Powder Bed Fusion Gettering for Low-Gas Metal Additive Manufacturing
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Solution Overview
Problem
Additive manufacturing processes, particularly powder bed fusion, are hindered by residual and reactive gases that contaminate the formed articles and unused feed materials, leading to deleterious effects on mechanical properties and necessitating disposal of unused feed materials due to contamination and thermal cycling.
Innovation Solution
A method involving evacuation and gettering of gases in a chamber using a getter, followed by additive manufacturing, reduces gas concentrations from 10s ppm to sub-ppm levels, allowing reuse and recycling of feed materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If powder bed fusion is conducted in a protective atmosphere, then oxidation and contamination are reduced, but residual and reactive gases remain at 10s ppm to 100s ppm levels which are still deleterious to article properties
Solution Approach 1:
The patent applies the inert atmosphere principle by using a protective gas environment (argon or nitrogen) in the chamber during additive manufacturing. This inert atmosphere prevents oxidation of the metal powder and formed articles by displacing reactive gases, thereby reducing contamination while maintaining material properties.
Solution Approach 2:
The patent introduces a getter material as an intermediary substance that actively removes residual reactive gases from the protective atmosphere. The getter acts as a mediator between the inert atmosphere and the metal powder, chemically binding with remaining oxygen and other reactive gases to reduce their concentrations to acceptable levels.
2Productivity
If unused feed material is heated to elevated temperatures during PBF, then the manufacturing process continues, but the feed material reacts with and incorporates residual gases, precluding reuse or recycling
Solution Approach 1:
The getter material serves as an intermediary that protects unused feed material from reacting with residual gases during thermal cycles. By chemically binding with reactive gases in the atmosphere, the getter prevents these gases from contaminating the metal powder, enabling safe reuse and recycling of unused feed material.
Solution Approach 2:
The patent changes the chemical composition parameters of the chamber atmosphere by introducing getter materials that actively reduce the concentration of reactive gases. This parameter change transforms the atmosphere from one that causes contamination to one that allows safe thermal cycling of feed material.
3Reliability
If feed material is disposed of due to contamination from residual gases, then article quality is maintained, but environmental hazards increase and material waste occurs
Solution Approach 1:
The getter material acts as an intermediary protective agent that prevents contamination of feed material during manufacturing. By removing reactive gases from the atmosphere, the getter eliminates the need to dispose of contaminated unused powder, thereby preventing environmental hazards associated with metal waste disposal.
Solution Approach 2:
The patent enables recovery and reuse of unused feed material by preventing contamination through gettering. Instead of discarding potentially contaminated powder, the system allows unused material to be safely collected, stored, and reused in subsequent manufacturing processes, reducing waste and environmental impact.
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 method improves the mechanical properties of formed articles and enables reuse of unused feed materials by minimizing gas contamination, adhering to industry standards and reducing environmental impact.
Implementation Method 1
gettering at least some of the first gas from the evacuated chamber using a getter located in the evacuated chamber
Implementation Method 2
heating, at least in part, the getter using a fusion source
Implementation Method 3
heating, at least in part, the feed material using the fusion source
Implementation Method 4
The feed materials are heated to elevated temperatures... At such temperatures, the feed material may react with reactive gases
Implementation Method 5
PBF techniques, such as direct metal laser sintering (DLMS), selective heat sintering (SHS), selective laser sintering (SLS)
Implementation Method 6
PBF techniques, such as direct metal laser sintering (DLMS)... selective laser melting (SLM)... laser metal deposition (LMD)
Implementation Method 7
electron beam melting (EBM)
Data Source
AI summary
A method of additive manufacturing an article from a feed material in a chamber includes evacuating at least some of a first gas from the chamber, thereby reducing a pressure therein from a first pressure to a second pressure and reducing the first gas from a first concentration to a second concentration. At least some of the first gas is then gettered from the chamber using a getter, thereby lowering the first gas concentration to a third concentration. The article is then additive manufactured from the feed material in the chamber using the getter as a substrate. The gettering comprises heating the getter at least in part using a fusion source, and the additive manufacturing comprises heating the feed material at least in part using the fusion source.