Optical Trepanning Head With Rotating Grating for Draft Angle Control
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Solution Overview
Problem
Current picosecond or femtosecond laser machining devices for deep holes lack flexibility and speed in controlling draft angles, particularly for high height-to-diameter ratio profiles, due to bulky refractive optical components that limit the compactness and movement of trepanation heads.
Innovation Solution
A compact optical trepanation device utilizing a rotating diffraction grating and a variable focal length lens system, allowing precise control of draft angles and adaptable to various materials, with a rotating diffraction grating and a movable conical second lens to modulate the laser beam's trajectory and focus.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If refractive optical components such as prisms are used in trepanning heads, then the laser beam can be directed onto the workpiece, but the device becomes bulky and movement is hindered
Solution Approach 1:
The patent replaces refractive optical components (prisms) with a reflective component (mirror) mounted on a galvanometric device. This substitution eliminates the bulk associated with refractive components while maintaining the ability to direct the laser beam onto the workpiece, thereby reducing the volume of the moving trepanning head without sacrificing beam direction control reliability
Solution Approach 2:
The galvanometric device with mirror serves multiple functions: it directs the laser beam onto the workpiece, enables circular movement for trepanning, and allows precise angular control for clearance angle compensation. This multi-functional component replaces what would otherwise require separate bulky refractive components, achieving both compactness and functional reliability
2Ease of operation
If a compact optical trepanning device is designed, then movement and orientation flexibility improve, but precise control of clearance angles becomes more difficult
Solution Approach 1:
The patent employs a galvanometric device that enables dynamic and precise angular adjustment of the mirror. This allows the compact trepanning head to move freely while maintaining precise control over the laser beam's incidence angle on the workpiece, thereby achieving both operational flexibility and manufacturing precision for clearance angle control
Solution Approach 2:
The galvanometric device incorporates precise control mechanisms that can accurately position the mirror at specific angles. This feedback-capable positioning system ensures that even in a compact configuration, the device can achieve and maintain the precise incidence angles required for accurate clearance angle control during machining
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
Enables high-precision machining of parts with large height-to-diameter ratios, achieving precise control over clearance angles and efficient machining of holes with diameters between 50 micrometers and 1 millimeter, suitable for materials with diverse thermal diffusion properties.
Implementation Method 1
The rotating device of the optomechanical system comprises a rotating diffraction grating, which can be of circular geometry
Implementation Method 2
The optomechanical system of the device according to the present invention comprises - a first lens, arranged between the laser source and the rotating device, the focal length of which can be variable. The optomechanical system of the device according to the present invention comprises - a second lens, arranged downstream of the rotating device and movable in translation along the longitudinal axis of the optomechanical system
Implementation Method 3
The last lens of the optomechanical system has a role of focusing lens
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
A machining device comprising an optical trepanning head (1), comprising an opto-mechanical system with a head body (21) provided with a rotary device (22), a picosecond or femtosecond pulsed laser source (3), and at least one optical fibre (4) wherein the rotary device (22) of the opto-mechanical system (2) comprises a rotary diffraction grating (R1). Method for machining by optical trepanning by means of this device.