Fabrication and characterization of polycarbonate-silica filaments for 3D printing applications

2021 ◽  
pp. 002199832110447
Author(s):  
Deepa Kodali ◽  
Chibu O Umerah ◽  
Mohanad O Idrees ◽  
S Jeelani ◽  
Vijaya K Rangari

Owing to its robustness, ability to achieve complex geometries, and ease of use, 3D printing has become one of the noteworthy applications in the field of engineering. Polycarbonate has become a thermoplastic of interest due to its excellent mechanical and optical properties. Especially when infused with nanosilica, polycarbonate becomes a potential candidate for 3D printing with enhanced properties. Polycarbonate nanocomposite filaments infused with AEROSIL (nanosilica) have been melt extruded with various filler loadings of 0.5, 1, and 3 wt% and are then 3D printed. The thermal analysis of the filaments has shown that thermal stability of the filaments increases with increase in filler loading. Tensile tests have shown that addition of nanosilica have enhanced the mechanical properties of the filaments as well as 3D printed films. The addition of silica in low concentrations exhibit higher transmittance of UV light, as silica restricts the mobility of polycarbonate. Despite 3D printing causing voids in bulk materials, silica at low concentration (0.5 and 1 wt%) can improve the mechanical and optical properties. These improvements are promising for applications in thin film interfaces and the automotive industry.

2021 ◽  
Vol 11 (6) ◽  
pp. 2563
Author(s):  
Ivan Grgić ◽  
Vjekoslav Wertheimer ◽  
Mirko Karakašić ◽  
Željko Ivandić

Recent soft tissue studies have reported issues that occur during experimentation, such as the tissue slipping and rupturing during tensile loads, the lack of standard testing procedure and equipment, the necessity for existing laboratory equipment adaptation, etc. To overcome such issues and fulfil the need for the determination of the biomechanical properties of the human gracilis and the superficial third of the quadriceps tendons, 3D printed clamps with metric thread profile-based geometry were developed. The clamps’ geometry consists of a truncated pyramid pattern, which prevents the tendons from slipping and rupturing. The use of the thread application in the design of the clamp could be used in standard clamping development procedures, unlike in previously custom-made clamps. Fused deposition modeling (FDM) was used as a 3D printing technique, together with polylactic acid (PLA), which was used as a material for clamp printing. The design was confirmed and the experiments were conducted by using porcine and human tendons. The findings justify the usage of 3D printing technology for parts manufacturing in the case of tissue testing and establish independence from the existing machine clamp system, since it was possible to print clamps for each prepared specimen and thus reduce the time for experiment setup.


Author(s):  
Yujun Hou ◽  
Chun Jiang

Since the growth of single layer of Si has emerged, silicene became a potential candidate material to make up the disadvantage of graphene. In this paper, the complex surface conductivity is applied to characterize the properties of silicene and we investigate the optical characterization of silicene-dielectric interfaces from IR to far UV range. The silicene-Si and silicene-Ge interfaces along both parallel and perpendicular polarization directions of electromagnetic field with normal incidence are considered in this work. The optical properties of the silicene-dielectric systems proposed in this paper lay a foundation for the performance of complex silicene-based optoelectronic devices such as sensors, detectors, filters, UV absorbers and so on.


Author(s):  
Azar Maalouf ◽  
Ronan Gingat ◽  
Vincent Laur

This study examines K-band rectangular waveguide terminations with three-dimensional (3D)-printed loads, and proposes an Asymmetrical Tapered Wedge topology. This geometry shows a good tradeoff between microwave performance and 3D-printing issues (printing directions and support material requirements), thus improving noticeably the reproducibility of the devices. The effect of the density of the 3D-printed load on the reflection parameter of the termination was investigated. Even for a low density, reflection level remained below −27.5 dB between 18 and 26.5 GHz. Reproducibility was demonstrated by the characterization of six loads that were 3D printed under the same conditions. Measurements demonstrate that a maximum reflection parameter level of −33.5 dB can be ensured over the whole frequency band without any post-machining of the 3D-printed devices.


2021 ◽  
Vol 105 (1) ◽  
pp. 431-440
Author(s):  
Pavel Šafl ◽  
Jana Zimáková ◽  
Tomáš Binar

The aim of this work is to study the climatic influences on 3D printed materials. This study focuses on the HIPS material, which was chosen as the starting material for further studies. The material in the field of 3D printing is known for its rapid photooxidation, which results in the formation of cracks in the final product. A climatic chamber was used for degradation, in which UV light, heat and increased humidity were applied to the material. The degree of degradation was then checked by tensile test and electron microscope.


Materials ◽  
2019 ◽  
Vol 12 (16) ◽  
pp. 2520 ◽  
Author(s):  
Piotr Olesik ◽  
Marcin Godzierz ◽  
Mateusz Kozioł

Low-density polyethylene (LDPE) composites reinforced with finely powdered waste glass were identified as a potential material for 3D printed structures for use in low-duty frictional applications. A recently published 3D printing model was used to calculate the limits in the filament feed rate and printing speed. Tribological tests (pin-on-disc method) of the printed composites were performed for different print-path directions. Differential scanning calorimetry (DSC) was performed on the samples and the composites showed a higher crystallinity compared with LDPE, which partially explains the higher elastic modulus of the composites determined during static tensile tests. Using a fine glass powder as reinforcement improved the wear resistance of LDPE by 50% due to the formation of a sliding film on the sample’s surface. An evident effect of friction direction vs. the printed path direction on wear was found; which was likely related to differences in the removal of friction products from the friction area for different print-path directions. The LDPE composites with fine waste glass particles are promising materials for low-duty frictional applications and should be the subject of further research.


2018 ◽  
Vol 939 ◽  
pp. 147-152 ◽  
Author(s):  
Anil K. Bastola ◽  
Milan Paudel ◽  
Lin Li

This article delineates the characterization of the 3D printed MR elastomer through a forced vibration technique in the squeeze mode of operation. An anisotropic hybrid magnetorheological (MR) elastomer is developed via 3D printing. The 3D printed MR elastomer consists of three different materials; magnetic particles, magnetic particles carrier fluid, and an elastomer. MR fluid filaments are encapsulated layer-by-layer within the elastomer matrix using a 3D printer. When a moderately strong magnetic field is applied, the 3D printed MR elastomer changes its elastic and damping properties. The hybrid 3D printed MR elastomer also shows an anisotropic behavior when the direction of the magnetic field is changed with respect to the orientation of the printed filaments. The relative MR effect is higher when the applied magnetic field is parallel to the orientation of the printed filaments. The maximum change in the stiffness is observed to be 65.2% when a magnetic field of 500 mT is applied to the MR elastomer system. This result shows that the new method, 3D printing could produce anisotropic hybrid MR elastomers or possibly other types.


Author(s):  
Yifan Yang ◽  
Yutaka Ohtake ◽  
Hiromasa Suzuki

Abstract Making arts and crafts is an essential application of 3D printing. However, typically, 3D printers have limited resolution; thus, the perceptual quality of the result is always low, mainly when the input mesh is a relief. To address this problem using existing 3D printing technology, we only operate the shape of the input triangle mesh. To improve the perceptual quality of a 3D printed product, we propose an integrated mesh processing that comprises feature extraction, 3D print preview, feature preservation test, and shape enhancement. The proposed method can identify and enlarge features that need to be enhanced without large-scale deformation. Besides, to improve ease of use, intermediate processes are visualized via user interfaces. To evaluate the proposed method, the processed triangle meshes are 3D printed. The effectiveness of the proposed approach is confirmed by comparing photographs of the original 3D prints and the enhanced 3D prints.


Author(s):  
Rytis Mitkus ◽  
Andreas Pierou ◽  
Julia Feder ◽  
Michael Sinapius

Abstract The present study demonstrates the manufacturing and characterization of 0-3 piezoelectric composites made of up to 10 vol% of Lead Zirconate Titanate (PZT) particles and photopolymer resins. The tape-casting method was used to investigate the curing behavior, PZT loading limitations and the overall feasibility of the suspensions for 3D printing. Piezoelectric composites were 3D printed with a commercial DLP type 3D printer. As a starting point, the maximum possible vol% loading of PZT ceramic for each photopolymer resin was investigated. Five different commercially available photopolymer resins from Formlabs (Somerville, MA, US) were used. It was found that the addition of PZT particles to the photopolymer increases the time required for the photopolymer to solidify because PZT particles scatter the UV light. The approximate solidification time of each composition was measured, followed by viscosity measurements. SEM imaging of the composites showed good particle dispersion with minimum agglomeration, low particle sedimentation, but the weak bond between PZT particles and the photopolymers. Best performed material composition with 10 vol% of PZT was used for 3D printing. An attempt to shorten exposure time during printing was done by adding photoinitiator TPO. Suspensions with and without TPO were 3D printed and compared.


Polymers ◽  
2021 ◽  
Vol 13 (18) ◽  
pp. 3162
Author(s):  
Maria A. Morales ◽  
Alejandro Maranon ◽  
Camilo Hernandez ◽  
Alicia Porras

Natural filler-based composites are an environmentally friendly and potentially sustainable alternative to synthetic or plastic counterparts. Recycling polymers and using agro-industrial wastes are measures that help to achieve a circular economy. Thus, this work presents the development and characterization of a 3D printing filament based on recycled polypropylene and cocoa bean shells, which has not been explored yet. The obtained composites were thermally and physically characterized. In addition, the warping effect, mechanical, and morphological analyses were performed on 3D printed specimens. Thermal analysis exhibited decreased thermal stability when cacao bean shell (CBS) particles were added due to their lignocellulosic content. A reduction in both melting enthalpy and crystallinity percentage was identified. This is caused by the increase in the amorphous structures present in the hemicellulose and lignin of the CBS. Mechanical tests showed high dependence of the mechanical properties on the 3D printing raster angle. Tensile strength increased when a raster angle of 0° was used, compared to specimens printed at 90°, due to the load direction. Tensile strength and fracture strain were improved with CBS addition in specimens printed at 90°, and better bonding between adjacent layers was achieved. Electron microscope images identified particle fracture, filler-matrix debonding, and matrix breakage as the central failure mechanisms. These failure mechanisms are attributed to the poor interfacial bonding between the CBS particles and the matrix, which reduced the tensile properties of specimens printed at 0°. On the other hand, the printing process showed that cocoa bean shell particles reduced by 67% the characteristic warping effect of recycled polypropylene during 3D printing, which is advantageous for 3D printing applications of the rPP. Thereby, potential sustainable natural filler composite filaments for 3D printing applications with low density and low cost can be developed, adding value to agro-industrial and plastic wastes.


BioTechniques ◽  
2021 ◽  
Author(s):  
Vedika J Shenoy ◽  
Chelsea ER Edwards ◽  
Matthew E Helgeson ◽  
Megan T Valentine

3D printing holds potential as a faster, cheaper alternative compared with traditional photolithography for the fabrication of microfluidic devices by replica molding. However, the influence of printing resolution and quality on device design and performance has yet to receive detailed study. Here, we investigate the use of 3D-printed molds to create staggered herringbone mixers (SHMs) with feature sizes ranging from ∼100 to 500 μm. We provide guidelines for printer calibration to ensure accurate printing at these length scales and quantify the impacts of print variability on SHM performance. We show that SHMs produced by 3D printing generate well-mixed output streams across devices with variable heights and defects, demonstrating that 3D printing is suitable and advantageous for low-cost, high-throughput SHM manufacturing.


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