Stereolithography Resin Layer Control to Prevent Over-Curing
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Solution Overview
Problem
Conventional stereolithography methods face challenges in shaping three-dimensional modeling objects with high accuracy due to excessive curing of photo-curable resin, leading to inaccuracies in layer formation.
Innovation Solution
A stereolithography apparatus and method that utilizes a platform and bulkhead system with precise control over resin layer thickness and internal chamber pressure to form accurate resin layers, preventing excessive curing and ensuring high accuracy in modeling object formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the modeling object is soaked in photo-curable resin during conventional regulated liquid level method, then the resin can continuously supply material for layer formation, but excessive curing occurs leading to reduced manufacturing precision
Solution Approach 1:
The patent divides the resin supply process into discrete controlled layers. Each layer is formed by lowering the platform by a precise predetermined distance, creating distinct resin layers that are cured individually. This segmentation prevents excessive curing by ensuring that only the necessary resin thickness is exposed to light at any given time, while still maintaining continuous production capability.
Solution Approach 2:
The platform is lowered by a predetermined distance before light irradiation begins, pre-forming the resin layer to the exact required thickness. This preliminary positioning ensures that the resin layer is ready for curing without requiring excessive resin to be present, thereby preventing over-curing while maintaining the ability to continuously form layers.
2Reliability
If a light transmission window is provided on the bottom surface of the liquid tank, then light can effectively cure the resin, but it becomes difficult to control the resin layer thickness uniformly
Solution Approach 1:
The patent replaces optical control methods with mechanical control for layer thickness management. Instead of relying on light transmission window geometry to control resin distribution, the system uses a precisely controlled platform lowering mechanism that mechanically sets the resin layer thickness before curing. This mechanical substitution ensures uniform layer thickness while maintaining effective light curing through the window.
3Productivity
If the base is pulled up by an amount corresponding to predetermined height, then new resin layers can be formed, but the modeling object remains soaked in resin causing potential over-curing
Solution Approach 1:
The patent inverts the conventional approach by lowering the platform into the resin rather than pulling the base up. This inversion allows the platform to carry the formed object down through the resin bath, with each lowering action creating a new resin layer of precise thickness. The object is not continuously soaked because the platform movement is controlled to create discrete layers, preventing over-curing while maintaining efficient lamination.
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 apparatus achieves high accuracy in shaping three-dimensional modeling objects by controlling resin layer thickness and chamber pressure, preventing excessive curing and improving overall modeling precision.
Implementation Method 1
a light irradiation unit that irradiates light for curing the photo-curable resin
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
A stereo lithography apparatus (10) includes a modeling tank (11) that retains a photo-curable resin (1) and in which a light transmission plate (14) is provided on a bottom surface of the modeling tank (11), a light irradiation unit (20) that irradiates light (L) for curing the photo-curable resin (1), a platform (12) is provided so as to be capable of being raised and lowered with respect to the modeling tank (11), bulkheads (13) each of which is formed in a cylindrical shape and forms an airtight space (3) in cooperation with the platform (12), a raising and lowering control unit (31) that forms a photo-curable resin layer having a predetermined thickness between the light transmission plate (14) and both a lower surface (13A) of each of the bulkheads (13) and a lower surface of the space (3), and an irradiation control unit (32) that forms a cured layer by irradiating the photo-curable resin layer with the light (L) corresponding to a cross-sectional shape of the modeling object (2) at a predetermined height position.