Laser Peening Liquid Flow Layout for Bubble-Free Irradiation
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Solution Overview
Problem
Laser peening processing is hindered by air bubbles forming at the irradiation point, which interrupt the optical path and attenuate the laser beam energy, leading to inconsistent processing conditions.
Innovation Solution
A laser peening processing device that inclines the workpiece and controls the liquid flow to reduce stagnation and air bubble accumulation, using a nozzle system with a condensing lens and optical elements to ensure the laser beam transmits through a liquid column, and a pressure control mechanism to minimize bubble formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If laser beam is irradiated on the surface to be processed, then laser peening processing is performed, but air bubbles are generated at the focused point which interrupt the optical path and attenuate the laser beam energy
Solution Approach 1:
The liquid supply nozzle is positioned upstream of the laser irradiation point, and liquid is supplied in advance to the surface to be processed before laser irradiation begins. This preliminary action ensures that the liquid is already in place to suppress bubble generation when the laser beam is focused on the surface, preventing optical path interruption and energy attenuation.
Solution Approach 2:
Liquid is introduced as an intermediary substance between the laser beam and the surface to be processed. The liquid serves as a medium that suppresses air bubble generation at the focused point, allowing the laser beam energy to be transmitted effectively to the surface without interruption, thereby maintaining processing consistency and preventing energy loss.
2Object-affected harmful factors
If liquid is supplied to the surface to be processed, then air bubbles are suppressed, but liquid flow creates stagnation points where air bubbles accumulate
Solution Approach 1:
The liquid supply nozzle is positioned at an asymmetric angle relative to the surface normal, specifically at an oblique angle. This asymmetric positioning creates a liquid flow pattern that reduces the formation of stagnation points where air bubbles would accumulate, while still maintaining effective bubble suppression at the laser irradiation point.
Solution Approach 2:
The liquid supply direction is changed from a vertical approach to an oblique approach, introducing a dimensional change in the flow direction. This oblique liquid supply creates a more uniform flow distribution across the surface, eliminating stagnant regions where air bubbles would accumulate, while still effectively suppressing bubble generation at the focused point.
3Object-affected harmful factors
If liquid flow velocity is increased to prevent bubble accumulation, then bubble suppression improves, but liquid spattering and surface waving occur
Solution Approach 1:
The liquid supply is directed specifically toward the laser irradiation point and the surrounding area where bubble generation occurs, rather than uniformly across the entire surface. This localized liquid supply effectively suppresses bubble accumulation at the critical region while using minimal liquid flow, thereby preventing liquid spattering and surface waving that would occur with high-velocity general flow.
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 reduces the number of stagnation points and allows for consistent, high-energy laser irradiation, improving the surface treatment by minimizing energy attenuation and enhancing the compressive residual stress applied to the workpiece.
Implementation Method 1
laser peening processing is performed by condensing and irradiating a laser beam on a surface to be processed of a workpiece in a state where the surface to be processed is covered with liquid
Implementation Method 2
plasma generated by irradiation of the laser beam can be sealed in the liquid
Implementation Method 3
a pressure of a shock wave is applied to the surface to be processed. Thereby, a compressive stress arising inside the workpiece can be made to remain as a residual stress
Implementation Method 4
a flow velocity and a flow rate of the liquid has also been proposed
Data Source
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AI summary
According to one embodiment, a laser peening processing device includes a laser peening processing device includes a laser oscillator, a nozzle and an inclining structure. The laser oscillator emits laser light. The nozzle condenses and irradiates the laser light toward a surface to be processed of a workpiece, with injecting liquid toward the surface to be processed. The inclining structure inclines at least one of the nozzle and the workpiece to make an injection direction of the liquid be different from a normal direction of the surface to be processed. The air bubbles arising by at least one of collision between the liquid and the surface to be processed and shock by irradiation of the laser light on the surface to be processed are flowed in a direction depending on an inclined direction of the surface to the injection direction of the liquid.