scholarly journals COLOROMETRIC ANALYSIS OF CHANGES IN POWDER BASED ON POLYAMIDE-12 IN THE PROCESS OF 3D PRINTING

2020 ◽  
Author(s):  
N.Ya. Mokshina ◽  
V.V. Khripushin ◽  
A.S. Efimov ◽  
N.D. Morozov
Keyword(s):  
3D Printing ◽  
Polyamide 12

scholarly journals Polyamide 12/Multiwalled Carbon Nanotube and Carbon Black Nanocomposites Manufactured by 3D Printing Fused Filament Fabrication: A Comparison of the Electrical, Thermoelectric, and Mechanical Properties

2021 ◽  
Vol 7 (2) ◽  
pp. 38
Author(s):  
Nectarios Vidakis ◽  
Markos Petousis ◽  
Lazaros Tzounis ◽  
Emmanuel Velidakis ◽  
Nikolaos Mountakis ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
3D Printing ◽  
Carbon Black ◽  
Large Scale ◽  
Fracture Mechanisms ◽  
Fused Filament Fabrication ◽  
Melt Mixing ◽  
Multiwalled Carbon ◽  
Electrically Conductive ◽  
Polyamide 12

In this study, nanocomposites with polyamide 12 (PA12) as the polymer matrix and multiwalled carbon nanotubes (MWCNTs) and carbon black (CB) at different loadings (2.5, 5.0, and 10.0 wt.%) as fillers, were produced in 3D printing filament form by melt mixing extrusion process. The filament was then used to build specimens with the fused filament fabrication (FFF) three-dimensional (3D) printing process. The aim was to produce by FFF 3D printing, electrically conductive and thermoelectric functional specimens with enhanced mechanical properties. All nanocomposites’ samples were electrically conductive at filler loadings above the electrical percolation threshold. The highest thermoelectric performance was obtained for the PA12/CNT nanocomposite at 10.0 wt.%. The static tensile and flexural mechanical properties, as well as the Charpy’s impact and Vickers microhardness, were determined. The highest improvement in mechanical properties was observed for the PA12/CNT nanocomposites at 5.0 wt.% filler loading. The fracture mechanisms were identified by fractographic analyses of scanning electron microscopy (SEM) images acquired from fractured surfaces of tensile tested specimens. The nanocomposites produced could find a variety of applications such as; 3D-printed organic thermoelectric materials for plausible large-scale thermal energy harvesting applications, resistors for flexible circuitry, and piezoresistive sensors for strain sensing.

Colorometric study of polyamide-12 powder aging

2020 ◽  
Vol 86 (10) ◽  
pp. 31-35
Author(s):  
N. Ya. Mokshina ◽  
V. V. Khripushin ◽  
M. S. Shcherbakova
Keyword(s):  
3D Printing ◽  
Selective Laser Sintering ◽  
Colorimetric Method ◽  
Critical Factor ◽  
Thermal Exposure ◽  
Practical Experience ◽  
Laser Sintering ◽  
Computer Processing ◽  
Polyamide 12 ◽  
Long Term Storage

The key point of 3D printing by selective laser sintering is the necessity of complete filling of the working chamber of the printer with a powder material. Since the powder is not completely consumed during the printing process, 25 – 30 wt.% of secondary (unused in the previous cycle) power is added to the primary material in each cycle. Repeated recirculation leads to degradation of the properties of the working powder mixture and increases the probability of rejects. We present the results of a colorimetric study of aging of polyamide-12 powder used in 3D printing by the method of selective laser sintering. Scanning and computer processing of digital images of primary and secondary polyamide powders obtained by colorimetry were performed using MathLab program package. Colorimetric analysis included the expression of the sample color using the parameters of color models applied in digital technologies for synthesizing colored images. The number of cycles before the onset of intensive destruction is no more than three, which is consistent with the practical experience in printing by selective laser sintering. The results characterizing change in the color of the secondary powder depending on the duration of thermal exposure and the gas medium are presented. It is shown that long-term storage of the powder for subsequent use is not advisable, since the initiators of destruction are already present in the material. Thermal oxidative destruction is shown to be a critical factor limiting the use of secondary powder along with changes in the crystallinity and fractional composition of particles. Computer processing of images of polymer powder obtained by the colorimetric method can be used to control the aging process of consumables and to predict the probability of rejections in 3D printing.

scholarly journals Poly(ethylene terephthalate) Powder—A Versatile Material for Additive Manufacturing

Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2041 ◽  
Author(s):  
Hao Gu ◽  
Fayez AlFayez ◽  
Toseef Ahmed ◽  
Zahir Bashir
Keyword(s):  
Mechanical Properties ◽  
Molecular Weight ◽  
3D Printing ◽  
Injection Molding ◽  
Ethylene Terephthalate ◽  
Detailed Comparison ◽  
Processing Parameters ◽  
Polyamide 12 ◽  
Poly Ethylene Terephthalate ◽  
Poly Ethylene

The 3D printing of articles by the effect of a directed laser beam on a plastic powder is a demanding process, and unlike injection molding, very few polymers work well enough with it. Recently, we reported that poly(ethylene terephthalate) (PET) powder has intrinsically good properties for 3D printing. Basic mechanical properties were shown earlier and it was demonstrated that unfused but heat-exposed PET powder does not degrade quickly allowing good re-use potential. In this work, we conducted a detailed comparison of the mechanical properties of PET and polyamide 12 from different build orientations. PET powders with two different molecular weights were used. With the high molecular weight powder, the processing parameters were optimized, and the printed bars showed little difference between the different orientations, which means there is low anisotropy in mechanical properties of built parts. Based on processing experience of the first powder, the second powder with a lower molecular weight was also very printable and complex parts were made with ease from the initial printing trials; since the process parameters were not optimized then, lower mechanical properties were obtained. While the intrinsic material properties of PET (melting and re-crystallization kinetics) are not the best for injection molding, PET is eminently suitable for powder bed fusion.

scholarly journals 3D Printing of Polymeric Multi-Layer Micro-Perforated Panels for Tunable Wideband Sound Absorption

Polymers ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 360 ◽  
Author(s):  
Yang ◽  
Bai ◽  
Zhu ◽  
Kiran ◽  
An ◽  
...  
Keyword(s):  
3D Printing ◽  
Sound Absorption ◽  
Selective Laser Sintering ◽  
Single Layer ◽  
Noise Pollution ◽  
Optimization Method ◽  
Absorption Coefficients ◽  
Absorption Frequency ◽  
Polyamide 12 ◽  
Subtractive Manufacturing

The increasing concern about noise pollution has accelerated the development of acoustic absorption and damping devices. However, conventional subtractive manufacturing can only fabricate absorption devices with simple geometric shapes that are unable to achieve high absorption coefficients in wide frequency ranges. In this paper, novel multi-layer micro-perforated panels (MPPs) with tunable wideband absorption are designed and fabricated by 3D printing or additive manufacturing. Selective laser sintering (SLS), which is an advanced powder-based 3D printing technique, is newly introduced for MPP manufacturing with polyamide 12 as the feedstock. The acoustic performances of the MPPs are investigated by theoretical, numerical, and experimental methods. The results reveal that the absorption frequency bandwidths of the structures are wider than those of conventional single-layer MPPs, while the absorption coefficients remain comparable or even higher. The frequency ranges can be tuned by varying the air gap distances and the inter-layer distances. Furthermore, an optimization method is introduced for structural designs of MPPs with the most effective sound absorption performances in the target frequency ranges. This study reveals the potential of 3D printing to fabricate acoustic devices with effective tunable sound absorption behaviors and provides an optimization method for future structural design of the wideband sound absorption devices.

3D Printing of a Robust Polyamide‐12‐Carbon Black Composite via Selective Laser Sintering: Thermal and Electrical Conductivity

2019 ◽  
Vol 304 (4) ◽  
pp. 1800718 ◽  
Author(s):  
Alejandro H. Espera ◽  
Arnaldo D. Valino ◽  
Jerome O. Palaganas ◽  
Lucio Souza ◽  
Qiyi Chen ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
3D Printing ◽  
Carbon Black ◽  
Selective Laser Sintering ◽  
Laser Sintering ◽  
Polyamide 12

Comparative study on 3D printing of polyamide 12 by selective laser sintering and multi jet fusion

2021 ◽  
Vol 288 ◽  
pp. 116882 ◽  
Author(s):  
Chao Cai ◽  
Wei Shian Tey ◽  
Jiayao Chen ◽  
Wei Zhu ◽  
Xingjian Liu ◽  
...  
Keyword(s):  
3D Printing ◽  
Comparative Study ◽  
Selective Laser Sintering ◽  
Laser Sintering ◽  
Polyamide 12

scholarly journals Sustainable Additive Manufacturing: Mechanical Response of Polyamide 12 over Multiple Recycling Processes

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 466
Author(s):  
Nectarios Vidakis ◽  
Markos Petousis ◽  
Lazaros Tzounis ◽  
Athena Maniadi ◽  
Emmanouil Velidakis ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
3D Printing ◽  
Mechanical Response ◽  
Positive Impact ◽  
Mechanical And Thermal Properties ◽  
Fused Filament Fabrication ◽  
Thermomechanical Process ◽  
Polyamide 12 ◽  
3D Printed ◽  
Multiple Recycling

Plastic waste reduction and recycling through circular use has been critical nowadays, since there is an increasing demand for the production of plastic components based on different polymeric matrices in various applications. The most commonly used recycling procedure, especially for thermoplastic materials, is based on thermomechanical process protocols that could significantly alter the polymers’ macromolecular structure and physicochemical properties. The study at hand focuses on recycling of polyamide 12 (PA12) filament, through extrusion melting over multiple recycling courses, giving insight for its effect on the mechanical and thermal properties of Fused Filament Fabrication (FFF) manufactured specimens throughout the recycling courses. Three-dimensional (3D) FFF printed specimens were produced from virgin as well as recycled PA12 filament, while they have been experimentally tested further for their tensile, flexural, impact and micro-hardness mechanical properties. A thorough thermal and morphological analysis was also performed on all the 3D printed samples. The results of this study demonstrate that PA12 can be successfully recycled for a certain number of courses and could be utilized in 3D printing, while exhibiting improved mechanical properties when compared to virgin material for a certain number of recycling repetitions. From this work, it can be deduced that PA12 can be a viable option for circular use and 3D printing, offering an overall positive impact on recycling, while realizing 3D printed components using recycled filaments with enhanced mechanical and thermal stability.

Michael Pawlyn: Push the limits of 3D printing

Nature ◽  
2013 ◽  
Vol 494 (7436) ◽  
pp. 174-174 ◽  
Author(s):  
Michael Pawlyn
Keyword(s):  
3D Printing
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