Laser Cutting Head Beam Shaping for Fast, Accurate Contours

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Solution Overview

Problem

Existing laser cutting devices face challenges in achieving high productivity and contour accuracy, particularly when cutting metal sheets of varying thickness and material, due to limitations in the dynamic movement of mechanical axes and the fixed optical imaging ratio of laser machining heads.

Innovation Solution

A device and method for laser cutting that incorporates a cutting head with a dynamic laser beam movement unit, allowing for high frequency beam-shaping movements perpendicular to the laser beam's direction of propagation. This is combined with a control unit that optimizes the movement trajectory of the machining laser beam by redundantly partitioning it between the cutting head movement unit and the laser beam movement unit, based on predetermined parameters such as movement tolerances and contour deviations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the optical axis of the machining laser beam is moved relative to the central axis of the exit aperture by means of actuators, then the adaptability to different workpiece thicknesses and materials is improved, but the device complexity increases

Engineering Contradiction:
Improveadaptability to different workpiece thicknesses and materialsVSAvoiddevice complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements dynamic beam shaping by oscillating the laser beam at high frequencies (100 Hz to 10 kHz) perpendicular to the propagation direction. This dynamic movement allows the same optical system to adapt to different workpiece thicknesses and materials by varying the oscillation parameters, eliminating the need for multiple fixed optical configurations or complex actuator systems for axis movement.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the oscillation parameters (frequency, amplitude, trajectory) of the laser beam to adapt to different cutting conditions. By modifying these parameters, the system can optimize cutting quality for various workpiece thicknesses and materials without requiring physical reconfiguration of the optical path or movement of the optical axis relative to the exit aperture.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If high frequency beam-shaping movement is applied perpendicular to the laser beam direction, then the manufacturing precision of cut contours is improved, but the device complexity increases

Engineering Contradiction:
Improvecontour accuracy of cut workpiece partsVSAvoiddevice complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent uses high-frequency oscillation of the laser beam (100 Hz to 10 kHz) to achieve precise contour cutting. The dynamic beam shaping creates an effective cutting width that can be controlled by adjusting oscillation parameters, allowing precise contour following without requiring complex mechanical positioning systems or multiple actuators.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent employs periodic oscillation of the laser beam at high frequencies to achieve precise contour cutting. The periodic motion creates a controlled effective cutting width, and by adjusting the oscillation frequency and amplitude, the system can accurately follow complex contours while maintaining simple optical hardware.

Inventive Principle:
Principle #19Periodic action

3Productivity

If the cutting head movement unit operates at high speeds to improve productivity, then the productivity increases, but the contour accuracy deteriorates due to mechanical axis limitations

Engineering Contradiction:
Improvecutting speed and productivityVSAvoidcontour accuracy
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent compensates for the limitations of mechanical axis movement at high speeds by superimposing high-frequency beam oscillation. This dynamic beam shaping allows the system to maintain contour accuracy even when the cutting head moves rapidly, as the oscillation creates an effective cutting width that smooths out mechanical positioning errors.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent adds a temporal dimension to the cutting process by introducing high-frequency oscillation in addition to the linear cutting head movement. This transforms the cutting mechanism from purely mechanical positioning to a combination of rapid linear motion with superimposed oscillatory motion, enabling high productivity while maintaining precision through the oscillation's averaging effect on contour errors.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

4Device complexity

If fixed optical imaging ratio is used in laser machining heads, then the device complexity is reduced, but the manufacturing precision and productivity deteriorate for medium to large metal sheet thicknesses

Engineering Contradiction:
Improvedevice complexityVSAvoidsurface roughness and burr adhesion quality
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent replaces fixed optical imaging with dynamic beam shaping through high-frequency oscillation. This allows the effective spot size and intensity distribution to be dynamically adjusted for different workpiece thicknesses and materials, achieving optimal cutting quality without requiring complex variable focal length optics or multiple imaging systems.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the oscillation parameters (frequency, amplitude, pattern) to optimize cutting quality for different workpiece conditions. By adjusting these parameters, the system can maintain appropriate effective spot sizes and intensity distributions for various metal sheet thicknesses, eliminating the need for fixed optical imaging ratios while keeping the optical hardware simple.

Inventive Principle:
Principle #35Parameter changes

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

The solution enables improved productivity and accuracy in laser cutting by compensating for contour errors and reducing the time required for cutting processes, especially in corners and small radii of workpiece parts, while maintaining high quality and precision.

Implementation Method 1

a laser source for generating a machining laser beam with a power of at least 200 W, in particular at least 1 kW

Methodology Applied
Scientific EffectLaser heating: Laser

Implementation Method 2

thermal separation of materials by means of laser beams, such as laser cutting

Methodology Applied
Scientific EffectThermal melting: Melting

Data Source

PatentEP4304802B1Device and method for laser cutting a workpiece and producing workpiece parts
Publication Date: 2025.01.29 BYSTRONIC LASER AG
  • EP4304802B1 patent drawingFigure 1
  • EP4304802B1 patent drawingFigure 2
  • EP4304802B1 patent drawingFigure 3

AI summary

A device (10; 100) for laser cutting a workpiece (12) and producing workpiece parts and a corresponding method are provided. The device has a cutting head (20) with laser beam optics (28) in which a dynamic laser beam movement unit (30) is provided. The device has a cutting head movement unit (32) for performing a movement of the laser beam over the workpiece and a control unit (34). The control unit has a determination module (36) for determining at least one movement trajectory of the laser beam according to at least one predetermined contour; a memory unit (38) from which at least one predetermined parameter selected from a movement parameter of the cutting head movement unit, a movement parameter of the laser beam movement unit and a parameter of a deviation of a cut contour from the predetermined contour is retrievable; and an optimisation module (40) for adjusting the movement trajectory by overlaying the movement of the laser beam via the cutting head (20) with a high frequency beam-shaping movement of the laser beam via the laser beam movement unit (30) based on the at least one predetermined parameter retrievable from the memory unit (38).