OPA and Risley Prism Beam Steering for Large-Area 3D Printing
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Solution Overview
Problem
Additive manufacturing systems face limitations in beam steering speed and precision, particularly with conventional approaches like galvo- or gantry-based systems, which restrict throughput and feature resolution, and are challenged by the modest steering angle of optical phased arrays (OPAs), limiting their scanning area and laser power handling.
Innovation Solution
Combining optical phased arrays (OPAs) with Risley prism assemblies to achieve high-speed, high-precision beam steering, where OPAs control beam phase and shape, and Risley prisms perform large-scale adjustments using wedge prisms and actuators to direct laser energy over a larger area, enabling simultaneous formation of multiple melt pools without sacrificing feature resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional galvo- or gantry-based beam steering systems are used, then beam steering precision can be maintained, but beam steering speed is limited and throughput is restricted
Solution Approach 1:
The patent replaces conventional mechanical beam steering systems (galvo scanners, gantry systems) with an optical phased array that uses electronic phase modulation to steer laser beams. This substitution of mechanical systems with optical-electronic systems enables much faster beam steering speeds without mechanical inertia limitations, directly resolving the contradiction between steering speed and productivity.
Solution Approach 2:
The patent changes the control parameter from mechanical position commands to optical phase differences. By controlling the phase of laser beams passing through the optical phased array, the system achieves rapid beam steering without mechanical movement, thereby increasing both beam steering speed and manufacturing throughput simultaneously.
2Speed
If optical phased arrays are used for high-speed beam steering, then beam steering speed improves, but the steering angle is modest and scanning area is limited
Solution Approach 1:
The patent combines an optical phased array (providing fine, high-speed beam steering) with a Risley prism assembly (providing large-angle scanning capability). The OPA is nested within the broader scanning system that includes the Risley prisms, allowing the composite system to achieve both high-speed fine positioning and large-area coverage by coordinating the actions of both subsystems.
Solution Approach 2:
The patent merges two different beam steering technologies - the optical phased array for rapid angular modulation and the Risley prism assembly for extended scanning range - into a unified system. This combination allows the system to leverage the high-speed capability of the OPA while simultaneously achieving the large scanning area provided by the Risley prisms, resolving the contradiction between speed and scanning area.
3Speed
If optical phased arrays are used, then high-speed scanning is achieved, but laser power handling capability is limited
Solution Approach 1:
The patent introduces the Risley prism assembly as an intermediary optical element between the laser source and the build surface. The Risley prisms are designed to handle high laser power and perform coarse beam steering, while the optical phased array performs fine steering with lower power requirements. This intermediary arrangement allows the system to process high laser powers that would otherwise be incompatible with standard OPA implementations.
4Area of stationary object
If Risley prism assemblies are used for large-scale scanning, then scanning area increases, but beam steering precision may be compromised
Solution Approach 1:
The patent segments the beam steering function into two distinct stages: coarse positioning performed by the Risley prism assembly and fine positioning performed by the optical phased array. This segmentation allows each subsystem to be optimized for its specific function - the Risley prisms for large-area coverage and the OPA for high-precision positioning - thereby achieving both large scanning area and high beam positioning precision simultaneously.
Solution Approach 2:
The patent implements a dynamic, two-level control system where the Risley prisms provide dynamic, large-range beam steering and the optical phased array provides dynamic, fine-range beam adjustment. The system dynamically coordinates both subsystems to achieve precise beam positioning across a large scanning area, resolving the contradiction between scanning area and positioning precision.
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 combination allows for faster, more accurate scanning and beam shaping, enabling even heating and preventing defects like keyhole porosity, with the Risley prism system tolerating higher laser powers and providing precise, large-scale scanning, enhancing additive manufacturing throughput and quality.
Implementation Method 1
The optical phased array includes one or more phase shifters operatively coupled to the one or more laser energy sources and configured to control a phase of the laser energy
Implementation Method 2
a Risley prism assembly comprising a plurality of wedge prisms. The optical phased array is configured to direct the laser energy towards the Risley prism assembly, and the Risley prism assembly is configured to direct the laser energy towards the build surface
Data Source
AI summary
Additive manufacturing systems and related methods are disclosed. In some embodiments, an additive manufacturing system includes a build surface, one or more laser energy sources configured to emit laser energy, an optical phased array operatively coupled to the one or more laser energy sources, and a Risley prism assembly comprising a plurality of wedge prisms. The optical phased array includes one or more phase shifters operatively coupled to the one or more laser energy sources and configured to control a phase of the laser energy. The optical phased array is configured to direct the laser energy towards the Risley prism assembly, and the Risley prism assembly is configured to direct the laser energy towards the build surface.