Laser-Fluid Jet Coupling for Stable Pressure-Balanced Beam Processing
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Solution Overview
Problem
Existing laser beam processing devices face challenges in maintaining the coherence and reliability of fluid jets due to pressure variations and air entrainment, leading to reduced processing capability, especially in cavities where fluid accumulation occurs, and require complex gas control systems to prevent fluid jet disruption.
Innovation Solution
A coupling device with a pressure chamber and throttle bores that regulate pressure ratios to maintain a stable fluid jet, avoiding positive or negative pressures that could cause the jet to fan out, allowing the laser beam to be directed accurately to the workpiece surface without auxiliary gas sheathing, and an annular gas jet for surface displacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If an enveloping gas flow is used to reduce friction and improve fluid jet coherence, then the coherence of the fluid jet is improved, but the kinetic energy of the fluid jet becomes insufficient to displace fluid in cavities, restricting processing capability
Solution Approach 1:
The gas flow system is segmented into two independent parts: an enveloping gas flow for coherence and a displacement gas flow for cavity clearing. This segmentation allows each gas flow to be optimized for its specific function without compromising the other, resolving the contradiction between maintaining jet coherence and ensuring processing capability in cavities
Solution Approach 2:
A second gas source acts as an intermediary to provide the displacement function that the primary enveloping gas flow cannot achieve alone. This additional gas flow mediates between the fluid jet and the accumulated fluid in cavities, enabling effective material removal while preserving the coherence-providing enveloping gas flow
2Productivity
If the passage chamber is placed under positive pressure to maintain gas flow, then the gas flow can displace fluid on the workpiece surface, but air particles are entrained by the fluid jet and can cause negative pressure, leading to fluid jet fanning out
Solution Approach 1:
The system uses pressure feedback control where the pressure in the passage chamber is monitored and regulated to maintain optimal conditions. The throttle bore and outlet opening dimensions are designed to create a pressure balance that prevents both excessive positive pressure (which would cause air entrainment) and negative pressure (which would cause jet fanning), ensuring stable operation
Solution Approach 2:
The system changes the pressure parameter dynamically by using a throttle bore to regulate gas flow into the passage chamber. By controlling the pressure ratio between the passage chamber and external environment, the system maintains fluid jet stability while enabling effective fluid displacement on the workpiece surface
3Productivity
If a complex gas control system with multiple gas sources is used to maintain positive pressure and prevent negative pressure, then fluid displacement capability is improved, but the device complexity increases
Solution Approach 1:
The gas control system is segmented into distinct functional zones: a pressure chamber for generating positive pressure, a passage chamber for fluid jet passage, and separate throttle bore and outlet opening for pressure regulation. This segmentation simplifies the control logic by assigning specific pressure management tasks to specific components, reducing overall system complexity while maintaining effective fluid displacement capability
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
Ensures a stable, laminar fluid jet is maintained for effective processing, preventing fluid jet disruption and allowing efficient material removal on both flat and convex surfaces, with reduced risk of dirt entry and simplified control systems compared to prior art.
Implementation Method 1
the laser beam has to be focused as sharply as possible so that energy for processing the workpiece is sufficiently present at the location of the processing of the workpiece
Implementation Method 2
the kinetic energy of said fluid jet is insufficient especially in cavities in the workpiece in which the fluid rapidly accumulates
Data Source
AI summary
Disclosed is a laser beam processing device, the main part of which is a coupling device (1) for coupling a focused laser beam (2) into a fluid jet (3) of a defined cross-section. The coupling device (1) comprises a housing (4), in which a fluid nozzle is configured for forming the fluid jet (3). In addition, an outlet opening (6) is provided in the housing, through which the fluid jet (3) exits from the housing (4) and the cross-section of which is larger than the cross-section of the fluid jet (3). A passage chamber is provided between the fluid nozzle (5) and the outlet opening (6) for the fluid jet (3). According to the invention, a throttle bore is provided, which connects the passage chamber (7) to the pressure chamber and is dimensioned in relation to the outlet opening so that, in the region of the passage chamber which is arranged about the fluid nozzle (5), there is a pressure that is smaller than the pressure in the pressure chamber so that an overpressure does not form in the passage chamber with respect to the pressure in the pressure chamber. In addition, a method is disclosed for setting a pressure in the passage chamber (7) in a coupling device of this type, in which the pressure does not exceed the pressure in the pressure chamber.