Laser Welding Diffractive Optical Element Power Density Control
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Solution Overview
Problem
Current laser welding technologies face limitations in flexibility and efficiency, particularly in controlling power density distribution during the welding process, which can lead to defects and increased processing time.
Innovation Solution
A laser welding apparatus that employs a diffractive optical element with distinct regions for diffraction grating and no diffraction grating, allowing for adjustable power density distribution by moving the incident point across the boundary between these regions, enabling flexible control of the irradiation pattern and reducing defects and processing time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single power density distribution is used for laser welding, then the welding process is simple, but it causes defects and requires longer processing time
Solution Approach 1:
The diffractive optical element is divided into multiple regions (first region with diffraction grating, second region without diffraction grating), each controlling different portions of the laser beam to create multiple irradiation patterns with different power density distributions simultaneously
Solution Approach 2:
Different regions of the irradiation position receive different power density distributions - the first irradiation pattern provides high power density for rapid heating and welding, while the second irradiation pattern provides low power density for preventing defects, allowing each area to be treated with the appropriate energy level
2Productivity
If high-density laser beams are used to reduce processing time, then welding speed increases, but temperature increases rapidly causing bumps and defects
Solution Approach 1:
The low-density laser beam (second irradiation pattern) is applied first to the irradiation position to perform preliminary heating in a controlled manner, establishing a temperature gradient that prevents rapid temperature increase when the high-density laser beam is subsequently applied
Solution Approach 2:
The system dynamically changes the power density parameter by switching between two irradiation patterns from the diffractive optical element - using low power density for pre-heating and high power density for rapid welding, thereby controlling the temperature profile to avoid defects
3Reliability
If flexible control of power density distribution is implemented, then welding quality improves, but the device complexity increases
Solution Approach 1:
A diffractive optical element serves as an intermediary device that passively creates multiple irradiation patterns with different power density distributions by its structural design (regions with and without diffraction grating), eliminating the need for complex active control systems while achieving flexible power density control
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 apparatus achieves more precise control over power density distribution, reducing defects and enabling faster welding by selectively varying the power density at different regions, thus improving the quality and efficiency of the welding process.
Implementation Method 1
a diffractive optical element that radiates a radiated beam toward the irradiation position from an incident point of the incident beam; the diffractive optical element includes a first region and a second region that are adjacently disposed, the first region is a region in which a diffraction grating is formed, the diffraction grating radiating the radiated beam having a first distribution profile of a power density
Implementation Method 2
A laser welding apparatus that irradiates a welding point with a laser beam so as to form a joined portion where joint target members are joined together
Data Source
AI summary
A laser welding apparatus according to the present invention includes a diffractive optical element, an incident-point changing unit, and a controller. The diffractive optical element includes a first region where there is formed a diffraction grating that radiates a radiated beam having a first distribution profile of a power density that is different from a distribution profile of a power density of the incident beam. The diffractive optical element further includes a second region that has a surface profile different from a surface profile of the first region, and radiates a radiated beam having a second distribution profile of the power density that is different from the first distribution profile of the power density. The controller carries out a joining control to move at least one point in the incident point across a boundary between the first region and the second region during the emission of the laser beam.