3
  • EP3023234B1 patent drawingFigure 4
  • EP3023234B1 patent drawingFigure 5~6

AI summary

A stiffened composite panel is fabricated using modular tooling. Composite pre-preg is laid up and formed over forming block modules (58) each of which is assembled by co-linearly arranging a plurality of forming block segments (70). The formed stiffeners (52) are respectively transferred to individual cure tool modules (162) that are assembled by co-linearly arranging a plurality of cure tool module segments (88). The stiffeners (52) are assembled by arranging the cure tool modules (60) side-by-side, and a composite skin (50) is placed on the assembled stiffeners (52). The panel is vacuum bagged using a segmented vacuum bag (98).