Facet Lens Laser Cutting for Thick-Sheet Surface Quality
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Laser processing machines using fiber or DDL oscillators, which emit laser beams with wavelengths in the 1 µm band or shorter, suffer from poor cutting surface quality and increased roughness with thicker sheets, leading to issues like dross formation and reduced surface quality compared to CO2 laser oscillators.
Innovation Solution
The laser processing machine employs a focusing optical element that condenses the laser beam onto multiple spots within a unit area, using assist gas at pressures between 2.0 MPa to 3.0 MPa, and optimizes the beam parameter product to 23 mm mrad to 28 mm mrad, improving cutting surface quality by adjusting the incident angle and absorption rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fiber laser oscillator or DDL oscillator is used, then the device size is reduced and running costs are lowered, but the cutting surface quality deteriorates and roughness increases
Solution Approach 1:
The patent applies parameter changes by optimizing the beam parameter product (BPP) to a specific range (15 mm mrad to 30 mm mrad) and controlling the mode field diameter ratio between fundamental mode and higher-order modes. This allows fiber laser oscillators to achieve cutting surface quality comparable to CO2 lasers while maintaining their size and cost advantages.
2Device complexity
If a fiber laser oscillator or DDL oscillator is used, then the device size is reduced and running costs are lowered, but dross formation increases on thick sheets
Solution Approach 1:
The patent controls the beam parameter product and mode field diameter ratio to optimize energy distribution during cutting. This parameter optimization prevents excessive energy concentration that causes dross formation, enabling clean cutting of thick sheets (3 mm or more) while using compact fiber laser oscillators.
3Manufacturing precision
If a CO2 laser oscillator is used, then the cutting surface quality is high and roughness is low, but the device size is large and running costs are high
Solution Approach 1:
The patent changes the laser beam parameters (BPP and mode field diameter ratio) to achieve cutting performance previously only attainable with CO2 lasers. This allows fiber laser oscillators to produce smooth cutting surfaces with minimal roughness while maintaining their compact size and lower operating costs.
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 configuration significantly enhances the quality of the cutting surface, reducing roughness and dross formation, even with thicker sheets, while maintaining a compact and cost-effective setup, comparable to CO2 laser systems.
Implementation Method 1
a focusing optical element that focuses the laser beam emitted from the laser oscillator on a plurality of spots in a unit area
Implementation Method 2
a laser oscillator that emits a laser beam with a wavelength in a 1 μm band or a shorter wavelength band
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A laser processing machine (100) includes a laser oscillator (11) . The laser oscillator (11) excites a laser beam having a wavelength in a 1 µm band or a shorter wavelength band. One process fiber (12) transmits the laser beam emitted from the laser oscillator (11). A focusing lens (27) that is formed of a facet lens is an example of a focusing optical element. The focusing optical element focuses, when a sheet metal (W1) as a workpiece is irradiated with the laser beam emitted from the process fiber (12), the laser beam on a plurality of spots in a unit area within a unit time, the unit area having a radius of 0.5 mm of an optical axis of the laser beam, and the unit time being a time from when the sheet metal (W1) starts to melt to when the melting of the sheet metal (W1) ends.