Handheld Laser Welding Gun With Light-Leak Weld Control

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Solution Overview

Problem

Conventional laser welding guns face challenges with complicated workpiece geometries, requiring multiple clamping and welding configurations, large and inefficient laser configurations, debris accumulation damaging optics, and lack of weld quality control, leading to reduced efficiency and high costs.

Innovation Solution

A hand-maneuverable laser welding gun with a robust, lightweight design featuring an overjet air delivery system to prevent debris damage, a high-power fiber laser, and an automatic weld quality control system using a photodetector to adjust laser output based on detected light leakage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If conventional CO2 or Nd:YAG laser configurations are used, then high power output can be achieved, but the physical size becomes large and energy conversion efficiency is low

Engineering Contradiction:
Improvelaser output powerVSAvoidlaser system size
Core Design Contradiction:
PowerVSVolume of moving object

Solution Approach 1:

The patent replaces conventional CO2 or Nd:YAG laser systems with a fiber laser system. Fiber lasers use optical fiber as the gain medium, eliminating the need for large mechanical laser cavities and associated cooling systems. This substitution achieves high power output (e.g., 2 kW, 3 kW, or higher) while dramatically reducing the physical footprint of the laser source, making it suitable for handheld or mobile welding applications.

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

2Adaptability or versatility

If multiple clamping and welding configurations are used to handle complicated workpiece geometries, then welding capability is improved, but device complexity and costs increase

Engineering Contradiction:
Improvewelding capability for complex geometriesVSAvoidnumber of clamping and welding apparatus
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent designs a universal handheld laser welding system that can handle various workpiece geometries through software control and adjustable parameters rather than requiring multiple physical configurations. The system includes programmable control that allows operators to adjust welding parameters (speed, power, focal position) for different geometries, and the handheld design itself provides flexibility to access difficult-to-reach areas, eliminating the need for multiple dedicated clamping and welding apparatus.

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

3Object-generated harmful factors

If cross-jet is used to remove welding debris, then debris evacuation is achieved, but pressure gradient damages optics and noise increases

Engineering Contradiction:
Improvewelding debrisVSAvoidoptics damage and noise
Core Design Contradiction:
Object-generated harmful factorsVSObject-affected harmful factors

Solution Approach 1:

The patent extracts the harmful cross-jet airflow from the system and replaces it with a controlled gas flow system that directs gas along the optical axis. This extraction of the problematic transverse jet eliminates the formation of pressure gradients that could damage optics, while still achieving effective welding debris evacuation through the controlled gas flow that pushes debris away from the focal area without creating damaging vortexes or high noise levels.

Inventive Principle:
Principle #2Taking out (Extraction)

4Reliability

If hermetic assemblies are used to protect laser components, then protection is improved, but manufacturing complexity increases

Engineering Contradiction:
Improveprotection of laser componentsVSAvoidassembly complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent employs protective measures that do not require complex hermetic assemblies. The fiber laser architecture inherently protects optical components through the fiber optic delivery system, which guides the laser beam through flexible fiber optics that can be routed through protective pathways. This approach provides adequate protection for laser components while maintaining manufacturing simplicity, as it avoids the need for complex hermetic sealing, flanges, and pressure-equalization systems.

Inventive Principle:
Principle #30Flexible shells and thin films

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

The solution enables efficient welding of complex geometries with reduced debris damage, improved laser beam quality, and precise weld quality control, enhancing productivity and reducing costs by eliminating the need for multiple guns and minimizing noise and debris accumulation.

Implementation Method 1

a fiber laser configured to emit a laser beam guided to the gun

Methodology Applied
Scientific EffectLaser: Laser

Implementation Method 2

The laser beam is guided through a protective sleeve to a beam focusing optics

Methodology Applied
Scientific EffectOptical fiber: Optical Fibre

Implementation Method 3

The laser beam is focused on the workpieces to be welded

Methodology Applied
Scientific EffectFocusing: Focusing

Implementation Method 4

an output protective window mounted to the gun and in fluid communication with the tunnel. A photodetector mounted to the stationary arm detects light leaking through the weld

Methodology Applied
Scientific EffectPhotoelectric effect: Photoelectric Effect

Data Source

PatentEP3357628B1Laser welding gun
Publication Date: 2021.07.21 IPG PHOTONICS CORP
  • EP3357628B1 patent drawingFigure 1
  • EP3357628B1 patent drawingFigure 2~3
  • EP3357628B1 patent drawingFigure 4A

AI summary

A hand maneuverable laser welding gun for joining metal pieces with a weld of predetermined strength, comprising a laser source, at least one arm provided with an interior which forms a tunnel configured to guide the laser light towards a welding zone to produce the weld, a light trap located on the back side of the welding zone, a light sensor coupled to the trap and operative to detect light, which propagates through the welding zone and output a signal upon detecting the light, and a controller to adjust the power of the beam to produce the weld of the predetermined strength. A welding gun can be equipped with an elongated support column and an optical head axially displaceable along the support column as well as with a first arm mounted to the support column along the path and movable with the head to a welding position in which the arm presses against a front metal piece for joining metal pieces spaced from one another.