Induction-Heated RTM Tooling for Rapid Thermal Cycle Control

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Solution Overview

Problem

Current resin transfer molding techniques face limitations in achieving optimal thermal cycles for rapid heating and controlled cooling, which are essential for producing composite components with desired material properties and high production rates, while also being cost-effective.

Innovation Solution

A resin transfer molding apparatus with tooling dies having small thermal mass, inductively coupled with electric coils for precise thermal and pressure control, and a cooling system that allows rapid cooling through air gaps and coolant delivery, enabling efficient heating and cooling of susceptors to form composite parts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If traditional heated dies are used for resin transfer molding, then heating capability is provided, but cooling control is insufficient and thermal cycles cannot be optimized

Engineering Contradiction:
Improvethermal cycle controlVSAvoidcooling control capability
Core Design Contradiction:
TemperatureVSEase of manufacture

Solution Approach 1:

The tooling system is segmented into separate heating and cooling functional zones. Heating is achieved through inductively coupled susceptors that can be selectively activated, while cooling is provided through dedicated coolant channels in the tooling plates. This segmentation allows independent optimization of heating and cooling cycles without the compromises inherent in traditional heated dies.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Susceptors serve as intermediary elements between the induction heating system and the composite workpiece. These susceptors absorb electromagnetic energy and convert it to thermal energy, providing rapid and controlled heating. The tooling plates with coolant channels act as intermediaries for heat removal, enabling precise thermal cycle control that neither traditional heated dies nor simple open molds can achieve.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If rapid heating and cooling are implemented to increase production rate, then productivity improves, but thermal management complexity increases

Engineering Contradiction:
Improveproduction rateVSAvoidthermal management system
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

Traditional mechanical heating systems (heated dies requiring external heating elements and insulation) are replaced with an electromagnetic induction system. Induction coils generate electromagnetic fields that directly induce currents in the susceptors, providing rapid and efficient heating. This substitution eliminates the need for complex insulation and heat distribution mechanisms while enabling faster thermal cycles.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The thermal management system employs periodic action through controlled induction heating cycles followed by active cooling periods. The induction coils can be pulsed to provide rapid heating when needed, then deactivated while coolant flows remove heat. This periodic heating and cooling pattern optimizes production rate by minimizing cycle time while maintaining control over the thermal history of the composite part.

Inventive Principle:
Principle #19Periodic action

3Manufacturing precision

If controlled cool-down is implemented to optimize material properties, then material quality improves, but processing time increases

Engineering Contradiction:
Improvematerial propertiesVSAvoidcooling time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The cooling system utilizes hydraulics by circulating coolant through channels in the tooling plates. This fluid-based cooling system provides efficient and controllable heat removal from the composite workpiece. The flow rate, temperature, and timing of coolant delivery can be precisely controlled to achieve optimal cool-down rates for material property optimization without excessive processing time.

Inventive Principle:
Principle #29Pneumatics and hydraulics

Solution Approach 2:

The system enables dynamic parameter changes during the molding cycle by adjusting coolant flow rate, temperature, and timing based on the specific requirements of each processing stage. During rapid cooling phases, higher flow rates are used to quickly reduce temperature. During controlled cool-down phases for material property optimization, flow parameters are adjusted to achieve precise cooling rates. This dynamic parameter adjustment optimizes both time and material quality.

Inventive Principle:
Principle #35Parameter changes

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 allows for rapid and precise thermal management, enhancing the production rate and material properties of composite parts while maintaining affordability and producibility, enabling the formation of high-quality composite components.

Implementation Method 1

induction coils inductively coupled with the first and second susceptors

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

inductively coupled with electric coils that rapidly heat the susceptors

Methodology Applied
Scientific EffectInduction heating: Induction Heating

Implementation Method 3

air gaps through which a coolant may flow in order to provide rapid cool down of the susceptors

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP2195156B1Apparatus for resin transfer molding composite parts
Publication Date: 2014.05.21 THE BOEING CO
  • EP2195156B1 patent drawingFigure 1~2
  • EP2195156B1 patent drawingFigure 3~4
  • EP2195156B1 patent drawingFigure 5~7

AI summary

A composite fabrication apparatus (1) which may include a first tooling die (3) and a second tooling die (9) movable with respect to each other; a temperature control system (27) having induction coils (26) disposed in thermal contact with the first tooling die and the second tooling die; a first die susceptor (20) provided on the first tooling die and a second die susceptor (21) provided on the second tooling die and connected to the induction coils (26); and a cooling system (14) disposed in thermal contact with the first tooling die and the second tooling die. A resin transfer system (55) delivers resin from a resin source to the tooling dies to allow resin transfer molding. A composite fabrication method is also disclosed.