Coaxial Laser Depth Detection for Machining Breakthrough
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Solution Overview
Problem
Laser machining technologies face challenges in accurately controlling machining depth and detecting breakthrough in complex workpieces, leading to potential back-strike damage and inefficiencies in feature formation, particularly in applications like gas turbine engine components.
Innovation Solution
A laser machining system incorporating a controller, a working laser, a sensing laser, and optical elements to form a coaxial beam for machining and sensing, with a sensor to maximize reflected beam intensity and determine machining parameters, enabling real-time depth and breakthrough detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If laser machining is performed without real-time depth detection, then machining speed can be maintained, but machining depth control precision deteriorates leading to potential back-strike damage
Solution Approach 1:
The system employs a sensing beam that continuously monitors the machining depth by detecting changes in reflected intensity. The controller receives this feedback signal and adjusts the working beam parameters in real-time to maintain precise depth control, preventing both under-machining and over-machining (back-strike damage) while maintaining efficient processing speeds
Solution Approach 2:
The patent replaces mechanical depth measurement methods with optical detection. A sensing laser beam is used to optically detect the machining depth through intensity variations in the reflected beam, eliminating the need for mechanical probes or interrupters that would slow down the machining process
2Measurement precision
If a sensing beam is added to detect machining depth, then depth control precision is improved, but device complexity increases
Solution Approach 1:
The sensing beam and working beam are merged into a single coaxial optical path using beam combining optics. This allows both the sensing and machining functions to share the same optical delivery system, reducing the number of separate components and simplifying the overall system architecture while maintaining precise depth detection capability
Solution Approach 2:
The optical system is designed to perform multiple functions: the same optical path delivers both the sensing beam for depth detection and the working beam for material removal. The beam combining optic enables this multi-functionality, allowing a single optical system to serve dual purposes and reducing device complexity
3Manufacturing precision
If real-time parameter adjustment is implemented, then manufacturing precision is improved, but control system complexity increases
Solution Approach 1:
The controller implements a feedback control loop that continuously monitors the reflected intensity signal from the sensing beam and automatically adjusts the working beam parameters (such as power or pulse duration) to maintain consistent machining depth and feature uniformity, compensating for variations in material properties or focal position
Solution Approach 2:
The system performs self-adjustment by using its own sensing beam to detect depth variations and automatically correcting the working beam parameters without external intervention. The controller uses the intensity signal from the reflected sensing beam to self-regulate the machining process, maintaining precision without requiring complex external measurement and control systems
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 system allows for precise control of machining depth and breakthrough detection, reducing back-strike damage, improving feature uniformity, and increasing the efficiency of laser machining processes by adjusting parameters in real-time.
Implementation Method 1
a second laser for generating a sensing beam... such that the working beam machines the workpiece and the sensing beam reflects from the workpiece
Implementation Method 2
Laser drilling and laser machining are forms of laser ablation, in which material is removed from a body by heating it with a laser so that it undergoes a chemical or physical phase change
Implementation Method 3
material is removed from a body by heating it with a laser
Data Source
AI summary
A system comprises a working laser beam, a sensing laser beam, first and second optical elements, an optical sensor, an aperture and a controller. The first optical element generates a coaxial beam from the working laser beam and the sensing laser beam. The second optical element focuses the coaxial beam onto a workpiece, such that the working laser beam machines the workpiece and the sensing laser beam reflects from the workpiece. The optical sensor senses an intensity of the reflected sensing beam. The aperture determines a focus position by translating along the reflected sensing beam, such that the reflected intensity is maximized. The controller determining a machining parameter of the working laser beam, based on the focus position.