Conductive Heating Roller Electrodes for Sheet Metal Forming

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Solution Overview

Problem

Current sheet metal forming processes require high energy consumption and are inefficient for heating non-rectangular sheets, leading to uneven heating and material hardening issues, particularly in the production of press-hardened components.

Innovation Solution

A method using a conductive heating device with rotatably mounted roller-shaped electrodes to heat sheet metal to the necessary temperature for forming, allowing for efficient heating of sheets with any shape, followed by a press hardening process that creates the desired martensitic structure through targeted cooling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If continuous furnaces are used to heat sheet metal, then the sheet metal reaches the required temperature for forming, but energy consumption increases and equipment complexity increases

Engineering Contradiction:
Improvesheet metal temperatureVSAvoidenergy consumption
Core Design Contradiction:
TemperatureVSUse of energy by moving object

Solution Approach 1:

The patent replaces the thermal field system (continuous furnace heating) with an electrical field system (conductive heating through roller electrodes). Electrical current is conducted through the sheet metal via contact with rotating roller electrodes, generating heat through Joule heating effect. This substitution achieves the required temperature rise while significantly reducing energy consumption and eliminating the need for large continuous furnace equipment.

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

Solution Approach 2:

The patent introduces roller-shaped electrodes as an intermediary medium between the power source and the sheet metal. These rollers conduct electrical current through direct contact with the sheet metal surface, enabling efficient conductive heating. The rollers serve as the mediating element that transfers electrical energy to the sheet metal, achieving temperature elevation without requiring continuous furnace equipment.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If conductive heating is applied to non-rectangular sheets, then heating efficiency improves, but current density varies causing uneven heating

Engineering Contradiction:
Improveheating efficiencyVSAvoidheating uniformity
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent employs rotating roller electrodes that dynamically adapt to the sheet metal's contour. The rollers rotate and conform to the varying geometry of non-rectangular sheets, maintaining consistent contact pressure and current density distribution across different sheet shapes. This dynamic adaptation ensures uniform heating efficiency regardless of sheet geometry, resolving the contradiction between heating efficiency and heating uniformity.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent controls and adjusts electrical parameters (current, voltage, contact pressure) during the conductive heating process to maintain uniform current density across non-rectangular sheets. By dynamically adjusting these parameters based on sheet geometry, the system achieves both high heating efficiency and uniform temperature distribution, eliminating the contradiction between productivity and manufacturing precision.

Inventive Principle:
Principle #35Parameter changes

3Temperature

If sheet metal is heated to high temperature for forming, then material formability improves, but processing time increases

Engineering Contradiction:
Improvesheet metal temperatureVSAvoidprocessing time
Core Design Contradiction:
TemperatureVSLoss of time

Solution Approach 1:

The patent replaces slow thermal conduction heating with rapid electrical conductive heating. By passing electrical current directly through the sheet metal via roller electrodes, the system generates heat internally and rapidly, achieving the required temperature for improved material formability in a fraction of the time required by conventional furnace heating, thus resolving the time-temperature contradiction.

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

4Strength

If press hardening is performed to achieve high tensile strength, then material strength increases, but equipment complexity and energy consumption increase

Engineering Contradiction:
Improvetensile strengthVSAvoidequipment complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent combines the heating function and the press hardening forming function into a single integrated process. The conductive heating rollers simultaneously heat the sheet metal and apply forming pressure, eliminating the need for separate heating equipment and reducing overall system complexity. This merging achieves high tensile strength through press hardening while simplifying the equipment configuration.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The roller electrodes serve multiple functions: they conduct electrical current for heating, provide mechanical contact for forming, and can be designed with cooling capabilities for controlled cooling during press hardening. This multi-functionality reduces equipment complexity while achieving the desired material strength properties.

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 approach reduces processing time and energy consumption, enabling the production of sheet metal components with varying material properties across different areas, achieving high tensile strength and elongation as needed, while maintaining uniform heating and avoiding unnecessary hardening.

Implementation Method 1

the sheet metal is conductively heated by means of a conductive heating device to a temperature necessary for sheet metal forming

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

the conductive heating device has at least two rotatably mounted, roller-shaped electrodes for conductively applying current to the sheet metal

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 3

the components have previously been passed through continuous furnaces... the sheet metal is heated to a temperature of approximately 950°C and then cooled down in a targeted manner during the forming process

Methodology Applied
Scientific EffectTargeted cooling: Cooling

Implementation Method 4

This cooling process hardens the sheet metal at least in some places by converting the sheet material structure into a martensitic structure

Methodology Applied
Scientific EffectPhase transformation: Phase Change

Data Source

PatentEP3589756B1Method for forming a sheet metal and manufacturing system with conductive heating device
Publication Date: 2024.05.15 GOTTFRIED WILHELM LEIBNIZ UNIV HANNOVER
  • EP3589756B1 patent drawingFigure 1
  • EP3589756B1 patent drawingFigure 2
  • EP3589756B1 patent drawingFigure 3

AI summary

The invention relates to a method for shaping a metal sheet into a three-dimensional component by metal-sheet shaping, the metal sheet being conductively heated to a temperature necessary for the metal-sheet shaping by means of a conductive heating device, characterized in that the conductive heating device has at least two rotatably mounted, roller-shaped electrodes for conductively applying current to the metal sheet, the metal sheet being fed between at least two roller-shaped electrodes set into rotation and being conductively heated by means of said electrodes, and the metal sheet being fed from the conductive heating device to a pressing device, while the metal sheet is still in the heated state from the conductive heating by means of the at least two roller-shaped electrodes set into rotation, and being shaped into the three-dimensional component there by pressing, while the metal sheet is still in the heated state from the conductive heating. The invention further relates to a production system for producing three-dimensional components from metal sheet and to a conductive heating device for conductively heating a metal sheet.