Electric Heating Sleeve for Metal Forming

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Solution Overview

Problem

The existing methods for forming collars on sheet metal workpieces, such as in the automotive industry, face limitations in achieving desired collar height due to material tearing risks and require time-consuming heating processes that compromise tool strength.

Innovation Solution

A device where only the workpiece is heated in the forming area using an electrically conductive sleeve and counter-holder, while the tool remains cold, reducing the risk of material tearing and maintaining tool strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the stamp is heated to apply heat to the forming zone, then the forming process is optimized and material tearing risk is reduced, but the stamp loses its strength and has only a short service life

Engineering Contradiction:
Improvereduction of material tearing riskVSAvoidstamp strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The heating function is segmented from the stamp tool and transferred to a separate electrical heating device. The heating device consists of independent heating elements that can apply heat to the workpiece without heating the stamp, thus resolving the contradiction between reducing material tearing risk through heating and maintaining stamp strength.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

An electrical heating device acts as an intermediary between the power source and the workpiece. This intermediary device applies heat directly to the forming zone of the workpiece without transferring heat to the stamp, thereby reducing material tearing risk while preserving stamp strength and service life.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Temperature

If electrodes are moved up to the workpiece and then moved away to make room for the ram approach, then heating can be applied, but the machining process is divided into two phases and takes a lot of time

Engineering Contradiction:
Improveworkpiece heatingVSAvoidmachining cycle time
Core Design Contradiction:
TemperatureVSLoss of time

Solution Approach 1:

The heating operation and the forming operation are merged into a single continuous process. The electrical heating device remains in position during both heating and forming phases, eliminating the need to move electrodes out of the way. This integration reduces the machining cycle time while maintaining effective workpiece heating.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The heating action continues uninterrupted during the entire forming process. The electrical heating device maintains continuous heat application to the workpiece throughout the forming operation, eliminating idle time phases and ensuring continuous useful action, thereby reducing overall process time.

Inventive Principle:
Principle #20Continuity of useful action

3Temperature

If a ram must be raised and then lowered again after heating, then sheet metal can be heated, but the process is time consuming

Engineering Contradiction:
Improvesheet metal heatingVSAvoidheating process time
Core Design Contradiction:
TemperatureVSLoss of time

Solution Approach 1:

The heating device is positioned and prepared in advance before the forming operation begins. The electrical heating elements are already in place and can immediately begin heating the sheet metal without requiring the ram to be raised and lowered, thus eliminating time-consuming movements and reducing the overall heating process time.

Inventive Principle:
Principle #10Preliminary action

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 improved collar formation with reduced tearing risk, enabling the use of high-strength thin sheet metals, saving weight and costs, and streamlining the machining process by focusing heat on a narrow area.

Implementation Method 1

a heating device with an electrical power source, wherein essentially only the workpiece is heated and only in the forming area

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

The sleeve serves as a hold-down device and at the same time as an electrode

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP3027335B1Device for forming metals
Publication Date: 2017.06.28 ALLGAIER WERKE GMBH
  • EP3027335B1 patent drawingFigure 1
  • EP3027335B1 patent drawingFigure 2
  • EP3027335B1 patent drawingFigure 3

AI summary

The invention relates to a device for processing a workpiece, said device comprising the following features: - a punch on the one side of the workpiece - a die on the opposite side of the workpiece; - a conductive electric heating system for generating an electric current that flows through the workpiece starting from a component situated on the one side of the workpiece outside of the punch to a component situated on the other side of the workpiece outside of the die.