Multi-Laser Scanning Optics Alignment Under Thermal Drift
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Solution Overview
Problem
Existing additive manufacturing systems using multiple laser beams face challenges in maintaining accurate alignment of scanning optics, particularly under conditions of thermal fluctuations, which can lead to misalignment and reduced quality in manufactured parts.
Innovation Solution
An automated calibration method is introduced, where calibration patterns are generated during the manufacturing process on an intermediate layer, using multiple laser beams to create geometric features, and image analysis is employed to derive spatial offsets, allowing for real-time adjustment of scanning optics to maintain alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple laser beams are used to increase building speed or object size, then productivity is improved, but alignment precision between scanning optics deteriorates due to thermal fluctuations
Solution Approach 1:
The system performs preliminary calibration by generating test patterns on the powder bed before actual manufacturing. The calibration patterns are created in advance to establish reference positions, and any misalignment detected during calibration is compensated for before production begins, preventing alignment errors from affecting manufacturing precision
Solution Approach 2:
The system continuously monitors alignment by periodically generating calibration patterns during the manufacturing process. Image processing algorithms analyze the actual positions of these patterns, detect deviations from expected positions, and provide feedback to adjust the scanning optics positions, thereby maintaining alignment precision despite thermal fluctuations
2Manufacturing precision
If calibration is performed frequently to maintain alignment precision, then manufacturing precision is improved, but production time increases
Solution Approach 1:
The system performs partial calibration by generating only simple test patterns at specific intervals during manufacturing, rather than performing complete recalibration. This partial action is sufficient to detect and correct drift while minimizing interruption to the production process
Solution Approach 2:
The system implements periodic calibration by automatically generating calibration patterns at predetermined intervals during the manufacturing process. This periodic approach balances the need for maintaining alignment precision with the need to minimize production time loss, calibrating only when necessary
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
Ensures consistent and high-quality production of three-dimensional objects with multiple laser beams by continuously aligning scanning optics, preventing misalignment issues due to thermal effects and ensuring precise laser beam coordination.
Implementation Method 1
a powdered material such as a metal or ceramic powder is irradiated with electromagnetic radiation... by irradiating the respective layers of powder with an irradiation beam such as a laser beam
Implementation Method 2
multiple irradiation beams can be used within one additive manufacturing device... the alignment of the coordinate systems of the underlying scanning optics that each direct a laser beam
Data Source
Figure 1
Figure 2~3
Figure 4A~4B
AI summary
A method of automated alignment of scanning optics (17A, 17B) includes the steps: irradiating (step 101) an object area (3A) of a layer of a powdered material (5) provided on a building platform (11) with at least one irradiation beam (15B); irradiating (step 103) a calibration area (21A) of the layer of the powdered material (5) with at least one irradiation beam (15B); guiding (step 105A) the first irradiation beam (15A) with the first scanning optic (17A) over the intermediate top face (31) and thereby melting a first calibration pattern (37) into the intermediate top face (31); guiding (step 105B) the second irradiation beam (15B) with the second scanning optic (17B) over the intermediate top face (31) and thereby melting a second calibration pattern (39) into the intermediate top face (31); acquiring (step 107) at least one image (35, 51A, 51B) of the intermediate top face (31); using the at least one image (35, 51A, 5IB), identifying (step 109) image points related to the geometrical features of the calibration patterns; from the image points, deriving (step 111) a spatial offset (O) between the second geometrical features; and aligning (step 113) at least one of scanning optic (17A) under consideration of the spatial offset (O).