Axial Beam Scanning for High-Resolution Tomographic 3D Printing
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Solution Overview
Problem
Tomographic additive manufacturing is compromised by lensing distortion from the cylindrical vial and beam spread due to diffraction, leading to reduced resolution and increased complexity in optical considerations.
Innovation Solution
Implement axial beam scanning by modulating the focal length of the light beam within the photo-curable material, using a tunable lens or translating the objective lens, to create a time-averaged beam that minimizes beam spread and achieves uniform resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a narrow, perfectly collimated light beam is used to achieve high resolution, then resolution is improved, but beam spread due to diffraction increases, deteriorating resolution at the edge of print volume
Solution Approach 1:
The patent applies dynamics by rapidly scanning the focused laser beam axially through the resin volume. Instead of using a static narrow beam that suffers from diffraction-induced beam spread, the system dynamically moves the focal point along the z-axis, creating a time-averaged uniform energy distribution that maintains high resolution throughout the entire print volume without edge deterioration
Solution Approach 2:
The patent employs periodic action through oscillatory axial scanning of the laser beam at specific frequencies. The beam is scanned back and forth along the z-axis in a periodic manner, with the scanning frequency tuned to resonate with the system, creating a stable time-averaged energy distribution that eliminates beam spread effects while maintaining consistent resolution
2Productivity
If tomographic additive manufacturing is implemented to eliminate mechanical overhead and increase print speed, then productivity is improved, but optical complexity increases due to lensing distortion from the cylindrical vial
Solution Approach 1:
The patent extracts and eliminates the problematic cylindrical vial interface from the optical path. By using a flat-bottomed container and projecting light from below, the system removes the curved refractive surface that causes lensing distortion, thereby reducing optical complexity while maintaining the productivity benefits of tomographic additive manufacturing
Solution Approach 2:
The patent introduces an index-matching liquid as an intermediary between the projection medium and the photopolymer resin. This intermediary layer eliminates refraction and lensing effects by matching the refractive index across the interface, simplifying the optical system while preserving the high-speed tomographic printing capability
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 method results in higher resolution and faster microscale 3D printing, reducing costs by 10-20 times and increasing print speed by 106 times compared to direct laser writing techniques.
Implementation Method 1
any beam will spread due to diffraction, which results in shallow depth of field, and the beam spread deteriorates the resolution at edge of print volume
Implementation Method 2
When a voxel of resin absorbs a threshold light dose, the resin polymerizes into a solid
Data Source
AI summary
A method for additive manufacturing of an object having a three-dimensional structure formed from a photo-curable material, the method implemented by a computing device comprising a processor and a computer readable medium having instructions executable by the processor, the method comprising at least the steps of: (a) rotating a vial containing the photo-curable material in a path of a light beam at a predefined rotation speed; (b) calculating patterns associated with a 3D geometry of the object; (c) modulating a focal length of the beam within the photo-curable material while projecting the beam comprising the patterns into the photo-curable material to form the object.