Aperture Division Multiplexing Optic for Additive Manufacturing
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Solution Overview
Problem
Current additive manufacturing (AM) systems, particularly selective laser melting (SLM), face limitations in build rate and component quality due to restricted optical access and process monitoring efficacy, largely attributed to the use of conventional f−θ lenses which cause nonlinear laser toolpath generation, barrel distortion, and optical aberrations.
Innovation Solution
The implementation of an aperture division multiplexing optic that subdivides a large effective aperture into sub-apertures, allowing multiple optical paths to be directed to a build platform independently, enhancing optical access and image quality for both laser delivery and process monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional f-θ lenses are used for laser delivery, then the laser beam can be focused and scanned across the build platform, but nonlinear mapping and barrel distortion occur that complicate toolpath generation and reduce manufacturing precision
Solution Approach 1:
The patent divides the aperture of the f-θ lens into multiple sub-apertures, each assigned to a dedicated light source. This segmentation allows each light source to utilize only the necessary portion of the lens aperture, enabling linear mapping and simplifying toolpath generation for each individual source while maintaining overall system functionality.
2Productivity
If the number of lasers is increased to achieve higher build rates, then more material can be processed simultaneously, but the machine size must be scaled up which limits the number of lasers per unit area
Solution Approach 1:
The patent enables a single build platform to be served by multiple light sources whose beams are multiplexed through the same f-θ lens aperture. This multi-functionality allows the system to achieve higher build rates equivalent to multiple machines without proportionally increasing the build platform area, as multiple lasers can operate simultaneously on the same platform.
3Device complexity
If f-θ lenses are used for both laser delivery and optical process monitoring, then a single optical path can be shared, but optical aberrations and distorted imaging occur that reduce measurement precision
Solution Approach 1:
The patent segments the lens aperture into dedicated sub-apertures for laser delivery and optical process monitoring. This allows each function to use an optimized optical path without interference, enabling high-quality imaging for process monitoring while maintaining effective laser delivery, thereby resolving the conflict between system simplicity and measurement precision.
4Area of moving object
If a single large aperture is used for laser delivery, then the field of view is maximized, but overlapping fields of view from multiple light sources cannot be achieved which limits build rate improvement
Solution Approach 1:
The patent divides the large aperture into multiple sub-apertures, each assigned to a dedicated light source. This segmentation enables each light source to have its own optimized field of view while allowing these fields to overlap on the build platform, facilitating simultaneous multi-point processing and significantly improving build rate without sacrificing field of view quality.
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 increases build rate by improving laser field of view overlap and reduces residual stresses in manufactured parts, while also providing better image quality for in-situ process monitoring, enabling more effective detection of defects and closed-loop control.
Implementation Method 1
Each sub-aperture can be configured to multiplex an optical path (i.e., receive an input optical path and focus the optical path) to a build platform
Implementation Method 2
dividing a theoretical input aperture of a multiplexing optic into a plurality of sub-apertures
Implementation Method 3
delivering light to at least one of the build surface, the at least one layer on the build surface, or the at least one additional layer
Implementation Method 4
The powder layer can be selectively irradiated via a laser... to melt more material per unit time
Data Source
AI summary
Systems, devices, and methods for additive manufacturing as disclosed allow for improved optical access to a build platform. In at least some embodiments a multiplexing optic of an additive manufacturing device is configured to multiplex an arbitrary number of optical paths to a build platform along a substantially common optical axis by dividing a theoretical input aperture of the multiplexing optic into a plurality of sub-apertures. Each sub-aperture can independently receive and direct an optical path to the build platform. An optical path can be a light path from a light source or an optical process monitoring path from an optical process monitoring system or optical process monitoring device. In some embodiments, an optical path can enter the multiplexing optic off-axis and/or off-angle with respect to an optical axis of the multiplexing optic. The multiplexing optic can include one or more lens elements and/or one or more mirror elements.