Set Of Process Parameters Research Articles

A novel method of water bath heating assisted small ball-end magnetorheological polishing for hemispherical shell resonators

Hemispherical shell resonator (HSR) is the core component of hemispherical resonator gyro. It is a ψ-shaped small-bore complex component with minimum curvature radius less than 3 mm. Thus, traditional polishing methods are difficult to polish it. Small ball-end magnetorheological polishing method can polish the small components with complicated three-dimensional surface and obtain non-destructive surface. Therefore, this method is suitable for polishing HSR. However, the material removal rate of the ordinary small ball-end magnetorheological polishing is low, leading to long polishing time and low output of HSR. To solve this problem, a water bath heating assisted small ball-end magnetorheological polishing method is proposed in this research. The influence rule of processing parameters on the material removal rate is studied experimentally. A set of optimal processing parameters is obtained to maximize the material removal rate. Compared with the ordinary method, the material removal rate of the new method can be improved by 143%. Subsequently, an HSR is polished by the new method. The results show that the polishing time can be reduced by 55%, and the polished surface roughness can reach 7.7 nm. The new method has the great potential to be used in actual production to improve the polishing efficiency of HSR.

Optimization of precision molding process parameters of viscoelastic materials based on BP neural network improved by genetic algorithm

Micro-structured optical components (MOC) are popular due to their unique optical and mechanical properties. Glass molding processing (GMP) is currently the main method of MOC manufacturing. In GMP, the process parameters determine the efficiency and quality of the glass processing. However, the optimization of their multi-objective molding process parameters has not been studied comprehensively enough. In this paper, a thermocompression model of a viscoelastic material and a mold is developed using coupled thermal-structural analysis in Abaqus. In addition, the data was analyzed to investigate the influence of process parameters on GMP performance. Then, a BP neural network model was built, and the model was trained and tested. A prediction model that can reasonably reveal the relationship between the process parameters and the molding effect was obtained. A multi-objective optimization algorithm GA was used to optimize the design of the hot-pressing process parameters. At last, a set of process parameters with the best forming effect was obtained. This study provides valuable insights into optimizing glass molding process parameters for practical production.

Research on warping optimization of automobile mesh based on artificial intelligence algorithm

Automobile mesh is a typical large plastic part prone to warping deformation in the manufacturing process, which seriously affects the quality of products. The traditional method is to find the optimal combination parameters to reduce warping deformation in the forming process through repeated trial or mold flow analysis with high cost. In this study, An optimization method based on an artificial intelligence algorithm is proposed to optimize the warping deformation of the automobile mesh. In the optimization method, artificial intelligence regression algorithm-support vector machine regression was used to establish the nonlinear function relationship (prediction function) between the molding process parameters and the warpage of automobile mesh, and the performance of the prediction function was optimized by a genetic algorithm. The optimized prediction function was taken as the fitness function, the warping value was regarded as the fitness value, and genetic algorithm is used again to obtain a set of optimal process parameters and minimum warpage values. Finally, the reliability of the optimization method is verified by the modal flow analysis software.

Assessing the wear performance of 3D printed polylactic acid polymer parts

Three-dimensional (3D) printing technology is an advanced manufacturing method used for the rapid manufacturing of functional products in industrial and biomedical fields. The study aims to evaluate the wear rate of the polylactic acid polymer by determining the optimum parameters for 3D printing. The process parameters were chosen, such as extrusion temperature, fill density, and nozzle speed. Taguchi L9 array was used to frame experiments and optimized the parameters to achieve the minimum wear rate. The samples were printed using the fused deposition modeling (FDM™) technique, also known as fused filament fabrication (FFF), and the wear rate was measured using a pin-on-disc apparatus. From work, it was concluded that the fill density significantly affected the wear rate, followed by extrusion temperature and nozzle speed. At a fill density of 100% and an extrusion temperature of 220 °C, the nozzle speed at 40 mm/s was the optimum set of process parameters.

Fracture analysis of friction stir spot welded acrylonitrile butadiene styrene sheet in butt configuration

The friction stir spot welding (FSSW) process is a novel technique that overcomes the limitation of resistance spot welding. Recently, FSSW used for welding of polymers which are difficult to be joined by traditional welding processes. The demand for Acrylonitrile Butadiene Styrene (ABS) for industrial applications has increased in recent years. However, to employ this technique the challenge is to get optimal FSSW parameters setting to achieve the best weld strength during the welding of ABS sheets. To achieve this, in the present work, full factorial experimental design layout was employed to investigate the effect of process parameters on weld strength i.e., ultimate tensile strength (UTS) and percentage elongation during FSSW of ABS-ABS sheet in butt configuration. To predict the UTS and percentage elongation, machine learning regression namely, linear, polynomial, support vector machine, and decision tree was used. Further, the study includes the identification of the fracture patterns post tensile test specimens based on the topography of the fracture surface under scanning electron microscopy. It was found that plunge depth is the most significant parameter followed by spindle speed and dwell time. The optimal setting of process parameters i.e., spindle speed of 1000 rpm, plunge depth of 1 mm, and dwell time of 40 s resulted in maximum UTS of 7.849 MPa. The maximum value of percentage elongation obtained was 5 at the parameter setting of spindle speed of 1000 rpm, plunge depth of 0.8 mm, and dwell time of 40 s. Polynomial regression outperformed in the prediction of UTS and percentage elongation with an R-square of 0.99.

Electron beam powder bed fusion processing of 2507 super duplex stainless steel. as-built phase composition and microstructural properties

This study focuses on adapting the Electron Beam Powder Bed Fusion (E-PBF) process for the manufacturing of parts from 2507 super duplex stainless steel, combining high strength and corrosion resistance, therefore presenting an interesting choice for E-PBF implementation. Samples manufactured using four sets of process parameters were characterized by scanning electron microscopy, tensile testing, X-ray diffraction analysis, energy dispersive X-ray spectroscopy and nanoindentation. The different E-PBF process temperatures investigated had the strongest influence on the phase characteristics and the resulting microstructure. The processability of the material was good, and high productivity rates were achieved, indicating good suitability for industrial transfer.

Experimental investigation on microhardness, surface roughness, and white layer thickness of dry EDM

In this research, the environment-friendly dry electrical discharge machining (EDM) process is investigated to improve the microhardness, surface finish, and white layer thickness of the machined surfaces using graphite-argon gas as a dielectric medium. The graphite powder, mixed with compressed argon gas, has been used to replace the existing dielectric medium in the EDM process. Gas pressure, discharge current, pulse width, and gap voltage were working as input parameters to reduce surface roughness and enhance the microhardness and white layer thickness. The Taguchi L16 orthogonal array is applied to the design and analysis of the experimental results. The minimum surface roughness (2.23 μm) of the HN31 steel has been attained by increasing the gas pressure up to 1.0 MPa and the minimum values of pulse width (40 μs), gap voltage (40 V), and discharge current (6 A). The maximum microhardness (501.04 HV) has been obtained at 1.2 MPa of gas pressure, 120 μs of pulse width, 60 V of gap voltage, and 18 A of discharge current. The maximum white layer thickness (16.24 μm) is achieved by the maximum values of gas pressure (1.2 MPa), pulse width (160 μs), gap voltage (70 V) and discharge current (18 A). The SEM analysis had been done to reveal the white recast layer thickness and surface roughness of the machined surfaces of the dry EDM process. The SR is increased by the recast layer, pores, and microcracks on the machined surfaces. Finally, the multi-criteria optimization technique: Weight Product Method (WPM) is applied to predict optimum process parameter settings: GP: 1.2 MPa, PW: 120 μs, GV: 50 V, and DC: 18 A to meet the best machining performances (MH = 493.32 HV, WLT = 14.28 μm, and SR = 3.82 μm). The validation tests were done to confirm the predicted results obtained by both the Taguchi and WSM methods.

Fabrication of through-holes of different shapes using foil tool in EDM: Process development and analysis

The use of a foil tool in the electrodischarge machining (EDM) process has been shown to be effective for slicing, fabrication of micro slots, and various other applications. EDM with a foil tool has an advantage over wire-EDM as it allows the use of a foil tool with a thickness less than the wire diameter and to use higher discharge current due to the no risk of tool breakage. This work attempted to fabricate through-holes of various shapes on the D2 steel plate by removing material only from the periphery using a Cu foil tool, rather than the entire cross-sectional area. The thin foil tools are brought into respective shapes by wrapping them around Cu blocks having a cross-sectional area of the respective shapes. Gravity assistance is preferred to be employed as it has been experimentally found that it improves the linear material removal rate (LMRR) up to 24.86% compared to EDM without gravity assistance at various discharge current levels and pulse on time. Further, for a gravity-assisted EDM process using the foil tool, the LMRR has been improved up to 54.43%, with a selection of suitable duty cycle settings. The set of process parameters with the highest LMRR was chosen to fabricate through holes of circular, elliptical, square, and triangular cross-sections. The time required to machine through holes of various shapes was found to be proportional to the perimeter of the cross-section.

Microstructure and wear behavior of arc-shaped 40CrNiMo steel after laser hardening

This study focuses on arc-shaped 40CrNiMo steel; the microstructure characteristics and formation mechanism of the hardened layer at different positions were investigated after laser hardening. Moreover, sliding friction experiments were conducted against GCr15 steel after the conventional heat treatment under dry friction conditions, and the wear characteristics of 40CrNiMo steel hardened after different laser process parameters was analyzed, the wear mechanism in different wear stages was studied. The results show that the martensite reliefs within different austenite grains have no effect on each other. The martensite relief within each individual austenite grain is closely related to the martensite growth in that grain. The laser hardening process parameters for obtaining the effective wear resistance performance of arc-shaped 40CrNiMo steel are as follows: the power was 2010 W, the spot size was 1 × 14 mm2 and the scanning speed was 800 mm/min. At the beginning of the friction wear tests, the wear type of arc-shaped 40CrNiMo steel is mainly abrasive wear. Abrasive wear causes spalling, and oxidation wear can easily occur at the peeling sites. As the dry friction wear tests continued, both oxidation wear and adhesive wear increased, and fatigue wear gradually occurred. The wear mechanism of the grinding plate with a similar hardness at different stages is similar to that of the circular-arc specimen.

Microstructure, Mechanical Properties, and Thermal Stability of Al-Al2O3 Nanocomposites Consolidated by ECAP or SPS from Milled Powders

Ultrafine-grained Al matrix nanocomposites, reinforced with Al2O3 nanoparticles, were produced from milled powders, either by equal channel angular pressing (ECAP), at room or high temperature, with or without back pressure, or by spark plasma sintering (SPS). Their microstructures, mechanical properties (compression, hardness, and sliding wear), and thermal stabilities (thermally induced softening and cracking) were compared, and the advantages and limitations of each process discussed on a scientific but also practical point of view. For the most successful set of process parameters, the yield stress in compression reached 380 MPa, the hardness, HV = 139, remained stable up to 500 °C, and the resistance to sliding wear was comparable to that of Al 5083, and better than that of Al 7075-T6. While the samples consolidated at high temperatures (by ECAP or SPS) showed a good thermal stability, those consolidated by ECAP at room temperature were prone to thermally induced softening and cracking, which was related to trapped and pressurized gases.

Optimization of Process Parameters for Carbon Fiber Reinforced Polyamide 6 Composites Fabricated by Self-Resistance Electric Heating Technology.

As an energy-saving and efficient composites-forming technology, the properties of carbon fiber self-resistance electric (SRE) heating technology still need to be improved, which is not conducive to the popularization and application of this technology. To deal with this problem, the SRE heating technology was combined with a compression molding process to form carbon-fiber-reinforced polyamide 6 (CF/PA 6) composite laminates in this study. Orthogonal experiments of three factors (temperature, pressure, and impregnation time) were designed to study the effect of process parameters on the impregnation quality and mechanical properties of CF/PA 6 composite laminates and to obtain the optimized set of process parameters. Furthermore, the effect of the cooling rate on crystallization behaviors and mechanical properties of laminates was studied according to the optimized settings. The results show that the laminates possess a good comprehensive forming quality under process parameters using a forming temperature of 270 °C, forming pressure of 2.5 MPa, and an impregnation time of 15 min. The ununiform impregnation rate is due to the ununiform temperature field in the cross-section. When the cooling rate decreases from 29.56 °C/min to 2.64 °C/min, the crystallinity of the PA 6 matrix increases from 25.97% to 37.22%; the α-phase of the matrix crystal phase also increases significantly. The effect of the cooling rate on crystallization properties also further affects the impact properties; laminates with a faster cooling rate have stronger impact resistance.

Development of an Integrated Continuous Manufacturing Process for the rVSV-Vectored SARS-CoV-2 Candidate Vaccine.

The administration of viral vectored vaccines remains one of the most effective ways to respond to the ongoing novel coronavirus disease 2019 (COVID-19) pandemic. However, pre-existing immunity to the viral vector hinders its potency, resulting in a limited choice of viral vectors. Moreover, the basic batch mode of manufacturing vectored vaccines does not allow one to cost-effectively meet the global demand for billions of doses per year. To date, the exposure of humans to VSV infection has been limited. Therefore, a recombinant vesicular stomatitis virus (rVSV), which expresses the spike protein of SARS-CoV-2, was selected as the vector. To determine the operating upstream process conditions for the most effective production of an rVSV-SARS-CoV-2 candidate vaccine, a set of critical process parameters was evaluated in an Ambr 250 modular system, whereas in the downstream process, a streamlined process that included DNase treatment, clarification, and a membrane-based anion exchange chromatography was developed. The design of the experiment was performed with the aim to obtain the optimal conditions for the chromatography step. Additionally, a continuous mode manufacturing process integrating upstream and downstream steps was evaluated. rVSV-SARS-CoV-2 was continuously harvested from the perfusion bioreactor and purified by membrane chromatography in three columns that were operated sequentially under a counter-current mode. Compared with the batch mode, the continuous mode of operation had a 2.55-fold increase in space-time yield and a reduction in the processing time by half. The integrated continuous manufacturing process provides a reference for the efficient production of other viral vectored vaccines.

Study of parametric effect on laser directed energy deposited Austenitic steel and Inconel functionally graded material

In this paper, the effect of process parameter on functionally graded materials (FGMs) of Inconel 625 (IN625) and Austenitic steel (SS304L) deposited by laser directed energy deposition (LDED) are investigated. For this purpose, FGM walls of different gradient of mix of IN625 and SS304L at different layers are deposited on Austenitic steel (SS316L) substrate at different sets of process parameters. For this study, the process parameters considered are laser power ( PL): 1000, 1300 and 1600 W, and scanning speed ( v): 0.3, 0.5 and 0.7 m/min. Deposited samples are then subjected to different tests such as energy dispersive spectroscopy (EDS), microhardness, scanning electron microscopy (SEM), X-ray diffraction (XRD), optical microscopy (OM), and nanoindentation. Tests performed on the samples revealed different effects of parameters on the deposition of the FGM wall. Based on the comparison of results of mechanical and metallurgical tests, it is observed that either at PL = 1300 W and/or v = 0.5 m/min, among the considered process parameters, show comparatively better results than the others.

Prediction and mechanism of surface evolution in high-pressure slurry jet micro-machining of channels

Recent advances in abrasive water jet (AWJ) processes have enabled controlled-depth micro milling for a variety of applications, such as micro fluidic chip manufacturing. However, AWJ micro milling can be difficult to control and its successful application requires judicious selection of the process parameters. Since the mechanics of the process have not been fully understood, prediction of the machined topography arising from a set of process parameters is difficult. The present work combines computational fluid dynamics, Lagrangian particle tracking, and a deformed geometry surface evolution technique into a comprehensive model that predicts the evolving shape of micro-channels milled on 6061-T6 aluminum plates using high-pressure abrasive slurry jet machining (HASJM). Requiring calibration using only a single channel centerline depth, the model could predict the machined profiles of micro-channels milled using multiple nozzle passes with less than a 2% error. The model was also used to investigate the underlying physics of the machining process. This allowed experimental observations to be explained in terms of the changes that occur, due to the evolving eroded shape, in stagnation zone size, particle ricochet behavior, secondary slurry flow, and local particle impact angles and velocities. Overall, the work shows that such models can not only very accurately predict evolving machined topography, but also be very useful tools to understand abrasive jet machining mechanisms which occur on time scales which are too brief to be directly observed experimentally.

Development and optimization of a novel industrial process solution for stripping of carbon dioxide and ammonia from bio-process wastewater

The production of biologic products by fermentation has grown significantly within the last decade and continues to grow further. Large volumes of wastewater are produced by anaerobic digesters, which contain dissolved CO2 and NH3 in addition to other compounds, making it difficult to treat in an economic way. In this work, we have developed a novel process solution of an NH3 recovery process that first strips off CO2 from the wastewater, then produces a concentrated NH3 solution. This solution not only avoids both precipitation of solids and the use of caustic, but also allows for adjustments of the composition of the concentrated NH3 solution, thus enabling its re-utilization in different applications. Based on this development, pilot plant tests were conducted with the aim of proving process feasibility. Then, a rigorous process optimization was carried out, where the optimal set of process parameters were determined. The results suggest that the optimal operation not only depends on the operating conditions, but also on the process configuration depending on the input and storage conditions; four different configurations were developed, which enable the selection of an optimal design that minimizes both the operating costs via external heat demand, and capital costs via process complexity.

Impact of process parameters on the specific volume of wholemeal wheat bread made using sourdough- and baker's yeast-based leavening strategies

The final quality of wholemeal wheat bread is determined by the process parameter settings and leavening strategy. We hypothesise that the used leavening strategy may influence the optimal process parameter settings and, as such, the specific volume of the bread loaf. To analyse this interaction, bread was leavened with (i) a type 1 sourdough (SB), (ii) a type 1 sourdough combined with baker's yeast (YSB), or (iii) baker's yeast (YB). For each leavening strategy, the specific volume of bread, in response to variations in mixing time (4–10/4–14 min), water absorption (60–85 %), and proofing time (1–7/1–3 h), was analysed using an I-optimal response surface experimental design. Data modelling identified a substantially lower maximal specific volume of SB (2.13 mL/g), compared to YSB (3.30 mL/g) and YB (3.26 mL/g). The proofing time and water absorption mostly influenced the specific volume of the SB and YSB, respectively. However, the mixing and proofing times mainly affected the specific volume of YB. The type 1 sourdough reduced the mixing time and water absorption required for an optimal specific volume of bread compared to baker's yeast. These results challenge the idea of yielding higher volumes upon using sourdough compared to baker's yeast and highlight the importance of optimisation of bread dough formulations and breadmaking processes.

Functional dyeable polypropylene fabric development and process parameter optimization. Part II: Development of graphene thermal insulation dyeable polypropylene fabric with process parameter optimization

This series of studies developed a nanographene modified dyeable polypropylene yarn with far-infrared properties making it suitable for winter clothing fabrics. In this paper, part II, the dyeable polypropylene granules developed in part I are used as a base material and, with the addition of graphene nanopowder, melt-mixed and melt-spun to produce 75 d/24 f fully drawn yarn. The physical properties of the yarn, namely, yarn count, tensile strength, elongation at break, far-infrared emissivity, and far-infrared temperature rise, are investigated, and the impact of the melt-spinning process parameters, namely, graphene nanopowder content, mold temperature, melt temperature, gear pump speed, hot roller speed and take-up speed on the quality of the yarn, is determined. The Taguchi method, combined with gray relational analysis, is used to design experiments through which an optimal set of melt-spinning process parameters maximizing the multi-characteristic quality of the yarn is obtained. This optimized nanographene modified dyeable polypropylene yarn has a tensile strength of 3.5 g/d, elongation at break of 41.0%, yarn count of 75.3 d, far-infrared emissivity of 82%, far-infrared temperature rise of 21.0°C, washing fastness grade of 3–4 and surface resistance of 3 × 108 Ω.

Study of Laser Welding Process Parameter on the Microstructure and Mechanical Properties of Dissimilar Joining of Dual-Phase DP780 and Cold-Rolled CR340 Steel

Abstract Laser welding was performed in dual-phase steel (DP780) and cold-rolled steel (CR340) at a series of weld parameters (series I up to series VII): power input, heat input, weld velocity, and focus offset. The study was aimed at improvement of joint performance on the laser welding process parameter settings on the weld bead morphology and thereby evaluating their microstructure and mechanical properties. Optical and scanning electron microscopy and uniaxial tensile tests were performed to observe the microstructural changes, phase formation, and evaluate the mechanical properties, respectively. Tensile strength, microhardness, and strain localization using a digital image correlation technique were investigated for acquainting the local strain mapping associated with the loading. Microstructure characterization revealed that the fusion zone consisted of martensitic structure, and the heat affected contained newly formed martensite in both steels. Vickers hardness revealed that during welding, there was a softening phenomenon at the CR340 end. The DP/CR welds show a mechanical behavior that is driven by both the DP780 and CR340 steel. The joints showed strength up to ∼410 MPa and fracture strain up to ∼16 %, however the weld join failed from CR340 steel end weld during tensile tests. The larger heat input at series VI guarantees joints with an adequate strength but wider weld seams and a lower energy efficiency.

Direct Energy Depositions of a 17-4 PH Stainless Steel: Geometrical and Microstructural Characterizations

Direct energy deposition (DED) is a widely accepted additive manufacturing process and a possible alternative to the subtractive manufacturing processes due to its high flexibility in fabricating new 3D parts. DED enables the manufacture of complex parts without using costly and time-consuming conventional processes, even though building parameters need to be accurately determined. In the present investigation, the effect of different process parameters on geometrical features, quality, microstructure, and microhardness of 17-4 PH stainless steel single tracks deposited onto an AISI 316L stainless steel substrate was investigated. Four sets of process parameters, considering different values of laser power, scanning speed, and powder feed rate, were selected in the manufacturing strategy, and specimens drawn from each single-track deposition were analyzed by stereomicroscopy, optical microscopy (OM), scanning electron microscopy (SEM-EDS), and X-ray diffraction (XRD). The results show that the optimized geometrical features of the track, together with the best microstructural and hardness properties, were obtained with the highest values of the laser energy input.

Decomposition kinetics of sodium amalgam in fixed bed of WC‐coated tubular SS‐304 packing: Modelling and validation

AbstractErosion of graphite packing in continuously operating fixed bed sodium amalgam decomposers leads to performance degradation accompanied by clogging in the downstream process lines which not only increases the maintenance and catalyst refilling costs but also aggravates the risk of mercury vapour exposure. To overcome this drawback, the present work utilizes tubular SS‐304 packing coated with tungsten carbide (WC) on the outer surface. The coating is obtained using an indigenously developed laser‐directed energy deposition facility. Dedicated experimental setup is developed for each set of process parameters to comparatively study the fixed bed decomposition kinetics at steady state for three types of WC‐coated SS‐304 packing and a conventional spherical graphite packing. In parallel, a numerical 3D–1D model is implemented using open source computational solvers and is experimentally validated. The algorithm of this model is based on proposed drop–fill approach for WC‐coated SS‐304 packing and modified drop approach for spherical graphite packing, respectively. In terms of decomposition rates, the performance of WC‐coated SS‐304 packing surpasses that of spherical graphite packing at high amalgam flowrates; meanwhile, the average alteration in experimental steady‐state temperature profile after continuous operation of 2 years is around 2% for WC‐coated SS‐304 packing as compared to nearly 17% for spherical graphite packing.