Occluding Fluids in Additive Manufacturing Vat
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Solution Overview
Problem
Current 3D printing methods using SLA and vat DLP face issues such as excessive resin usage, resin aging, part distortion due to monomer swelling, difficulty in printing soft materials, and incompatibility with certain fluids like aqueous or small molecule alcohol-based fluids, leading to inefficiencies and increased costs.
Innovation Solution
The use of occluding fluids, either high-density z-fluids or low-density a-fluids, which displace resin in the vat, reducing the amount of resin needed, increasing resin refresh rate, decreasing resin aging, and minimizing the need for support structures, while being compatible with various additive manufacturing chemistries and suitable for printing soft materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If top-down or bottom-up printing methods are used with excess resin in the vat, then the part can be printed, but 80-90% of the resin remains unreacted leading to increased cost and resin aging
Solution Approach 1:
The patent extracts the harmful excess resin from the printing system by introducing an occluding fluid that selectively removes unreacted resin from the vat after printing, leaving only the cured part. This resolves the contradiction by eliminating the waste resin that causes aging and cost issues while maintaining the printing process.
Solution Approach 2:
The patent changes the density parameter of the fluid in the vat by introducing an occluding fluid with different density than the resin. This density difference enables the occluding fluid to float above or sink below the resin, creating distinct layers that allow selective removal of excess resin without affecting the cured part.
2Stability of the object's composition
If high monomer content resin is used in top-down or bottom-up systems, then the resin can flow easily, but the printed part becomes submerged in unreacted resin causing monomer swelling and part distortion
Solution Approach 1:
The occluding fluid extracts the harmful unreacted monomer resin from around the printed part, preventing it from causing swelling and distortion. The occluding fluid creates a barrier that removes excess monomers while leaving the cured part intact and stable.
3Strength
If soft materials are printed without occluding fluid, then the material can be deposited, but the initial printed state is too weak to support its own weight causing collapse
Solution Approach 1:
The occluding fluid provides buoyant support that counteracts the weight of soft printed materials. This buoyant force prevents collapse of weak initial prints by providing upward support equal to the weight of the displaced fluid, allowing soft materials to be printed without requiring excessive support structures.
4Ease of operation
If aqueous or small molecule alcohol based fluids are used in resin vats, then the fluid can be easily handled, but the solvent volatilizes leading to densification and increased viscosity
Solution Approach 1:
The patent changes the volatility parameter by selecting occluding fluids with low vapor pressure and high boiling points, such as perfluorinated fluids or long-chain alcohols. This prevents volatilization and the associated densification and viscosity increases that occur with more volatile solvents like water or small alcohols.
5Ease of operation
If aqueous or small molecule alcohol based fluids are used in resin vats, then the fluid can be easily handled, but the solvent interpolates into the printing resin causing resin inversion
Solution Approach 1:
The patent applies local quality by selecting occluding fluids with specific chemical properties (low polarity, low solubility in resin) that create a stable interface with the printing resin. This prevents interpolation and inversion at the interface while maintaining ease of handling.
Solution Approach 2:
The patent uses composite fluid systems where the occluding fluid is specifically selected to be chemically incompatible with the resin in a controlled way - immiscible yet stable. This composite arrangement prevents unwanted interpolation while maintaining system reliability.
6Ease of operation
If aqueous or small molecule alcohol based fluids are used in resin vats, then the fluid can be easily handled, but the solvent reacts with nucleophiles such as isocyanates in the printing resin
Solution Approach 1:
The patent creates a chemically inert environment by selecting occluding fluids that do not react with nucleophilic groups in the resin. Perfluorinated fluids and other inert occluding fluids are used to prevent unwanted chemical reactions while maintaining ease of handling.
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 significantly reduces resin usage by up to 95%, decreases post-processing time, and extends the shelf-life of the resin, enabling the printing of complex and soft materials with improved part stability and reduced distortion.
Implementation Method 1
Some embodiments include a method for producing a three-dimensional object, comprising: (i) placing a liquid polymer resin and at least one occluding fluid in a vat
Implementation Method 2
SLA and vat DLP use light to cause liquid resin to solidify into polymerized objects
Implementation Method 3
Another problem that may be encountered is that the printing of soft materials is often difficult because the initial printed state of the soft material is too weak to support its own weight
Data Source
AI summary
The present disclosure relates to the use of occluding fluids, such as a high-density fluid (a “z-fluid”) or a low-density fluid (an “a-fluid”), to displace resin within a vat during 3D printing. Further, an a-fluid may act as a protective boundary for a 3D printing resin wherein the a-fluid sits on top of the printing resin. Another embodiment of the disclosure provides a process of assessing which regions of a computer-aided design (CAD) model take advantage of a buoying force supplied by the occluding fluid, such that fewer support structures are needed for printing a final CAD model compared to printing the CAD model without the occluding fluid.