Variable Beam Shaping for Precise High-Rate Laser Ablation
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Solution Overview
Problem
Current laser machining techniques for three-dimensional microgeometries are inefficient due to long process times, which can be mitigated by increasing removal rates, but this often results in loss of precision and the quasi-melt-free, quasi-burr-free material removal advantages.
Innovation Solution
A method and apparatus utilizing a variable beam shaping device to adjust the laser beam profile, allowing for different patterns of illuminated and unlit areas on the workpiece surface, enabling high removal rates while maintaining precision through adjustable beam profiles and intensity distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the pulse energy is increased to increase the removal rate, then the productivity is improved, but the manufacturing precision deteriorates due to loss of quasi-melt-free and quasi-burr-free material removal
Solution Approach 1:
The laser beam is divided into multiple sub-beams arranged in a specific pattern, allowing simultaneous processing of multiple locations on the workpiece. This segmentation enables increased total material removal rate while each sub-beam maintains lower energy density to preserve quasi-melt-free material removal characteristics.
Solution Approach 2:
Different regions of the beam profile are assigned different intensity characteristics. The beam is shaped to create a pattern where multiple local spots deliver controlled energy for precise material removal, while the overall beam distribution enables higher total productivity through parallel processing zones.
2Productivity
If the pulse frequency is increased to increase the removal rate, then the productivity is improved, but the manufacturing precision deteriorates due to pulse overlay effects
Solution Approach 1:
The single high-frequency pulse stream is segmented into multiple spatially separated sub-beams. This allows the system to utilize high pulse frequency for increased productivity while the spatial separation prevents pulse overlay effects that would compromise geometry precision and surface quality.
Solution Approach 2:
The problem is solved by transitioning from temporal multiplexing (single beam scanning) to spatial multiplexing (multiple simultaneous beams). The beam shaping device creates a two-dimensional array of sub-beams, adding a spatial dimension to the processing approach that enables high frequency operation without pulse interference.
3Productivity
If the feed rate is increased to maintain constant pulse overlay at higher repetition rates, then the productivity is improved, but the manufacturing precision deteriorates due to reduced processing time
Solution Approach 1:
The processing task is segmented across multiple simultaneous beam locations rather than sequential scanning. This parallel processing approach eliminates the need to increase feed rate, as material removal occurs at multiple points concurrently, maintaining both high productivity and sufficient dwell time for precision.
Solution Approach 2:
Multiple sub-beams operate simultaneously and continuously across different locations, eliminating the intermittent nature of sequential scanning. This continuous parallel action maintains high productivity while ensuring each location receives adequate processing time for precision material removal.
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 faster and more precise three-dimensional machining with reduced melting and burr formation, allowing for increased pulse energy use without losing quasi-melt-free and quasi-burr-free advantages, by controlling the beam profile and intensity distribution dynamically.
Implementation Method 1
For a material removal, in particular, lasers with ultrashortes of laser pulses (UKP) are used... Such ultra-ferrous pulse laser allows, in particular, a quasi-melt-free and grass-free removal of the material
Implementation Method 2
The laser beam is influenced in the proposed method by means of at least a variable beam shaping device and then applies to at least one processing surface of the workpiece. By means of the beam shaping device, at least one predetermined adjustable beam profile is impressed to the laser beam
Data Source
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AI summary
The invention relates to a method for machining a workpiece (110) using laser radiation, in particular for the purpose of laser ablation. At least one laser beam (130) is provided which is influenced by means of at least one variable beam-shaping device (132). The laser beam (130) then impinges on at least one machining surface (112) of the workpiece (110). At least one specified adjustable beam profile (116, 118, 120) is applied to the laser beam (130) at the location of the machining surface (112) by means of the beam-shaping device (132).