Solid-State Welding Current Staging for Lower Joining Load

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Solution Overview

Problem

Existing solid state welding methods require high loads to join metal workpieces, which can reduce the strength of the metal and increase the size of the welding apparatus, making it less durable.

Innovation Solution

A solid state welding apparatus and method using a pair of compression bars and electrodes, where a controller passes a first current to soften the metal workpieces and apply a reduced load, followed by a second current to join them without melting, thereby reducing the overall load required for welding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If high load is applied to join metal workpieces in solid state welding, then the joining strength is improved, but the apparatus size increases and durability decreases

Engineering Contradiction:
Improvejoining strengthVSAvoidapparatus durability
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The welding process is divided into two distinct stages: a first conduction stage with lower current and load for preliminary bonding, and a second conduction stage with higher current and load for final strengthening. This segmentation allows the apparatus to use reduced load during the critical bonding phase, improving durability while achieving the required joining strength through the combined two-stage process

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The first conduction stage performs preliminary action by creating an initial bond between workpieces using reduced current and load. This preliminary bonding prepares the interface for the subsequent second conduction stage, allowing the final strengthening to occur more efficiently and reducing the peak load requirements compared to single-stage welding

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

The method allows for joining metal workpieces with a reduced load, enhancing the durability of the apparatus and preventing metal strength reduction, while maintaining the integrity of the workpieces.

Implementation Method 1

passes a first current through the pair of electrodes while controlling the pair of compression bars to cause a first load to act on each of the first and second workpieces to bring the workpieces into contact with each other, and subsequently passes a second current larger than the first current through the pair of electrodes

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP4470705A1Solid state welding apparatus and solid state welding method
Publication Date: 2024.12.04 DAIHEN CORP
  • EP4470705A1 patent drawingFigure 1
  • EP4470705A1 patent drawingFigure 2
  • EP4470705A1 patent drawingFigure 3(A)~3(D)

AI summary

A solid state welding apparatus (1) comprises a pair of compression bars (11) and (12) that presses a first metal workpiece (W10) and a second metal workpiece (W20) on sides opposite in a direction of a thickness of the workpieces, a pair of electrodes (21) and (22) disposed around the pair of compression bars (11) and (12), respectively, and a controller (30). The controller (30) passes a first current (X1) through the pair of electrodes (21) and (22) while controlling the pair of compression bars (11) and (12) to cause a first load (F1) to act on each of first and second workpieces (W10) and (W20) to bring the workpieces into contact with each other, and subsequently passes a second current (X2) larger than the first current (X1) through the pair of electrodes (21) and (22) while controlling the pair of compression bars (11) and (12) to cause a second load (F2) to act on each of first and second workpieces (W10) and (W20).