Liquid-Jet Laser Coupling to Protect Nozzle and Window Life
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Solution Overview
Problem
Existing liquid-jet guided laser systems face challenges in reliably coupling high-power laser beams without damaging the nozzle and protection window, leading to short operational lifetimes and instability, especially in industrial environments requiring continuous operation.
Innovation Solution
The method involves configuring the liquid-jet guided laser system by setting parameters such as the focus point, focus cone angle, and effective width of the laser beam based on power density profiles, ensuring the focus point is below the nozzle inlet plane and optimizing the numerical aperture to prevent damage to the nozzle and protection window, allowing for longer operational times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high laser power is used for material treatment, then processing capability is improved, but the nozzle and protection window are damaged
Solution Approach 1:
The patent applies preliminary action by pre-calculating and setting the optimal focus point position below the nozzle inlet plane before operation. This predetermined configuration ensures that the laser beam is properly focused and contained within the liquid jet from the start, preventing damage to the nozzle and protection window while enabling high power operation. The coupling point CP is calculated using the formula CP = (CF × DN) / (2 × NA) to establish the correct focus position in advance.
Solution Approach 2:
The patent applies parameter changes by optimizing key parameters including the focus point position (set below nozzle inlet plane), numerical aperture (NA between 0.25-0.75), and focus cone angle (θ). These parameter adjustments ensure proper laser beam containment within the liquid jet, allowing high power operation without damaging the nozzle and protection window. The effective width parameter (Deff = CF × DN) is also optimized to match the laser beam profile with the liquid jet dimensions.
2Use of energy by moving object
If exact focus alignment is used, then laser energy coupling into liquid-jet is improved, but the system complexity increases
Solution Approach 1:
The patent applies self-service by designing a system where the liquid jet itself guides and contains the laser beam through total internal reflection at the liquid-air interface. The liquid jet automatically provides the necessary optical confinement without requiring external alignment mechanisms or complex control systems. The laser beam naturally couples into the liquid jet when the focus point is positioned below the nozzle inlet plane, leveraging the liquid jet's own properties for beam guidance.
3Productivity
If continuous operation is required for industrial environments, then productivity is improved, but the nozzle and protection window degrade over time
Solution Approach 1:
The patent applies preliminary action by pre-configuring the optimal operating parameters (focus point position, numerical aperture, focus cone angle) before continuous operation begins. This predetermined setup ensures that the laser beam is properly contained within the liquid jet from the start of each operational cycle, preventing cumulative damage to the nozzle and protection window during extended 3-shift industrial operation.
Solution Approach 2:
The patent converts the potentially harmful high laser power that could damage components into a beneficial force by properly confining it within the liquid jet. The liquid jet acts as an optical waveguide, transforming the high-power laser beam into a controlled energy delivery mechanism that maintains component integrity while enabling continuous high-productivity operation in industrial environments.
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 configuration enables reliable coupling of high-power laser beams, significantly increasing the lifetime of the nozzle and protection window, enabling true unattended 3-shift operation in industrial environments by minimizing energy exposure and optimizing power transfer.
Implementation Method 1
Light guiding inside a liquid-jet, also of laser light with an energy level below a material damage threshold, is a well-known effect
Implementation Method 2
the laser beam generated in a laser source is coupled into a liquid jet directed onto the surface to be machined and emerging from a nozzle by means of focusing optics
Data Source
Figure 1A~1B
Figure 2A~2D
Figure 3A~3C
AI summary
Reliable coupling of a high-power laser beam 180 into a liquid-jet 125 in a liquid-jet guided laser system can be achieved with high lifetime performance of the nozzle 130, 140 and the protection window 170, through setting the parameters of the liquid-jet guided laser system according to an optimum relationship that links the focus point of the laser, the focus cone angle, the laser beam energy distribution profile and the nozzle geometry.