Volumetric 3D Printing with Subsampled Slice Exposure
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Solution Overview
Problem
Existing three-dimensional printing methods face challenges in achieving high resolution and uniformity in volumetric printing of objects in photopolymerizable liquids, often requiring support structures and post-processing steps to separate the printed object from a fixed substrate.
Innovation Solution
A method involving slicing a three-dimensional object into two-dimensional slices, processing each slice into subsampled images, and sequentially exposing these images at different locations using excitation light, with each pixel or grouping of pixels separated to prevent optical communication, and applying a sampling grid mask with positional offsets to improve resolution and uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If existing three-dimensional printing methods are used to print objects in photopolymerizable liquids, then objects can be formed, but support structures are required and post-processing steps are needed to separate the printed object from the fixed substrate
Solution Approach 1:
The printing process is segmented into multiple sequential exposures of subsampled images at different z-locations. Each subsampled image exposes only a portion of the final slice, and by accumulating multiple subsampled images, the complete slice is formed without requiring support structures. This segmentation approach divides the printing process into manageable steps that can be performed sequentially.
Solution Approach 2:
The invention introduces a temporal dimension to the printing process by sequentially exposing subsampled images at different z-locations over time. Instead of exposing the entire slice at once at a fixed substrate, the method uses multiple z-locations and sequential exposures to build up the complete image, eliminating the need for support structures and simplifying post-processing.
2Manufacturing precision
If high resolution is achieved in volumetric printing, then printing quality improves, but uniformity and optical communication between pixels become challenging
Solution Approach 1:
Each slice is divided into multiple subsampled images, where each subsampled image contains only a subset of the pixels needed for the complete slice. By sequentially exposing these subsampled images at different z-locations, the method achieves high resolution while preventing optical communication between pixels that would occur if all pixels were exposed simultaneously at a single location.
Solution Approach 2:
The method applies local quality by exposing different subsets of pixels at different z-locations. Each subsampled image is optimized for its specific z-location, ensuring that pixels are exposed under optimal conditions for their local position. This local optimization maintains uniformity across the entire slice while achieving high resolution.
3Manufacturing precision
If sequential exposure of subsampled images is performed at different z-locations, then resolution and uniformity improve, but exposure time increases
Solution Approach 1:
The printing process uses periodic action by sequentially exposing multiple subsampled images at different z-locations in a repeating cycle. Each subsampled image is exposed for a optimized duration, and the cycle repeats for all subsampled images. This periodic approach allows the system to achieve high resolution and uniformity while managing exposure time through efficient sequencing.
Solution Approach 2:
The method maintains continuity of useful action by continuously exposing subsampled images at different z-locations without idle time. The sequential exposure process ensures that the light source is constantly performing useful work of polymerizing the photopolymerizable liquid, minimizing downtime and optimizing the overall exposure time while maintaining high resolution and uniformity.
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 enhances resolution and uniformity in three-dimensional printing, allowing for objects to be formed without support structures and reducing post-processing steps, thereby improving efficiency and reducing costs.
Implementation Method 1
printing a three-dimensional object in a volume of a photopolymerizable liquid by photopolymerization
Data Source
AI summary
A method for printing a three-dimensional object in a volume of a photopolymerizable liquid by photopolymerization, the method comprising: (a) providing a digital representation of a three-dimensional object that has been sliced into a plurality of sequential two-dimensional image slices along the z-direction; (b) processing each of the two-dimensional slices of the three-dimensional object into a sequence of subsampled images, each subsampled image comprising an arrangement of pixels wherein each pixel has defined x and y dimensions; (c) sequentially exposing each of the sequence of subsampled images of a slice at a selected location along the z-direction in the volume using excitation light until the volume at the selected location along the z-direction has been exposed to all of the subsampled images of the slice, and (d) sequentially repeating step (c) for a previously unexposed sequential slice of the three-dimensional object, each at different selected location along the z-direction, until the three-dimensional object is formed. A pixel can comprise a single pixel or a grouping of pixels. Preferably the pixels in a grouping of pixels are adjacent pixels. Preferably, the pixels of a subsampled image are separated from each other by a distance. Other methods are further disclosed.