Laser Welding Through-Hole Joint for Steel-Aluminum Assembly

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Solution Overview

Problem

Conventional spot welding methods are inefficient for joining different-type materials like steel and aluminum, requiring complex rivet designs, lengthy processing times, and limited flexibility in product design due to the need for precise positioning and pressure application, which results in reduced joint stiffness and increased production costs.

Innovation Solution

A laser welding method that involves placing a third material with a through-hole between the first and second materials, allowing laser emission to weld them via the through-hole, with specific gap configurations to ensure proper alignment and fusion, thereby compressively fixing the third material between the welded metals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If spot welding is used to join different-type materials (steel and aluminum), then joint strength can be achieved, but the welding process requires complex rivet designs, lengthy processing times, and limited flexibility in product design

Engineering Contradiction:
Improvejoint strengthVSAvoidproduction time
Core Design Contradiction:
StrengthVSProductivity

Solution Approach 1:

The patent replaces the conventional mechanical spot welding process with laser welding technology. The laser welding method uses optical energy instead of mechanical pressure and electrical current, enabling faster welding speeds and eliminating the need for complex rivet designs while maintaining joint strength between different-type materials

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

Solution Approach 2:

The patent changes the welding parameters by using laser energy with specific power density and focal point control. By adjusting laser power, welding speed, and focal position, the process achieves efficient joining of steel and aluminum without the time-consuming mechanical pressuring and cooling periods required by conventional spot welding

Inventive Principle:
Principle #35Parameter changes

2Strength

If spot welding is used to join different-type materials, then joint strength can be achieved, but complex rivet designs with precise positioning are required, increasing device complexity

Engineering Contradiction:
Improvejoint strengthVSAvoidrivet design complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent replaces the complex mechanical rivet system with a laser welding system. The laser apparatus with focal point control and positioning mechanisms is simpler than the multi-component rivet design with chamfered edges, annular grooves, and flat parts, while achieving the same joint strength

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

Solution Approach 2:

The patent extracts and eliminates the intermediate rivet component from the joining process. By using laser welding to directly fuse the steel and aluminum materials, the complex rivet structure with its multiple geometric features is removed, simplifying the overall device while maintaining connection strength

Inventive Principle:
Principle #2Taking out (Extraction)

3Strength

If conventional spot welding is used, then materials can be joined, but the welding gun needs space on both sides of the material and applies pressure, limiting product shape flexibility

Engineering Contradiction:
Improvewelding capabilityVSAvoidproduct shape flexibility
Core Design Contradiction:
StrengthVSAdaptability or versatility

Solution Approach 1:

The patent replaces the mechanical spot welding gun that requires bilateral access and pressure application with a laser welding system. The laser can be applied from a single side and does not require physical contact or clamping, enabling welding of complex-shaped components and one-side welding configurations

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

Solution Approach 2:

The patent transitions from a mechanical process requiring three-dimensional access (both sides of the material) to an optical process that can be applied from a single direction. The laser beam delivers energy through space without requiring physical access to the welding zone from multiple sides, expanding design flexibility

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 method significantly reduces production time, enhances joint stiffness, and increases design flexibility by eliminating the need for complex rivet designs and precise positioning, while maintaining high weld quality and productivity.

Implementation Method 1

a laser welding method includes a step of emitting laser light from a first material side toward a region corresponding to the protrusion part

Methodology Applied
Scientific EffectLaser heating: Laser

Implementation Method 2

In laser welding, metal materials are melted at a welding position

Methodology Applied
Scientific EffectMelting: Melting

Data Source

PatentEP3437785B1Laser welding method
Publication Date: 2024.05.01 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD
  • EP3437785B1 patent drawingFigure 1A~1D
  • EP3437785B1 patent drawingFigure 2A~2E
  • EP3437785B1 patent drawingFigure 3

AI summary

A laser welding method includes a step of placing a third material between a first material and a second material. The first material and the second material are of metals so as to be weldable to each other, and at least one of which has a protrusion part. The third material is difficult to weld to the first material and the second material and has a through-hole part into which the protrusion part is inserted. The method also includes a step of emitting laser light from the first material side toward a region corresponding to the protrusion part under condition in which the third material is sandwiched between the first material and the second material, so that the first material and the second material are welded via the through-hole part. In the step in which the third material is sandwiched between the first material and the second material, a first gap is disposed between the protrusion part and the inner peripheral face of the through-hole part, and a second gap depending on the plate thickness of the first material in the region corresponding to the protrusion part is disposed between the first material and the second material in the region corresponding to the protrusion part.