Laser Array Pixel Position Detection for Accurate Powder Bed Fusion
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Solution Overview
Problem
Additive manufacturing systems, such as powder bed fusion, face limitations in manufacturing speed and throughput due to the rate of material fusion, which is constrained by laser power and scan speed, leading to potential defects from Rayleigh instability when power and speed exceed critical limits.
Innovation Solution
Implementing a system with a plurality of laser energy sources forming an array of laser energy pixels, where the optics assembly is movable to direct laser energy precisely onto a build surface, and a laser array position detector is used to determine the exact position and orientation of each pixel relative to a reference position, ensuring accurate and high-resolution manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If laser power and scan speed are increased to improve manufacturing speed, then productivity increases, but defects from Rayleigh instability occur
Solution Approach 1:
The system divides a single high-power laser beam into multiple lower-power laser beams using beam splitting optics. This segmentation allows the total laser power to be distributed across multiple beams that scan more slowly, avoiding Rayleigh instability defects while maintaining high overall productivity through parallel processing of multiple layers or regions.
Solution Approach 2:
The invention introduces a temporal dimension by overlapping scans of the same layer and utilizing inter-layer time for powder indexing. This allows the system to maintain high productivity without increasing scan speed, as the effective processing time is extended across multiple passes and layers rather than relying on faster single-pass scanning.
2Productivity
If single laser systems are used to maintain system simplicity, then device complexity is reduced, but manufacturing speed is limited
Solution Approach 1:
The system segments the laser processing function into multiple beams generated from a single laser source through beam splitting optics. This approach achieves multi-laser productivity while maintaining a single laser source, thereby increasing manufacturing speed without proportionally increasing system complexity.
Solution Approach 2:
A single laser source is made multi-functional by using beam splitting optics to generate multiple laser beams that can process different regions or layers simultaneously. This universal approach allows one laser source to perform the work of multiple lasers, improving productivity while avoiding the complexity of multiple independent laser systems.
3Productivity
If laser beams are scanned quickly to improve throughput, then productivity increases, but laser spot size and power density become difficult to control
Solution Approach 1:
By segmenting the total power into multiple beams, each beam can be scanned at moderate speeds while maintaining adequate power density. The segmentation allows for better control of individual beam parameters without sacrificing overall throughput, as multiple beams process the material in parallel.
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 allows for increased power delivery to the build volume without exceeding critical limits, enhancing fusion rates while maintaining accuracy and preventing defects, thereby improving manufacturing speed and throughput.
Implementation Method 1
a sensor configured to detect the laser energy from the laser energy pixel after passing through the aperture
Implementation Method 2
an optics assembly movable relative to a build surface and configured to direct laser energy from the plurality of laser energy sources towards the build surface
Implementation Method 3
configured to direct laser energy from the plurality of laser energy sources towards the build surface and to form an array of laser energy pixels on the build surface
Implementation Method 4
The controller is configured to move the optics assembly relative to the aperture to scan the laser energy pixel across the aperture
Implementation Method 5
If the various laser parameters, such as laser power, laser spot size, and/or laser scanning speed are in a regime in which the delivered energy is sufficient to melt the particles of metal powder, one or more melt pools may be established on a build surface
Implementation Method 6
the delivered energy is sufficient to melt the particles of metal powder
Data Source
AI summary
Aspects described herein relate to additive manufacturing systems and related methods. In some embodiments, an additive manufacturing system includes a laser array position detector to determine a position and/or orientation of laser energy pixels in a laser array. The laser array position detector may include an aperture and an optical sensor positioned within the aperture to detect laser energy from a laser energy pixel when the laser array is scanned across the aperture.