Dual-Wavelength Fiber Laser Beam Control for Welding Quality
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Solution Overview
Problem
Existing laser processing technologies face challenges in quickly and accurately controlling the power distribution of combined laser light with different wavelengths, especially when processing workpieces with changing shapes, leading to difficulties in maintaining processing quality.
Innovation Solution
A laser processing device that includes a laser oscillator generating laser light with two different wavelengths, an optical fiber with multiple claddings, a beam control mechanism that adjusts the incident position of each laser light wavelength on the optical fiber, and a controller to manage the power distribution by changing the optical path of the second laser light wavelength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the position of the condenser lens is moved by an actuator to change the incident position of laser light, then the incident position can be adjusted, but the responsiveness is slow and it is difficult to quickly change the optical path
Solution Approach 1:
The patent replaces the mechanical actuator system with an optical path changing mechanism that uses mirrors or prisms to redirect laser light. This substitution eliminates the need for physical movement of the condenser lens, achieving both precise incident position control and rapid responsiveness by changing the optical path direction through mechanical mirrors rather than moving the lens itself.
2Measurement precision
If the condenser lens is moved on a straight line by an actuator to change incident position, then positional accuracy can be achieved, but responsiveness deteriorates due to the mechanical movement requirement
Solution Approach 1:
The patent segments the optical path into multiple sections using separate mirrors or prisms for different wavelengths. By dividing the optical path control into independent segments, each wavelength can be controlled separately without requiring the entire condenser lens assembly to move, thus reducing the time required for position changes while maintaining accuracy.
3Adaptability or versatility
If optical elements are moved during continuous laser oscillation, then the incident position can be changed, but laser light is scattered by the edge portion causing defects
Solution Approach 1:
The patent pre-positions the optical path changing mechanism outside the main laser beam path. The mirrors or prisms are arranged to redirect the laser light before it enters the workpiece area, ensuring that the laser beam is already properly positioned and collimated before reaching the workpiece. This preliminary arrangement prevents scattering by ensuring the beam does not pass near moving mechanical edges during operation.
4Adaptability or versatility
If the reflector or condenser lens is moved by a piezo actuator to change incident position, then beam profile can be adjusted, but the system complexity increases and responsiveness is limited
Solution Approach 1:
The patent introduces an intermediary optical path changing mechanism that acts as a mediator between the laser source and the workpiece. Instead of directly moving the reflector or condenser lens, the system uses intermediate mirrors or prisms to redirect the beam. This intermediary approach simplifies the control system by decoupling the beam profile adjustment from the incident position control, reducing overall system complexity while maintaining versatility.
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 device effectively controls the power distribution of multiplexed laser light, improving the welding quality of workpieces by reliably forming molten pools and keyholes, and preventing defects such as air bubbles and uneven surfaces.
Implementation Method 1
a first condenser lens that receives the first laser light, and condenses the first laser light at a predetermined magnification
Implementation Method 2
a second condenser lens that receives the second laser light, and condenses the second laser light at a predetermined magnification
Implementation Method 3
an optical combining member that receives the first laser light condensed by the first condenser lens and the second laser light condensed by the second condenser lens, superimposes optical axes of the first laser light and the second laser light on each other, and forms laser light
Implementation Method 4
a beam control mechanism that is provided in the laser oscillator, and introduces the laser light into the incident end face of the optical fiber... an optical path changing and holding mechanism that is disposed on at least one of an optical path of the first laser light between the first condenser lens and the optical combining member and an optical path of the second laser light between the second condenser lens and the optical combining member
Data Source
AI summary
A laser processing device includes a laser oscillator, optical fiber (90), beam control mechanism (20), and a laser light emitting head. The laser oscillator includes first and second laser oscillation units that generate first and second laser light rays (LB1) and (LB2), respectively. Beam control mechanism (20) includes optical path changing and holding mechanism (40) that is disposed between second condenser lens (32) that condenses second laser light (LB2) and dichroic mirror (33) that multiplexes first and second laser light rays (LB1) and (LB2) and causes the multiplexed light to be incident on optical fiber (90). Beam control mechanism (20) changes an incident position of second laser light (LB2) on optical fiber (90).