3D Printing Resin Polymerization Above Glass Transition
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Solution Overview
Problem
Conventional additive manufacturing methods, such as indirect stereolithography and DLP, often suffer from delamination issues due to tension buildup and uneven layer density, resulting in decreased product quality and strength.
Innovation Solution
The method involves polymerizing the resin at a temperature above the glass transition temperature of the polymerized resin, enhancing flowability and reducing moisture content, which prevents tension buildup and improves layer adhesion, leading to increased density and reduced delamination in the final product.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If polymerization is performed at room temperature, then the resin maintains structural stability, but tension builds up during polymerization causing delamination and cracking
Solution Approach 1:
The patent changes the temperature parameter from room temperature to above the glass transition temperature of the resin. This parameter change allows the resin to maintain flowability during polymerization, preventing tension buildup while ensuring strong layer attachment. The temperature parameter is specifically controlled to be above Tg but below degradation temperature.
Solution Approach 2:
The patent makes the resin dynamic by keeping it above its glass transition temperature during polymerization. This allows the resin to remain in a more flexible, flowable state rather than being rigid, enabling it to accommodate polymerization shrinkage and reduce internal tensions that cause delamination.
2Device complexity
If polymerization is performed at room temperature, then the process is simple, but the layer density is uneven causing delamination issues
Solution Approach 1:
The patent changes the temperature parameter to above the glass transition temperature, which fundamentally alters the resin's flow characteristics. This ensures uniform layer density by maintaining resin flowability during polymerization, eliminating the density unevenness that causes delamination, while the process remains relatively simple.
3Strength
If the resin is polymerized at elevated temperature, then flowability increases improving layer adhesion, but the resin may degrade
Solution Approach 1:
The patent precisely controls the temperature parameter within a specific range: above the glass transition temperature to ensure flowability and strong adhesion, but below the degradation temperature to maintain resin stability. This controlled parameter change resolves the contradiction between improved adhesion and potential degradation.
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 results in three-dimensional objects with improved strength, reduced delamination, and enhanced quality by ensuring stress-free and homogeneous microstructure, particularly effective for small particles like zirconia, silicon carbide, and silicon nitride.
Implementation Method 1
a photoinitiator which forms free radicals upon absorption of radiation and initiates polymerization of the monomer
Implementation Method 2
at a temperature above room temperature and above the glass transition temperature of the polymerized resin
Data Source
Figure 1~2
AI summary
The present invention concerns a method for the manufacture of a three-dimensional object, comprising (a) providing a three-dimensional model of the object, which divides the object in voxels; (b) applying a first layer of a radiation-curable slurry onto a target surface, wherein the slurry contains a polymerizable resin and a photoinitiator; (c) polymerizing the resin by illuminating the voxels of the first layer in accordance with the model with radiation at a temperature above room temperature and above the glass transition temperature of the polymerized resin, to cause polymerization of the resin to form a cross-linked polymeric matrix; (d) applying a subsequent layer of the slurry on top of the first layer; (e) polymerizing the resin by scanning the voxels of the subsequent layer in accordance with the model with radiation at a temperature above room temperature and above the glass transition temperature of the polymerized resin, to cause polymerization of the resin to form a cross-linked polymeric matrix; (f) repeating steps (d) and (e), wherein each time a subsequent layer is applied onto the previous layer, to produce a green body; and optionally (g) debinding and (h) sintering of the three-dimensional object. The invention further concerns the three-dimensional object obtained thereby and an additive manufacturing system suitable for performing the method according to the invention.