Conductive Heating Plates for Homogeneous Sheet Metal Hot Forming

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Solution Overview

Problem

Current hot-forming processes for producing high-strength sheet metal products face inefficiencies in heating metal blanks due to the need for large, complex furnace systems for homogeneous heating, and inductive heating methods that are less efficient and more inhomogeneous.

Innovation Solution

A hot-forming line with a rationally designed conductive heating system using a heating station with a lower and upper tool, where a metal plate is heated conductively through direct or indirect resistance heating, utilizing a heating plate with a conductive material and surface heating elements that can be selectively controlled to achieve efficient and homogeneous heating.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If continuous furnaces are used for heating metal blanks, then homogeneous heating is achieved, but the system becomes complex and requires large space

Engineering Contradiction:
Improvehomogeneous heatingVSAvoidsystem complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The heating system is segmented into multiple independent heating zones along the conveyor path, each zone equipped with its own heating elements. This allows distributed heating across different sections of the metal blank while maintaining overall system simplicity and reducing space requirements compared to a single large furnace.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The heating process transitions from a three-dimensional furnace chamber to a linear conveyor-based system with heating zones arranged along the length of the conveyor. This dimensional change reduces the space required while maintaining heating effectiveness through sequential exposure to multiple heating zones.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Speed

If inductive heating is used, then heating speed increases, but heating homogeneity decreases and efficiency depends on inductor distance

Engineering Contradiction:
Improveheating speedVSAvoidheating homogeneity
Core Design Contradiction:
SpeedVSStability of the object's composition

Solution Approach 1:

The heating process is divided into multiple sequential heating zones along the conveyor, each contributing to the overall temperature rise. This segmentation allows fast heating while maintaining homogeneity through distributed thermal input across different sections of the metal blank.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The heating process operates continuously as metal blanks move through multiple heating zones on the conveyor. This continuous action ensures consistent and homogeneous heating throughout the heating process while maintaining high heating speeds, eliminating the need for repeated heating cycles.

Inventive Principle:
Principle #20Continuity of useful action

3Loss of energy

If larger distance between inductor and component is used, then energy loss to inductor decreases, but heating efficiency decreases

Engineering Contradiction:
Improveenergy loss to inductorVSAvoidheating efficiency
Core Design Contradiction:
Loss of energyVSUse of energy by moving object

Solution Approach 1:

The heating function is distributed across multiple heating zones rather than relying on a single inductor. This segmentation allows each heating element to operate at optimal distances from the metal blank, balancing energy transfer efficiency with reduced energy loss to the heating elements themselves.

Inventive Principle:
Principle #1Segmentation

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 system enables rapid and efficient heating of metal blanks to the required temperatures for hot-forming, minimizing heat loss and distortion, with the ability to heat different areas of the metal plate to varying temperatures, and can handle blanks with varying thicknesses and cross-sections.

Implementation Method 1

The heat is transferred from the surface heating element to the metal plate by thermal conduction as a result of the at least indirect contact between the surface heating element and the metal plate to be heated

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

The warming up or heating up of a metal plate in the heating station takes place conductively through direct or indirect resistance heating. The heat is generated outside the metal board and reaches the metal board itself via its surface

Methodology Applied
Scientific EffectElectrical resistance heating: Joule Heating

Data Source

PatentEP2907881B2Thermoforming line and method for the preparation of thermoformed sheet metal products
Publication Date: 2021.11.10 BENTELER AUTOMOBILTECHNIK GMBH
  • EP2907881B2 patent drawingFigure 1a~2b
  • EP2907881B2 patent drawingFigure 3a~4b
  • EP2907881B2 patent drawingFigure 5

AI summary

A hot forming line for the production of hot-formed and press-hardened sheet metal products from metal blanks 6 comprises a heating station 1 and a forming station 2. The heating station 1 has a lower die 3 and an upper die 4, between which a metal blank 6 is held for heating. The heating of the metal blank 6 in the heating station 1 is effected by indirect resistance heating. The heat is generated outside the metal blank 6 and is transferred to the metal blank 6 itself by thermal conduction. For this purpose, the lower die 3 and/or the upper die 4 has an electric resistance heater 7 with at least one surface heating element. According to the invention, the surface heating element is a heating plate 8 with a plate body 9 made of an electrically conductive material, wherein the plate body 9 is designed as a heating conductor 11.For this purpose, the plate body 9 is slotted and, for example, provided with a slot 10 which extends over the thickness d of the plate body 9.