Welding Electrode With Integrated Ultrasonic Probe

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Solution Overview

Problem

Capacitor discharge welding processes face challenges in efficiently monitoring the quality of welded connections during the joining process, particularly due to heat loss and energy inefficiency, and existing ultrasonic monitoring methods require active water cooling which is not suitable for high-alloy or press-hardened materials.

Innovation Solution

A welding head with an integrated ultrasonic testing head and a closable fluid reservoir filled with a sound-conducting liquid or solid coupling agent, allowing for effective acoustic coupling and eliminating the need for active water cooling, enabling quality monitoring through ultrasonic methods during capacitor discharge welding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If ultrasonic through-transmission method is used for quality monitoring, then measurement precision is improved, but device complexity increases due to requiring both transmitter and receiver units in separate electrodes

Engineering Contradiction:
Improvequality monitoring precisionVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines the ultrasonic transmitter and receiver into a single integrated unit positioned in one welding electrode, eliminating the need for a separate receiver in the other electrode. This merging reduces device complexity while maintaining quality monitoring capability through pulse-echo method

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single welding electrode is equipped with both transmitting and receiving functions, making it a multi-functional device that can perform both ultrasonic emission and reception, thereby simplifying the overall system architecture

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

2Temperature

If active water cooling is used during welding, then temperature control is improved, but loss of energy increases and it is not suitable for high-alloy or press-hardened materials

Engineering Contradiction:
Improvetemperature controlVSAvoidenergy loss
Core Design Contradiction:
TemperatureVSLoss of energy

Solution Approach 1:

The patent removes the active water cooling system from the welding process, extracting this function entirely. Instead, it relies on the natural thermal characteristics of capacitor discharge welding which provides inherently better temperature control without the energy-intensive cooling infrastructure

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The welding system utilizes its own thermal characteristics and the thermal mass of the workpiece to manage temperature, rather than requiring external active cooling. The process self-regulates temperature through the capacitor discharge mechanism

Inventive Principle:
Principle #25Self-service

3Ease of operation

If ultrasonic testing head is externally coupled, then ease of operation is improved, but measurement precision deteriorates due to coupling agent requirements

Engineering Contradiction:
Improveease of operationVSAvoidmeasurement precision
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The ultrasonic testing head is integrated directly into the welding electrode structure, merging the testing function with the welding function. This eliminates the need for external coupling agents and ensures consistent acoustic contact, improving measurement precision while maintaining ease of operation

Inventive Principle:
Principle #5Merging (Combining)

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 solution allows for efficient energy use and quality control of capacitor discharge welded connections without water cooling, preventing overheating and extending electrode cap lifespan by using contactless infrared temperature monitoring and ensuring precise temperature control.

Implementation Method 1

an ultrasonic testing head (18) which is designed for transmitting and/or receiving ultrasonic waves

Methodology Applied
Scientific EffectUltrasonic wave transmission: Ultrasound

Implementation Method 2

filled with a fluidic respectively liquid, sound-conducting coupling agent (14), or solid sound conducting layer

Methodology Applied
Scientific EffectAcoustic coupling: Sound

Implementation Method 3

the high electrical energy that is required for melting the material at the welding location results from a pulse-like discharge of at least one capacitor

Methodology Applied
Scientific EffectCapacitor discharge: Capacitance

Implementation Method 4

This welding current leads to a local input of heat into the workpieces, so that at a welding location there locally forms a pool of molten metal

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 5

contactless infrared temperature monitoring

Methodology Applied
Scientific EffectInfrared radiation detection: Infrared Radiation

Data Source

PatentEP3144093B1Welding electrode with built-in ultrasonic probe for a capacitor discharge welding device and capacitor discharge welding device
Publication Date: 2018.08.08 DR ING H C F PORSCHE AG
  • EP3144093B1 patent drawingFigure 1
  • EP3144093B1 patent drawingFigure 2

AI summary

The invention relates to a welding electrode (1) for a capacitor discharge welding device (100), comprising an electrode shank (10) with a connecting portion (12), a welding cap (11), which is attached to the connecting portion (12) of the electrode shank (10), and also an ultrasonic testing head (18) for transmitting and/or receiving ultrasonic waves, which is arranged within the electrode shank (10), wherein the welding electrode (1) comprises a closable fluid reservoir or a capsule (13), within which the ultrasonic testing head (18) is accommodated and which is at least partially filled with a sound-conducting coupling agent (14). In addition, the invention relates to a capacitor discharge welding device (100), comprising a first welding electrode (1a) and a second welding electrode (1b), which are connected to at least one capacitor.