Horizontal Vat Lithography for Ceramic Photopolymer Layering
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Solution Overview
Problem
Current methods for producing ceramic dental restoration elements using rapid prototyping face challenges with ceramic-filled photopolymers, including low green strength, light diffusion, non-uniform polymerization, and increased viscosity, which affect bonding and mechanical loading capabilities.
Innovation Solution
A device and method for processing light-polymerizable materials using a horizontally movable vat and controlled build platform, with a feed device for uniform material distribution and exposure unit for selective positioning, allowing for precise layer formation and reduced mechanical stress during the buildup process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If ceramic-filled photopolymer material is used for rapid prototyping, then the object can be built up in layers with predetermined geometry, but the green strength of the polymerized object is significantly lower than unfilled polymer
Solution Approach 1:
The patent changes the exposure parameters (intensity, duration, distribution) to optimize polymerization of ceramic-filled photopolymer. By adjusting these parameters, the patent achieves sufficient green strength while maintaining the layered construction capability, resolving the contradiction between manufacturability and strength.
2Quantity of substance
If ceramic-filled photopolymer material is processed, then the object can be built up with ceramic particles, but pronounced light diffusion occurs and depth of penetration is significantly reduced
Solution Approach 1:
The patent applies local quality by varying the light intensity distribution across the exposure area. Regions with higher ceramic particle concentration receive adjusted exposure intensity to compensate for light diffusion, ensuring uniform polymerization throughout the material volume while maintaining high ceramic content.
Solution Approach 2:
The patent uses periodic exposure action with multiple exposure steps at different intensities or durations to achieve complete polymerization despite light diffusion caused by ceramic particles. This periodic action ensures thorough curing while maintaining high ceramic particle content.
3Quantity of substance
If ceramic-filled photopolymer material is used, then the object can be built up with ceramic reinforcement, but non-uniform polymerization occurs in the z direction
Solution Approach 1:
The patent changes exposure parameters (intensity, duration) as a function of the z-direction position to compensate for non-uniform polymerization. By adjusting these parameters layer by layer, the patent achieves uniform polymerization throughout the object height while maintaining high ceramic particle proportion.
4Quantity of substance
If ceramic-filled photopolymer material is processed, then the object can be built up with ceramic particles, but the material is significantly more viscous
Solution Approach 1:
The patent applies dynamics by making the build platform movable rather than stationary. The build platform moves vertically to control material flow and layer formation, accommodating the high viscosity of ceramic-filled photopolymer while maintaining high ceramic particle proportion.
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 enables better processing of high-viscosity ceramic-filled photopolymers by ensuring reproducible layer formation, improved bonding, and enhanced mechanical strength, addressing the limitations of existing techniques.
Implementation Method 1
a control unit, which is arranged for polymerizing in successive exposure steps layers lying one above the other on the build platform, respectively with predetermined geometry, by controlling the exposure unit
Data Source
AI summary
A method and a device for processing light-polymerizable material for the assembly of a mold, utilizing a lithography-based generative manufacturing technique wherein a layer of a light-polymerizable material, the material being located in at least one trough (4) having a particularly light-transmissive, horizontal bottom (6), is polymerized by illumination on at least one horizontal platform (12), the platform having a prespecified geometry and projecting into a trough (4), in an illumination field, wherein the platform (12) is displaced vertically to form a subsequent layer, light-polymerizable material is then added to the most recently formed layer, and repetition of the foregoing steps leads to the layered construction of the mold in the desired form, which arises from the succession of layer geometries. The invention is characterized in that the trough (4) can be shifted horizontally to a supply position, and the supply device (8) brings light-polymerizable material at least to an illumination field of the trough bottom (6), before the at least one trough (4) is shifted to an illumination position in which the illumination field is located below the platform (12) and above the illumination unit (10), and illumination is carried out.