Multi-Projector Calibration for High-Resolution Photoreactive 3D Printing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional additive manufacturing systems using digital light processing (DLP) face a decrease in resolution and energy density as layer size increases, leading to reduced part accuracy and prolonged print times due to increased pixel size and decreased projected energy density.
Innovation Solution
A photoreactive 3D printing system (PRPS) with multiple image projectors and a calibration fixture equipped with light sensors is used to project and adjust sub-images, applying digital filters for geometric correction, edge blending, and irradiance normalization to maintain high resolution and energy density across large build areas.
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 covered by a separate DLP projector. Instead of using one large projector that would require large pixels, multiple smaller projectors are arranged to cover different regions. Each projector maintains its native high resolution while collectively covering a large build area, thus resolving the contradiction between large build area and high resolution.
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 leading to slower print times
Solution Approach 1:
By segmenting the build area across multiple projectors, each projector can operate at its optimal energy density without the dilution effect of covering a large area alone. This maintains high curing efficiency while achieving large build volumes, thus resolving the contradiction between build area and print speed.
Solution Approach 2:
Multiple DLP projectors are merged to work simultaneously on different regions of the same build area. Their combined output achieves both large coverage area and high energy density, as each projector contributes its full energy to its designated zone without the energy being spread thin across the entire large area.
3Manufacturing precision
If multiple image projectors are used to maintain high resolution across large build areas, then resolution is improved, but system complexity increases due to calibration requirements
Solution Approach 1:
The system performs preliminary calibration by projecting test patterns and using cameras to capture images of known features. This preliminary action establishes the transformation parameters needed to correct geometric distortions and align all projectors before actual manufacturing, thus reducing the operational complexity despite multiple projectors being used.
Solution Approach 2:
The system uses cameras to capture feedback images of calibration features projected by each DLP projector. This feedback is processed to calculate geometric transformation parameters that correct distortions. The system continuously monitors and adjusts projector outputs based on this feedback, automatically compensating for misalignments and reducing manual calibration complexity.
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
The system achieves high-resolution and high-energy density printing by minimizing image distortions and variations, ensuring accurate part production and reducing print time through precise calibration and adjustment of sub-image properties and alignment.
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 (PRPS)
Data Source
AI summary
The present disclosure provides techniques for calibration systems and methods for additive manufacturing systems with multiple image projection. In some embodiments, a method of calibrating two or more image projectors of a photoreactive 3D printing system (PRPS) includes: projecting a sub-image from each of the two or more image projectors; measuring light from an image projector using a light sensor of a calibration system; receiving a signal from the light sensor; processing information from the light sensor; and changing a parameter of a sub-image based on the processed information. In some cases, a PRPS includes a calibration fixture comprising the light sensor. In some cases, a PRPS can be calibrated using a modular calibration fixture comprising the light sensor, wherein the modular calibration fixture can be coupled to the PRPS, leveled and height adjusted, and then a calibration routine can be performed.