Laser Peening of Hole Inner Walls With Bubble-Removing Fluid Flow
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Solution Overview
Problem
During laser peening, air bubbles formed by instantaneous boiling or cavitation interfere with the laser beam, leading to a decrease in intensity and variability of compressive residual stress on the component's surface, particularly in the inner walls of branch holes, which hinders the enhancement of component strength.
Innovation Solution
A component manufacturing method involving the use of a fluid flow to guide air bubbles away from the laser beam's path, with the laser beam irradiated from the outer surface through the opening, and setting the irradiation area to ensure partial overlap and shifting of spots to allow for air bubble movement, thereby maintaining consistent compressive residual stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If laser peening is performed on the inner wall of a branch hole by irradiating from the outer side at a predetermined incident angle, then the laser beam can reach the inner wall, but air bubbles accumulate inside the branch hole and interfere with the laser beam, causing decrease in intensity and variation in compressive residual stress
Solution Approach 1:
The patent extracts the harmful air bubbles from the laser beam path by introducing a fluid flow that carries the bubbles away from the irradiation area. The fluid flow system separates the bubbles from the critical processing zone, allowing consistent laser irradiation without bubble interference.
Solution Approach 2:
The patent introduces a fluid (water or gas) as an intermediary medium that serves dual purposes: it suppresses plasma expansion to enhance compressive residual stress while simultaneously carrying away air bubbles to prevent laser beam interference. This intermediary enables both improved strength and consistent stress distribution.
2Strength
If air bubbles are present in the fluid during laser peening, then the laser beam intensity decreases, but the fluid flow can remove the air bubbles to maintain consistent compressive residual stress
Solution Approach 1:
The patent establishes continuous fluid flow during the laser peening process to continuously remove air bubbles as they form. This continuous action ensures that the laser beam maintains consistent intensity throughout the entire processing sequence, enabling reliable enhancement of compressive residual stress without interruptions or reprocessing.
3Strength
If the laser beam is irradiated at high intensity to ensure sufficient compressive residual stress, then air bubbles absorb the plasma pressure and cause variation in stress among spots, but reducing intensity fails to impart sufficient stress
Solution Approach 1:
The patent converts the harmful effect of air bubbles into a beneficial process by using the fluid flow to deliberately capture and remove bubbles. The fluid, which initially causes bubble formation through plasma interaction, is instead used to transport bubbles away from the irradiation area, transforming a source of variability into a mechanism for maintaining uniformity.
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 method enhances the strength of components by ensuring consistent and high compressive residual stress distribution on the inner walls of holes, counteracting tensile stresses and reducing processing time.
Implementation Method 1
laser peening involves focusing a laser beam on a surface of a component in water to laser-ablate the surface. Thus, plasma is generated on the surface of the component
Implementation Method 2
The pressure of the generated plasma causes shockwaves, which plastically deform the surface of the component
Implementation Method 3
The pressure of the generated plasma causes shockwaves, which plastically deform the surface of the component
Implementation Method 4
creating a flow of the fluid such that air bubbles resulting from laser peening performed by irradiating an inner wall of the hole of the unprocessed component with a laser beam in the fluid flow along the hole
Implementation Method 5
air bubbles due to an instantaneous boiling phenomenon or cavitation air bubbles forming upon disappearance of plasma
Implementation Method 6
air bubbles due to an instantaneous boiling phenomenon or cavitation air bubbles forming upon disappearance of plasma
Data Source
AI summary
A component manufacturing method includes: disposing, in a fluid, an unprocessed component having a hole that has an opening in an outer surface of the unprocessed component; creating a flow of the fluid such that air bubbles resulting from laser peening performed by irradiating an inner wall of the hole of the unprocessed component with a laser beam in the fluid flow along the hole; setting an irradiation area of the laser beam in an inner surface of the hole; and in the fluid of which the flow has been created, irradiating the irradiation area with the laser beam from the side of the outer surface through the opening.