Stereolithography Parallel Coating and Curing with Digital Shadow
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Solution Overview
Problem
Current 3D printing systems, particularly stereolithography, face challenges in improving productivity due to sequential dispensing and curing processes, which can lead to increased fabrication time and potential quality issues from fluidic wakes during layer formation.
Innovation Solution
A 3D printing system that concurrently translates a coater blade and selectively images the build plane, utilizing a digital shadow to avoid fluidic wake interference, while computing the width of the fluidic wake based on parameters like resin viscosity and blade geometry to optimize the process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If sequential dispensing and curing processes are used, then system complexity is reduced, but productivity is decreased and fabrication time is increased
Solution Approach 1:
The coater blade is positioned and the resin surface is leveled in advance before the imaging system begins selective curing. The controller pre-calculates the digital shadow region that will be created by the coater blade, allowing the imaging system to plan its curing path ahead of time. This preliminary preparation enables the subsequent parallel execution of coating and curing operations without interference.
Solution Approach 2:
The patent introduces a temporal dimension to the traditionally sequential process by executing coating and curing operations simultaneously in different spatial zones. The coater blade operates in the current scan position while the imaging system cures previously coated regions, effectively adding a time dimension to the process flow and transforming sequential operations into parallel ones.
2Productivity
If concurrent dispensing and imaging are implemented, then productivity is increased, but fluidic wake interference may degrade layer quality
Solution Approach 1:
The patent extracts and isolates the fluidic wake effect by defining a digital shadow region that represents the area affected by the coater blade's movement. This digital shadow is calculated based on the coater blade geometry, resin viscosity, and scanning speed parameters. By identifying and excluding this region from the curing operation, the system prevents the imaging system from curing resin that has been disturbed by the coater blade, thereby maintaining layer quality while allowing concurrent operations.
Solution Approach 2:
The digital shadow acts as an intermediary between the coater blade and the imaging system. It serves as a virtual boundary that mediates the interaction between these two subsystems, allowing them to operate concurrently without direct interference. The digital shadow region is dynamically updated based on the coater blade's position and the fluidic wake characteristics, ensuring that cured regions are always free from wake-induced defects.
3Manufacturing precision
If digital shadow calculation is performed, then layer quality is maintained, but computational requirements and processing time increase
Solution Approach 1:
The system pre-calculates and stores the digital shadow parameters, including the wake width W as a function of coater blade geometry, resin viscosity, and scanning speed. These pre-computed values are stored in lookup tables or memory structures, allowing the controller to quickly retrieve and apply the appropriate digital shadow region during operation without performing complex calculations in real-time, thus minimizing computational overhead.
Solution Approach 2:
The patent models the digital shadow region using simplified geometric parameters, such as a fixed wake width W that depends on coater blade geometry and resin properties. By changing the representation from complex fluid dynamics simulations to simple geometric parameters, the computational complexity is dramatically reduced while maintaining sufficient accuracy for practical applications. The controller can efficiently calculate and update the digital shadow region using basic arithmetic operations.
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 reduces total fabrication time and maintains layer quality by parallel processing the coating and curing steps, enhancing productivity without adverse effects from fluidic wakes.
Implementation Method 1
A typical stereolithography system utilizes a resin vessel, an imaging system, and a build plate within liquid photocurable resin held by the resin vessel. An article is manufactured in a layer-by-layer manner by selectively imaging and radiatively curing layers of the photocurable resin over the build plate.
Implementation Method 2
translate a lower edge of the coater blade over the build plane along a scan direction
Data Source
AI summary
A three-dimensional (3D) printing system includes a vessel configured to contain a photocurable resin, a coating subsystem including a coater blade, a build plate coupled to a vertical movement mechanism, an imaging system configured to selectively image the photocurable resin at a build plane, and a controller. The controller is configured to operate the vertical movement mechanism to position an upper surface of the build plate at the build plane, translate a lower edge of the coater blade over the build plane along a scan direction, and concurrent with translating the lower edge of the coater blade, operate the imaging system to selectively image the build plane while maintaining an exclusion zone that includes a digital shadow that translates with the coater blade, the digital shadow includes an area of the coater blade and a fluidic wake area that follows the coater blade.