Convergent-Divergent Laser Cutting Nozzle for Stable Long-Range Gas Flow
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Solution Overview
Problem
Modern laser machining units face challenges in maintaining precise nozzle-workpiece distance and angle, leading to quality losses and increased risk of collisions during high-speed machining of complex three-dimensional workpieces, particularly in corner and angled cuts.
Innovation Solution
A laser cutting nozzle with a convergent-divergent passage design, where the wall inclination is limited to at most 5° in the divergence portion and the passage is shaped to ensure constant fluid dynamic ratios over a large distance, allowing the cutting gas to reach supersonic speed and maintain it effectively, preventing gas flow detachment and inhomogeneity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the nozzle distance from the workpiece is reduced to improve machining precision, then cutting quality improves, but the risk of component collisions increases
Solution Approach 1:
The patent employs dynamic nozzle distance control that adapts the working distance based on workpiece geometry. The system transitions from fixed distance to variable distance operation, allowing the nozzle to maintain optimal positioning for different workpiece features while avoiding collisions through real-time adjustment of the machining parameters.
2Productivity
If the machining speed is increased to improve productivity, then output increases, but cutting quality deteriorates due to inability to maintain constant parameters
Solution Approach 1:
The system dynamically changes multiple parameters including nozzle distance, laser power, and gas pressure in coordination with machining speed. This multi-parameter adaptation allows the system to maintain optimal cutting conditions across varying speeds, eliminating the trade-off between productivity and quality by adjusting the complete process parameter set rather than relying on fixed settings.
3Device complexity
If a conventional conical nozzle design is used to simplify manufacturing, then device complexity decreases, but the working distance range is limited
Solution Approach 1:
The nozzle is divided into distinct functional sections: a conical section for basic flow direction, a cylindrical section for flow stabilization, and a specialized mouth region for gas jet shaping. This segmentation allows each section to perform its specific function optimally, enabling the nozzle to accommodate variable working distances while maintaining manufacturing feasibility through modular design.
4Manufacturing precision
If the nozzle mouth cross-sectional area is reduced to improve gas jet concentration, then cutting precision improves, but the working distance is restricted to very small values
Solution Approach 1:
The patent transitions from considering only the cross-sectional area of the nozzle mouth to incorporating the third dimension of axial length. By designing a cylindrical section with specific length-to-diameter ratio and controlling the mouth region geometry in three dimensions, the system achieves gas jet concentration suitable for precision cutting while extending the effective working distance through optimized volumetric gas flow characteristics.
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 nozzle design ensures consistent and high-quality cutting results over extended distances, enabling error-free machining at high speeds and large working distances, with improved reliability and reduced collision risk, even in restricted spaces.
Implementation Method 1
the passage converging continuously, towards the mouth thereof, in a convergence portion, as far as a constriction of the passage... the passage diverging continuously in a divergence portion, proceeding from the constriction
Implementation Method 2
the cutting gas to reach supersonic speed and maintain it effectively
Data Source
AI summary
A laser cutting nozzle for a laser machining unit is described, the nozzle including a passage for the laser beam and cutting gas. The passage extends between a nozzle inlet and a nozzle mouth along a passage longitudinal axis. The passage comprises a convergence portion and a divergence portion. In the entire divergence portion, the wall of the passage forms an angle of inclination relative to the passage longitudinal axis of at most 5°. In addition, the length of the divergence portion is less than 5 times the diameter of the constriction.