Laser Focusing Aberration for Low-Spatter Deep Penetration Welding
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Solution Overview
Problem
Laser processing machines using near-infrared lasers face issues with spatter production, leading to degraded processing quality due to unstable keyhole formation caused by the lack of control over the light-focusing state of the laser beam.
Innovation Solution
A laser processing machine equipped with a light-focusing optical system that has aberration, specifically a lateral aberration of 0.2 mm or more at the light-focusing point, which shapes the laser beam into a witch hat profile, reducing spatter formation by altering the molten metal flow direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a near-infrared laser is used to generate highly-focused high-output laser beams, then processing speed and penetration depth are improved, but spatter production increases and processing quality degrades
Solution Approach 1:
The patent introduces a specific parameter control mechanism by adjusting the lateral aberration of the light-focusing optical system to 0.2 mm or more. This parameter change modifies the laser beam's intensity distribution and focusing characteristics, thereby controlling the keyhole shape and molten metal flow to reduce spatter while maintaining high productivity
Solution Approach 2:
The patent implements a feedback control system that monitors the light-focusing state of the laser beam and adjusts the optical system accordingly. This feedback mechanism ensures stable keyhole formation and consistent processing quality by dynamically compensating for variations in focusing conditions
2Length of moving object
If the laser beam is highly focused to achieve deep penetration, then welding depth is improved, but keyhole shape becomes unstable and spatter increases
Solution Approach 1:
The patent controls the lateral aberration parameter of the optical system to achieve a balanced focusing state. By setting the lateral aberration to 0.2 mm or more, the system maintains stable keyhole geometry while achieving sufficient welding depth, preventing both excessive focusing (which causes spatter) and insufficient focusing (which reduces penetration)
Solution Approach 2:
The patent employs a dynamic optical system that can adjust its focusing characteristics during processing. The light-focusing optical system with controllable lateral aberration adapts to varying processing conditions, maintaining optimal keyhole shape stability across different welding depths and speeds
3Device complexity
If conventional optical systems are used without aberration control, then device complexity is reduced, but processing quality becomes unstable due to uncontrolled light-focusing state
Solution Approach 1:
Instead of adding complex optical components, the patent achieves quality control by adjusting the lateral aberration parameter of existing optical elements. This approach maintains relatively simple device architecture while significantly improving processing quality through precise parameter control of the light-focusing state
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 stabilizes the processing quality by reducing spatter generation and maintaining high-quality welds with deep penetration, effective across a wide range of optical-axis positions and processing conditions.
Implementation Method 1
a light-focusing optical system to focus the laser beam onto a workpiece for performing a laser processing
Implementation Method 2
When a workpiece is irradiated with a laser beam from a laser processing machine, a portion of the workpiece irradiated with the laser beam instantaneously melts and evaporates
Implementation Method 3
a portion of the workpiece irradiated with the laser beam instantaneously melts and evaporates
Implementation Method 4
Convection of the molten metal occurs inside the keyhole
Data Source
AI summary
A laser processing machine to perform laser processing by focusing a laser beam onto a workpiece, includes a light-focusing optical system to focus the laser beam, wherein the light-focusing optical system has an aberration, and a lateral aberration with respect to a laser beam diameter:D86.5 containing 86.5% of the laser power of a laser beam before being focused is 0.2 mm or more, the lateral aberration being at a light focusing point relative to a light beam corresponding to the laser beam diameter:D86.5.