Simultaneous Laser Welding Light Pipe for Curved Surfaces

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Solution Overview

Problem

Laser welding of complex curved surfaces in automobile lighting, such as headlight and back light plastic parts, faces instability due to irregular shapes and angles, leading to incomplete energy focusing and reflection defects.

Innovation Solution

A device and process for simultaneous laser welding using a light pipe made of transparent materials like polycarbonate or glass, positioned between the laser source and lens, to focus the laser beam onto the welding region, combined with a clamping mechanism to press the base and lens together, ensuring stable energy delivery and minimizing waste.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If laser beam is reflected onto irregular curved surfaces through laser mirror, then welding can be performed on complex shapes, but energy focusing becomes incomplete and reflection defects occur

Engineering Contradiction:
Improvewelding capability on irregular curved surfacesVSAvoidenergy focusing precision
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent introduces a light pipe as an intermediary component between the laser source and the workpiece. The light pipe transmits and focuses the laser beam along its internal structure, enabling precise energy delivery to irregular curved surfaces without the limitations of traditional mirror-based systems. This mediator resolves the contradiction by providing both adaptability to complex geometries and precise energy focusing.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the mechanical mirror-based laser delivery system with a light pipe-based optical transmission system. This substitution eliminates the reflection and focusing issues associated with mirrors while maintaining the ability to weld complex curved surfaces, thereby resolving the precision problem while preserving adaptability.

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

2Productivity

If laser beam energy is partially reflected due to irregular surfaces, then welding can proceed, but welding stability deteriorates

Engineering Contradiction:
Improvewelding process continuityVSAvoidwelding bead stability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The light pipe acts as a stable intermediary that consistently guides and focuses laser energy along a controlled path. This eliminates the instability caused by unpredictable reflections from irregular surfaces, ensuring reliable and stable welding beads while maintaining continuous productivity.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the fundamental parameter of laser energy delivery from a free-space reflected beam to a guided and focused beam through the light pipe. This parameter change stabilizes the energy distribution on the workpiece surface, resulting in consistent welding bead quality and improved reliability.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If laser welding is performed on thin-wall materials, then high precision welding is achieved, but heat conduction control becomes critical

Engineering Contradiction:
Improvewelding precisionVSAvoidheat conduction control
Core Design Contradiction:
Manufacturing precisionVSTemperature

Solution Approach 1:

The light pipe enables highly localized and concentrated laser energy delivery to the welding zone. This local quality of energy distribution allows precise heating of thin-wall materials without excessive heat diffusion, maintaining both high welding precision and effective heat conduction control.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The substitution of the mirror system with a light pipe provides more precise control over the spatial distribution and concentration of laser energy. This enables better management of heat input to thin-wall materials, achieving both precision and thermal control.

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

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 approach achieves stable and efficient welding with reduced waste selvage size (<0.4 mm) and high precision, eliminating powder generation and defects, while maintaining the mechanical and thermal integrity of the welded components.

Implementation Method 1

a light pipe positioned between the laser source and lens, to focus the laser beam onto the welding region

Methodology Applied
Scientific EffectLight transmission and focusing: Lens

Implementation Method 2

laser welding is an efficient and precise welding method using a laser beam with high-energy density as heat source

Methodology Applied
Scientific EffectLaser heating: Laser

Implementation Method 3

the welding process belongs to heat conduction, i.e. laser radiation heats the workpiece surface; the heat of the surface diffuses into the interior via heat conduction

Methodology Applied
Scientific EffectHeat conduction: Conduction (thermal)

Implementation Method 4

a clamping mechanism to press the base and lens together, ensuring stable energy delivery

Methodology Applied
Scientific EffectMechanical force: Mechanical Force

Data Source

PatentEP3117979B1Process and device for simultaneous laser welding
Publication Date: 2019.08.21 SHANGHAI SEEYAO ELECTRONICS CO LTD
  • EP3117979B1 patent drawingFigure 1
  • EP3117979B1 patent drawingFigure 2~3
  • EP3117979B1 patent drawingFigure 4~5

AI summary

This invention provides a process and device for simultaneous laser welding; after using the moving lower die (5) and the fixing upper die (6) to make the base (14) and the lens (13) attached, by using the light pipe (12) to make the laser, which is emitted from the laser source (11), emit through the lens (13) to a welding region of the base (14) after being processed, to operate rapid and average heating to the welding region; meanwhile, using the welding cylinder (3) to press the base (14) and the lens (13) together, to make base (14) and the lens (13) pressed and welded together in molten state, and when welding, it does not generate powder or other defects, and, at the same time, it can make the height H and the width w of the generated waste selvage between [0, 0.4] mm, which can improve the performance of welding object more efficiently.