Laser Cutting Head Optics With Movable Surface Beam Shaping

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Solution Overview

Problem

Conventional laser machining cutting heads with fixed optical images compromise on cut quality and feed rate for various materials and thicknesses, especially at medium laser powers above 1 kW, due to rigid beam parameters.

Innovation Solution

A machining apparatus with a stationary laser beam guiding device featuring a movable surface that adjusts the focal length and beam parameter product over time, enabling both static and dynamic beam shaping, allowing for flexible focal length modification and beam parameter adjustment, thus optimizing laser machining for different materials and thicknesses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a fixed optical image of the laser beam is used in the machining head, then the device structure is simple and stable, but the cut quality and feed rate are compromised for different materials and thicknesses

Engineering Contradiction:
Improvestability of optical systemVSAvoidadaptability to different materials and thicknesses
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent applies dynamic beam shaping by continuously oscillating the laser beam at frequencies between 100 Hz to 10 kHz using a beam oscillation device. This dynamic movement allows the beam parameter product to be changed over time, enabling adaptation to different materials and thicknesses while maintaining a stable fixed optical image structure in the machining head.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the beam parameter product dynamically through beam oscillation, allowing the same optical system to achieve different effective beam parameters for different materials and thicknesses. This parameter change approach resolves the contradiction by enabling versatility without requiring multiple fixed optical configurations.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If zoom optics are used to change the focal length within a certain range, then the adaptability to different workpiece types and thicknesses is improved, but the device complexity increases

Engineering Contradiction:
Improveadaptability to different workpiece types and thicknessesVSAvoidcomplexity of optical system
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines beam oscillation with a fixed focal length optical system, merging the functions of beam parameter adjustment and focusing into a single configuration. This approach achieves adaptability through dynamic beam shaping rather than through complex zoom optics with multiple movable elements.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent replaces the mechanical zoom optics system (which would require multiple movable optical elements) with a beam oscillation system that achieves parameter adjustment through controlled beam movement. This substitution reduces mechanical complexity while maintaining adaptability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Adaptability or versatility

If the entire laser beam guiding device is made movable to achieve beam shaping, then the beam parameter product can be adjusted, but the device complexity and space requirements increase

Engineering Contradiction:
Improveadjustability of beam parameter productVSAvoidcomplexity of beam guiding system
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent extracts the beam shaping function from the main movable beam guiding device and implements it separately through beam oscillation. This allows the primary optical system to remain stationary and simple, while the beam oscillation device provides the necessary parameter adjustment capability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces beam oscillation as an intermediary mechanism between the fixed optical system and the workpiece. This intermediary enables beam parameter adjustment without requiring the entire beam guiding device to be movable, thus reducing complexity and space requirements.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 solution enables high-quality laser machining with adjustable focal length and beam shaping, improving cut quality and feed rate across a range of materials and thicknesses, and supports laser powers up to 4 kW and above without requiring the entire beam guiding device to move, allowing for a space-saving and efficient setup.

Implementation Method 1

a stationary laser beam guiding device (22) with at least one movable surface (24), wherein the at least one movable surface (24) can be adjusted such that it modifies the focal length of the optical system

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

the at least one movable surface (24) can be adjusted such that it modifies the focal length of the optical system and the beam parameter product of the machining laser beam integrated over time

Methodology Applied
Scientific EffectDynamic beam shaping through surface movement:

Implementation Method 3

an optical system (20, 22) with: at least one optical unit (20) that adjusts the focal length of the optical system

Methodology Applied
Scientific EffectOptical focusing: Focusing

Data Source

PatentEP3898063B1Machining apparatus for laser machining a workpiece and method for laser machining a workpiece
Publication Date: 2023.08.16 BYSTRONIC LASER AG
  • EP3898063B1 patent drawingFigure 1
  • EP3898063B1 patent drawingFigure 2
  • EP3898063B1 patent drawingFigure 3

AI summary

A machining apparatus for laser machining a workpiece in a machining zone is provided, having an interface for a machining laser source for generating a machining laser beam with a direction of propagation; an outlet opening for the machining laser beam; and an optical system between the interface and the outlet opening, wherein the optical system has: at least one optical unit that adjusts the focal length of the optical system, and at least one stationary laser beam guiding device with at least one movable surface, wherein the at least one movable surface can be adjusted such that it modifies the focal length of the optical system and/or the beam parameter product of the machining laser beam integrated over time in at least one operating mode. Further provided is a method for laser machining a workpiece.