3D Printed Elastomer Filaments With Tunable Anisotropic Mechanics
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Solution Overview
Problem
Current 3D printing methods struggle to create soft, flexible components with spatially varying mechanical properties, as they often rely on fillers that compromise flexibility, transparency, or processability, and lack control over nanostructure orientation, limiting their applicability in soft robotics and biomedical applications.
Innovation Solution
A high operating temperature direct ink writing (HOT-DIW) process that extrudes thermoplastic elastomers with controlled shear rates and extensional flows, followed by thermal annealing, to align nanostructures and achieve anisotropic mechanical properties, enabling the fabrication of components with tailored mechanical functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If fillers or reinforcing agents are incorporated into the polymer matrix to create anisotropic properties, then mechanical strength is improved, but flexibility and processability are compromised
Solution Approach 1:
The patent changes the processing parameters by controlling shear rate (at least 1 s−1) and draw ratio (DR>1) during extrusion to align the block copolymer nanostructures. This allows achieving anisotropic mechanical properties through processing conditions rather than adding fillers, thus maintaining the inherent flexibility and processability of the thermoplastic elastomer while obtaining the desired mechanical strength and directional properties.
2Strength
If conventional thermoplastic materials are used for 3D printing, then structural properties are adequate, but elastomeric characteristics and flexibility are lacking
Solution Approach 1:
The patent employs thermoplastic elastomers which are composite materials consisting of block copolymers with alternating hard and soft segments. The hard segments provide mechanical strength and structural properties, while the soft segments contribute elastomeric characteristics and flexibility. This composite structure at the molecular level allows the material to simultaneously achieve adequate structural properties and desirable elastomeric behavior for soft robotics and biomedical applications.
3Adaptability or versatility
If nanostructure orientation is not controlled during processing, then material properties are isotropic, but spatially varying mechanical functionality cannot be achieved
Solution Approach 1:
The patent applies local quality by creating spatially varying mechanical properties through controlled nanostructure orientation at different locations within the printed component. By manipulating shear rate and draw ratio during extrusion, the patent achieves different degrees of anisotropy in different regions, enabling tailored mechanical functionality where specific regions can be designed to be stiffer or more flexible based on the local orientation of the block copolymer nanostructures.
4Strength
If high shear rates are applied during extrusion to align nanostructures, then anisotropic mechanical properties are achieved, but energy consumption increases
Solution Approach 1:
The patent optimizes the shear rate parameter to at least 1 s−1, which is sufficient to align the block copolymer nanostructures and achieve anisotropic mechanical properties without excessively high energy consumption. This represents a balanced parameter selection that achieves the desired mechanical property control while maintaining reasonable energy efficiency in the extrusion process.
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 process allows for the creation of 3D printed components with controlled strain localization and directional mechanical responses, enhancing structural integrity and flexibility, suitable for applications like soft robotics and biomedical devices.
Implementation Method 1
causing a filament material to experience a shear rate ({dot over (γ)}) of at least 1 s−1 within a print nozzle
Implementation Method 2
The method also comprises, after extruding the filament, thermally annealing the filament
Implementation Method 3
These materials consist of block copolymers with alternating hard and soft segments that create a microphase-separated structure
Data Source
AI summary
A method for printing via a high operating temperature direct ink writing process is disclosed. The method comprises extruding a filament by causing a filament material, which includes a thermoplastic elastomer, to experience a shear rate of at least 1 s−1 within a print nozzle, increasing anisotropy by increasing a translational velocity of a print nozzle to achieve a draw ratio>1, and then annealing the filament. Also provided is a component formed via 3D printing, comprising a layer from a 3D printed filament composed of an anisotropic nanostructured thermoplastic elastomer, where at least one portion of the component has at least two macro segments arranged linearly in series or a combination of segments both in series and in parallel, where the at least two macro segments are configured to tune the mechanical functionality of the at least one portion of the component.