Coherent Beam Combining for Precise 3D Printing Irradiation

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Solution Overview

Problem

Existing additive manufacturing technologies face limitations in the movement and geometry adjustment of energy beams, particularly when creating complex patterns with sharp edges or requiring fast movements, due to mechanical scanner limitations and inflexible energy distribution.

Innovation Solution

The apparatus employs a modulation unit to combine multiple coherent energy beams, allowing for adjustable intensity, spot geometry, and focal position of the combined energy beam, enabling advanced irradiation patterns without relying on mechanical movement of a single beam spot, and compensating for deviations in beam properties across the build plane.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If a mechanical scanning unit with movable mirrors is used to guide the energy beam across the build plane, then the apparatus can achieve beam movement and positioning, but the maximum movement speed is limited by the inertia of the movable mirror and position noise, making fast movements and sharp edges difficult to irradiate

Engineering Contradiction:
Improvebeam movement speedVSAvoidirradiation pattern precision
Core Design Contradiction:
SpeedVSManufacturing precision

Solution Approach 1:

The patent replaces the mechanical scanning system (movable mirrors) with an optical field modulation system. Multiple stationary laser beams are generated and their interference patterns are modulated using spatial light modulators or acousto-optic modulators to create the desired irradiation patterns directly in the build plane, eliminating mechanical movement limitations and enabling instantaneous pattern changes without inertia or position noise.

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

Solution Approach 2:

The patent transitions from controlling beam position in space through mechanical movement to controlling the intensity distribution across the beam cross-section through optical modulation. By modulating the amplitude or phase of multiple coherent beams in the optical domain, complex two-dimensional irradiation patterns can be created simultaneously without mechanical scanning, effectively adding a dimension of control through optical field manipulation.

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

2Adaptability or versatility

If the spot geometry and energy distribution are varied by including or removing optical components in the beam path, then the beam geometry can be adjusted, but the system complexity increases and flexibility is reduced

Engineering Contradiction:
Improvebeam geometry adjustment flexibilityVSAvoidoptical component configuration
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent employs dynamically controllable optical modulators (spatial light modulators or acousto-optic modulators) that can change the amplitude or phase of laser beams in real-time through electrical or acoustic signals. This allows the beam geometry and energy distribution to be adjusted dynamically without physically adding or removing optical components, providing high flexibility while maintaining a fixed, manageable optical system configuration.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent controls beam properties by changing the amplitude or phase parameters of multiple coherent laser beams through optical modulators. By varying these parameters electronically or acoustically, the spot geometry and intensity distribution can be continuously adjusted without mechanical reconfiguration, simplifying the overall system while achieving versatile beam shaping capabilities.

Inventive Principle:
Principle #35Parameter changes

3Power

If the energy source is designed for a defined range of energy output, then the energy beam can be generated with adequate intensity, but filter units are required to decrease intensity to match process requirements, resulting in energy waste

Engineering Contradiction:
Improveenergy beam intensityVSAvoidenergy waste through filtering
Core Design Contradiction:
PowerVSLoss of energy

Solution Approach 1:

The patent uses multiple coherent laser beams with different amplitudes or phases that are modulated independently. By controlling the contribution of each individual beam through optical modulators, the total energy delivered to specific regions of the build plane can be precisely controlled locally. This allows high-power laser sources to be used efficiently without requiring energy-reducing filters, as the intensity is controlled through constructive and destructive interference patterns rather than bulk attenuation.

Inventive Principle:
Principle #3Local quality

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 enhances the flexibility and precision of energy deposition in additive manufacturing, enabling the creation of complex patterns and improving the additive manufacturing process by dynamically controlling the intensity distribution and beam properties, reducing the need for mechanical movement and optimizing energy input.

Implementation Method 1

a modulation unit (5) which is adapted to combine the at least two energy beams (7) to a combined energy beam (8)

Methodology Applied
Scientific EffectCoherent beam combining: Interference

Implementation Method 2

successive selective layerwise consolidation of layers of a powdered build material (3) which can be consolidated by means of an energy beam (7, 8)

Methodology Applied
Scientific EffectLaser heating: Laser

Implementation Method 3

selective laser melting apparatus

Methodology Applied
Scientific EffectSelective laser melting: Melting

Data Source

PatentEP3597406B1Apparatus for additively manufacturing three-dimensional objects
Publication Date: 2023.08.30 CONCEPT LASER
  • EP3597406B1 patent drawingFigure 1
  • EP3597406B1 patent drawingFigure 2
  • EP3597406B1 patent drawingFigure 3~4

AI summary

Apparatus (1) for additively manufacturing three-dimensional objects (2) by means of successive layerwise selective irradiation and consolidation of layers of a build material (3) which can be consolidated by means of an energy beam, wherein an irradiation device (4) is provided that is adapted to generate at least two coherent energy beams (7), wherein the irradiation device (4) comprises a modulation unit (5) that is adapted to combine the at least two energy beams (7) to a combined energy beam (8) and to adjust at least one combined beam property of the combined energy beam (8).