Forming Tool Thermocouple for Real-Time Workpiece Temperature

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Solution Overview

Problem

Current methods for monitoring the temperature of a workpiece during forming processes in metalworking are unreliable due to limited accessibility, harsh conditions, and the inability to provide real-time measurements, leading to challenges in maintaining high workpiece quality and desired material properties.

Innovation Solution

A forming tool equipped with a temperature monitoring system that uses a voltmeter connected between two electrically conductive tool members, forming a thermocouple to measure the workpiece temperature through the Seebeck effect, allowing for real-time temperature monitoring independent of the workpiece material composition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If contact thermometers are used to measure workpiece temperature, then direct temperature measurement is achieved, but accessibility to the workpiece is limited and the measurement reliability diminishes with increasing distance

Engineering Contradiction:
Improvetemperature measurement accuracyVSAvoidworkpiece accessibility
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent uses the forming tool members themselves as intermediaries to transfer thermal energy from the workpiece to external temperature sensors. The tool members are in direct contact with the workpiece during forming, and their temperature (which equilibrates with the workpiece temperature) is measured by sensors mounted on the tool members, eliminating the need for direct sensor contact with the workpiece while maintaining measurement accuracy

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces direct mechanical contact measurement (contact thermometers touching the workpiece) with indirect thermal conduction measurement through the tool members. Instead of mechanically attaching sensors to the workpiece, the system uses the natural thermal conduction that occurs through the tool-workpiece interface during forming operations

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

2Ease of operation

If radiation thermometers are used to measure workpiece temperature, then non-contact measurement is achieved, but sufficient free surface exposure is required which limits applicability

Engineering Contradiction:
Improveworkpiece accessibilityVSAvoidapplicability to different forming configurations
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The patent creates a universal temperature measurement system that works across different forming configurations (hot stamping, forging, rolling, etc.) by measuring the temperature of the tool members that are universally present in all forming operations. The tool members serve as universal thermal mediators between the workpiece and sensors, making the system adaptable to various forming processes regardless of workpiece geometry or accessibility

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Reliability

If temperature sensors are embedded within the forming tool, then workpiece temperature can be monitored, but the accuracy diminishes with increasing distance due to thermal dissipation and time offset

Engineering Contradiction:
Improvetemperature monitoring capabilityVSAvoidtemperature measurement accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent segments the temperature measurement function across multiple tool members (first tool member and second tool member) that are in direct contact with the workpiece. By placing temperature sensors on each tool member at the contact interface, the system eliminates thermal dissipation and time offset issues that would occur with distant embedded sensors, as each sensor measures the temperature at the exact point of workpiece contact

Inventive Principle:
Principle #1Segmentation

4Loss of information

If micrograph or material probe analysis is used to determine workpiece temperature, then temperature information can be obtained, but real-time monitoring during the forming process is not possible

Engineering Contradiction:
Improvetemperature information availabilityVSAvoidreal-time monitoring capability
Core Design Contradiction:
Loss of informationVSLoss of time

Solution Approach 1:

The patent performs temperature measurement in advance of the forming operation by pre-heating the tool members to the desired workpiece temperature. The temperature sensors continuously monitor the tool member temperatures before and during the forming process, providing real-time temperature information that enables process control before the actual forming occurs, rather than requiring post-process analysis

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

Enables accurate and reliable real-time temperature measurement of the workpiece during forming processes, improving the precision and consistency of the forming tool's temperature monitoring, suitable for both warm and hot forming processes.

Implementation Method 1

measuring a temperature of the workpiece being formed based on a voltage measurement corresponding to a voltage thermoelectrically induced between the first tool member and the second tool member through the workpiece

Methodology Applied
Scientific EffectSeebeck effect: Seebeck Effect

Data Source

PatentEP4122619B1Forming tool and method for temperature-controlled forming of a workpiece
Publication Date: 2024.08.07 TECHNISCHE UNIVERSITAT MUNCHEN
  • EP4122619B1 patent drawingFigure 1~2
  • EP4122619B1 patent drawingFigure 3~4
  • EP4122619B1 patent drawingFigure 5~6

AI summary

The invention refers to a forming tool (10) for forming a workpiece (30) configured for serving as a measuring tool for determining the temperature of the workpiece being formed, by being used as a thermocouple. The workpiece is arranged between a first tool member (12a) and a second tool member (12b). A voltmeter (20) is connected between a first electrical contact (16a) of the first tool member (12a) and a second electrical contact (16b) of the second tool member (12b). A first electrical path (18a) defined in the first tool member (12a) between the workpiece (30) and the first electrical contact (16a) comprises at least a portion of a first electrically conductive material. A second electrical path (18b) defined in the second tool member (12b) between the workpiece (30) and the second electrical contact (16b) comprises at least a portion of a second electrically conductive material different from the first electrically conductive material. A voltage measured by the voltmeter (20) corresponds to a voltage thermoelectrically induced between the first tool member (12a) and the second tool member (12b) through the workpiece (30) due to the Seebeck effect and allows inferring the temperature of the workpiece (30). The invention further refers to a related method of measuring a temperature of a workpiece (30) being formed in a forming tool.