Additive Manufacturing Beam Spot Control for Melt Pool Stability
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Solution Overview
Problem
In additive manufacturing, varying thicknesses within a three-dimensional article can lead to undesired material properties, such as porosities and widened melt pools, due to inconsistent energy beam settings.
Innovation Solution
The method involves varying the Full Width Half Maximum (FWHM) of a high energy beam as a function of the already fused thickness of the three-dimensional article, using focus lenses, astigmatism lenses, vacuum levels, or aperture sizes to maintain optimal beam spot size and shape, thereby counteracting the widening of the melt pool and ensuring consistent material characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the high energy beam spot size is kept constant during additive manufacturing, then the manufacturing process is simple, but the melt pool widens as the article thickness increases leading to porosities and poor material characteristics
Solution Approach 1:
The patent applies dynamics by making the beam spot size variable rather than constant. The FWHM of the high energy beam is dynamically adjusted as a function of the already fused thickness of the three-dimensional article. This allows the beam characteristics to adapt to changing process conditions, maintaining optimal melt pool dimensions throughout the build process regardless of article thickness variations.
Solution Approach 2:
The patent implements parameter changes by modifying the FWHM parameter of the high energy beam based on the already fused thickness. This parameter adjustment compensates for the natural widening tendency of the melt pool as the article grows taller, ensuring consistent material properties and eliminating porosities in negative surfaces and thin overhangs.
2Reliability
If the high energy beam FWHM is decreased for thinner already fused thickness, then porosities are reduced, but the beam control becomes more complex
Solution Approach 1:
The patent employs feedback by using the already fused thickness as a control parameter to adjust the beam FWHM. The system continuously monitors the build progress and adapts the beam characteristics accordingly, creating a closed-loop control system that ensures optimal processing conditions are maintained throughout the additive manufacturing process.
Solution Approach 2:
The patent makes the beam control dynamic by varying the FWHM as a function of the already fused thickness. This dynamic adjustment allows the system to respond to changing process conditions in real-time, improving material characteristic consistency while managing control complexity through automated thickness-based regulation.
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 reduces or eliminates porosities in negative surfaces and allows for the successful building of thinner overhangs without inclusions, improving the overall material characteristics and structural integrity of the final product.
Implementation Method 1
a high energy beam source for emitting a high energy beam for heating or fusing the powder material
Implementation Method 2
the energy beam is a laser beam or an electron beam
Implementation Method 3
using focus lenses, astigmatism lenses, vacuum levels, or aperture sizes to maintain optimal beam spot size and shape
Data Source
AI summary
Various embodiments of the present invention relate to a method of using of a focus lens in additive manufacturing for forming a three-dimensional article through successive fusion, with a high energy beam, of parts of at least one layer of a powder bed provided on a work table, which parts correspond to successive cross sections of the three dimensional article, said method comprising the step of: using said focus lens for varying a spot size of said high energy beam on said powder bed as a function of an already fused thickness of said three-dimensional article below said powder which is to be fused. The invention is also related to a method for forming a three dimensional article.