Off-Axis Beam Measurement for LPBF Laser Profile Alignment
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Solution Overview
Problem
Traditional laser powder bed fusion systems face challenges in accurately measuring and maintaining the laser beam profile across different locations on the build platform, leading to inconsistent print results and potential defects due to factors like aberrations, astigmatism, and misalignment of lasers.
Innovation Solution
A beam measurement system that includes a device with an imager and optical elements, a positioning apparatus, and a control system to adjust the beam measurement device's position and optical path, allowing for off-axis laser beam measurement and alignment with the intended measurement position, ensuring accurate beam profile analysis and triggering alerts for deviations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a fixed laser position is used in LPBF systems, then the system structure is simple and easy to operate, but measurement accuracy and consistency of laser beam profile across different build locations deteriorate
Solution Approach 1:
The beam measurement device is made dynamically adjustable through a positioning apparatus that enables movement along X, Y, Z axes and rotational adjustment. This dynamic positioning capability allows the device to adapt to different measurement locations and angles, resolving the contradiction by enabling high measurement precision without requiring a completely fixed rigid system structure.
Solution Approach 2:
The beam measurement device is designed as a universal measurement tool that can measure laser beam profiles at multiple locations and angles on the build platform. By integrating positioning capabilities and multiple measurement functions into a single device, the system achieves comprehensive measurement coverage without requiring multiple separate fixed measurement systems.
2Adaptability or versatility
If the beam measurement device is positioned off-axis to measure laser beam profile at different locations, then measurement versatility improves, but alignment precision and optical path consistency worsen
Solution Approach 1:
The control system continuously monitors the position and orientation of the beam measurement device and adjusts the optical path length dynamically to maintain consistency. This feedback mechanism ensures that even when measuring at off-axis locations with different geometries, the optical path remains optimized for accurate beam profile measurement, preserving alignment precision while enabling measurement versatility.
Solution Approach 2:
The system dynamically changes optical parameters including path length, angle of incidence, and positioning coordinates to adapt to different measurement locations. By adjusting these parameters in real-time based on the target measurement position, the system maintains optimal measurement conditions across the entire build platform.
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 measurement of the laser beam profile at any location on the build platform, ensuring consistent print quality, reducing defects, and enabling feedback control of the laser focus, particularly beneficial for multi-laser systems by ensuring proper alignment and uniformity.
Implementation Method 1
an imager and a plurality of optical elements configured to form an optical path to the imager within the beam measurement device
Data Source
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AI summary
A laser beam measurement system (101) comprising: a beam measurement device (104; 302) comprising an imager (144; 414) and a plurality of optical elements (146; 404, 406, 408) configured to form an optical path (148; 402) to the imager (144; 414) within the beam measurement device (104; 302); a positioning apparatus (151) configured to adjust a position of the beam measurement device (104; 302) relative to a build plate (108; 200; 308) of a laser powder bed fusion system (100; 300); and a control system (130) configured to determine an intended measurement position to observe a laser beam profile of the laser powder bed fusion system (100; 300), determine a target position of the beam measurement device (104; 302) to align with the intended measurement position, and command an adjustment of one or more aspects of the beam measurement device (104; 302) to achieve alignment of the target with the intended measurement position.