Ethylene-Vinyl Ester Polymers for 3D Printing Warpage Control
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Solution Overview
Problem
Current 3D printing technologies face challenges with semi-crystalline polymers, such as polyolefins, due to thermal gradients causing internal stresses, deformation, and poor adhesion, especially in filament-based systems, which limits the printability and processability of flexible parts.
Innovation Solution
Development of an ethylene-vinyl ester polymer-based additive-manufacture feedstock with a controlled melt flow rate, vinyl ester content, and Shore A hardness, optimized for filament extrusion in FFF technology, providing improved adhesion and dimensional accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If vinyl acetate content is increased to reduce crystallization and improve adhesion, then polarity and adhesion are improved, but hardness decreases below required levels for successful printing
Solution Approach 1:
The patent applies parameter changes by precisely controlling the vinyl ester content within a specific range (1-30 wt%) rather than simply increasing it. This optimized parameter range balances the competing requirements: sufficient vinyl ester content to provide polarity and adhesion, while limiting it to maintain hardness above 60 Shore A for successful filament-based printing.
2Strength
If semi-crystalline polymers are used for 3D printing, then material strength is improved, but thermal gradients cause internal stresses and deformation
Solution Approach 1:
The patent applies local quality by creating a polymer composition with heterogeneous structure - a semi-crystalline polyolefin base matrix with dispersed amorphous vinyl ester copolymer phases. The amorphous regions act as stress-relief zones that locally accommodate thermal expansion differences, while the crystalline matrix maintains overall structural strength, thus resolving the contradiction between strength and dimensional accuracy.
3Adaptability or versatility
If filament-based 3D printing is used for flexible parts, then soft-elastomer properties are achieved, but lack of piston effect causes buckling and printing failures
Solution Approach 1:
The patent applies composite materials by combining semi-crystalline polyolefin with amorphous vinyl ester copolymer in a blended composition. This composite structure provides the flexibility of soft-elastomers from the amorphous phases while the semi-crystalline matrix maintains sufficient rigidity to provide the necessary piston effect for reliable filament feeding and extrusion, thus enabling both flexibility and printability.
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 ethylene-vinyl ester polymer feedstock enables high consistency and accuracy in 3D printing with minimized warpage and excellent layer adhesion, overcoming the limitations of traditional polyethylene copolymers in filament-based 3D printing.
Implementation Method 1
The technology involves melting or softening the polymer materials, in the forms of filaments or pellets, to produce polymer strands
Implementation Method 2
This differential temperature combined with the temperature of the environment contribute to cooling the deposited polymer from a molten state to a solid state
Implementation Method 3
For semi-crystalline polymers, the thermal gradients induce crystallization as the material cools down and subsequently shrinks in volume
Data Source
AI summary
The invention relates to an additive-manufacture feedstock, comprising an ethylene-vinyl ester polymer having a melt flow rate of from 0.1 to 150 g/10 min (190° C./2.16 kg), measured according to ASTM D 1238, and a vinyl ester content of from about 1.0 wt % to about 30 wt %, wherein the ethylene-vinyl ester polymer exhibits a Shore A hardness of at least about 60. The pellets and filaments produced from the additive-manufacture feedstock have a high degree of printability in material-extrusion-based 3D printing technology, and can be used to produce 3D printing articles with a high consistency to the targeted 3D model and substantially no warpage. The invention also relates to methods of making the additive-manufacture feedstock and methods of 3D printing using the additive-manufacture feedstock in various forms.