Overlapping Wall Structures for Self-Sealing 3D Print Compartments

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Solution Overview

Problem

Existing powder bed additive manufacturing machines face issues with powder leakage due to seal degradation from environmental factors like friction, heat, and radiation, leading to contamination and loss of reusable powder.

Innovation Solution

A self-sealing build compartment design with overlapping inner and outer cylindrical wall structures that prevent powder flow by utilizing the angle of repose of powders, allowing for a variable volume expansion and easy cleaning, and incorporating a mechanism for powder removal and temperature control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If compressible sealing material is used between movable table and build compartment, then powder leakage is prevented, but seal material degrades due to friction, heat, and radiation causing contamination

Engineering Contradiction:
Improvesealing effectivenessVSAvoidcontamination from degraded seal
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent removes the compressible sealing material from the build compartment entirely, replacing it with a self-sealing wall structure. The extraction is achieved by using overlapping wall structures that create a seal through their geometric configuration rather than through contact with degradable sealing materials.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent eliminates the need for replaceable seal materials by using a permanent self-sealing wall structure. Instead of relying on consumable sealing components that degrade and need replacement, the design uses the building process itself to maintain the seal.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Volume of stationary object

If wall structures with horizontal gaps are used, then variable volume expansion is enabled, but powder flow control becomes challenging

Engineering Contradiction:
Improvebuild compartment volumeVSAvoidpowder containment
Core Design Contradiction:
Volume of stationary objectVSReliability

Solution Approach 1:

The patent implements dynamic wall structures that can move relative to each other during the building process. The horizontal gaps between wall structures allow for volume expansion while the overlapping configuration maintains powder containment by utilizing the angle of repose of the powder material.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the physical parameters of the wall structures by introducing horizontal gaps that allow for volume adjustment. The gaps are designed to maintain sealing effectiveness while enabling the build compartment to expand as needed during the additive manufacturing process.

Inventive Principle:
Principle #35Parameter changes

3Object-affected harmful factors

If overlapping wall structures are used for self-sealing, then powder leakage is prevented without seal material, but device complexity increases

Engineering Contradiction:
Improvepowder leakage preventionVSAvoidwall structure configuration
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent divides the wall structure into multiple segments including first and second wall structures with horizontal gaps between them. This segmentation allows each wall section to function independently while collectively providing the self-sealing effect through their overlapping arrangement.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent employs a nested configuration where wall structures are positioned within or adjacent to each other in a hierarchical arrangement. The first wall structure and second wall structure are nested or overlapping in such a way that they create the self-sealing effect while maintaining a compact overall structure.

Inventive Principle:
Principle #7Nested doll (Nesting)

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 effectively prevents powder leakage, maintains cleanliness, and optimizes the manufacturing process by ensuring the quality of the three-dimensional object and reducing waste, while allowing for efficient powder reuse and improved cooling/heating capabilities.

Implementation Method 1

A self-sealing build compartment design with overlapping inner and outer cylindrical wall structures that prevent powder flow by utilizing the angle of repose of powders

Methodology Applied
Scientific EffectAngle of repose: Angle of Repose

Data Source

PatentEP3784473B1Build compartment with self-sealing design
Publication Date: 2023.06.07 FREEMELT AB
  • EP3784473B1 patent drawingFigure 1A~1B
  • EP3784473B1 patent drawingFigure 2A~2B
  • EP3784473B1 patent drawingFigure 3A~3B

AI summary

The present invention relates to a build compartment used in 3D printing systems based on powder beds. The build compartment is the volume in a 3D printing apparatus where 3D objects (206) are formed by successive consolidation of thin layers of powder. The build compartment is designed with at least two vertical wall structures (203, 204) movable in relation to each other. The movable wall structures (203, 204) are at least partly overlapping in the movable direction, providing self-sealing for a variable volume for enclosing powder. Contrary to other available designs, this solution does not need a compressible sealing material, for example an elastomer, a textile felt or a braided rope, to prevent powder leakage from the build compartment. The advantages are more reliable sealing and no risk of contamination of the powder by debris from sealing material.