Resin Circulatory System for Vat Polymerization Temperature Control
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Solution Overview
Problem
In additive manufacturing, the exothermic polymerization process of photo-sensitive resins during 3D printing leads to localized heating, which can cause unintended curing and affect the quality of printed layers, especially in continuous operations.
Innovation Solution
A resin circulatory system that includes a tank with an exit and entrance port, pumps, valves, and a cooling system to circulate and cool the resin, along with a membrane assembly and tension adjustment mechanisms to manage resin flow and tension, ensuring efficient cooling and filtration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If continuous or near-continuous printing operations are performed, then productivity is improved, but the resin accumulates excessive heat leading to unintended curing and degraded print quality
Solution Approach 1:
The patent extracts the heated resin from the build area using a circulatory system that pumps resin out from the bottom of the tank and replaces it with cooler resin from the top, effectively removing excess heat from the printing zone to maintain print quality during continuous operations
Solution Approach 2:
The patent employs asymmetric sampling depths for resin temperature monitoring, taking measurements at different depths (e.g., top and bottom) of the resin tank to detect temperature gradients and optimize the cooling strategy accordingly
2Temperature
If resin is circulated and cooled outside the build area, then temperature control is improved, but the system complexity increases due to additional components
Solution Approach 1:
The circulatory system is designed to perform multiple functions simultaneously: it cools the resin by removing heated resin from the build area, filters particulates from the resin, and enables temperature monitoring at various depths, thereby reducing the need for separate cooling, filtration, and monitoring systems
Solution Approach 2:
The system uses the resin's own circulation and convection currents to facilitate cooling, rather than requiring external cooling mechanisms, thereby simplifying the overall system design while maintaining effective temperature control
3Measurement precision
If resin is sampled at multiple depths for temperature monitoring, then temperature measurement precision is improved, but the difficulty of detecting and measuring increases
Solution Approach 1:
The patent introduces an intermediary sampling mechanism that draws resin samples from different depths through a centralized monitoring system, allowing temperature measurements at multiple locations without requiring direct sensor placement throughout the entire resin volume, thereby simplifying the measurement process
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 effectively cools the resin, prevents unintended curing, and maintains print quality by managing resin flow and tension, enhancing the reliability and consistency of the 3D printing process.
Implementation Method 1
The system is configured to extract heated resin from a bottom portion of the tank and flow the resin towards a reservoir. The system also supplies cooler resin from the reservoir to the tank, creating a circulation pattern that removes heat from the build area.
Implementation Method 2
a photo-sensitive resin within a tank is cured through exposure to radiation when fabricating an object
Implementation Method 3
The polymerization process by which the liquid resin solidifies into the desired object layers is exothermic
Data Source
Figure 1A
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Figure 1C
AI summary
A vat polymerization apparatus configured with a resin circulatory system that includes pumps arranged to extract used photo-curing resin from a tank and refresh or replace it with new resin, another fluid, or a combination of new resin and the fluid. Resin flow is regulated using a plurality of valves which are opened and closed to achieve a desired circulation process. Additional aspects of the apparatus include a membrane assembly in which a radiation-transparent flexible membrane is supported in a frame that stretches the membrane. A lip of the frame is secured to a bottom rim of the tank; thus, when the membrane assembly is in place it forms a bottom of the tank. A tension adjustment mechanism may be employed to adjust the tension of the membrane within the frame. The frame may be aligned with the tank with the aid of magnetized alignment aids distributed about the frame.