scholarly journals 3D-Printed Soft Structure of Polyurethane and Magnetorheological Fluid: A Proof-of-Concept Investigation of its Stiffness Tunability

Micromachines ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 655 ◽  
Author(s):  
Seong-Woo Hong ◽  
Ji-Young Yoon ◽  
Seong-Hwan Kim ◽  
Sun-Kon Lee ◽  
Yong-Rae Kim ◽  
...  

In this study, a soft structure with its stiffness tunable by an external field is proposed. The proposed soft beam structure consists of a skin structure with channels filled with a magnetorheological fluid (MRF). Two specimens of the soft structure are fabricated by three-dimensional printing and fused deposition modeling. In the fabrication, a nozzle is used to obtain channels in the skin of the thermoplastic polyurethane, while another nozzle is used to fill MRF in the channels. The specimens are tested by using a universal tensile machine to evaluate the relationships between the load and deflection under two different conditions, without and with permanent magnets. It is empirically shown that the stiffness of the proposed soft structure can be altered by activating the magnetic field.

2021 ◽  
pp. 002199832098856
Author(s):  
Marcela Piassi Bernardo ◽  
Bruna Cristina Rodrigues da Silva ◽  
Luiz Henrique Capparelli Mattoso

Injured bone tissues can be healed with scaffolds, which could be manufactured using the fused deposition modeling (FDM) strategy. Poly(lactic acid) (PLA) is one of the most biocompatible polymers suitable for FDM, while hydroxyapatite (HA) could improve the bioactivity of scaffold due to its chemical composition. Therefore, the combination of PLA/HA can create composite filaments adequate for FDM and with high osteoconductive and osteointegration potentials. In this work, we proposed a different approache to improve the potential bioactivity of 3D printed scaffolds for bone tissue engineering by increasing the HA loading (20-30%) in the PLA composite filaments. Two routes were investigated regarding the use of solvents in the filament production. To assess the suitability of the FDM-3D printing process, and the influence of the HA content on the polymer matrix, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM) were performed. The HA phase content of the composite filaments agreed with the initial composite proportions. The wettability of the 3D printed scaffolds was also increased. It was shown a greener route for obtaining composite filaments that generate scaffolds with properties similar to those obtained by the solvent casting, with high HA content and great potential to be used as a bone graft.


2020 ◽  
Vol 64 (2) ◽  
pp. 231-234 ◽  
Author(s):  
Heechul Kim ◽  
Doyun Lee ◽  
Soo Young Lee ◽  
Hongso Yang ◽  
Sang-Won Park ◽  
...  

2020 ◽  
Vol 15 ◽  
pp. 155892502093344 ◽  
Author(s):  
Timo Grothe ◽  
Bennet Brockhagen ◽  
Jan Lukas Storck

The combination of textiles and three-dimensional printing offers a wide range of research and application areas, but only publications in combination with fused deposition modeling processes can be found so far. In this article the possibility of printing resin directly on textiles in the stereolithography process is presented. A broad spectrum of textiles and surfaces is examined to clearly present the feasibility. It was found that printing directly on most textiles can be performed without major difficulties, while problems were only observed on smooth surfaces and coatings on textiles.


2019 ◽  
Vol 30 (10) ◽  
pp. 1518-1526 ◽  
Author(s):  
Austin Smith ◽  
SM Mahdi Mofidian ◽  
Hamzeh Bardaweel

This work explores the feasibility of commercially available elastic filament and desktop fused deposition modeling three-dimensional printing as a simple and cost-effective route to develop flexible sensors. The fabricated sensor consists of a three-dimensional printed flexible substrate with embedded U-shaped channels that are filled with Galinstan (Ga 68.5% In 21.5% Sn 10%) liquid metal conductor. When the sensor is strained, the cross-sectional area of the channels decreases causing a reduction in the conducting area and, therefore, a change in resistance. First, sensors measuring approximately 2100 μm by 200 μm are fabricated. Results demonstrate gauge factors of approximately 2.1 at 38.8% strain with high linearity and little hysteresis. In addition, smaller strain sensors, measuring approximately 696 µm by 203 µm, are fabricated with gauge factors of nearly 1.0 at 13.2% strain. Results show that substrate relaxation plays an essential role in determining the functionality of these sensors. The Mullins effect largely influences the recovery properties of the rubber-like sensor substrate. This leads to a noticeable relaxation in the substrate during cyclic loading. The results demonstrate the potential of commercially available fused deposition modeling three-dimensional printing technology and filaments to produce complex designs and sensor platforms.


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