Lithography-Based Additive Manufacturing Bubble Displacement
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Solution Overview
Problem
High-viscosity photopolymerizable materials, especially those with ceramic fillers, pose challenges in lithography-based additive manufacturing due to the formation of gas bubbles during the construction process, leading to defects in the component structure that can result in cracking and failure during debinding and sintering.
Innovation Solution
The method involves varying the layer thickness of the photopolymerizable material in a lateral direction to influence the contact point between the construction platform and the material layer, ensuring a greater thickness in areas where gas bubbles are likely to form, thereby minimizing their entrapment and promoting material flow to displace them, and adjusting the material layer thickness dynamically based on the geometry of the preceding layers to optimize bubble displacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If high-viscosity photopolymerizable material is used for layered construction, then the material can maintain shape and reduce sagging, but gas bubbles form during the construction process leading to defects
Solution Approach 1:
The trough base is pre-heated to a temperature between 40°C and 80°C before the construction process begins. This preliminary thermal treatment reduces the viscosity of the high-viscosity photopolymerizable material, preventing gas bubble formation during platform immersion while maintaining shape stability during construction.
Solution Approach 2:
The temperature of the trough base is dynamically adjusted during the construction process. By changing the thermal parameter, the material viscosity is optimized to eliminate gas bubble entrapment while preserving the shape-holding capability of the high-viscosity material.
2Ease of manufacture
If the construction platform is lowered into the material to form layers, then layers can be constructed, but gas bubbles are trapped between the platform and material surface
Solution Approach 1:
The trough base is pre-heated before construction begins, which pre-conditionsthe material to a lower viscosity state. This preliminary action ensures that when the platform is lowered, the material flows smoothly without trapping gas bubbles, while still enabling precise layer construction.
Solution Approach 2:
By changing the temperature parameter of the trough base, the material's flow characteristics are modified to eliminate gas bubble entrapment during platform immersion, while maintaining the ability to form precise layers.
3Device complexity
If material layer thickness is uniform, then the construction process is simple, but gas bubbles cannot be effectively displaced from the exposure area
Solution Approach 1:
The trough base is divided into zones with different temperatures. The region beneath the exposure area is heated to a higher temperature to reduce material viscosity and facilitate gas bubble displacement, while other regions maintain lower temperatures to preserve material stability and shape.
Solution Approach 2:
Spatial variation in the temperature parameter across the trough base enables localized control of material properties. This allows gas bubbles to be displaced from the exposure area through thermal thinning of the material, while maintaining overall process simplicity.
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 effectively reduces the number of air bubbles in the exposed area, enhancing the processability of high-viscosity materials and minimizing defects in the final component, while also optimizing material flow to prevent bubble entrapment and improving the precision and quality of the constructed parts.
Implementation Method 1
a layer of the highly viscous photopolymerizable material forms between the construction platform or the shaped body and the trough floor, which layer is formed in particular by irradiation through the trough floor is cured in a location-selective manner to form the desired shape of the molded body layer
Data Source
Figure 1
Figure 2~3
Figure 4a~5c
AI summary
The invention relates to a method for the layered construction of a shaped part (10) from a highly-viscous photopolymerisable material, where layers (11) of said shaped part are formed one after the other and one on top of the other, a material layer (6) of a predetermined thickness (a) of said highly-viscous photopolymerisable material being formed in a basin (1), and the construction platform (5), or the shaped part (11) at least partially formed on said construction platform (5), being lowered into the material layer (6) such that, between said construction platform (5) or shaped part (11), and the base (2) of the basin, a layer of said highly-viscous photopolymerisable material is formed which, in particular, is cured by means of locationally-selective irradiation through the base (2) of the basin in order to form the desired shape for the shaped part layer (10). In said method, at least one material layer (6) demonstrates a variation in layer thickness in the lateral direction. The invention also relates to a device for carrying out said method.