O. Pozo, B. Soulestin and N. Olivi‐Tran
We set up an original apparatus to measure the grain grain friction stress inside a granular medium composed of sodo‐silicate‐glass beads surrounded by a water vapor atmosphere.We…
Abstract
We set up an original apparatus to measure the grain grain friction stress inside a granular medium composed of sodo‐silicate‐glass beads surrounded by a water vapor atmosphere.We analyze here the influence of the physico chemistry of water on our glass beads and its consequences on our shear experiment. We found two scales in the analysis of the shear stress signal. On the microscopic scale of one bead, the experimental results show a dependence on the size of beads, on the shear rate and on humidity for the resulting stick slip signal. On the macroscopic scale of the whole assembly of beads, the behavior of the total amplitude of the shear stress depends on the size of the beads and is humidity dependent only for relative humidity larger than 80%. For high degrees of humidity, on the microscopic scale, water lubricates the surface of the beads leading to a decrease in the microscopic resistance to shear while on the macroscopic scale the resistance to shear is increased: the assembly of very humid grains behaves as a rheothickening fluid.
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Mohamad Nordin Mohamad Norani, Mohd Fadzli Bin Abdollah, Muhammad Ilman Hakimi Chua Abdullah, Hilmi Amiruddin, Faiz Redza Ramli and Noreffendy Tamaldin
This study aims is to investigate the correlation between tribological and mechanical properties of the fused filament fabrication 3D-printed acrylonitrile butadiene styrene (ABS…
Abstract
Purpose
This study aims is to investigate the correlation between tribological and mechanical properties of the fused filament fabrication 3D-printed acrylonitrile butadiene styrene (ABS) pin with different internal geometries.
Design/methodology/approach
The tribological properties were determined by a dry sliding test with constant test parameters, while the hardness and modulus of elasticity were determined by microhardness and compression tests.
Findings
Although the internal geometry of the pin sample slightly affects the coefficient of friction (COF) and the wear rate of the 3D-printed ABS, it was important to design a lightweight tribo-component by reducing the material used to save energy without compromising the strength of the component. The COF and wear rate values are relatively dependent on the elastic modulus. A 3D-printed ABS pin with an internal triangular flip structure was found to have the shortest run-in period and the lowest COF with high wear resistance. Abrasive wear and delamination are the predominant wear mechanisms involved.
Research limitations/implications
The findings are the subject of future research under various sliding conditions by investigating the synergistic effect of sliding speeds and applied loads to validate the results of this study.
Originality/value
The internal structure affects the mechanical properties and release stress concentration at the contact point, resulting in hypothetically low friction and wear. This approach may also reduce the weight of the parts without scarifying or at least preserving their preceding tribological performance. Therefore, based on our knowledge, limited studies have been conducted for the application of 3D printing in tribology, and most studies focused on improving their mechanical properties rather than correlating them with tribological properties that would benefit longer product lifespans.
Peer review
The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-04-2020-0143/
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Marta Igual, Juan Vicente Lopez Baldo, Purificación García-Segovia and Javier Martínez-Monzó
This study aimed to evaluate the enrichment with UD powder effects on phenols, antioxidant capacity, color, texture and extrusion parameters of extruded snacks.
Abstract
Purpose
This study aimed to evaluate the enrichment with UD powder effects on phenols, antioxidant capacity, color, texture and extrusion parameters of extruded snacks.
Design/methodology/approach
Extrudates were produced with a single-screw extruder. It operated at a 3:1 compression ratio, loaded with prepared corn samples at a constant dosing speed of 18 rpm. The screw was rotated constantly at 150 rpm and temperatures of barrel sections 1–4 were set to 25, 70, 170 and 175°C, respectively; the nozzle diameter was 3 mm.
Findings
Extrudate parameters were fitted against UD concentration and presented equations close to the experimental data, according to the obtained adjusted R2. Using UD powder in the mixture to obtain extruded corn snacks increased their phenols content and antioxidant capacity. However, high UD concentration in the mixtures caused low expansion and porous extrudates; nevertheless, it lowered possible molecular damage risk by molecules solubilized in water, making them more stable. Using 7.5% UD percentage in mixtures is recommended for extruded snacks to maintain typical extrudate characteristics. Higher UD concentration provokes more hygroscopic, dense and compact snacks.
Originality/value
These findings confirm that using U. dioica L. powder in the mixture to obtain extruded corn improves the functional value of snacks, maintaining extruded characteristics.
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Nur Hidayah Musa, Nurainaa Natasya Mazlan, Shahir Mohd Yusuf, Farah Liana Binti Mohd Redzuan, Nur Azmah Nordin and Saiful Amri Mazlan
Material extrusion (ME) is a low-cost additive manufacturing (AM) technique that is capable of producing metallic components using desktop 3D printers through a three-step…
Abstract
Purpose
Material extrusion (ME) is a low-cost additive manufacturing (AM) technique that is capable of producing metallic components using desktop 3D printers through a three-step printing, debinding and sintering process to obtain fully dense metallic parts. However, research on ME AM, specifically fused filament fabrication (FFF) of 316L SS, has mainly focused on improving densification and mechanical properties during the post-printing stage; sintering parameters. Therefore, this study aims to investigate the effect of varying processing parameters during the initial printing stage, specifically nozzle temperatures, Tn (190°C–300°C) on the relative density, porosity, microstructures and microhardness of FFF 3D printed 316L SS.
Design/methodology/approach
Cube samples (25 x 25 x 25 mm) are printed via a low-cost Artillery Sidewinder X1 3D printer using a 316L SS filament comprising of metal-polymer binder mix by varying nozzle temperatures from 190 to 300°C. All samples are subjected to thermal debinding and sintering processes. The relative density of the sintered parts is determined based on the Archimedes Principle. Microscopy and analytical methods are conducted to evaluate the microstructures and phase compositions. Vickers microhardness (HV) measurements are used to assess the mechanical property. Finally, the correlation between relative density, microstructures and hardness is also reported.
Findings
The results from this study suggest a suitable temperature range of 195°C–205°C for the successful printing of 316L SS green parts with high dimensional accuracy. On the other hand, Tn = 200°C yields the highest relative density (97.6%) and highest hardness (292HV) in the sintered part, owing to the lowest porosity content (<3%) and the combination of the finest average grain size (∼47 µm) and the presence of Cr23C6 precipitates. However, increasing Tn = 205°C results in increased porosity percentage and grain coarsening, thereby reducing the HV values. Overall, these outcomes suggest that the microstructures and properties of sintered 316L SS parts fabricated by FFF AM could be significantly influenced even by adjusting the processing parameters during the initial printing stage only.
Originality/value
This paper addresses the gap by investigating the impact of initial FFF 3D printing parameters, particularly nozzle temperature, on the microstructures and physical characteristics of sintered FFF 316L SS parts. This study provides an understanding of the correlation between nozzle temperature and various factors such as dimensional integrity, densification level, microstructure and hardness of the fabricated parts.
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Xikun Wu, Geoffrey Ginoux, Joseph Paux and Samir Allaoui
This study aims to assess the relationships between limit parametric settings of in-nozzle impregnation additive manufacturing, namely, nozzle temperature and layer height, on the…
Abstract
Purpose
This study aims to assess the relationships between limit parametric settings of in-nozzle impregnation additive manufacturing, namely, nozzle temperature and layer height, on the micromorphology and induced mechanical properties of continuous flax yarns-reinforced biocomposites.
Design/methodology/approach
The additively manufactured biocomposites with different printing parameters were characterized by X-ray microcomputed tomography and tensile testing to link the process–structure–properties relationships regarding the internal morphologies of yarns, matrix and porosities and tensile properties.
Findings
Several types of morphology were defined regarding fiber, void, raster and interfaces. The results showed a competition between porosity development, coating effect and variation in fiber volume fraction on the biocomposite quality and mechanical performance when simultaneously varying the layer height and the temperature due to rheology-related phenomena and process-induced defects.
Originality/value
To the best of the authors’ knowledge, no previous study has been carried out on the relation between the internal micromorphologies in three directions of continuous biocomposites manufactured by in-nozzle impregnation additive manufacturing and the limit printing parameters. The findings are thought to help manufacturers master this technology for high-end applications.
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Martin Novák, Berenika Hausnerova, Vladimir Pata and Daniel Sanetrnik
This study aims to enhance merging of additive manufacturing (AM) techniques with powder injection molding (PIM). In this way, the prototypes could be 3D-printed and mass…
Abstract
Purpose
This study aims to enhance merging of additive manufacturing (AM) techniques with powder injection molding (PIM). In this way, the prototypes could be 3D-printed and mass production implemented using PIM. Thus, the surface properties and mechanical performance of parts produced using powder/polymer binder feedstocks [material extrusion (MEX) and PIM] were investigated and compared with powder manufacturing based on direct metal laser sintering (DMLS).
Design/methodology/approach
PIM parts were manufactured from 17-4PH stainless steel PIM-quality powder and powder intended for powder bed fusion compounded with a recently developed environmentally benign binder. Rheological data obtained at the relevant temperatures were used to set up the process parameters of injection molding. The tensile and yield strengths as well as the strain at break were determined for PIM sintered parts and compared to those produced using MEX and DMLS. Surface properties were evaluated through a 3D scanner and analyzed with advanced statistical tools.
Findings
Advanced statistical analyses of the surface properties showed the proximity between the surfaces created via PIM and MEX. The tensile and yield strengths, as well as the strain at break, suggested that DMLS provides sintered samples with the highest strength and ductility; however, PIM parts made from environmentally benign feedstock may successfully compete with this manufacturing route.
Originality/value
This study addresses the issues connected to the merging of two environmentally efficient processing routes. The literature survey included has shown that there is so far no study comparing AM and PIM techniques systematically on the fixed part shape and dimensions using advanced statistical tools to derive the proximity of the investigated processing routes.
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Amin Barzegar, Mohammadreza Farahani and Amirreza Gomroki
Material extrusion-based additive manufacturing is a prominent manufacturing technique to fabricate complex geometrical three-dimensional (3D) parts. Despite the indisputable…
Abstract
Purpose
Material extrusion-based additive manufacturing is a prominent manufacturing technique to fabricate complex geometrical three-dimensional (3D) parts. Despite the indisputable advantages of material extrusion-based technique, the poor surface and subsurface integrity hinder the industrial application of this technology. The purpose of this study is introducing the hot air jet treatment (HAJ) technique for surface treatment of additive manufactured parts.
Design/methodology/approach
In the presented research, novel theoretical formulation and finite element models are developed to study and model the polishing mechanism of printed parts surface through the HAJ technique. The model correlates reflow material volume, layer width and layer height. The reflow material volume is a function of treatment temperature, treatment velocity and HAJ velocity. The values of reflow material volume are obtained through the finite element modeling model due to the complexity of the interactions between thermal and mechanical phenomena. The theoretical model presumptions are validated through experiments, and the results show that the treatment parameters have a significant impact on the surface characteristics, hardness and dimensional variations of the treated surface.
Findings
The results demonstrate that the average value of error between the calculated theoretical results and experimental results is 14.3%. Meanwhile, the 3D plots of Ra and Rq revealed that the maximum values of Ra and Rq reduction percentages at 255°C, 270°C, 285°C and 300°C treatment temperatures are (35.9%, 33.9%), (77.6%,76.4%), (94%, 93.8%) and (85.1%, 84%), respectively. The scanning electron microscope results illustrate three different treatment zones and the treatment-induced and manufacturing-induced entrapped air relief phenomenon. The measured results of hardness variation percentages and dimensional deviation percentages at different regimes are (8.33%, 0.19%), (10.55%, 0.31%) and (−0.27%, 0.34%), respectively.
Originality/value
While some studies have investigated the effect of the HAJ process on the structural integrity of manufactured items, there is a dearth of research on the underlying treatment mechanism, the integrity of the treated surface and the subsurface characteristics of the treated surface.