Process Chamber Gas Flow Guidance for Cleaner 3D Powder Bed Builds

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Solution Overview

Problem

In additive manufacturing processes like Selective Laser Sintering or Laser Melting, contamination such as spatter, fumes, smoke, vapors, and gases can spread within the process chamber, affecting the manufacturing quality due to the energy input during selective solidification of powdered building materials, and existing gas flow methods are inefficient in removing these contaminants effectively.

Innovation Solution

A method and device that utilize a main gas flow directed over the entire construction area, with a secondary flow interacting with the main flow, and the introduction of a boundary zone or guide gas flow to improve flow homogeneity and containment of contaminants within the process chamber, ensuring effective removal of impurities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-generated harmful factors

If a gas flow is introduced through a gas inlet in the lower section of the process chamber and discharged through a gas outlet to remove contaminants, then contaminant removal capability is improved, but flow homogeneity and directional stability deteriorate due to unguided flow spreading into lateral areas

Engineering Contradiction:
Improvecontaminant removal capabilityVSAvoidflow homogeneity and directional stability
Core Design Contradiction:
Object-generated harmful factorsVSStability of the object's composition

Solution Approach 1:

The patent introduces flow-guiding elements (such as walls, partitions, or structured surfaces) within the process chamber that act as intermediaries to direct and contain the gas flow. These elements guide the main flow along a defined path from the gas inlet to the gas outlet, preventing it from spreading uncontrollably into lateral areas, thereby maintaining flow homogeneity and directional stability while preserving contaminant removal capability.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If the gas inlet and gas outlet have a width smaller than the width of the process chamber, then device complexity is reduced, but flow effectiveness deteriorates as the main flow spreads and velocity decreases

Engineering Contradiction:
Improvegas inlet/outlet structure simplicityVSAvoidflow velocity and contaminant removal efficiency
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

Flow-guiding elements are introduced as simple structural intermediaries that channel the gas flow along a defined path. These elements prevent the main flow from spreading into lateral areas, maintaining flow velocity and directional stability throughout the process chamber. The solution maintains simple gas inlet and outlet structures while using internal flow guidance to preserve flow effectiveness.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Device complexity

If lateral areas in the process chamber are not specifically traversed by the main flow, then device complexity is reduced, but flow characteristics deteriorate due to turbulence and flow widening

Engineering Contradiction:
Improveflow guidance structure complexityVSAvoidmain flow velocity and directional stability
Core Design Contradiction:
Device complexityVSStability of the object's composition

Solution Approach 1:

The patent employs flow-guiding elements as intermediaries that define the boundaries of the main flow path. These structures (such as side walls or partition elements) prevent the main flow from diverting into lateral areas, thereby maintaining flow velocity and directional stability. The flow-guiding elements are designed to be as simple as possible while effectively containing the flow within the desired path.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 enhances the removal of contaminants by improving the flow properties of the main gas flow, leading to better directional stability and homogeneity, which results in improved manufacturing quality and efficiency by keeping the process chamber clean and free from interfering particles.

Implementation Method 1

a gas flow is typically introduced into the process chamber through a gas inlet in a lower section of the chamber and discharged through a gas outlet, thus generating a gas flow that is essentially directed from the gas inlet to the gas outlet

Methodology Applied
Scientific EffectGas flow: Convection

Data Source

PatentEP3620245B1Flow method for additive manufacturing apparatus
Publication Date: 2023.06.07 EOS GMBH ELECTRO OPTICAL SYST
  • EP3620245B1 patent drawingFigure 1
  • EP3620245B1 patent drawingFigure 2
  • EP3620245B1 patent drawingFigure 3a

AI summary

A method serves to supply a process chamber (3) of a device (1) for producing a three-dimensional object (2) by layering and selectively solidifying a build material in a build area (8), wherein in the method the process chamber (3) is supplied with a process gas in a lower height region (h1) of the process chamber (3). The process chamber (3) comprises a gas inlet (32, 132, 232) for introducing the process gas into the process chamber (3) and a gas outlet (34) for releasing the process gas from the process chamber (3), wherein the gas inlet (32) and the gas outlet (34) are provided in the lower height region (h1) of the process chamber (3) and the process gas flows in a main flow (30) from the gas inlet (32) to the gas outlet (34), and wherein a secondary flow (37) is located in a sub-region of the lower height region that lies above a floor surface of the process chamber (3) surrounding the construction area (8).is localized. In the process, a boundary zone is positioned at least section by section between the secondary flow (37) and the main flow (30) at least during the selective solidification of at least one layer of the build-up material, essentially in the part of the lower height range that lies above the ground surface surrounding the construction area (8), due to at least one of the following influencing measures: Influencing measure I: Positioning at least one guide element (101a, 101b, 102a, 102b, 103a, 103b, 204, 205, 306; 307) as a boundary zone in the process chamber (3), wherein the at least one guide element has at least one guide surface (111, 112, 113, 113', 212, 212', 312, 312') for at least section by section guiding the main flow (30) and/or the secondary flow. (37) exhibits; Control measure II: Controlled, at least section-by-section modification of the flow characteristics of the secondary flow (37),in particular in their direction and/or speed and/or volume flow; Control measure III: Controlled, at least section-by-section displacement of the bypass flow (37).,