Diode Laser Beam Rotation for Asymmetric Profile Alignment

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Solution Overview

Problem

Existing laser processing machines using diode lasers face issues with power concentration due to limited beam quality and asymmetry, leading to inefficient cutting and welding processes, with prior solutions either compromising beam quality or resulting in high power losses and complex machine designs.

Innovation Solution

The laser processing machine optimally aligns the asymmetrical beam cross-section of the diode laser with the processing direction, allowing for precise control of the beam's main axis and polarization to achieve maximum cutting speed and efficient energy absorption, enabling cutting along any linear path without the need for beam axis shifting, and allowing for versatile cutting and welding capabilities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the laser beam is guided through a circular fiber to homogenize the asymmetrical beam, then the beam quality becomes more uniform in all transverse directions, but the beam quality in the first transverse direction deteriorates and coupling efficiency decreases

Engineering Contradiction:
Improvebeam quality uniformityVSAvoidbeam quality and coupling efficiency
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent extracts the laser beam from the circular fiber and directs it through a reflective prism instead. This removes the beam from the deteriorating circular fiber path while maintaining the ability to control and shape the beam for optimal cutting performance

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The reflective prism acts as an intermediary element between the laser source and the workpiece. It enables beam rotation and directional control without requiring the beam to pass through a circular fiber, thus avoiding the associated quality deterioration and coupling losses

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If a long transmission path through absorbing prism material is used to rotate the beam, then beam rotation is achieved, but enormous power losses occur at high power levels and significant thermally induced beam fluctuations arise

Engineering Contradiction:
Improvebeam rotation capabilityVSAvoidpower losses and thermal fluctuations
Core Design Contradiction:
Ease of operationVSLoss of energy

Solution Approach 1:

The patent employs a rotatable reflective prism that can dynamically adjust the beam orientation. This dynamic system allows beam rotation without requiring a long fixed transmission path through absorbing material, minimizing power losses and thermal effects

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent replaces the mechanical transmission path through absorbing prism material with a reflective prism system. This substitution uses reflection rather than transmission, dramatically reducing power losses and thermally induced beam fluctuations while maintaining beam rotation capability

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

3Adaptability or versatility

If the beam axis is shifted to enable linear cutting paths, then universal linear cutting capability is achieved, but the machine design becomes technically complex and error-prone

Engineering Contradiction:
Improvelinear cutting capabilityVSAvoidmachine complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The reflective prism system provides universal beam direction control, enabling linear cutting paths without requiring separate beam shifting mechanisms. The single prism system handles both rotation and directional control functions

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the beam rotation and beam direction control functions into a single reflective prism system. This consolidation eliminates the need for separate beam shifting mechanisms, reducing machine complexity and error potential while maintaining universal linear cutting capability

Inventive Principle:
Principle #5Merging (Combining)

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 approach results in improved cutting efficiency, reduced power requirements, and increased versatility, enabling efficient cutting of thicker materials and universal linear cutting capabilities without the complexity of circular path limitations, while maintaining high absorption and minimal thermal effects.

Implementation Method 1

a laser processing machine (1) comprising a diode laser (2), the beam (A) of which can be directed onto a workpiece (7) and is provided for processing the same

Methodology Applied
Scientific EffectLaser: Laser

Implementation Method 2

means for rotating the laser beam (A) around its axis

Methodology Applied
Scientific EffectBeam rotation:

Implementation Method 3

A high-energy beam of light is directed at a material, which melts, vaporizes and/or burns it. In this way, materials can be separated (laser cutting) but also joined (laser welding)

Methodology Applied
Scientific EffectLaser heating: Laser

Implementation Method 4

maximum absorption of the laser radiation is achieved by changing the angle of inclination of the cutting front

Methodology Applied
Scientific EffectLight absorption: Absorption (EM radiation)

Data Source

PatentEP2468445B1Laser processing machine with a diode laser, which laser beam can rotate around its axis, and method of machining a workpiece
Publication Date: 2016.08.24 BYSTRONIC LASER AG
  • EP2468445B1 patent drawingFigure 1~2c
  • EP2468445B1 patent drawingFigure 3a~5
  • EP2468445B1 patent drawingFigure 6

AI summary

The laser processing machine (1) comprises a diode laser (2), whose beam is aligned to a workpiece (7) for processing the workpiece, a unit for rotating the laser beam around its jet axis, a controller, and a unit for varying a polarization of the diode laser. The unit for rotating the laser beam is formed by a: drive, which is prepared to rotate the diode laser such that the emitted laser beam is rotated about its beam axis; and a rotatable, motor driven optical element, which is prepared to move a part of the laser beam in the beam path lying behind the optical element. The laser processing machine (1) comprises a diode laser (2), whose beam is aligned to a workpiece (7) for processing the workpiece, a unit for rotating the laser beam around its jet axis, a controller, and a unit for varying a polarization of the diode laser. The unit for rotating the laser beam is formed by a: drive, which is prepared to rotate the diode laser such that the emitted laser beam is rotated about its beam axis; and a rotatable, motor driven optical element, which is prepared to move a part of the laser beam in the beam path lying behind the optical element such that the partial beam is rotated about its beam axis. The optical element is executed as a: light guide, one end of which is disposed adjacent to the diode laser and an other end is motor-driven; Dove prism; and combination of a first mirror, a second mirror and a third mirror, where the mirrors are arranged such that the laser beam from the first mirror is radially directed away from the original axis, from the second mirror is radially directed to the original axis and from the third mirror is radially directed into the original axis. One of the mirrors is driven by a motor. The diode laser is arranged directly above a movable machining head (4) relative to the workpiece. The controller is setup to align the main axis of an asymmetric beam profile and a polarization direction of the diode laser along a machining direction of the laser processing machine, where the main axis of the beam profile and the polarization direction of the diode laser are equally aligned. An independent claim is included for a method of machining a workpiece.