Laser Keyhole Joining of Dissimilar Materials Without Deformation

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Solution Overview

Problem

Existing methods for joining dissimilar materials, such as friction lap welding, are labor-intensive and cause deformation due to the need for chemical coatings and weights, which complicates the process.

Innovation Solution

A method involving surface treatment, overlaying, and laser irradiation to form a keyhole, allowing secure joining of dissimilar materials without additional weights or chemicals, utilizing laser patterning to create an uneven surface for anchor effects and heating the joined member below its melting point.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If friction lap welding is used to join dissimilar materials, then joining of different materials is achieved, but the process becomes labor intensive and causes deformation due to chemical coatings and weights

Engineering Contradiction:

Improvejoining of dissimilar materialsVSAvoidprocess complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical friction-based joining system with a laser-based thermal system. Instead of using friction lap welding with weights and chemical coatings, the invention uses laser irradiation to heat and melt the joining surfaces, enabling dissimilar materials to be joined through controlled melting and bonding without mechanical pressure or chemical treatments

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the fundamental parameter of the joining process from mechanical friction to thermal energy input. By controlling laser power, irradiation time, and focal position, the process achieves joining of dissimilar materials with different thermal properties without requiring mechanical pressure or chemical coatings, thereby simplifying the overall process

Inventive Principle:

Principle #35Parameter changes

2Force

If weights are applied to joining members in conventional methods, then joining force is sufficient, but member deformation occurs

Engineering Contradiction:

Improvejoining forceVSAvoidmember deformation

Core Design Contradiction:

ForceVSManufacturing precision

Solution Approach 1:

The patent replaces mechanical pressure application with optical energy input. The laser beam delivers sufficient energy to melt and bond materials without requiring physical weights or clamps, thereby achieving strong joining force while preventing deformation that would result from mechanical pressure

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent utilizes phase transition (melting) of the joining surfaces through laser heating. By controlling the laser parameters, the materials are heated to their melting points, allowing them to bond upon cooling without requiring external mechanical pressure, thus avoiding deformation while achieving adequate joining force

Inventive Principle:

Principle #36Phase transitions

3Strength

If chemical coatings are applied to joining members, then adhesion is improved, but the process becomes labor intensive

Engineering Contradiction:

Improveadhesion strengthVSAvoidprocess efficiency

Core Design Contradiction:

StrengthVSProductivity

Solution Approach 1:

The patent replaces chemical surface treatment with direct laser heating. Instead of applying chemical coatings to improve adhesion, the laser irradiation directly heats the joining surfaces to melting temperature, creating strong bonds through controlled melting and solidification, thereby eliminating the labor-intensive chemical coating step

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The laser irradiation process itself performs the function of surface preparation and bonding simultaneously. The high-energy laser beam directly modifies the surface properties through heating and melting, creating the necessary adhesion conditions without requiring separate chemical treatment steps, thus improving productivity

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

Enables secure joining of dissimilar materials like metals and resins without deformation, simplifying the process and eliminating the need for chemical coatings or weights.

Implementation Method 1

heating the joined member by irradiating a laser on a surface of the joining member at a side opposite to the joining surface at an irradiation condition that forms a keyhole

Methodology Applied

Scientific EffectLaser heating: Laser

Implementation Method 2

irradiation condition that forms a keyhole

Methodology Applied

Scientific EffectKeyhole formation: Laser Beam Welding

Implementation Method 3

utilizing laser patterning to create an uneven surface for anchor effects

Methodology Applied

Scientific EffectLaser patterning: Laser Ablation

Implementation Method 4

joining the joining member and the joined member

Methodology Applied

Scientific EffectLaser welding: Laser Beam Welding

Data Source

PatentUS20260070154A1Joining method of dissimilar materials

Publication Date: 2026.03.12 KK TOSHIBA

AI summary

A joining method of dissimilar materials, the dissimilar materials being a joining member and a joined member, the method including: performing surface treatment of a joining surface of the joining member; overlaying the joining member and the joined member; heating the joined member by irradiating a laser on a surface of the joining member at a side opposite to the joining surface, the laser being irradiated at an irradiation condition that forms a keyhole; and joining the joining member and the joined member.