Structured Electrode for Uniform Sheet Metal Heating

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Solution Overview

Problem

Conventional conductive heating methods for metal sheets are inefficient for irregularly shaped components, leading to uneven heating, hotspots, and inability to achieve desired material properties, particularly in edge areas, resulting in material waste and increased tool wear.

Innovation Solution

A method and device using electrodes with an uneven, structured contact area and separate current feed and discharge electrodes adapted to the metal sheet's contour, ensuring homogeneous current densities and reducing hotspots, allowing for efficient heating of irregularly shaped metal sheets without the need for additional processing steps.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If conventional conductive heating methods are used on irregularly shaped metal sheets, then heating speed is improved, but heating uniformity deteriorates causing hotspots and uneven temperature distribution

Engineering Contradiction:
Improveheating speedVSAvoidheating uniformity
Core Design Contradiction:
SpeedVSManufacturing precision

Solution Approach 1:

The heating process is segmented into multiple independent heating zones, each with its own electrode pair. Current feed and discharge electrodes are arranged in sections along the sheet contour, allowing independent control of current density in different areas to achieve uniform heating across irregular shapes

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different areas of the metal sheet receive tailored heating conditions through locally adapted electrode arrangements. The electrode configuration and current density are optimized for each specific region's geometry, ensuring appropriate heat input for both rectangular and irregularly shaped areas

Inventive Principle:
Principle #3Local quality

2Productivity

If electrodes are brought into contact with edge areas of metal sheets for heating, then heating efficiency is improved, but material waste increases due to insufficient hardening in contact areas

Engineering Contradiction:
Improveheating efficiencyVSAvoidmaterial waste
Core Design Contradiction:
ProductivityVSLoss of substance

Solution Approach 1:

Instead of avoiding edge areas or accepting insufficient hardening, the invention inverts the approach by specifically designing electrode contact to occur at edge areas. The electrode arrangement ensures these previously problematic zones receive adequate heat treatment for proper hardening, eliminating the need for trim loss

Inventive Principle:
Principle #13The other way round (Inversion)

3Speed

If current is introduced at certain points during conductive heating, then heating speed is improved, but hotspots are created causing uneven heating

Engineering Contradiction:
Improveheating speedVSAvoidheating uniformity
Core Design Contradiction:
SpeedVSManufacturing precision

Solution Approach 1:

The concentrated point heating is segmented into multiple distributed contact points along the sheet contour. Instead of single-point current introduction, multiple electrode pairs are arranged sectionally, distributing the heat input across many locations to maintain heating speed while eliminating hotspots

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The current density parameter is varied across different zones by adjusting electrode arrangement and dimensions. This allows optimization of heat input distribution, maintaining high heating rates while preventing localized overheating through controlled parameter variation

Inventive Principle:
Principle #35Parameter changes

4Device complexity

If conventional heating methods are used for metal sheets, then equipment simplicity is maintained, but heating time increases causing scale formation and tool wear

Engineering Contradiction:
Improveequipment simplicityVSAvoidheating time
Core Design Contradiction:
Device complexityVSLoss of time

Solution Approach 1:

The conventional thermal conduction heating mechanism is replaced with direct electrical heating through Joule heating in the metal sheet. This substitution dramatically reduces heating time from minutes to seconds, minimizing scale formation while maintaining process simplicity through direct energy conversion

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

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

Achieves uniform heating of metal sheets, reducing material waste and tool wear, enabling rapid heating to the desired temperature with minimal scaling, and eliminating the need for additional processing steps like edge removal.

Implementation Method 1

The sheet metal is heated by applying an electric current through the resulting Joule heat

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

conductive heating

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP3259377B1Method for conductively heating sheet metal and heating device therefor
Publication Date: 2019.09.25 GOTTFRIED WILHELM LEIBNIZ UNIV HANNOVER
  • EP3259377B1 patent drawingFigure 1~2
  • EP3259377B1 patent drawingFigure 3
  • EP3259377B1 patent drawingFigure 4~5

AI summary

The invention relates to a method for conductively heating sheet metal, wherein the sheet metal or at least a region of the sheet metal to be conductively heated has an outer contour which is rectangular or non-rectangular, wherein, in order to carry out the conductive heating, at least one electrode having a contact region is brought into electrical contact with the sheet metal and the electrical current is fed into and/or discharged out of the sheet metal in order to carry out the conductive heating, wherein the electrode has an uneven, structured contact region having a plurality of contact surfaces spaced apart from each other, via which a plurality of individual contact points are formed, spaced apart from each other between the electrode and the sheet metal. The invention further relates to an electrode for conductively heating a plate and a conductive heating apparatus for carrying out a method for conductively heating sheet metal.