Laser Machining of Bar Workpiece Surfaces With Low Roughness
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Solution Overview
Problem
Existing methods for producing tool surfaces like nuts on rod-shaped workpieces using pulsed lasers face challenges in achieving both high material removal rates and low surface roughness, with most procedures either achieving high removal rates at the cost of rough surfaces or vice versa.
Innovation Solution
A machining process using a laser with a deflection device and machine drive system that aligns and moves the laser head and workpiece in multiple degrees of freedom, directing laser beam pulses tangentially to the workpiece surface to create a nuts area with precise control over pulse surface geometry and energy distribution, ensuring low roughness and high removal efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a pulse surface is moved across the workpiece surface perpendicular to the laser beam radiation direction, then high material removal rates are achieved, but the manufactured workpiece surfaces exhibit high roughness
Solution Approach 1:
Instead of moving the pulse surface perpendicular to the laser beam direction (conventional approach), the patent inverts the approach by moving the pulse surface parallel to the laser beam radiation direction. This inversion of the movement direction allows the laser beam to consistently strike the workpiece at optimal angles, achieving both high material removal rates and low surface roughness simultaneously.
Solution Approach 2:
The patent changes the movement parameters by aligning the pulse surface movement direction with the laser beam radiation direction. Additionally, the pulse duration is controlled to be less than 12 ms, and the pulse frequency is maintained between 1-1000 Hz. These parameter changes enable efficient material removal while maintaining smooth surface quality.
2Manufacturing precision
If multiple processing passes are used to achieve low surface roughness, then surface quality improves, but productivity decreases due to repeated movements
Solution Approach 1:
The patent implements continuous useful action by moving the pulse surface parallel to the laser beam direction in a single continuous pass rather than multiple discrete passes. The laser beam consistently removes material along the desired path while maintaining surface quality, eliminating the need for repeated movements and post-processing operations.
Solution Approach 2:
The pulse surface is pre-positioned and oriented parallel to the laser beam radiation direction before processing begins. This preliminary alignment ensures that the laser beam strikes the workpiece at optimal angles throughout the entire processing path, achieving both high removal rates and low roughness in a single pass without requiring corrective post-processing.
3Productivity
If the pulse surface is moved parallel to the workpiece surface in axial direction, then layer removal efficiency increases, but surface roughness becomes insufficiently low
Solution Approach 1:
The patent inverts the conventional approach by moving the pulse surface parallel to the laser beam radiation direction rather than perpendicular to it. This inversion enables the laser beam to efficiently remove material layers while simultaneously maintaining smooth surface quality, resolving the contradiction between removal rate and surface roughness.
Solution Approach 2:
The patent changes the dimensional relationship between pulse surface movement and laser beam direction. By aligning the movement direction with the beam direction (changing from perpendicular to parallel orientation), the system achieves efficient material removal along the axial direction while maintaining surface smoothness through consistent beam incidence angles.
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
The process enables the production of nuts with very low roughness and high material removal rates, eliminating the need for post-processing and allowing for complex geometries and varying material sections, while minimizing heat input to prevent material brittleness.
Implementation Method 1
A machining process using a laser with a deflection device and machine drive system that aligns and moves the laser head and workpiece in multiple degrees of freedom, directing laser beam pulses tangentially to the workpiece surface to create a nuts area
Data Source
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AI summary
The invention relates to a method for producing a workpiece surface (23) or a groove inner surface (25) on a bar-shaped, in particular cylindrical, workpiece (11). A rotary tool (40) is intended to be produced from the workpiece (11). The material removal to produce the workpiece surface (23) is brought about with the aid of laser beam pulses (B) which are directed via a deflecting device (14) onto impingement points (31) within a pulse area (22) with a predetermined outer contour (K) and onto the workpiece (11). Positioning between the workpiece (11) and the deflecting device (14) is obtained here via a plurality of machine axis drives (18) in such a way that the pulse area (22) is oriented substantially at right angles to the emission direction (R) of the laser beam pulses and at right angles to the portion of the workpiece surface (23) which has already been produced and adjoins the pulse area (22). During material removal, the pulse area (22) is moved via the at least one machine axis drive (18) along a predetermined movement path (38) while maintaining the orientation relative to the workpiece (11).