Off-Axis Laser Beam Profiling for Uniform LPBF Build Quality
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Solution Overview
Problem
Existing additive manufacturing systems, particularly Laser Powder Bed Fusion (LPBF), face challenges in ensuring consistent laser beam profiles across different locations on the build platform due to factors like aberrations, astigmatism, and thermal lensing, leading to inconsistent print results and potential defects.
Innovation Solution
A beam measurement system with a positioning apparatus and control system that adjusts the beam measurement device's position and optical elements to align with the intended measurement position, allowing for off-axis laser beam profile measurement, ensuring consistent beam profiles across the build platform.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a fixed laser position is used in LPBF systems, then the system structure is simple and easy to operate, but the laser beam profile becomes inconsistent across different locations on the build platform due to aberrations, astigmatism, and thermal lensing
Solution Approach 1:
The system implements feedback control by measuring the laser beam profile at the actual focal point on the build platform and using this information to adjust the laser parameters or positioning to maintain consistent beam profiles across different locations. The beam measurement device provides real-time feedback about beam characteristics that is used to correct deviations.
Solution Approach 2:
A beam measurement device is introduced as an intermediary component between the laser source and the build platform. This device measures the beam profile without interfering with the primary manufacturing process, enabling quality control and consistency maintenance across the build platform.
2Productivity
If batch processing of multiple parts is performed by machining down to a lowest common dimension, then productivity is improved, but the manufacturing precision and quality control of individual parts are compromised
Solution Approach 1:
The system performs preliminary measurement of the laser beam profile before the actual manufacturing process. By characterizing the beam characteristics in advance at different build platform locations, the system can pre-compensate for variations and ensure consistent quality across all parts in a batch, even when machining down to common dimensions.
3Manufacturing precision
If off-axis beam measurement is implemented to observe laser beam profile at different positions, then manufacturing precision is improved, but the device complexity and measurement system requirements increase
Solution Approach 1:
The beam measurement device is designed with multi-functionality to perform measurements at multiple positions and angles on the build platform. By making the measurement system universal rather than position-specific, the system can characterize beam profiles across the entire build platform using a single device that can be positioned and oriented as needed.
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 laser beam profiles across the build platform, reducing defects and increasing the uniformity of the additive manufacturing process, enabling feedback control of the laser focus and alignment of multiple beams.
Implementation Method 1
a beam measurement device, a positioning apparatus, and a control system. The beam measurement device can include an imager and a plurality of optical elements configured to form an optical path to the imager within the beam measurement device
Data Source
AI summary
Disclosed herein is a laser beam measurement system that includes a beam measurement device, a positioning apparatus, and a control system. The beam measurement device can include an imager and a plurality of optical elements configured to form an optical path to the imager within the beam measurement device. The positioning apparatus is configured to adjust a position of the beam measurement device relative to a build plate of a laser powder bed fusion system. The control system is configured to determine an intended measurement position to observe a laser beam profile of the laser powder bed fusion system, determine a target position of a beam measurement device to align with the intended measurement position, and command an adjustment of one or more aspects of the beam measurement device to achieve alignment of the target with the intended measurement position.