Influence Of Process Parameters Research Articles

Understanding the role of laser processing parameters and position-dependent heterogeneous elastocaloric effect in laser powder bed fused NiTi thin-walled structures

To reduce the driving load and enhance the heat exchange capacity and elastocaloric refrigeration efficiency, increasing interests in porous structure design and laser-based additive manufacturing (LAM) of NiTi materials with a large specific surface area have been emerging. As a type of characteristic unit of porous components, we mainly focused on the LAM process optimization and elastocaloric effect of NiTi-based thin-walled structures (TWSs) in this work. Firstly, we systemically studied the influence of laser processing parameter on the forming quality and phase transformation behavior of NiTi-based TWS samples. Results showed that high relative density (>99.0%) was inclined to be obtained in a range of 67–133 J mm−3 (laser energy density). Besides, the transformation temperatures (TTs) and enthalpy change roughly showed a positive linear relationship with the applied laser energy density. At an optimized parameter (P = 100 W and v = 1000 mm s−1), the sample exhibited a high relative density (99.88%), good dimensional accuracy, and the lowest TTs. Then, this work emphatically unveiled the position-dependence of phase transformation behavior and elastocaloric effect (eCE) in a NiTi-based TWS sample. It was found that both the TTs and enthalpy change monotonously decreased along the building direction, while the transformation strain kept an increase trend. As a result, the middle portion of the sample exhibited the largest adiabatic temperature change which reached 6.5 K at the applied stain of 4%. The variation in TTs and eCE could be attributed to the heterogeneous solidification microstructure induced by the thermal cycle nature of LAM process.

Investigation of microstructural and mechanical properties in AA2024-T351 multi-layer friction surfacing

This study on multi-layer friction surfacing (MLFS) as a process for additive manufacturing focuses on the influence of process parameters on the resulting microstructural properties for the precipitation-hardenable Al-Cu-Mg alloy AA2024. The energy input, which is determined by the process parameters, is correlated with the process temperature, which has a direct influence on the microstructure and mechanical properties. At higher process temperatures, e.g. at 450.1∘C, larger average grain sizes, i.e. 2.5 μm, were observed in the deposited material compared to lower temperatures, i.e. 1.2 μm at 380.6∘C. At the same time, hardness (109.2 HV0.1 ↔ 115.7 HV0.1) and ultimate tensile strength (360.8 MPa ↔ 423.3 MPa) were lower at higher temperatures, in particular due to a pronounced overaging. In terms of overall mechanical behavior, the interfaces between the first layer and the substrate are the weak points of MLFS, as they exhibit lower tensile strength compared to the interfaces between the layers. Within the MLFS, the interfaces have a slightly higher hardness, which can be attributed to locally smaller grains.

Supercritical enhanced atomization induced particle entrapment for continuous production of injectable micro and nano-suspensions

The production of micro- and nanosized dry powder formulations of pharmaceutical drugs by spraying methods with high yields and desired rheological characteristics is typically challenging from laboratory up to commercial scales. In this work, supercritical CO2 was used in a supercritical enhanced atomization (SEA) process as a bottom-up method to create micro- and nanoparticles, with an enhanced control over their physicochemical properties, to produce injectable aqueous suspensions of itraconazole (ITZ). The existing drying chamber design was optimized to significantly improve the SEA process product yield. Additionally, a novel set-up was integrated for the continuous production of ITZ particles directly collected in an aqueous stabilizer media by the supercritical enhanced atomization-induced particle entrapment into suspension (SEA-PES) process. To evaluate the influence of various SEA-PES processing parameters on the particle size, morphology, residual solvent, and particle collection yield of each experimental run utilising the in-house built continuous set-up, a solvent screening study followed by a design of experiments (DoE) was carried out. Based on the given output parameters, tetrahydrofuran (THF) was selected as the optimum solvent for ITZ. The best excipient/s for stabilising ITZ micro- and nanoparticles in suspension, respectively, have previously been discovered to be vitamin E TPGS (0.5% w/w) in combination with PVP K30 (0.5% w/w). Using both the SEA and SEA-PES methods, homogeneous ITZ micro- and nanosuspensions (solid content of 200 mg/g) with D50 0.23 ± 0.06 μm and 3.5 ± 0.2 μm were produced, respectively. These suspensions were stable and resuspendable after 365 days of storage at 25 °C. Finally, utilising a newly developed discriminatory dissolution method, the in vitro release characteristics of ITZ micro- and nanosuspensions were evaluated. There was no significant difference between the SEA and SEA-PES methods to generate the drug micro- and nanosuspensions, according to both solid-state and in vitro release profiles analysis. This work provides proof of concept for establishing a cost-effective experimental platform for the continuous production of injectable micro-and nanosuspensions of ITZ.

Impact Fracture Resistance of Fused Deposition Models from Polylactic Acid with Respect to Infill Density and Sample Thickness

Fused deposition modeling (FDM) is widely employed in prototyping due to its cost-effectiveness, speed, and ability to produce detailed and functional prototypes using a variety of materials. Simultaneously, consideration for the use of biodegradable polymers and a general reduction in their usage while enhancing the production of polymer-based products is at the forefront of sustainable practices and environmental consciousness. This study investigates the impact fracture resistance of FDM models fabricated from Polylactic Acid (PLA), examining the influence of infill density (50% and 100% infill) and sample thickness (2 mm, 3 mm, and 5 mm). Optical microscopy, FTIR spectroscopy, and SEM analysis of PLA filament and fractured FDM PLA surfaces in impacted samples were conducted to ascertain the influence of process parameters on impact damage and failure mechanisms. The results indicate that a 100% infill profile with a 2 mm thickness should be avoided due to unpredictable behavior under impact. Conversely, a 5 mm thickness demonstrates significantly higher durability in comparison to a 50% infill profile. Optimal impact strength is observed in samples with a 3 mm thickness, suggesting potential material savings with 50% infill without compromising mechanical properties. The findings contribute valuable insights for refining FDM parameters and advancing the understanding of material behaviors in sustainable manufacturing practices.

Influence of process parameters on tribological behavior of Hemp powder reinforced epoxy composites

Influence of process parameters on tribological behavior of Hemp powder reinforced epoxy composites

Peningkatan Kuat bentur Produk 3D Printing Fused Deposition Modeling menggunakan Filamen Polypropylene

In the world of manufacturing technology there is the latest breakthrough called 3D Printing which is based on layer manufacturing. In making products, a method of adding material in layers is used, usually called additive manufacturing. The principle used in this manufacturing process technology is layered modeling, by converting 3D data directly from computer-aided design (CAD) into a physical model. Many manufacturing technologies have been developed to make prototypes according to needs, for example FDM (Fused Deposition Modeling). Setting factors and experimental levels is an important step in maximizing the quality of research level products referring to transparent materials formed from polypropylene filaments. The factors that vary are Nozzle Temperature, Bed Temperature, Print Speed, and Layer Height. This research design uses the Taguchi method. This research uses an L9 orthogonal matrix with 3 levels. Based on the results of the research carried out, we can conclude that in the impact strength test there is an increase in the results of the impact strength test with the most influential process parameters, respectively, namely Print Speed (35mm/s), Layer Height (0.3mm), Bed Temperature (97 °C) and Nozzle Temperature (215°C) using Polypropylene filament. So the strongest impact strength test value is in experiment no. 2 with an average value of 0.03370 Joules and the weakest is in experiment no. 1 with an average value of 0.02959 Joules.

Coaxial electrospinning of polycaprolactone – A design of experiments approach

Coaxial electrospinning is a commonly used technique in pharmaceutical sciences that allows producing polymeric nano- or microfibers with core-shell structure. In addition to process parameters such as voltage and flow rate of the polymer solutions, the properties of such fibers are influenced by solution properties including the total polymer concentration and the polymer ratio between fiber core and shell. As these parameters are typically changed empirically during development of electrospinning methods, there is a lack of structured studies that determine the optimal settings for the production of homogeneous, mechanically stable fibers. Therefore, we used a design of experiments approach to systematically address the coaxial electrospinning process of polycaprolactone, a polymer for biomaterials applied to the skin, for instance in the form of patches for wound healing or the treatment of skin cancer. We set out to investigate the influence of different process parameters on the fiber morphology (diameter and size distribution) as well as their mechanical properties as these properties are decisive determinants for handling and pharmaceutical efficacy of such patches. The investigated process parameters were the polymer concentration in the electrospinning solution and the ratio of polymer between fiber core and shell. We additionally investigated the impact of the presence of the model drug hydrocortisone in the fiber core on the electrospinning outcome and the drug release. The experiments revealed that the fiber diameter increases with increasing total polymer concentration, correlating with a narrower fiber size distribution. In addition, our results show that a higher ratio of polymer content in core and shell leads to more mechanically stable fibers (higher tensile strength, higher Young’s modulus). Taken together, the results obtained in this study contribute to a better understanding of the electrospinning process of polycaprolactone.

Studying the API Distribution of Controlled Release Formulations Produced via Continuous Twin-Screw Wet Granulation: Influence of Matrix Former, Filler and Process Parameters.

Hydroxypropyl methylcellulose (HPMC) is a preferred hydrophilic matrix former for controlled release formulations produced through continuous twin-screw wet granulation. However, a non-homogeneous API distribution over sieve fractions with underdosing in the fines fraction (<150 µm) was previously reported. This could result in content uniformity issues during downstream processing. Therefore, the current study investigated the root cause of the non-homogeneous theophylline distribution. The effect of process parameters (L/S-ratio and screw configuration) and formulation parameters (matrix former and filler type) on content uniformity was studied. Next, the influence of the formulation parameters on tableting and dissolution behavior was investigated. Altering the L/S-ratio or using a more aggressive screw configuration did not result in a homogeneous API distribution over the granule sieve fractions. Using microcrystalline cellulose (MCC) as filler improved the API distribution due to its similar behavior as HPMC. As excluding HPMC or including a hydrophobic matrix former (Kollidon SR) yielded granules with a homogeneous API distribution, HPMC was identified as the root cause of the non-homogeneous API distribution. This was linked to its fast hydration and swelling (irrespective of the HPMC grade) upon addition of the granulation liquid.

Enhancing the grinding performance of RB-SiC ceramic using abrasive water jet dressed diamond grinding wheels

Reaction-bonded silicon carbide (RB-SiC) is regarded as difficult-to-machine ceramic materials with extremely high strength and hardness. The work focuses on the grinding performance evaluation of RB-SiC ground by the dressing diamond grinding wheel with AWJ. Orthogonal experiments studied the influence of processing parameters on grinding force and 3D surface roughness, with the response surface method identifying optimal parameters. Explanation of the ground surface topography and 3D surface roughness in a comprehensive manner shows that an erosion of the bonding material by micro-cutting but diamond grains are being pulled out rather than cut. Results reflect a correlation between surface topography and diamond wheel dressing. The results are of great significance for future formulating an appropriate grinding process to machine RB-SiC ceramics.

Pure niobium manufactured by Laser-Based Powder Bed Fusion: influence of process parameters and supports on as-built surface quality

Niobium (Nb) is a transition metal commonly used as an alloying element for increasing strength, toughness, corrosion resistance, and other properties of steel and superalloys. Pure Nb, however, is a very interesting metal for its excellent superconductivity. This makes it suitable for producing superconducting magnets and devices for particle acceleration systems and particle physics research (e.g., superconducting resonant cavities). In this work, the production of Nb by the Laser-Based Powder Bed Fusion (PBF-LB/M, also known as Laser Powder Bed Fusion or LPBF) process was examined. Manufacturing parameters were investigated to achieve additively manufactured parts with a relative density higher than 99.5% and showing a down-skin surface roughness in the range of 20–70 μm, depending on the inclination angle. Studies related to the limiting angle of self-supported Nb parts were also conducted, and innovative non-contact supporting structures were successfully developed. These allowed to creation of parts with very small overhang angles, without compromising the downward-facing surfaces; indeed at the same time, the as-built surface finish was improved.

Thermo-Mechanical Characterization of Metal-Polymer Friction Stir Composite Joints-A Full Factorial Design of Experiments.

With the increasing demand for lighter, more environmentally friendly, and affordable solutions in the mobility sector, designers and engineers are actively promoting the use of innovative integral dissimilar structures. In this field, friction stir-based technologies offer unique advantages compared with conventional joining technologies, such as mechanical fastening and adhesive bonding, which recently demonstrated promising results. In this study, an aluminum alloy and a glass fiber-reinforced polymer were friction stir joined in an overlap configuration. To assess the main effects, interactions, and influence of processing parameters on the mechanical strength and processing temperature of the fabricated joints, a full factorial design study with three factors and two levels was carried out. The design of experiments resulted in statistical models with excellent fit to the experimental data, enabling a thorough understanding of the influence of rotational speed, travel speed, and tool tilt angle on dissimilar metal-to-polymer friction stir composite joints. The mechanical strength of the composite joints ranged from 1708.1 ± 45.5 N to 3414.2 ± 317.1, while the processing temperature was between 203.6 ± 10.7 °C and 251.5 ± 9.7.

Plasma-Assisted N2O Oxidation (PANO) in an Industrial Direct Plasma Reactor for TOPCon Production

Plasma-Enhanced Chemical Vapor Deposition (PECVD) is an attractive tool for TOPCon production, as it enables uniformly in situ doped amorphous silicon (a-Si) and dielectric layer depositions with high throughput. However, a lean process requires in situ interfacial oxide growth in the same tool. In this work, we use Plasma-Assisted N2O Oxidation (PANO) in an industrial kHz direct plasma reactor (centrotherm c.PLASMA) to grow the oxide and deposit in situ phosphorus doped a-Si(n) as well as SiNx on asymmetric lifetime samples. Before optimization, the oxide thickness is non uniform on the wafer, and we show that it correlates with the passivation, the contact resistivity, and the doping profile in n-type TOPCon test structures. The passivation seems to benefit more from moderate in-diffusion in the case with PANO than in the case with thermal oxidation. This is probably due to enhanced field-effect passivation compensating for lower chemical passivation, which likely results from plasma-induced damage. After studying the influence of PANO process parameters on the oxide thickness and uniformity, we optimize them to obtain a non-uniformity as low as ±2% and a recombination current density down to 2.3 fA/cm² on planar wafers.

Investigation of mechanical properties of luffa fibre reinforced natural rubber composites: Implications of process parameters

Natural fiber-reinforced composite materials are highly beneficial due to their excellent strength-to-weight ratio, and the compression molding process is frequently used to prepare natural fiber composites. The primary objective of the present work is to optimize the process parameters of the compression molding method to prepare luffa fiber-reinforced natural rubber composite and investigate the influence of process parameters on mechanical properties. Pre-processing parameters, specifically oven-dry temperature and time, processing parameters such as soaking temperature, time, and compression pressure, and post-processing parameters, such as oven-dry temperature and time, were considered to optimize. Natural rubber in its latex phase is utilized as a matrix material, and luffa fiber is used as reinforcement. The Plackett-Burman screening design technique was employed to identify the impact of different processing parameters on the mechanical properties of the luffa fiber-reinforced natural rubber (LNR) composite, and based on Taguchi's design of experiments, several process parameters were utilized to create L27 orthogonal array and the mentioned composites prepared accordingly. The ASTM standard is followed while testing the composite samples to determine their density, shore A hardness, and tensile strength. The density of the composite is unaffected by the process parameters; however, the shore A hardness of the composite is significantly affected. All the processing parameters most significantly impacted the tensile strength of LNR composites. The optimized process parameters for preparing LNR composite are the pre-oven temperature of 65 °C and time of 150min, the soaking temperature of 75 °C and time of 5min, compression pressure of 1.5 MPa, and the post-oven dry temperature of 55 °C and time of 45min. LNR composite can absorb energy due to its rubber matrix, making it useful for high-impact applications.

Research on Grinding Force Prediction of Flexible Abrasive Disc Grinding Process of TC17 Titanium Alloy

Abrasive disc grinding is currently a key manufacturing process to achieve better accuracy and high-quality surfaces of TC17 components. Grinding force, which results from the friction and elastic–plastic deformation during the contact and interaction between the abrasive grains and the workpiece, is a critical parameter that represents the grinding accuracy and efficiency. In order to understand the influence factors of grinding force, the characteristics of the flexible abrasive disc grinding process were studied. Considering the contact state between the abrasive tool and the workpiece, the theoretical model of normal grinding force was established in detail, from macro- and micro-perspectives. By conducting single-factor and orthogonal grinding experiments of TC17 components, the influence of different process parameters on the normal grinding force was revealed. The normal grinding force prediction models of the abrasive disc grinding process were developed based on the Box–Behnken design (BBD) and particle swarm optimization–back propagation (PSO-BP) neural networks, respectively. The results showed that the normal grinding force was negatively correlated with the disc rotational speed, and positively correlated with the contact angle, grinding depth, and feed rate, and the interaction of the factor feed rate and grinding depth was the more influential factor. Both the BBD and PSO-BP force models had good reliability and accuracy, and the mean absolute error (MAE) and mean relative error (MRE) of the above two prediction models were 0.22 N and 0.16 N, and 13.3% and 10.9%, respectively.

3D micro/nano hydrogel structures fabricated by two-photon polymerization for biomedical applications.

Hydrogels are three-dimensional natural or synthetic cross-linked networks composed of polymer chains formed by hydrophilic monomers. Due to the ability to simulate many properties of natural extracellular matrix, hydrogels have been widely used in the biomedical field. Hydrogels can be obtained through a variety of polymerization strategies such as heating and redox. However, photochemistry is one of the most interesting methods for researchers in this field. Gelatin-methacryloyl (GelMA) inherits the biological activity of gelatin and has become one of the gold standards in the field of biomaterials. GelMA, as a photopolymerizable hydrogel precursor, can be used to fabricate 3D porous structures for biomedical applications through two-photon polymerization. We report a new formulation of GelMA-based photoresist and used it to manufacture a series of two-photon polymerization structures, with a maximum resolution less than 120nm. The influence of process parameters on 3D structures manufacturing is studied by adjusting the scanning speed, laser power, and layer spacing values in two-photon polymerization processing. In vitro biological tests show that the 3D hydrogel produced by two-photon polymerization in this paper is biocompatible and suitable for MC3T3-E1 cell.

Advancements and Applications of Friction Stir Welding: A Comprehensive Review

Friction Stir Welding (FSW) has emerged as a groundbreaking joining technique revolutionizing the field of manufacturing and engineering. This review paper provides an in-depth analysis of the evolution, principles, process parameters, advancements, challenges, and diverse applications of FSW. It discusses the fundamental mechanisms governing FSW, explores the latest developments in tool materials and designs, examines the influence of process parameters on weld quality, and highlights the innovative applications of FSW across various industries. Additionally, this paper addresses the current challenges and future prospects to further enhance the efficiency, reliability, and versatility of FSW technology. Keywords: Friction Stir Welding, Joining Techniques, Weld Quality, Process Optimization, Advanced Materials, Applications, Challenges, Future Directions.

Analysis of Coefficient of Friction of Deep-Drawing-Quality Steel Sheets Using Multi-Layer Neural Networks

This article presents the results of an analysis of the influence of friction process parameters on the coefficient of friction of steel sheets 1.0347 (DC03), 1.0338 (DC04) and 1.0312 (DC05). A special tribometer was designed and manufactured in order to simulate the friction phenomenon occurring in the blankholder area in deep drawing operations. Lubricant was supplied to the contact zone under pressure. The value of the coefficient of friction was determined under various contact pressures and lubrication conditions. Multi-layer artificial neural networks (ANNs) were used to predict the value of the coefficient of friction. The input parameters considered were the kinematic viscosity of lubricants, contact pressure, lubricant pressure, selected mechanical properties and basic surface roughness parameters of sheet metals. The value of the coefficient of friction of 1.0312 steel sheets was predicted based on the results of friction tests on 1.0347 and 1.0338 steel sheets. Many ANN models were built to find a neural network that will provide the best prediction performance. It was found that to ensure a high performance of ANN prediction, it is necessary to simultaneously take into account all the considered roughness parameters (Sa, Ssk and Sku). The predictive performance of the ‘best’ network was greater than R2 = 0.98. The lubricant pressure had the greatest impact on the coefficient of friction. Increasing the value of this parameter reduces the value of the coefficient of friction. However, the greater the contact pressure, the smaller the beneficial effect of pressure-assisted lubrication. The third parameter of the friction process, the kinematic viscosity of the oil, exhibited the smallest impact on the coefficient of friction.

Influence of processing parameters on the resin pocket geometry of smart composites embedded with Fiber Bragg Grating sensor and its fast prediction

AbstractSmart composites embedded with Fiber Bragg Grating (FBG) sensors are getting increasingly popular in aircraft structures due to their self‐sensing and monitoring capability. However, a resin pocket around the FBG sensor would be formed in the manufacturing process, which strongly impacts the mechanical properties of the composite host. Therefore, the influence of primary processing parameters (FBG orientation angle, preforming temperature, and preforming pressure) on the formation of resin pockets was investigated in this work. It is found that there is a sinusoidal relation between the resin pocket geometry and the FBG orientation angle. A negative linear relation is noted between the resin pocket geometry and the preforming temperature and pressure. A prediction model based on the backpropagation neural network (BPNN) was established, which was able to quickly and accurately predict resin pocket geometry subjected to given processing parameters. This work provides useful guidance for the processing control of smart composites embedded with FBG sensors.Highlights Resin pocket geometry was formed primarily in the preforming stage. Effect of processing parameters on resin pocket geometry was characterized. A BPNN model was established for the fast prediction of resin pocket geometry.

Preparation and Characterization of Calcium Hydroxide from Cockle Shell Waste via Sol-Gel Method: Effect of HCl Concentration

Continuous cockle shell dumping in open areas has become a global problem which generate major environmental issues. The conversion of the wastes into value-added products is highly desirable and economic. This work aimed to investigate the influence of sol-gel processing parameter on the properties of the synthesized calcium hydroxide (Ca(OH)2). In this study, cockle shell waste was used as calcium carbonate (CaCO3) precursor in the preparation of Ca(OH)2 via sol-gel method and the processing parameter varied was hydrochloric acid (HCl) concentration (0.5, 1.0 and 2.0 M). The cockle shell based CaCO3 and the prepared Ca(OH)2 powders were characterized by X-ray diffraction (XRD), Fourier transform infra-Red (FTIR), field emission scanning electron microscopy with energy dispersive X-ray (FESEM-EDX), X-ray fluorescent (XRF) and particle size analyzer (PSA). The XRD analysis indicates that the calcium carbonate obtained from cockle shell was mainly in the form of aragonite polymorph. Upon sol-gel processing, the analysis of the sample shows the presence of portlandite and small traces of aragonite in all samples suggesting an incomplete reaction of the hydrolysis process. Ca(OH)2 powder prepared using 1M HCl yields the smallest particle size.

Electron beam powder bed fusion of Ti-6Al-2Sn-4Zr-2Mo lattice structures: morphometrical and mechanical characterisations

Metallic light and complex structures, such as lattice, made by Ti-6Al-2Sn-4Zr-2Mo (Ti6242) have potential applications in many different industries, especially in light and high-temperature-resistant aerospace and aeronautical components. An advantage of the electron beam powder bed fusion (PBF-EB) process over conventional and other additive manufacturing processes is the ability to fabricate lattice structures easily. However, the control of the effect of the manufacturing process for fabricating such small features is central to define the structure’s mechanical properties. This work investigates the effects of PBF-EB parameters on the geometrical quality of Ti6242 lattice structures. The selected cell consists of 12 rhombic areas connected by 24 struts joined in 12 vertices. The structures were produced in two cell sizes and two strut diameters under nine different process sets. X-ray computed tomography and scanning electron microscopy analyses were used to characterise the morphometrical parameters of each as-built cell and the interlayer integrity of the struts. Evolution under compressive loads was used to determine the mechanical properties of the lattice structures and the failure mechanism underlying the influence of process parameters on the mechanical properties. The as-built Ti6242 lattices were well-formed without voids and cracks. The outcomes revealed a significant effect of the considered lattice structure and process setup on the morphometric parameters. Even minor variations of the main processing parameters considerably impacted the mechanical properties of the structure.