Ring Laser Beam Shaping for Uniform Melt Pools in Fine AM Features
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Solution Overview
Problem
Existing laser powder bed fusion systems face challenges in creating uniform melt pools due to Gaussian beam distribution, leading to non-uniform melting and potential material vaporization when focusing the beam further.
Innovation Solution
Utilizing a ring laser with a unique power distribution and optical systems to narrow the beam size, creating a more uniform melt pool by focusing energy at the edges rather than the center, thereby improving the melting process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a Gaussian beam laser is used for melting powder particles, then the laser can effectively melt and fuse the material, but the non-uniform beam distribution leads to non-uniform melt pools and potential material vaporization
Solution Approach 1:
The patent applies local quality by using a ring-shaped laser beam that concentrates energy at the periphery rather than uniformly across the center. This creates a specific energy distribution pattern where the edges of the melt pool receive higher energy density, promoting uniform melting without excessive heat accumulation at the center that would cause vaporization. The ring beam geometry directly addresses the non-uniformity problem by design.
Solution Approach 2:
The patent changes the fundamental parameter of laser beam spatial distribution from Gaussian (center-concentrated) to ring-shaped (periphery-concentrated). This parameter change transforms the energy distribution profile, allowing the same laser power to produce a more uniform melt pool while avoiding the vaporization issues associated with Gaussian beams. The optical system modifies the beam parameters to achieve the desired energy distribution.
2Manufacturing precision
If the laser beam is focused to a smaller spot size to improve resolution, then finer features can be manufactured, but the energy density increases causing material vaporization and worsening melt pool uniformity
Solution Approach 1:
The ring-shaped beam applies local quality by directing higher energy density to the periphery of the focal spot rather than the center. This allows the use of smaller spot sizes for higher resolution while the peripheral energy distribution prevents excessive heat accumulation at the focal point that would cause vaporization. The energy is distributed in a ring pattern that matches the desired melt pool geometry.
Solution Approach 2:
The patent inverts the conventional approach to beam focusing. Instead of concentrating energy at the center (Gaussian), it inverts the distribution to concentrate energy at the periphery (ring-shaped). This inversion allows small spot sizes to achieve high resolution while the inverted energy distribution prevents the central hot spot that causes vaporization, thus resolving the contradiction between resolution and vaporization.
3Ease of manufacture
If a conventional Gaussian laser beam is used, then the system is simpler to implement, but the melt pool uniformity is poor and requires additional process optimization
Solution Approach 1:
The ring-shaped laser beam implements local quality by creating a predetermined non-uniform energy distribution that directly produces a uniform melt pool. The peripheral energy concentration in the ring beam compensates for heat loss at the melt pool edges, achieving uniform melting without complex process optimization. This geometric approach to energy distribution simplifies the overall process control.
Solution Approach 2:
The patent changes the beam spatial distribution parameter from Gaussian to ring-shaped, which fundamentally alters the melting behavior. This parameter change in the laser beam geometry directly improves melt pool uniformity while maintaining system simplicity, as the improved uniformity is achieved through the beam shape itself rather than complex process parameters or additional system components.
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
Achieves a more uniform melt pool distribution, reducing material vaporization and enhancing the quality of additively manufactured components.
Implementation Method 1
repeatedly applying energy from the ring laser to successively applied incremental quantities of a powder particles to fuse the powder particles
Implementation Method 2
applying energy from the ring laser to successively applied incremental quantities of a powder particles
Implementation Method 3
passing the energy from the ring laser through an optical system to narrowing a width of the beam size to create a smaller beam size
Data Source
Figure 1A~1B
Figure 2
Figure 3
AI summary
A method for making an article includes inputting a digital model of the article into an additive manufacturing apparatus or system comprising an energy source (112), wherein the energy source (112) is a ring laser having a beam size and repeatedly applying energy from the ring laser to successively applied incremental quantities of a powder particles to fuse the powder particles to form the article corresponding to the digital model. Applying the energy includes passing the energy from the ring laser through an optical system (116, 118) to narrowing a width of the beam size to create a smaller beam size before the energy reaches the powder particles.