Laser Joining Structure for Resin Members

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Solution Overview

Problem

Existing methods for joining different resin members using laser bonding face limitations in bonding strength due to compatibility issues between resin components, restricting the range of applicable resin combinations.

Innovation Solution

A joining structure where a laser-absorbing resin member includes a second resin component compatible with the laser-transmitting resin member, with a higher abundance ratio in the joining portion to enhance bonding strength, allowing for a wider range of resin combinations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If laser bonding is used to join different resin members, then bonding speed and recyclability are improved, but bonding strength is insufficient when resin compatibility is low

Engineering Contradiction:
Improvebonding speedVSAvoidbonding strength
Core Design Contradiction:
ProductivityVSStrength

Solution Approach 1:

A compatibilizing agent is introduced as an intermediary substance within the resin members to facilitate bonding between incompatible resins. The compatibilizing agent acts as a mediator that enables laser bonding between resin members that would otherwise be difficult to join, thereby maintaining high bonding strength while preserving the productivity benefits of laser bonding.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The resin members are designed as composite materials containing multiple components including the compatibilizing agent. This composite structure allows the resin to maintain its primary properties while incorporating the bonding-enhancing compatibilizing agent, enabling both high bonding strength and efficient laser bonding process.

Inventive Principle:
Principle #40Composite materials

2Adaptability or versatility

If a compatibilizing agent is added to enable wide resin compatibility, then the range of applicable resin combinations is expanded, but the bonding strength reliability varies due to dependency on compatibilizing agent characteristics

Engineering Contradiction:
Improveresin combination rangeVSAvoidbonding strength reliability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The compatibilizing agent is strategically positioned and concentrated at the joining portion between resin members rather than being uniformly distributed throughout. This local concentration ensures reliable bonding at the critical interface while maintaining versatility in resin combinations. The abundance ratio of the compatibilizing agent in the joining portion is controlled to be higher than in other parts of the resin member.

Inventive Principle:
Principle #3Local quality

3Strength

If the abundance ratio of the second resin component in the joining portion is increased, then bonding strength is improved, but the complexity of controlling resin composition increases

Engineering Contradiction:
Improvebonding strengthVSAvoidresin composition control
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The compatibilizing agent is pre-incorporated into the resin members during the molding process before the actual bonding operation. This preliminary incorporation ensures that the correct abundance ratio is achieved in the joining portion without requiring complex real-time control during bonding. The resin members are prepared in advance with the appropriate composition to ensure reliable bonding when joined by laser irradiation.

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

This configuration ensures reliable and strong bonding between laser-transmitting and laser-absorbing resin members, even when the first resin component is not compatible, by increasing the abundance of the second resin component in the joining area, thereby improving the bonding strength and expanding the applicability of resin combinations.

Implementation Method 1

a laser-absorbing resin member that absorbs the irradiated laser beam to generate heat

Methodology Applied
Scientific EffectLaser absorption: Absorption (EM radiation)

Implementation Method 2

different types of resin members have been frequently joined by laser bonding using a laser beam

Methodology Applied
Scientific EffectLaser beam welding: Laser Beam Welding

Data Source

PatentEP3381682B1Joining structure
Publication Date: 2023.03.29 OMRON CORP
  • EP3381682B1 patent drawingFigure 1
  • EP3381682B1 patent drawingFigure 2
  • EP3381682B1 patent drawingFigure 3

AI summary

Provided is a joining structure that is composed of a laser-transmitting resin member and a laser-absorbing resin member. The laser-absorbing resin member includes a first resin component, which is not compatible with the laser-transmitting resin member, and a second resin component, which is compatible with the laser-transmitting resin member. The abundance ratio of the second resin components in a melted/solidified part that constitutes the joining portion of the laser-transmitting resin member and the laser-absorbing resin member is higher than the abundance ratio of the second resin components in the laser-absorbing resin member.