PVOH Support Structure Mixture for 3D Printing
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Solution Overview
Problem
Current 3D printing processes using polyvinyl alcohol (PVOH) as a support structure face challenges with low melt flow rate and high moisture sensitivity, leading to difficulties in printing speed and filament handling, as well as reduced shelf life due to moisture absorption, resulting in poor adhesion to thermoplastic materials and uncontrolled melt release.
Innovation Solution
A mixture of at least 50% PVOH with polymers such as polyvinyl butyral, ethylene-vinylalcohol-vinylacetate terpolymer, or vinyl acetate-vinyl pyrrolidone copolymer, combined with plasticizers like trimethylolpropane or polycaprolactone, to enhance melt flow rate and adhesion while minimizing moisture uptake, allowing for faster printing and improved support structure solubility in water.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pure PVOH is used as support structure, then water solubility is good, but melt flow rate is low and moisture sensitivity is high
Solution Approach 1:
The patent uses composite materials by combining PVOH with polymers having lower polarity (such as polyvinyl butyral, polylactic acid, or ABS terpolymer). This composite approach allows the support structure to maintain water solubility from PVOH while gaining improved melt flow rate and reduced moisture sensitivity from the less polar polymer components.
Solution Approach 2:
The patent changes the chemical composition parameters of the support structure by controlling the ratio of PVOH to less polar polymer (within specific ranges to maintain solubility). It also adjusts molecular weight parameters and adds plasticizers to modify the melt flow characteristics while preserving the essential water solubility property.
2Ease of manufacture
If plasticizers are added to increase melt flow rate, then processability improves, but moisture sensitivity increases and shelf life decreases
Solution Approach 1:
The patent optimizes the plasticizer content within a specific range (0.1-20 wt%) to achieve adequate processability and melt flow rate while preventing excessive moisture uptake. It also selects plasticizers with appropriate properties and combines them with less polar polymers that have lower moisture sensitivity, thereby balancing processability with long-term stability.
3Productivity
If printing speed is increased, then productivity improves, but adhesion between thermoplastic material and support structure deteriorates
Solution Approach 1:
The composite support structure material provides optimized rheological properties that enable better adhesion to thermoplastic materials during high-speed printing. The combination of PVOH and less polar polymers creates a support structure that maintains appropriate bonding characteristics even at increased printing speeds.
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 solution significantly increases the melt flow rate and adhesion strength of the PVOH-based support structures, enabling reliable high-speed 3D printing without detachment from the support structures and extending the shelf life by reducing moisture absorption, ensuring better print quality and handling.
Implementation Method 1
PVOH is a thermoplastic material with a broad melting range which can be easily removed from the final printed structure by dissolving in water or aqueous alkaline solution
Implementation Method 2
depositing and solidifying molten polyvinyl alcohol (PVOH) to form a support structure
Data Source
AI summary
A process of manufacturing a three-dimensional object includes a step of depositing and solidifying molten polyvinyl alcohol to form a support structure; and a step of depositing and solidifying a molten thermoplastic polymer on the support structure to form a three-dimensional preform. The support structure has a mixture of at least 50% by weight of polyvinyl alcohol and at most 50% by weight of at least one polymer of polyvinyl butyral, polylactid acid, ethylene-vinylalcohol-vinylacetate terpolymer, vinyl acetate-vinyl pyrrolidone copolymer, acrylonitrile-butadiene-styrene terpolymer, polycaprolactone, vinyl acetate-vinyl caprolactame copolymer, and polyvinyl alcohol having a degree of hydrolysis DH of 30-65%. The support structure can be dissolved to form the three-dimensional object.