Dual-Material Elastomeric Filament for Buckling-Resistant 3D Printing
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Solution Overview
Problem
Conventional 3D printing with fused filament fabrication (FFF) results in mechanically weak parts, particularly when loaded parallel to the build direction (z-direction), due to insufficient time for molecular entanglement at the interface between layers, and struggles with printing soft elastomeric materials, leading to buckling, inconsistent printing, and poor cold weather toughness.
Innovation Solution
A dual material filament comprising an elastomeric and non-elastomeric component, where the non-elastomeric core stabilizes the filament during handling and printing, allowing consistent printing of soft elastomers, and the combination provides mechanical resilience at low temperatures and improved cold weather durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If soft elastomeric filament is used for printing, then the printed part achieves softness and flexibility, but the filament buckles during feeding and extrusion stops
Solution Approach 1:
The patent uses a composite filament structure with a rigid core (first material) and elastomeric sheath (second material). The rigid core provides structural support to prevent buckling during feeding, while the elastomeric sheath provides the desired softness and flexibility in the printed part. This composite structure resolves the contradiction between softness and printing reliability.
Solution Approach 2:
The filament is segmented into two distinct functional zones: a rigid core for structural support and feeding stability, and an elastomeric sheath for flexibility and softness. This segmentation allows each material to perform its optimal function without interfering with the other, enabling consistent printing of soft materials.
2Reliability
If rigid thermoplastic is used for printing, then the filament feeds consistently, but the part is mechanically weak when loaded parallel to build direction
Solution Approach 1:
The composite filament combines rigid thermoplastic core for consistent feeding with elastomeric sheath that improves interlayer bonding and mechanical strength. The elastomeric material allows for better molecular entanglement at layer interfaces, resolving the weakness in z-direction strength while maintaining feeding consistency through the rigid core.
3Manufacturing precision
If rigid thermoplastic part is used, then geometric accuracy is achieved, but cold weather toughness is poor
Solution Approach 1:
The elastomeric sheath material maintains flexibility and toughness at low temperatures, preventing brittle failure in cold weather. The rigid core maintains geometric accuracy during printing. The combination allows the part to achieve both geometric precision and cold weather durability.
4Adaptability or versatility
If soft elastomeric material is used, then flexibility is achieved, but printing precision and surface finish deteriorate
Solution Approach 1:
The rigid core provides structural support that maintains filament shape and dimensional stability during printing, enabling precise deposition and good surface finish. The elastomeric sheath provides flexibility in the final part. This composite approach allows soft materials to be printed with high precision.
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 dual material filament enables consistent printing of soft elastomers, enhances mechanical strength and stiffness, and maintains toughness at low temperatures, resulting in parts with balanced mechanical properties and improved cold weather durability.
Implementation Method 1
the non-elastomeric core stabilizes the filament during handling and printing
Implementation Method 2
the combination provides mechanical resilience at low temperatures and improved cold weather durability
Implementation Method 3
the interface between these two materials is only hot and soft for a few seconds, which is not enough time for the processes of wetting and molecular reptation necessary to form a molecularly entangled, high strength interface
Data Source
AI summary
We disclose dual filament-based flexible material extrusion which is suitable of additive manufacturing for of at least two thermoplastic elastomers. To enhance printability of a thermoplastic elastomer (TPE), a series of core-shell filaments comprising a TPE shell and a rigid core are fabricated, such as ABS with the ABS volume fraction varying from 11% to 78%, in one particular embodiment. The presence of an ABS core imparts rigidity to the filament to inhibit buckling and allow for successful high-fidelity 3D printing. Rheological characterizations of TPE and ABS using capillary and parallel-plate viscometry point to the optimized extrusion parameters suitable for filament coextrusion, printability, and wettability between the print interfaces. Printed specimens with less than 20% ABS preserve the hardness, providing flexibility and a soft touch to the printed structures. Lower ABS content exhibits higher flexibility and impact resistance, while higher ABS imparts higher stiffness and tensile strength.