Dual-Seal Powder Bed Chamber Sealing With Extraction Channel
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Solution Overview
Problem
In additive layer manufacturing methods, particularly powder bed fusion, mechanical components experience increased wear due to abrasive powders, leading to seal wear and contamination of the environment, with existing seal systems failing to effectively manage powder and maintain cleanliness and safety.
Innovation Solution
A seal system with a channel formed between two seals, one of which is wear-optimised and the other gas-seal-optimised, utilizing a gas flow to extract powder and cool components, preventing wear and contamination by directing powder back into the powder circuit and maintaining a controlled temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single seal is used between the plate assembly and process chamber wall, then the structure is simple, but the seal experiences rapid wear due to powder adhesion and abrasion
Solution Approach 1:
The single seal is divided into two separate seals: a first seal optimized for wear resistance and a second seal optimized for gas sealing. This segmentation allows each seal to perform its specific function effectively, with the first seal handling abrasive powder exposure and the second seal maintaining the vacuum barrier.
Solution Approach 2:
Different regions of the sealing system are assigned different properties: the first seal is positioned and designed for wear resistance to handle powder abrasion, while the second seal is positioned and designed for gas tightness to maintain vacuum. This local optimization ensures each component performs its specific function effectively.
2Productivity
If powder is allowed to circulate freely in the process chamber, then the additive manufacturing process can continue, but the powder causes abrasive wear to mechanical components
Solution Approach 1:
A channel is introduced between the two seals that extracts powder particles as they pass through the first seal. This extracted powder is directed back into the process chamber through a different path, preventing it from causing wear to external mechanical components while maintaining manufacturing continuity.
Solution Approach 2:
The channel acts as an intermediary system between the process chamber and external environment. It captures powder particles that would otherwise cause wear, redirects them back into the chamber, and thus mediates the harmful interaction between powder and mechanical components.
3Power
If the seal system is exposed to high temperatures from the laser process, then the manufacturing process can proceed, but the heat accelerates seal degradation
Solution Approach 1:
A cooling channel is introduced as an intermediary element between the heat source and the seals. This channel allows cooling fluid to circulate and remove heat from the seal area, protecting the seals from thermal degradation while allowing the laser process to continue at full power.
Solution Approach 2:
A fluid cooling system is implemented using hydraulic or pneumatic principles. Cooling fluid is circulated through channels in the seal housing or adjacent structures, using fluid convection to transfer heat away from the seals and extend their service life.
4Duration of action of stationary object
If the first seal is made wear-resistant to handle powder abrasion, then seal life is extended, but gas sealing performance may be compromised
Solution Approach 1:
The sealing function is segmented into two separate seals: the first seal is designed with wear-resistant properties to handle powder abrasion, while the second seal is designed with optimal gas sealing properties. This segmentation allows each seal to be optimized for its specific function without compromise.
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 seal system significantly reduces mechanical component wear, prolongs the life of seals and components, maintains a clean environment, and ensures occupational safety by effectively managing powder and temperature through controlled gas flow.
Implementation Method 1
utilizing a gas flow to extract powder and cool components
Implementation Method 2
utilizing a gas flow to extract powder and cool components
Data Source
AI summary
The invention relates to a seal system (100, 200, 300) for an installation (400) for producing a three-dimensional workpiece by means of an additive layer manufacturing method, the seal system (100, 200, 300) comprising: a first seal (102), which is configured to seal an intermediate space (116) at a first periphery (108) between a process chamber inner wall (110) and a powder-material-supporting plate assembly (112) in a process chamber (410) of the installation (400); and a second seal (104), which is configured to seal the intermediate space (116) at a second periphery (114) between the process chamber inner wall (110) and the powder-material-supporting plate assembly (112) in the process chamber (410) of the installation (400), the first seal (102) being spaced apart from the second seal (104) such that, when the intermediate space (116) is sealed between the process chamber inner wall (110) and the plate assembly (112) by means of the first seal (102) and the second seal (104), a channel (106) is formed between the first seal (102) and the second seal (104) at an edge of the seal system (110).