Laser Soldering Optics for Coated Sheet Metal Wetting Control

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Solution Overview

Problem

Existing laser welding technologies face challenges when joining workpieces with coatings, such as zinc-magnesium, as the coatings are difficult to wet and have different heating behaviors, leading to issues like bubble formation and inclusion in the seam, which affect the quality of the joining process.

Innovation Solution

A device using a separate secondary fiber and laser beam source to decouple and adapt the laser beam, forming a scalable beam line or optical structure that vaporizes or heats the coating before soldering, improving wetting and reducing contamination, and allowing for precise adjustment of the beam's intensity profile.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single laser beam source is used for joining coated workpieces, then the joining process is simple, but the coating causes poor wetting and heating issues leading to bubbles and inclusions

Engineering Contradiction:
Improvejoining qualityVSAvoidlaser beam system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The laser beam system is segmented into two separate beam sources: a primary laser beam for heating the workpiece and a secondary laser beam for melting the solder. This segmentation allows independent optimization of each beam's parameters to handle the coating challenges, with the primary beam addressing heating uniformity and the secondary beam addressing solder flow and wetting, thereby improving joining quality without excessive complexity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A beam combining unit serves as an intermediary component that merges the primary and secondary laser beams into a single optical path. This intermediary device enables the use of two separate laser sources while maintaining a relatively simple overall system structure, resolving the contradiction between using multiple beams for quality improvement and maintaining system simplicity

Inventive Principle:
Principle #24Intermediary (Mediator)

2Temperature

If the laser beam intensity is increased to improve heating, then heating effectiveness improves, but coating vaporization and contamination increase

Engineering Contradiction:
Improveworkpiece heatingVSAvoidcoating vaporization
Core Design Contradiction:
TemperatureVSObject-generated harmful factors

Solution Approach 1:

The heating function is separated from the solder melting function by using distinct laser beams. The primary laser beam is optimized for gentle, uniform heating that avoids excessive temperature rise and coating vaporization, while the secondary beam provides the concentrated energy needed for solder melting. This segmentation resolves the contradiction between effective heating and harmful vaporization

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The laser processing is divided into sequential stages: first the primary beam performs heating, then the secondary beam performs solder melting. This periodic or sequential action allows each beam to operate within optimal intensity ranges, preventing the need for excessively high intensity that would cause coating vaporization while still achieving effective heating

Inventive Principle:
Principle #19Periodic action

3Ease of manufacture

If a common beam path is used for multiple laser beams, then installation effort is reduced, but beam projection and incidence angles are limited

Engineering Contradiction:
Improvesystem installationVSAvoidbeam projection flexibility
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

A beam combining unit acts as an intermediary that accepts multiple laser beams from different directions and merges them into a common output path. This intermediary component provides the flexibility to accommodate various beam projection angles and positions while still achieving a unified beam delivery system, thus maintaining ease of installation without sacrificing adaptability

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The beam combining unit serves multiple functions: it combines beams from different sources, adjusts their relative positions and angles, and delivers a unified beam to the workpiece. This multi-functional component provides the system with versatility in beam projection while maintaining a relatively simple overall structure that is easy to install

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 solution enhances the joining process by improving wetting of coatings, reducing contamination, and allowing for precise adaptation of the beam to the workpieces' materials, resulting in higher quality solder joints and improved corrosion resistance.

Implementation Method 1

forming a scalable beam line or optical structure that vaporizes or heats the coating before soldering

Methodology Applied
Scientific EffectVaporization: Evaporation

Implementation Method 2

a laser beam is split into at least two partial beams, characterized in that at least one partial beam serves to melt a solder material, while the other partial beam(s) serves to heat the workpieces to be joined

Methodology Applied
Scientific EffectHeating: Heating

Data Source

PatentEP3486019B1Laser soldering lens for joining coated workpieces
Publication Date: 2021.11.03 II VI DELAWARE INC
  • EP3486019B1 patent drawingFigure 1
  • EP3486019B1 patent drawingFigure 2
  • EP3486019B1 patent drawingFigure 3

AI summary

The invention relates to a device for joining workpieces using a laser beam and a method for using the device for soldering sheet metal. A device for joining workpieces using a laser beam is provided, comprising a laser optic and a two-core fiber with a main fiber and a secondary fiber, wherein the main fiber is connected to a fiber coupling of the laser optic and the secondary fiber is arranged between a second laser beam source and a receptacle on a wire guide of the solder of the device.