Laser Processing Assembly for Reflective Workpieces
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Solution Overview
Problem
Processing highly reflective workpieces such as copper and aluminum with laser beams is challenging due to difficulties in achieving effective absorption and maintaining processing quality, especially in industries like electronics, medical, and jewelry.
Innovation Solution
A laser processing arrangement using a fiber laser with a pulsed primary beam of less than 1nm bandwidth, combined with a frequency multiplier module, optical adjustment, and circular polarizer, along with deflection optics and transport fibers, to improve absorption and suppress spatter formation, while decoupling and analyzing axial radiation for process control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional fiber laser with bandwidth less than 0.3 nm is used for processing highly reflective workpieces, then the laser beam can be generated, but the absorption is insufficient and processing quality deteriorates
Solution Approach 1:
The patent applies parameter changes by broadening the laser bandwidth from less than 0.3 nm to less than 1 nm, and by frequency multiplication to generate secondary beams at different wavelengths. This changes the physical parameters of the laser radiation to improve absorption in highly reflective materials like copper and aluminum.
Solution Approach 2:
The patent uses a composite approach by combining multiple laser beams with different wavelengths (primary beam and frequency-multiplied secondary beams) to process the workpiece. This multi-wavelength composite radiation enables better energy coupling with highly reflective materials compared to a single wavelength.
2Loss of energy
If the intensity of the primary laser beam is increased to improve processing effectiveness, then absorption may improve, but spatter formation increases and processing reliability deteriorates
Solution Approach 1:
The patent segments the laser energy into multiple wavelength components (primary beam and multiple secondary beams at different frequencies). This segmentation allows the energy to be distributed across different wavelengths that are better absorbed by the material, reducing the need for high intensity at a single wavelength and thereby reducing spatter.
Solution Approach 2:
The frequency multiplier module acts as an intermediary that converts the primary laser beam into secondary beams at different wavelengths. These intermediate wavelength components serve as mediators that improve energy coupling with the workpiece material, enabling effective processing at lower intensities and reducing harmful spatter formation.
3Stability of the object's composition
If a narrow bandwidth laser beam is used to maintain beam quality, then the laser can be generated, but absorption in highly reflective materials is insufficient
Solution Approach 1:
The patent changes the bandwidth parameter from less than 0.3 nm to less than 1 nm, and introduces frequency multiplication to create multiple wavelength components. This parameter change maintains beam quality while significantly improving absorption in highly reflective materials through multi-wavelength radiation.
4Loss of energy
If the laser beam parameters are adjusted to improve absorption, then processing effectiveness improves, but control and reproducibility become more difficult
Solution Approach 1:
The patent employs feedback mechanisms where radiation emanating from the workpiece is detected and analyzed, and control signals are generated to adjust the laser beam parameters in real-time. This closed-loop control ensures reproducible processing results even when absorption conditions vary.
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
Significantly enhances processing quality and reproducibility for highly reflective materials by adapting radiation energy to the processing geometry and controlling the machining process, reducing spatter and improving precision.
Implementation Method 1
a fiber laser as a laser beam source for generating a pulsed primary laser beam
Implementation Method 2
If a frequency multiplier module for generating at least one frequency-multiplied secondary laser beam is arranged in the beam path of the primary laser beam
Implementation Method 3
a deflection mirror which is narrow-band, highly reflective for the primary and the secondary laser beam(s) and which is permeable to plasma and thermal radiation emanating from the workpiece
Implementation Method 4
one or a plurality of transport fibers are provided for guiding the laser beams
Implementation Method 5
a processing head which includes a collimator device, deflection optics and focusing optics for focusing the laser beam or beams onto the workpiece
Implementation Method 6
the absorption is improved and the processing quality and reproducibility in the case of highly reflective workpieces are significantly improved
Data Source
Figure 1
AI summary
The invention relates to an assembly for processing a workpiece (22) by means of a laser beam (L), in particular for processing a highly reflective workpiece, comprising a fiber laser (1) as a laser beam source for producing a pulsed primary laser beam (L1) having a bandwidth that is less than 1 nm.