Reactive Fluid Control in Laser Additive Manufacturing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing laser additive manufacturing (LAM) techniques face challenges due to the reactivity of powder materials with air, leading to microstructural defects, porosity, and residual stress in fabricated products.
Innovation Solution
The method involves using reactive fluids or fluid mixtures to actively manipulate the surface chemistry of the base material before, during, or after the additive manufacturing process, thereby modifying the surface properties to enhance mechanical and chemical properties of the fabricated products.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If reactive fluids are introduced to modify surface chemistry, then mechanical properties and surface resistance are improved, but process complexity increases
Solution Approach 1:
A reactive fluid (such as hydrogen-containing gas or reducing atmosphere) is introduced as an intermediary substance between the laser beam and the metal powder particles. This reactive fluid modifies the surface chemistry of the powder particles during the additive manufacturing process, reducing oxide formation and improving mechanical properties without requiring separate post-processing steps.
Solution Approach 2:
The chemical composition and reactive properties of the atmosphere surrounding the build chamber are modified by introducing specific gases (e.g., hydrogen, carbon monoxide, or controlled oxygen levels). This parameter change in the atmospheric composition allows for in-situ surface modification of the metal powder during deposition, enhancing mechanical strength and reducing residual stress.
2Reliability
If reactive fluids are used to manipulate surface chemistry, then wear and corrosion resistance are enhanced, but manufacturing cost increases
Solution Approach 1:
The reactive fluid treatment is performed preliminarily during the additive manufacturing process itself, rather than as a separate post-processing step. By controlling the atmospheric composition and introducing reactive gases during powder deposition and laser sintering, the surface chemistry is modified in advance, reducing the need for additional coating or treatment operations.
3Object-affected harmful factors
If traditional inert atmosphere handling is used, then safety is improved, but powder production and handling cost increase
Solution Approach 1:
The atmospheric parameters in the build chamber are dynamically controlled by introducing reactive fluids with specific chemical properties. By adjusting the composition and reactivity of the gas atmosphere, the process achieves both safety (through controlled reactions) and cost-effectiveness (by reducing the need for expensive inert gas handling infrastructure).
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 improves the mechanical properties of metallic products by reducing residual stress, enhancing wear and corrosion resistance, and increasing mechanical strength, while also reducing the cost of powder production and improving safety handling.
Implementation Method 1
a reactive fluid is contacted with a base material, such as but not limited to a powder, plasma, rod, wire or liquid wherein the reactive fluid modifies the surface of the base material to have a desired chemistry
Implementation Method 2
uses an energy beam, for example, an electron beam or electromagnetic radiation such as a laser beam, to sinter or melt a material
Implementation Method 3
The physical processes associated with laser sintering or laser melting include heat transfer to a powder material
Implementation Method 4
Fluids including gas mixtures containing hydrogen, carbon monoxide or other gas components that chemically reduce surface oxides
Data Source
AI summary
The present invention generally relates to methods and apparatuses adapted to perform additive manufacturing (AM) processes and the resulting products made therefrom, and specifically, to AM processes that employ an energy beam to selectively fuse a base material to produce an object. More particularly, the invention relates to methods and systems that use reactive fluids to actively manipulate the surface chemistry of the base material prior to, during and/or after the AM process.