Beam Splitting for Continuous Powder Bed Laser Melting

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Solution Overview

Problem

Powder-bed-based jet melting processes, such as selective laser melting, face inefficiencies due to non-value-adding processes and technical dead times during beam deflection, leading to suboptimal utilization of beam sources and reduced productivity in industrial series production.

Innovation Solution

The method involves dividing energetic beams into individual beams through temporal modulation, allowing for dynamic beam guidance and independent deflection, which maximizes the use of beam power by minimizing dead times and ensuring continuous exposure during processing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If galvanometer scanners are used for beam deflection, then dynamic beam guidance is achieved, but dead times occur during mirror movement and acceleration phases reducing beam source utilization

Engineering Contradiction:
Improvedynamic beam guidanceVSAvoidbeam source utilization
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The patent segments the single beam path into multiple parallel beam paths by splitting the beam into multiple individual beams. Each beam can be deflected independently by separate galvanometer scanners, allowing simultaneous operation of multiple scanners to eliminate dead times during mirror movement and acceleration phases.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent combines multiple beam deflection operations into a coordinated system where multiple galvanometer scanners work simultaneously on different beam segments. This merging of parallel operations eliminates the sequential dead times that occur when a single scanner must complete all deflection movements.

Inventive Principle:
Principle #5Merging (Combining)

2Productivity

If multiple separate beam sources are used to increase spot arrangement, then melting capacity scales, but costs and design effort increase linearly

Engineering Contradiction:
Improvemelting capacityVSAvoidsystem design complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent segments a single high-power beam into multiple lower-power individual beams using beam splitting optics. This allows the system to achieve multi-spot melting capacity equivalent to multiple beam sources while using only one physical beam source, thereby reducing system complexity and cost.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent creates multiple copies of the beam path through optical splitting, where each split beam is directed to a different location on the powder bed. This optical copying approach achieves the effect of multiple beam sources without the need for multiple physical sources, reducing both cost and design complexity.

Inventive Principle:
Principle #26Copying

3Productivity

If beam power is distributed across multiple individual beams, then continuous processing is achieved, but power losses occur due to optical components

Engineering Contradiction:
Improvecontinuous processing capabilityVSAvoidoptical power losses
Core Design Contradiction:
ProductivityVSLoss of energy

Solution Approach 1:

The patent employs periodic switching between multiple beam paths, where beams are activated in alternating sequences rather than continuously simultaneously. This periodic action allows the system to maintain continuous processing coverage while minimizing the number of active optical splitting paths at any given moment, thereby reducing cumulative power losses.

Inventive Principle:
Principle #19Periodic action

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 significantly increases the productivity of the system by maximizing the utilization of beam sources, potentially accelerating the exposure process by 15% to 250%, making powder bed-based jet melting more economically viable for industrial series production.

Implementation Method 1

at least one of the energetic beams is split into several individual beams by temporal modulation

Methodology Applied
Scientific EffectTemporal modulation:

Implementation Method 2

These individual beams are directed onto the layer to be processed in a spatially separated manner, in particular via different beam guidance and/or beam deflection elements

Methodology Applied
Scientific EffectDynamic beam guidance:

Implementation Method 3

one or more energetic beams, particularly laser beams

Methodology Applied
Scientific EffectLaser melting: Laser

Implementation Method 4

selectively melted according to the geometric information from the 3D CAD model using one or more energetic beams

Methodology Applied
Scientific EffectSelective laser melting: Selective Laser Sintering

Data Source

PatentEP3538349B1Method and device for machining a material layer using energetic radiation
Publication Date: 2023.01.18 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV
  • EP3538349B1 patent drawingFigure 1~2
  • EP3538349B1 patent drawingFigure 3

AI summary

The invention relates to a method and a device for machining a material layer using energetic radiation, in particular in order to produce three-dimensional components by melting a particulate material in layers. In the method, one or more energetic beams (7) of one or more beam sources (6) are directed onto a layer to be machined and guided over the layer by means of a dynamic beam guidance system in order to machine regions of the layer. The method is characterized in that at least one of the energetic beams (7) is divided into multiple individual beams (9) by modulating the beam over time, said individual beams being directed onto the layer to be machined in a spatially separated manner. The separation is carried out such that the sum of the power of the individual beams (9) corresponds to the power of the respective energetic beam (7) minus power losses caused by the separation process. By using the proposed method and the corresponding device, the beam sources (6) used for the machining processes can be better used such that the proportion of the value-adding process to the entire process time can be maximized in the case of additive manufacturing processes, and the productivity of the manufacturing system can be increased.