Bottom-Up 3D Printer Vat Rotation Mechanism
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Solution Overview
Problem
Current 3D printing technologies face challenges such as high mechanical complexity, high costs, and health and safety risks due to the use of high power lasers and UV light sources, as well as difficulties in reducing separation forces and fabrication time in bottom-up fabrication methods.
Innovation Solution
An apparatus with a vat containing photosensitive polymer, a build platform, and an elevator mechanism, combined with a rotation mechanism that allows the vat to rotate relative to the build platform, reducing separation forces and eliminating the need for additional steps in the fabrication process, while using a low-power 405 nm LED for electromagnetic radiation and a liquid silicone rubber vat to inhibit curing and reduce surface tension.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a top-down arrangement with high power laser or UV light source is used, then the photosensitive polymer can be cured to form layers, but the mechanical complexity and health and safety risks increase
Solution Approach 1:
The patent inverts the conventional top-down arrangement by using a bottom-up configuration where the light source is positioned below the vat. This inversion allows the use of low-power 405 nm LED instead of high-power lasers or UV sources, reducing mechanical complexity and safety risks while maintaining curing effectiveness through the optically clear vat floor.
Solution Approach 2:
The patent replaces expensive, complex, and hazardous high-power laser or UV light sources with inexpensive, simple, and safe low-power 405 nm LED. The LED provides sufficient curing capability without the mechanical complexity and health and safety risks associated with traditional light sources.
2Ease of operation
If a bottom-up arrangement with optically clear vat floor is used, then the surface levelling issues are avoided, but the separation forces increase when the photosensitive polymer hardens
Solution Approach 1:
The patent introduces a non-stick coating as an intermediary layer between the optically clear vat floor and the photosensitive polymer. This coating prevents the cured polymer from bonding to the vat floor, significantly reducing separation forces while maintaining the advantages of bottom-up arrangement including easy surface levelling.
3Productivity
If high power light sources are used for rapid curing, then the fabrication speed increases, but the health and safety risks increase
Solution Approach 1:
The patent replaces hazardous high-power light sources with safe low-power 405 nm LED. The LED provides sufficient curing speed for practical fabrication while eliminating the health and safety risks associated with high-power lasers and UV sources, making the system suitable for broader applications including educational and medical fields.
4Productivity
If the build platform is raised frequently to separate layers, then the fabrication process continues, but the fabrication time increases
Solution Approach 1:
The non-stick coating acts as a mediator that prevents bonding between the cured photosensitive polymer and the vat floor. This elimination of bonding allows the build platform to remain in position without frequent raising, reducing fabrication time while maintaining continuous layer separation and enabling uninterrupted fabrication.
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 solution simplifies the mechanical complexity, reduces costs, and enhances safety by minimizing separation forces and fabrication time, allowing for more efficient and cost-effective bottom-up 3D printing with reduced risk of damage to the printed objects.
Implementation Method 1
Exposed photosensitive polymer undergoes a chemical reaction leading to polymerization and solidification. The solidification of the photosensitive polymer is commonly known as 'curing'
Implementation Method 2
A coating of PDMS (an optically clear oxygen rich resin) is applied to the bottom of the vat, the presence of oxygen inhibits the cure of acrylate polymers thus creating a layer of uncured liquid polymer
Implementation Method 3
a rotation mechanism capable of varying the relative rotational position of the vat relative to the build platform, the relative rotation being about an axis which is normal to the working surface of the vat
Data Source
AI summary
An apparatus for bottom-up fabrication of three dimensional objects, the apparatus comprising: a vat for a photosensitive polymer, the floor of the vat including a working surface arranged such that, in use, light incident on the working surface interacts with the photosensitive polymer at the working surface to fabricate a portion of the three dimensional object; a build platform capable of being inserted into the vat, the build platform having a planar surface; an elevator mechanism capable of adjusting the separation between the working surface of the vat and the planar surface of the build platform; and a rotation mechanism capable of varying the relative rotational position of the vat relative to the build platform, the relative rotation being about an axis which is normal to the working surface of the vat.