Multi-Projector Calibration Fixture for Large-Area 3D Printing
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Solution Overview
Problem
Conventional additive manufacturing systems using digital light processing (DLP) face challenges with increasing layer size, leading to reduced resolution and energy density, which affects part accuracy and surface finish.
Innovation Solution
A method and system for calibrating multiple image projectors in a photoreactive 3D printing system using a calibration fixture with light sensors to adjust sub-image parameters, employing digital filters for warp correction, edge blending, and irradiance masking to improve image alignment and quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the layer size increases in conventional DLP systems, then the build area is enlarged, but the pixel size increases proportionally causing resolution to decrease
Solution Approach 1:
The patent divides the build area into multiple zones, each served by a dedicated image projector. Instead of using a single projector that must scale up pixel size for larger build areas, multiple projectors maintain their native high resolution while collectively covering the expanded build area. Each projector projects a sub-image to a specific zone, avoiding the resolution degradation that occurs when a single projector scales to cover the entire large build area.
2Area of stationary object
If the layer size increases in conventional DLP systems, then the build area is enlarged, but the projected energy density decreases slowing down the print process
Solution Approach 1:
The build area is segmented into multiple zones, each receiving concentrated energy from its dedicated projector. This prevents the dilution of energy density that occurs in single-projector systems when the build area is enlarged. Each projector maintains high energy density in its assigned zone, enabling faster curing speeds even as the total build area expands.
Solution Approach 2:
Multiple image projectors work simultaneously to cover the entire build area, with each projector functioning as an independent energy source for its designated zone. This multi-functional approach allows the system to maintain high energy density across the entire build area by distributing multiple energy sources, rather than relying on a single projector that would need to spread its energy thin across the large area.
3Manufacturing precision
If multiple image projectors are used to maintain resolution in large build areas, then resolution is improved, but system complexity increases
Solution Approach 1:
The patent incorporates calibration fixtures with light sensors that provide feedback on the actual light output and positioning of each projector. This feedback mechanism enables automatic adjustment and synchronization of multiple projectors, reducing the operational complexity that would otherwise result from having to manually calibrate and coordinate multiple independent projectors. The system self-regulates to maintain alignment and intensity consistency across all projector zones.
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
Enhances resolution and energy density in large build areas, ensuring accurate and high-quality printed parts by minimizing distortions and variations between sub-images.
Implementation Method 1
measuring light from an image projector of the two or more image projectors using the light sensor
Implementation Method 2
photoreactive 3D printing system
Data Source
AI summary
The techniques described herein relate to systems and methods for calibrating two or more image projectors of a photoreactive 3D printing system (PRPS). The method includes: coupling a modular calibration fixture to the PRPS; leveling the modular calibration fixture using two or more height adjusting motors; adjusting a height of a light sensor of the modular calibration fixture using the two or more height adjusting motors; measuring light from the two or more image projectors of the PRPS in a plurality of measurement locations; and adjusting a parameter of a sub-image based on the light measured at the plurality of measurement locations. A modular calibration system including a light sensor, a carriage assembly that moves the light sensor, two or more levelling motors, and a controller, can be used to perform the method.