3D Powder Bed Fusion Beam Sequencing for Uniform Molten Surfaces
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Solution Overview
Problem
Existing three-dimensional powder bed fusion additive manufacturing (PBF-AM) apparatuses face issues with unevenness and defects in molten surfaces at the start and end of beam scanning lines, leading to non-uniform molten surfaces and reduced quality of the built structures.
Innovation Solution
A three-dimensional PBF-AM apparatus and method that utilizes a beam deflector controlled by a controller to determine next irradiation positions based on ranks assigned to unirradiated areas, updating these ranks based on the molten state, and employing a recommended movement range to minimize settling time deviations, ensuring uniform molten surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If beam scanning is performed sequentially line by line, then the manufacturing process is simple and efficient, but unevenness and defects occur in molten surfaces at the start and end of lines
Solution Approach 1:
The build region is divided into multiple lines, and beam scanning is performed sequentially on each line. This segmentation allows systematic coverage of the entire powder bed while maintaining manageable scan lengths that prevent excessive heat accumulation at line boundaries, thereby achieving both efficient processing and uniform molten surfaces.
Solution Approach 2:
Dummy scanning is performed before the actual beam scanning begins. This preliminary action pre-heats the powder material in the build region, ensuring that the starting conditions for beam scanning are uniform and free from cold spots that would cause uneven melting. This eliminates surface unevenness at the start of line scanning while maintaining overall scanning efficiency.
2Manufacturing precision
If dummy scanning is performed between lines, then molten surface uniformity is improved, but manufacturing time is increased
Solution Approach 1:
Dummy scanning is performed only at the beginning of the beam scanning process, not between every line. This preliminary heating action ensures uniform starting conditions for the actual melting process, improving molten surface uniformity while minimizing the time added to the manufacturing cycle.
Solution Approach 2:
Instead of performing dummy scanning throughout the entire process, the invention applies dummy scanning partially only when needed (at the start). This partial application provides sufficient uniformity improvement without the excessive time cost that would result from continuous dummy scanning between all lines.
3Device complexity
If beam irradiation is performed in a fixed sequence, then the control system is simple, but molten surface uniformity deteriorates due to heat accumulation
Solution Approach 1:
The beam scanning sequence is made dynamic by adjusting the scanning direction and pattern based on the current state of the powder bed. The control system adapts the irradiation sequence to prevent heat accumulation in specific areas, improving molten surface uniformity while maintaining manageable control complexity through algorithmic rather than mechanical adjustments.
Solution Approach 2:
The control system monitors the melting state of the powder material and adjusts the beam scanning sequence accordingly. By incorporating feedback about the molten surface conditions, the system can dynamically modify the irradiation pattern to prevent uneven heat distribution, achieving uniform molten surfaces without requiring overly complex hardware modifications.
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 solution enables the formation of uniform molten surfaces and improves the quality of the three-dimensional structures by prioritizing beam irradiation based on molten state and reducing settling time deviations, resulting in enhanced build quality.
Implementation Method 1
The beam emitter emits a beam toward the powder layer spread on the stage
Implementation Method 2
irradiate the powder layer with the beam to melt and coagulate the powder material
Implementation Method 3
The beam deflector deflects the beam emitted from the beam emitter
Implementation Method 4
melt and coagulate the powder material
Data Source
AI summary
A three-dimensional PBF-AM apparatus reflecting one aspect of the present invention includes a stage, a beam emitter, a beam deflector, and a control apparatus. The beam deflector deflects a beam emitted from the beam emitter. The control apparatus controls the beam deflector. The control apparatus determines a next irradiation position, which is a position to be irradiated with the beam, next based on a rank assigned to each of unirradiated positions that have not yet been irradiated with the beam. Further, the control apparatus controls the beam deflector to irradiate the next irradiation position with the beam. The rank is determined based on a molten state around each of the unirradiated positions and is updated every time the beam is emitted.