Active Thermal Buffer for Uniform Joule Heating at Blank Ends

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Joule heating of materials is inconsistent due to thermal effects from electrical terminals, which act as heat sinks, causing uneven heating and dimensional instability in formed metal components.

Innovation Solution

An active thermal buffer element is interposed between the material and electrical terminals, creating a temperature gradient that maintains the material's end portions at the desired temperature while the terminals act as thermal sinks, thereby ensuring consistent joule heating and reducing deformation during the forming process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If electrical terminals are used for joule heating, then heating capability is improved, but thermal effects from terminals cause inconsistent heating and dimensional instability

Engineering Contradiction:
Improveheating capabilityVSAvoiddimensional stability
Core Design Contradiction:
PowerVSManufacturing precision

Solution Approach 1:

A thermal buffer element is introduced as an intermediary component between the electrical terminal and the material blank. This buffer element absorbs the thermal effects from the terminal, preventing direct thermal interference with the material being heated. The buffer element acts as a mediator that decouples the heating function from the dimensional stability requirement, allowing the terminal to provide power while the buffer protects the material from harmful thermal effects.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Temperature

If electrical terminals act as heat sinks, then heat management is improved, but end portions of material remain underheated

Engineering Contradiction:
Improveheat managementVSAvoidheating consistency
Core Design Contradiction:
TemperatureVSManufacturing precision

Solution Approach 1:

The thermal buffer element creates a localized thermal management solution by positioning itself specifically at the interface between the terminal and material. Different regions of the system are given different thermal characteristics: the buffer element absorbs excess heat from the terminal while allowing controlled heat transfer to the material, ensuring uniform heating across the material surface without compromising overall heat management.

Inventive Principle:
Principle #3Local quality

3Adaptability or versatility

If flexible couplings are used to accommodate terminal movement, then adaptability is improved, but deformation of material increases

Engineering Contradiction:
Improvemovement accommodationVSAvoiddimensional stability
Core Design Contradiction:
Adaptability or versatilityVSShape

Solution Approach 1:

The thermal buffer element serves as a mechanical intermediary that accommodates movement between the rigid electrical terminal and the material blank. By providing a compliant interface, the buffer element allows for relative movement and positioning adjustments without transmitting deforming forces to the material, thus maintaining both adaptability and dimensional stability.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

The active thermal buffer element allows for more consistent and efficient joule heating of materials, preventing under- or over-heating and maintaining dimensional stability by absorbing the thermal effects of the electrical terminals, enabling full utilization of the material without the need for end portion removal.

Implementation Method 1

Joule heating, also referred to as resistive heating, is the generation of heat by passing an electric current through an electrically conductive material

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

creating a temperature gradient that maintains the material's end portions at the desired temperature

Methodology Applied
Scientific EffectTemperature gradient: Temperature Gradient

Implementation Method 3

the electrical connections can act as heat sinks which draw heat away from the end portions 22,24 so that they remain at a lower temperature

Methodology Applied
Scientific EffectHeat sink effect: Heat Sink

Data Source

PatentEP3815191B1System and method employing active thermal buffer element for improved joule heating
Publication Date: 2023.09.20 SPIRIT AEROSYSTEMS INC
  • EP3815191B1 patent drawingFigure 1~2
  • EP3815191B1 patent drawingFigure 3
  • EP3815191B1 patent drawingFigure 4

AI summary

A system and method for more consistent joule heating of a material blank to a desired temperature. An electrical terminal delivers a current to an end portion of the blank. The terminal has a heat sink effect which would otherwise prevent the end portion from reaching the desired temperature. An active thermal buffer element is interposed between the terminal and the end portion. The buffer element includes a first surface which abuts the end portion and a second surface which abuts the terminal. The buffer element is joule heated with the blank, and a temperature gradient is created across the buffer element such that the first surface is at the desired temperature and the second surface is at a lower temperature due to the heat sink effect of the terminal. The buffer element thereby compensates for the heat sink effect and allows the end portion to reach the desired temperature.