Dynamically Grown Build Envelope for Large-Scale Additive Manufacturing
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Solution Overview
Problem
Conventional additive manufacturing systems face challenges in scaling up to larger formats, leading to issues with uniform layer-wise powder distribution, effective gas plume management, and control of laser energy density, resulting in defects and inferior surface finishes on large parts.
Innovation Solution
The system employs a build unit with a powder dispenser, recoater blade, and irradiation emission directing device, capable of moving in three dimensions, along with a laminar gasflow zone for efficient gas management and a positioning system that allows for independent movement of the build unit and laser source, ensuring uniform powder distribution and controlled laser application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of stationary object
If conventional additive manufacturing systems are scaled up to larger formats, then the build volume increases, but uniform layer-wise powder distribution deteriorates
Solution Approach 1:
The recoater blade is made movable rather than fixed, allowing it to dynamically adjust its position and orientation during the layer deposition process. This enables the blade to maintain optimal contact with the powder bed across large build volumes, ensuring uniform powder distribution even as the build envelope expands to accommodate larger parts.
Solution Approach 2:
The powder distribution process is segmented into multiple zones managed by different portions of the recoater blade. The blade can independently control powder flow to different regions of the build envelope, allowing each zone to receive uniformly distributed powder despite the overall large build volume. This segmentation enables precise local control across the entire build area.
2Volume of stationary object
If conventional additive manufacturing systems are scaled up to larger formats, then the build volume increases, but effective gas plume management deteriorates
Solution Approach 1:
A laminar gas flow system is introduced as an intermediary between the laser processing zone and the surrounding environment. This controlled gas flow acts as a mediator that captures and directs the gas plume generated during laser processing, preventing it from contaminating the powder bed and build area while maintaining a stable processing environment across the entire large build volume.
Solution Approach 2:
Pneumatic systems are employed to generate controlled laminar gas flows that actively manage the gas plume. By using pressurized gas streams, the system creates directed airflow patterns that efficiently evacuate harmful gases and vapors from the processing zone, maintaining air quality and process stability throughout the large build envelope.
3Volume of stationary object
If conventional additive manufacturing systems are scaled up to larger formats, then the build volume increases, but control of laser energy density deteriorates
Solution Approach 1:
The laser system is made dynamically controllable, with real-time adjustment of laser power, scan speed, and focal position. This dynamic control allows the system to maintain consistent energy density across different regions of the large build envelope, compensating for variations in powder bed conditions, ambient temperature, and processing parameters that arise in large-format manufacturing.
Solution Approach 2:
A feedback control system continuously monitors laser processing parameters and adjusts them in real-time to maintain optimal energy density. Sensors detect variations in melt pool characteristics, powder absorption, and processing conditions, and the control system automatically compensates by adjusting laser power and scan parameters, ensuring uniform quality across the entire large build volume.
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 enables the production of large, high-precision additively manufactured objects with improved surface finish and reduced defects by maintaining uniform energy density and efficient gas flow, overcoming the limitations of traditional systems.
Implementation Method 1
a laminar gasflow zone for efficient gas management
Implementation Method 2
irradiating at least part of the first layer of powder within the first build area to form a first fused layer
Implementation Method 3
irradiation emission directing device that directs an energy beam, for example, an electron beam or a laser beam, to sinter or melt a powder material
Implementation Method 4
a positioning system that allows for independent movement of the build unit and laser source, ensuring uniform powder distribution and controlled laser application
Implementation Method 5
moving a recoater blade to form a first layer of powder over at least a portion of a first build area
Data Source
AI summary
The present disclosure generally relates to additive manufacturing systems and methods on a large-scale format. One aspect involves a build unit that can be moved around in three dimensions by a positioning system, building separate portions of a large object. The build unit has an energy directing device that directs, e.g., laser or e-beam irradiation onto a powder layer. In the case of laser irradiation, the build volume may have a gasflow device that provides laminar gas flow to a laminar flow zone above the layer of powder. This allows for efficient removal of the smoke, condensates, and other impurities produced by irradiating the powder (the “gas plume”) without excessively disturbing the powder layer. The build unit may also have a recoater that allows it to selectively deposit particular quantities of powder in specific locations over a work surface to build large, high quality, high precision objects.