Composite Beam Shaping for SLM Microstructure Control
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Solution Overview
Problem
In Selective Laser Melting, controlling material microstructure and properties is challenging due to restricted solidification parameters, making it difficult to achieve fully dense objects with desired structures and properties.
Innovation Solution
A composite beam generator is developed, combining a first directed beam for melting and a second directed beam with a non-circular transverse energy distribution profile to control temperature variation, allowing for the creation of objects with specific structures and properties by adjusting the energy distribution profiles of the beams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If selective laser melting is performed with optimized parameters to achieve fully dense objects, then the density and strength of the fabricated object is improved, but the ability to control material microstructure and properties is restricted
Solution Approach 1:
The laser beam is segmented into multiple independent controllable beams (e.g., multiple Gaussian beams or Bessel beams) that can be selectively applied to different regions of the powder bed. This allows different processing parameters (power, speed, pulse duration) to be applied simultaneously to different zones, enabling independent control of microstructure and properties in different regions while maintaining overall density
Solution Approach 2:
Different regions of the powder bed are subjected to different laser processing conditions. For example, high power density is applied to achieve full melting and density in load-bearing regions, while lower power density or different pulse patterns are used in non-critical regions to control microstructure for specific properties like ductility or thermal conductivity
2Productivity
If a single laser beam is used for powder melting, then the process is simple and fast, but the temperature distribution and solidification control are insufficient
Solution Approach 1:
The single laser beam is replaced with multiple independent laser beams that can be positioned and controlled separately. This segmentation allows the system to maintain high processing speed by parallel processing while achieving precise temperature distribution control through independent adjustment of each beam's parameters and positioning
Solution Approach 2:
The processing approach transitions from single-point sequential scanning to multi-point parallel processing in the spatial dimension. Multiple beams operate simultaneously at different locations, increasing productivity while the ability to independently control each beam's position and parameters provides enhanced temperature distribution control
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 solution enables precise control over the solidification process, allowing for the formation of objects with desired microstructures and properties by effectively combining beams with different energy profiles, enhancing the capabilities of additive manufacturing techniques like Selective Laser Melting.
Implementation Method 1
laser irradiated the powder and molten or sintered layer by layer to form the object
Implementation Method 2
The second directed beam has a second transverse energy distribution profile with non-circular for adjusting the temperature variation of the powder layer before or after the powder being melted to control the solidification
Implementation Method 3
A beam combiner is for receiving the first and the second directed beam, and combining them into a composite beam
Implementation Method 4
a beam splitter for splitting a beam into a first directed beam and a second directed beam
Implementation Method 5
A beam shaper shapes a transverse energy distribution profile of the second directed beam to make it non-circular
Data Source
Figure 1~3
Figure 4(a)~4(d)
Figure 5~7
AI summary
This disclosure provides a composite beam generator (400) and a method of performing powder melting or sintering in additive manufacturing process using the same. The composite beam generator comprises: a beam splitter (420) for splitting a beam into a first directed beam (412) and a second directed beam (413); a beam shaper (440) for shaping a transverse energy distribution profile of the second directed beam to non-circular; at least one beam delivery unit (460) for guiding the first directed beam or the second directed beam; and a beam combiner (450) for receiving the first directed beam and the second directed beam, and respectively generating a first output beam (415) and a second output beam (416), and combining them into the composite beam.