Induction Welding Temperature Control Without Embedded Sensors

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Solution Overview

Problem

Induction welding of lightweight materials like fiber composites faces challenges in temperature control and measurement, particularly due to interference from thermocouples and electromagnetic fields, leading to inaccurate temperature readings and risks of overheating or underheating during the welding process.

Innovation Solution

A system where an inductor acts both as a welding device and a sensor, generating an electromagnetic field to heat the workpieces while simultaneously measuring parameters to estimate temperature, allowing for closed-loop control without external sensors, using neural networks, transfer models, or autoregressive models to determine the temperature and adjust the welding process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If thermocouples or other sensors are integrated into the workpiece for temperature measurement, then temperature control accuracy is improved, but the thermal and mechanical performance of the material deteriorates and the device complexity increases

Engineering Contradiction:
Improvetemperature measurement accuracyVSAvoidmaterial thermal and mechanical performance
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent uses electromagnetic field parameters (voltage, current, frequency, impedance) as an intermediary to indirectly measure temperature. Instead of directly measuring temperature with sensors that interfere with the material, the system measures changes in electromagnetic field characteristics caused by temperature-induced material property changes, thereby avoiding direct sensor-material contact and preserving material integrity

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the mechanical/physical sensor system (thermocouples, resistance thermometers) with an electromagnetic field-based measurement system. By using the inductor's electromagnetic field to sense temperature through parameter changes, the system eliminates the need for physical sensors that would mechanically and thermally interfere with the workpiece

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

2Reliability

If external temperature sensors are used for indirect measurement, then material interference is reduced, but measurement accuracy deteriorates and device complexity increases

Engineering Contradiction:
Improvematerial thermal and mechanical performanceVSAvoidtemperature measurement accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The inductor serves dual functions: it both heats the workpiece through electromagnetic induction and simultaneously measures temperature by detecting changes in its own electromagnetic parameters. This multi-functionality eliminates the need for separate measurement devices while maintaining measurement accuracy through direct coupling between the heating field and sensing mechanism

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

Solution Approach 2:

The system uses itself for measurement - the inductor measures the temperature it is creating by detecting changes in its own operating parameters (voltage, current, frequency, impedance). This self-service approach eliminates external sensors and their associated complexity while maintaining accurate temperature monitoring through the inherent relationship between electromagnetic field parameters and material temperature

Inventive Principle:
Principle #25Self-service

3Measurement precision

If thermocouples are used for temperature measurement, then temperature control is improved, but the electromagnetic fields heat the sensors and disturb accurate readings

Engineering Contradiction:
Improvetemperature measurement accuracyVSAvoidelectromagnetic field interference with sensors
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent converts the harmful effect of electromagnetic fields heating sensors into a beneficial measurement mechanism. Instead of trying to shield or protect sensors from electromagnetic heating, the system uses the electromagnetic field's interaction with the workpiece material (which changes with temperature) as the measurement signal, thereby transforming potential interference into useful information

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

4Reliability

If complex geometrical arrangements are used for indirect temperature measurement, then sensor interference is reduced, but manufacturing reproducibility deteriorates and device complexity increases

Engineering Contradiction:
Improvemanufacturing reproducibilityVSAvoidgeometrical arrangement complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The inductor measures temperature through its own electromagnetic parameters without requiring complex external sensor arrangements or geometrical configurations. The measurement is achieved through the inherent interaction between the electromagnetic field and the workpiece material properties, eliminating the need for reproducible complex geometrical setups and simplifying the overall system

Inventive Principle:
Principle #25Self-service

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 provides accurate temperature control, reduces the risk of overheating or underheating, ensures high-quality welds, and eliminates the need for external sensors, resulting in cost-effective and reliable induction welding with improved reproducibility and reduced material interference.

Implementation Method 1

a processing means configured to generate an electromagnetic field by applying an alternating voltage to the inductor so as to inductively heat the at least one of the surfaces

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

generate an electromagnetic field by applying an alternating voltage to the inductor so as to inductively heat the at least one of the surfaces

Methodology Applied
Scientific EffectInduction heating: Induction Heating

Implementation Method 3

The processing means is also configured to simultaneously measure at least one parameter of the at least one workpiece, at least based on the generated electromagnetic field

Methodology Applied
Scientific EffectElectromagnetic field sensing: Electromagnetic Induction

Data Source

PatentEP3967437B1Inductive welding of workpieces
Publication Date: 2024.12.04 COREBON AB
  • EP3967437B1 patent drawingFigure 1
  • EP3967437B1 patent drawingFigure 2a~2c
  • EP3967437B1 patent drawingFigure 3a~3b

AI summary

A system for controlled induction welding of at least one weld seam area (A) of at least two surfaces of at least one workpiece (20, 21) is provided. The system comprises an inductor (10) configured to be arranged in conjunction with the at least one workpiece (20, 21), a processing means (30) configured to generate an electromagnetic field by applying an alternating voltage to the inductor (10) so as to inductively heat at least one of the surfaces so that the weld seam area (A) is welded together, simultaneously measure at least one parameter (P) of the at least one workpiece (20, 21) at least based on the generated electromagnetic field, detect a change of the at least one parameter (P), and determine a temperature estimation of the at least one workpiece (20, 21) based on said detected change