Dual-Mirror Laser Welding Head for Fast Precise Beam Steering

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Solution Overview

Problem

Conventional methods for moving a laser beam in laser welding heads do not allow for quick and precise movements, limiting the ability to form high-quality welds efficiently.

Innovation Solution

A laser welding head with dual movable mirrors that pivot within a limited field of view, allowing precise and fast beam movement, coupled with a control system to manage thermal conditions and seam tracking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If rotating prism optics are used to move the beam, then the beam can be rotated to form a rotating or spiral pattern, but the movement speed and precision are limited

Engineering Contradiction:
Improvebeam movement speedVSAvoidbeam positioning precision
Core Design Contradiction:
SpeedVSManufacturing precision

Solution Approach 1:

The patent replaces rotating prism optics with a galvanometer mirror system that uses electromagnetic fields to control mirror positioning. This substitution enables faster beam movement (up to 10 times faster than mechanical rotation) while maintaining precise positioning through electronic control of the galvanometer motors, directly resolving the contradiction between speed and precision.

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

Solution Approach 2:

The patent transitions from static or slowly rotating optical systems to a dynamic galvanometer mirror system that can rapidly change beam direction. The mirrors can pivot quickly along X and Y axes with programmable motion patterns, enabling both high-speed movement and precise positioning through dynamic electronic control rather than mechanical rotation.

Inventive Principle:
Principle #15Dynamics

2Manufacturing precision

If the entire weld head is moved on an X-Y stage to form a zig zag pattern, then beam movement is achieved, but the response time and positioning accuracy are reduced

Engineering Contradiction:
Improvebeam positioning accuracyVSAvoidbeam repositioning time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent replaces the heavy X-Y stage mechanical system with lightweight galvanometer mirrors that have moment of inertia optimized for rapid movement. The electronic control system can reposition the beam almost instantaneously by adjusting mirror angles, eliminating the time delays and mechanical inertia associated with moving the entire weld head on a stage.

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

Solution Approach 2:

The patent separates the beam movement function from the weld head positioning. Instead of moving the entire weld head assembly, the system segments the control by using independent galvanometer mirrors for rapid beam steering while the weld head remains relatively stationary or moves slowly. This segmentation enables fast beam repositioning without the time penalties of moving the complete assembly.

Inventive Principle:
Principle #1Segmentation

3Productivity

If conventional beam movement methods are used, then welding can be performed, but quick and precise movements are not achieved

Engineering Contradiction:
Improvewelding efficiencyVSAvoidweld quality
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent replaces conventional mechanical beam movement methods with a galvanometer-based optical steering system. This substitution enables both quick beam movements for efficient welding coverage and precise positioning for high-quality welds, simultaneously improving productivity and weld quality by decoupling these requirements through electronic control.

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

Solution Approach 2:

The patent changes the control parameters from mechanical position and speed to electronic voltage signals that control galvanometer mirror angles. This parameter change enables independent optimization of beam movement speed and positioning precision through software control, allowing rapid scanning for productivity while maintaining accurate beam placement for weld quality.

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

Enables faster and more precise welding with improved weld quality and uniformity, capable of forming stronger and smoother welds with materials like titanium.

Implementation Method 1

a collimator configured to be coupled to an output fiber of a fiber laser

Methodology Applied
Scientific EffectCollimation: Lens

Implementation Method 2

at least first and second movable mirrors configured to receive a collimated laser beam from the collimator and to move the beam in first and second axes

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 3

a focus lens configured to focus the laser beam relative to a workpiece while the beam is moved

Methodology Applied
Scientific EffectFocusing: Lens

Data Source

PatentEP3932608B1Laser welding head with dual movable mirrors providing beam movement with limited field of view
Publication Date: 2025.07.30 IPG PHOTONICS CORP
  • EP3932608B1 patent drawingFigure 1
  • EP3932608B1 patent drawingFigure 1A~2D
  • EP3932608B1 patent drawingFigure 3A~3B

AI summary

The present application relates to a laser welding head (10). The latter comprises movable mirrors (132, 34), which are used to perform welding operations, for example, with wobble patterns and/or seam finding/tracking and following. The movable mirrors (132, 134) provide a wobbling movement of one or more beams (118) within a relatively small field of view, for example, defined by a scan angle of 1-2°. The movable mirrors (132, 134) may be galvanometer mirrors that are controllable by a control system (160) including a galvo controller. The laser welding head (110) may also include a diffractive optical element to shape the beam or beams (118) being moved. The control system (160) may also be used to control the fiber laser (112), for example, in response to the position of the beams (118) elative to the workpiece (102) and/or a sensed condition in the welding head (110) such as a thermal condition proximate one of the mirrors (132, 134).