Workpiece Heating System with Axial Gas Flow for Composite Curing

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Solution Overview

Problem

Conventional large autoclaves for curing composite parts are inefficient for small parts due to long curing cycle times, non-uniform heating, and high capital and operational costs, especially when multiple units are required for batch processing.

Innovation Solution

A workpiece heating system that includes a gas displacement device and heat exchanger to uniformly heat a mandrel and supported workpiece, using a hood system to direct heated gas in a controlled axial flow path, allowing for efficient heating and reducing the need for multiple large autoclaves.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If large autoclaves are used for batch curing of small composite parts, then the mechanical properties of cured parts can be maintained, but the curing cycle time increases significantly

Engineering Contradiction:
Improvemechanical properties uniformityVSAvoidcuring cycle time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The autoclave chamber is divided into multiple independently controllable heating zones along the axial direction, allowing different regions to be heated at different rates. This enables small parts to be cured faster while maintaining uniform mechanical properties by optimizing temperature distribution across zones.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Each heating zone has independently adjustable heating power and temperature control, allowing local optimization of curing parameters. Small composite parts can receive concentrated heating in specific zones to reduce overall curing time while maintaining quality standards.

Inventive Principle:
Principle #3Local quality

2Productivity

If large autoclaves are used for batch curing, then production capacity can be maintained, but the heating uniformity across all parts deteriorates

Engineering Contradiction:
Improvebatch curing capacityVSAvoidheating uniformity
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

Multiple heating zones with independent control allow simultaneous processing of multiple parts at different stages of curing. Each zone can be optimized for uniform temperature distribution, ensuring heating uniformity even when processing batches of varying sizes.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Temperature sensors in each heating zone provide real-time feedback to the control system, which adjusts heating power to maintain uniform temperature distribution. This feedback mechanism ensures consistent heating uniformity across all parts in the batch.

Inventive Principle:
Principle #23Feedback

3Reliability

If multiple large autoclaves are installed to maintain production rate during maintenance, then production continuity is ensured, but capital investment and operating costs increase significantly

Engineering Contradiction:
Improveproduction continuityVSAvoidcapital investment cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The autoclave system is designed with modular heating zones that can be independently maintained or repaired without shutting down the entire system. Other zones continue operation, ensuring production continuity while reducing the need for backup autoclaves.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The single autoclave with multiple heating zones can handle various part sizes and curing requirements through flexible zone configuration. This multi-functionality replaces the need for multiple specialized autoclaves, reducing capital investment while maintaining production capacity.

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

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 system enables faster and more uniform curing of small composite parts, reducing production costs and increasing efficiency by allowing for the use of smaller, less expensive equipment while maintaining uniform mechanical properties across the cured parts.

Implementation Method 1

The heat exchanger is configured to heat the gas prior to entering the gas displacement device

Methodology Applied
Scientific EffectHeat transfer: Heat Exchanger

Implementation Method 2

The gas displacement device has an outer circumferential exit configured to discharge a gas along a direction toward the mandrel backside

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 3

heating the mandrel in response to directing the gas through the first annular gap and the second annular gap

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP3466633B1High-performance workpiece heating system and method
Publication Date: 2019.11.13 THE BOEING CO
  • EP3466633B1 patent drawingFigure 1~3
  • EP3466633B1 patent drawingFigure 4~5
  • EP3466633B1 patent drawingFigure 6

AI summary

A workpiece heating system (200) includes an outer shell (102) configured to receive a mandrel (300) having a mandrel partside (310) configured to support a workpiece (418). A gas displacement device (150) is configured to discharge a gas (152) toward a mandrel backside (312). At least one heat exchanger (200) is configured to heat the gas (152) prior to the gas (152) entering the gas displacement device (150). A hood system (220) is configured to at least partially envelope the mandrel (300) when positioned within the outer shell (102). A hood first wall (222) and the mandrel backside (312) define a first annular gap (256) configured to receive the gas (152) discharged from the gas displacement device (150), and direct the gas (152) axial from the mandrel proximal end (304) to the mandrel distal end (306). A hood second wall (224) and the mandrel partside (310) define a second annular gap (260) configured to receive the gas (152) from the first annular gap (256) and direct the gas (152) axial from the mandrel distal end (306) to the mandrel proximal end (304).