Laser Welding Beam Homogenization via Diffractive Optical Element
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Solution Overview
Problem
Conventional laser welding systems using point-focused laser beams result in non-uniform fusion due to Gaussian intensity distribution, leading to precise positioning requirements and increased error risk, particularly in materials like spring steel where improper positioning can cause burn-outs.
Innovation Solution
Incorporating an optical element, such as microlenses or diffractive optical elements, between the collimator and focusing means to spread the laser beam power distribution along desired angles, creating a more homogeneous welding region by redistributing energy across a larger area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a point-focused laser beam with Gaussian intensity distribution is used for welding, then deep and concentrated weld seams can be achieved, but non-uniform fusion occurs and precise positioning is required
Solution Approach 1:
The patent applies local quality by creating different intensity zones within the welding spot. The annular beam profile concentrates energy at the periphery rather than the center, creating a localized high-intensity region that ensures uniform fusion across the weld zone while maintaining high power density for deep penetration welding.
Solution Approach 2:
The patent transitions from a point-focused beam (0D) to an annular ring-shaped beam (1D linear structure). This dimensional change distributes energy along a circular path rather than concentrating it at a single point, reducing sensitivity to positioning errors while maintaining concentrated heating capability for deep weld seams.
2Productivity
If a point-focused laser beam is used for welding, then welding speed can be increased, but error risk increases due to non-uniform fusion
Solution Approach 1:
By creating an annular intensity distribution with enhanced peripheral energy concentration, the patent ensures uniform material fusion across the weld zone. This local quality enhancement eliminates weak spots that would require rework, thereby increasing welding reliability while maintaining high welding speeds through efficient energy utilization.
Solution Approach 2:
The patent converts the typically wasted peripheral energy in Gaussian beams into the primary heating zone. By redistributing energy to create an annular profile, what would have been low-intensity edge regions become the high-intensity welding zone, improving both reliability and efficiency simultaneously.
3Measurement precision
If a point-focused laser beam is used for welding thin materials, then precise control is achieved, but burn-out risk occurs with positioning errors
Solution Approach 1:
The annular beam profile inherently provides a cushion against positioning errors by distributing energy along a circular path. Even if the beam center shifts, the annular structure ensures that high-intensity energy remains distributed around the intended weld zone, preventing localized burn-out while maintaining effective welding.
Solution Approach 2:
By transitioning from point-focused (0D) to annular (1D) energy distribution, the patent creates a more tolerant welding profile for thin materials. The extended energy distribution along the circular path provides a buffer zone that prevents burn-out even when positioning precision is compromised, while still achieving sufficient energy concentration for effective welding.
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 approach ensures more uniform energy input and reduced error risk during welding, allowing for effective line welding and improved robustness against positioning inaccuracies, particularly beneficial for applications like stamping operations.
Implementation Method 1
Incorporating an optical element, such as microlenses or diffractive optical elements, between the collimator and focusing means to spread the laser beam power distribution along desired angles
Implementation Method 2
Incorporating an optical element, such as microlenses or diffractive optical elements, between the collimator and focusing means to spread the laser beam power distribution
Data Source
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AI summary
The present invention relates to a laser welding system comprising a source (1) for a laser beam, a collimator (2) which is adapted to collimate the laser beam, and a focusing means (3) which is adapted to focus the collimated laser beam onto a concentrated point on a workpiece (4) to be welded. In order to allow for a homogeneous welding region, an optical element (5) is arranged between the collimator (2) and the focusing means (3), the optical element being adapted to spread a power distribution of the laser beam along a first direction running at an angle to an axis of the collimated laser beam. According to an alternative solution, the optical element (5) is arranged between the source (1) for the laser beam and the collimator (2).