The cellular responses of human macrophages seeded on 3D printed thermoplastic polyurethane scaffold

This study has investigated the physical properties of 3D-printable shape memory thermoplastic polyurethane (SMTPU) filament and its 3D-printed sinusoidal pattern obtained by fused deposition modeling (FDM) technology. To investigate 3D filaments, thermoplastic polyurethane (TPU) and SMTPU filament were examined by conducting infrared spectroscopy, x-ray diffraction (XRD), dynamic mechanical thermal analysis (DMTA), differential scanning calorimetry (DSC) and a tensile test. Then, to examine the 3D-printed sinusoidal samples, a sinusoidal pattern was developed and 3D-printed. Those samples went through a three-step heating process: (a) untreated state; (b) 5 min heating at 70°C, cooling for 30 min at room temperature; and (c) a repeat of step 2. The results obtained by the three different heating processes of the 3D-printed sinusoidal samples were examined by XRD, DMTA, DSC and the tensile test to obtain the effect of heating or annealing on the structural and mechanical properties. The results show significant changes in structure, crystallinity and thermal and mechanical properties of SMTPU 3D-printed samples due to the heating steps. XRD showed the increase in crystallinity with heating. In DMTA, storage modulus, loss modulus and the tan σ peak position also changed for various heating steps. The DSC result showed that the Tg for different steps of the SMTPU 3D-printed sample remained almost the same at around 51°C. The tensile property of the TPU 3D-printed sinusoidal sample decreased in terms of both load and elongation with increased heating processes, while for the SMTPU 3D-printed sinusoidal sample, the load decreased but elongation increased about 2.5 times.

Download Full-text

Compressive behaviour of 3D printed thermoplastic polyurethane honeycombs with graded densities

Materials & Design ◽

10.1016/j.matdes.2018.11.019 ◽

2019 ◽

Vol 162 ◽

pp. 130-142 ◽

Cited By ~ 21

Author(s):

Simon R.G. Bates ◽

Ian R. Farrow ◽

Richard S. Trask

Keyword(s):

Thermoplastic Polyurethane ◽

Compressive Behaviour ◽

3D Printed

Download Full-text

DESIGN OF A 3D-PRINTED THREE-CLAW ROBOTIC GRIPPER END-EFFECTOR

ASEAN Engineering Journal ◽

10.11113/aej.v11.17865 ◽

2021 ◽

Vol 11 (4) ◽

pp. 70-79

Author(s):

Dino Dominic Forte Ligutan ◽

Argel Alejandro Bandala ◽

Jason Limon Española ◽

Richard Josiah Calayag Tan Ai ◽

Ryan Rhay Ponce Vicerra ◽

...

Keyword(s):

3D Printing ◽

Polylactic Acid ◽

Grip Force ◽

Thermoplastic Polyurethane ◽

Robotic Arm ◽

End Effector ◽

Design Considerations ◽

3D Printed ◽

Materials Used ◽

Metal Work

The development of a novel 3D-printed three-claw robotic gripper shall be described in this paper with the goal of incorporating various design considerations. Such considerations include the grip reliability and stability, grip force maximization, wide object grasping capability. Modularization of its components is another consideration that allows its parts to be easily machined and reusable. The design was realized by 3D printing using a combination of tough polylactic acid (PLA) material and thermoplastic polyurethane (TPU) material. In practice, additional tolerances were also considered for 3D printing of materials to compensate for possible expansion or shrinkage of the materials used to achieve the required functionality. The aim of the study is to explore the design and eventually deploy the three-claw robotic gripper to an actual robotic arm once its metal work fabrication is finished.

Download Full-text

EXPERIMENTAL INVESTIGATION AND SIMULATION OF 3D-PRINTED LATTICE STRUCTURES

Acta Polytechnica CTU Proceedings ◽

10.14311/app.2019.25.0052 ◽

2019 ◽

Vol 25 ◽

pp. 52-57

Author(s):

Eva Heiml ◽

Anna Kalteis ◽

Zoltan Major

Keyword(s):

Mechanical Performance ◽

Bulk Material ◽

Deformation Behaviour ◽

Lightweight Design ◽

Thermoplastic Polyurethane ◽

Selective Laser Sintering ◽

Structural Performance ◽

Lattice Structures ◽

3D Printed ◽

Manufacturing Techniques

Lattice structures are currently of high interest, especially for lightweight design. They generally have better structural performance per weight than parts made of bulk material. With conventional manufacturing techniques they are diﬃcult to produce, but with additive manufacturing (AM) fabricationisfeasible. To better understand their behaviour under various loading conditions two lattice structures in diﬀerent conﬁgurations were observed. For each structure three diﬀerent test specimens were designed and manufactured using selective laser sintering (SLS). To investigate the mechanical performance under large deformations the specimens were made of a thermoplastic polyurethane(TPU), which shows a hyperelastic material behaviour. Beside the experimental observations also ﬁnite element analyses (FEA) were conducted to investigate the deformation behaviour in more detail.

Download Full-text

Electrospinning on 3D Printed Polymers for Mechanically Stabilized Filter Composites

Polymers ◽

10.3390/polym11122034 ◽

2019 ◽

Vol 11 (12) ◽

pp. 2034 ◽

Cited By ~ 10

Author(s):

Tomasz Kozior ◽

Al Mamun ◽

Marah Trabelsi ◽

Martin Wortmann ◽

Sabantina Lilia ◽

...

Keyword(s):

3D Printing ◽

Thermoplastic Polyurethane ◽

High Surface ◽

Antimicrobial Properties ◽

Mechanical Damage ◽

Volume Ratio ◽

Electrospun Nanofiber ◽

Polymer Nanofiber ◽

3D Printed ◽

Nanofiber Mats

Electrospinning is a frequently used method to prepare air and water filters. Electrospun nanofiber mats can have very small pores, allowing for filtering of even the smallest particles or molecules. In addition, their high surface-to-volume ratio allows for the integration of materials which may additionally treat the filtered material through photo-degradation, possess antimicrobial properties, etc., thus enhancing their applicability. However, the fine nanofiber mats are prone to mechanical damage. Possible solutions include reinforcement by embedding them in composites or gluing them onto layers that are more mechanically stable. In a previous study, we showed that it is generally possible to stabilize electrospun nanofiber mats by 3D printing rigid polymer layers onto them. Since this procedure is not technically easy and needs some experience to avoid delamination as well as damaging the nanofiber mat by the hot nozzle, here we report on the reversed technique (i.e., first 3D printing a rigid scaffold and subsequently electrospinning the nanofiber mat on top of it). We show that, although the adhesion between both materials is insufficient in the case of a common rigid printing polymer, nanofiber mats show strong adhesion to 3D printed scaffolds from thermoplastic polyurethane (TPU). This paves the way to a second approach of combining 3D printing and electrospinning in order to prepare mechanically stable filters with a nanofibrous surface.

Download Full-text

Retracted Article: 3D printed highly flexible strain sensor based on TPU–graphene composite for feedback from high speed robotic applications

Journal of Materials Chemistry C ◽

10.1039/c8tc03423k ◽

2019 ◽

Vol 7 (16) ◽

pp. 4692-4701 ◽

Cited By ~ 13

Author(s):

Jahan Zeb Gul ◽

Memoon Sajid ◽

Kyung Hyun Choi

Keyword(s):

High Speed ◽

Thermoplastic Polyurethane ◽

Three Dimensional ◽

Strain Sensor ◽

Graphene Composite ◽

Retracted Article ◽

3D Printed ◽

Resistive Type ◽

Flexible Strain Sensor ◽

Robotic Applications

A novel, highly flexible and electrically resistive-type strain sensor with a special three-dimensional conductive network was 3D printed using a composite of conductive graphene pellets and flexible thermoplastic polyurethane (TPU) pellets.

Download Full-text

Investigating the Potential of Commercial-Grade Carbon Black-Filled TPU for the 3D Printing of Compressive Sensors

Micromachines ◽

10.3390/mi10010046 ◽

2019 ◽

Vol 10 (1) ◽

pp. 46 ◽

Cited By ~ 1

Author(s):

Claudio Manganiello ◽

David Naso ◽

Francesco Cupertino ◽

Orazio Fiume ◽

Gianluca Percoco

Keyword(s):

3D Printing ◽

Carbon Black ◽

Thermoplastic Polyurethane ◽

Hollow Structure ◽

Soft Or ◽

Commercial Grade ◽

Displacement Sensors ◽

Commercial Carbon ◽

3D Printed ◽

Mechanical Devices

The present research aims to exploit commercially available materials and machines to fabricate multilayer, topologically designed transducers, which can be embedded into mechanical devices, such as soft or rigid grippers. Preliminary tests on the possibility of fabricating 3D-printed transducers using a commercial conductive elastomeric filament, carbon black-filled thermoplastic polyurethane, are presented. The commercial carbon-filled thermoplastic polyurethane (TPU), analyzed in the present paper, has proven to be a candidate material for the production of 3D printed displacement sensors. Some limitations in fabricating the transducers from a 2.85 mm filament were found, and comparisons with 1.75 mm filaments should be conducted. Moreover, further research on the low repeatability at low displacements and the higher performance of the hollow structure, in terms of repeatability, must be carried out. To propose an approach that can very easily be reproduced, only commercial filaments are used.

Download Full-text

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

Micromachines ◽

10.3390/mi10100655 ◽

2019 ◽

Vol 10 (10) ◽

pp. 655 ◽

Cited By ~ 1

Author(s):

Seong-Woo Hong ◽

Ji-Young Yoon ◽

Seong-Hwan Kim ◽

Sun-Kon Lee ◽

Yong-Rae Kim ◽

...

Keyword(s):

Fused Deposition Modeling ◽

Permanent Magnets ◽

Thermoplastic Polyurethane ◽

Three Dimensional ◽

Magnetorheological Fluid ◽

Three Dimensional Printing ◽

Fused Deposition ◽

Deposition Modeling ◽

3D Printed ◽

Dimensional Printing

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.

Download Full-text

A shape memory alloy–actuated soft crawling robot based on adaptive differential friction and enhanced antagonistic configuration

Journal of Intelligent Material Systems and Structures ◽

10.1177/1045389x20942319 ◽

2020 ◽

Vol 31 (16) ◽

pp. 1920-1934 ◽

Cited By ~ 2

Author(s):

Chen Liang ◽

Yongquan Wang ◽

Tao Yao ◽

Botao Zhu

Keyword(s):

Shape Memory Alloy ◽

Shape Memory ◽

Stride Length ◽

Parametric Design ◽

Thermoplastic Polyurethane ◽

Interaction Mechanism ◽

Experimental Tests ◽

The Body ◽

3D Printed ◽

Miniature Robot

This article presents a soft crawling robot prototype with a simple architecture inspired by inchworms. The robot functionally integrates the torso (body) and feet in a monolithic curved structure that only needs a single shape memory alloy coil and differential friction to actuate it. A novel foot configuration is proposed, which makes the two feet, with an anti-symmetrical friction layout, can be alternately anchored, to match the contraction–recovery sequence of the body adaptively. Based on the antagonistic configuration between the shape memory alloy actuator and the elastic body, a vertically auxiliary spring was adopted to enhance the interaction mechanism. Force and kinematic analysis was undertaken, focusing on the parametric design of the special foot configuration. A miniature robot prototype was then 3D-printed (54 mm in length and 9.77 g in weight), using tailored thermoplastic polyurethane elastomer as the body material. A series of experimental tests and evaluations were carried out to assess its performance under different conditions. The results demonstrated that under appropriate actuation conditions, the compact robot prototype could accomplish a relative speed of 0.024 BL/s (with a stride length equivalent to 27% of its body length) and bear a load over five times to its own weight.

Download Full-text