Laser Nozzle Focus Positioning for Stable Thick-Plate Cutting
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Solution Overview
Problem
The existing laser machining apparatus requires additional optical components to form a ring-shaped laser beam, leading to frequent machining defects and deterioration in machining quality due to contamination and thermal lens effects.
Innovation Solution
A laser machining apparatus with a laser oscillator outputting 1 μm wavelength light, a machining head featuring a divergent-shaped nozzle and a condensing lens, and a controller that controls the focus position inside the machining head, away from the nozzle's smallest inner diameter, emitting laser light and machining gas coaxially without forming a ring beam.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a ring-shaped laser beam is formed using additional optical components, then thick workpieces can be cut, but machining quality deteriorates due to contamination and thermal lens effects
Solution Approach 1:
The patent removes the ring beam forming optical components from the system entirely. Instead of using a ring beam, the invention employs a Gaussian beam with a specific focus position inside the workpiece that achieves effective thick workpiece cutting without the contamination and thermal lens problems associated with ring beam optical components
Solution Approach 2:
The patent changes the focus position parameter to be inside the workpiece (positive focus position) rather than at the surface or outside. This parameter change allows the Gaussian beam to effectively process thick workpieces by creating a focused energy distribution deep within the material, eliminating the need for ring beam geometry
2Length of moving object
If additional optical components are added to form a ring beam, then thick workpiece cutting capability is achieved, but device complexity increases
Solution Approach 1:
The patent extracts and removes the ring beam forming optical components (such as cylindrical lenses or holographic elements) from the optical system. The simplified system uses only a standard condensing lens to focus a Gaussian beam, significantly reducing device complexity while maintaining thick workpiece cutting capability through internal focusing
Solution Approach 2:
The condensing lens in the patent serves multiple functions: it focuses the Gaussian beam to a point inside the workpiece for cutting, and its position can be adjusted to adapt to different workpiece thicknesses. This universal component replaces the need for specialized ring beam forming optics
3Length of moving object
If additional optical components are used to form a ring beam, then thick workpiece cutting is enabled, but reliability decreases due to frequent contamination
Solution Approach 1:
By removing the ring beam forming optical components that are positioned close to the workpiece, the patent eliminates the sources of contamination (dust, spatter, molten material) that would deposit on these components. The simplified optical path with fewer components near the machining zone significantly improves reliability and reduces maintenance requirements
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
Stably cuts thick workpieces with high quality, reducing machining defects and maintaining stability across varying material compositions and surface states without the need for a special optical system, thus improving manufacturing efficiency and cost-effectiveness.
Implementation Method 1
a condensing lens to condense the laser light at a focus position
Implementation Method 2
machining a workpiece by irradiating the workpiece with laser light
Implementation Method 3
ejects an oxygen gas along a ring axis of the ring-shaped laser beam
Data Source
AI summary
A laser machining apparatus includes a laser oscillator, a machining head, and a controller. The laser oscillator outputs laser light. The machining head includes: a nozzle having a divergent-shape on an outlet side thereof through which the laser light is emitted to a workpiece; and a condensing lens that condenses the laser light at a focus position. The machining head ejects machining gas to the workpiece and ejects cooling gas to the nozzle through a path different from a path for the machining gas. The controller controls the focus position of the laser light such that the focus position is located inside the machining head and away from a smallest-inner-diameter portion of the nozzle in a direction toward the condensing lens. The laser light is emitted to the workpiece without a ring beam being formed. The machining gas is ejected to the workpiece coaxially with the laser light.