Process-related Parameters Research Articles

Surface Mechanical Property Prediction and Process Optimization of 18CrNiMo7-6 Carburized Steel Stator Guide Based on Radial Basis Function Neural Network and NSGA-II Algorithm

The carburizing process is a key technology that affects the mechanical properties of the surface of the hydraulic motor stator guide rail, and the related process parameters have an important influence on surface hardness, the thickness of the carburized layer, and the deformation of the guide rail. However, at present, the relationship between the carburizing process parameters and the surface mechanical properties of the target is not clear. This paper proposes a “hardness prediction and process parameter optimization” method. Firstly, a finite element model is established, with carburizing time, temperature, and carbon potential as the three input factors; the optimal Latin hypercubic experimental design and sensitivity analysis are applied. Secondly, surface hardness, carburized layer thickness, and deformation are taken as the output values, and an RBF neural network is used to construct the prediction model. The results show that the RBF neural network can be accurately used for the prediction of surface hardness, the thickness of the carburized layer, and deformation, and for the optimization of process parameters. The optimized parameters of surface hardness and the thickness of the carburized layer were increased by 4.2% and 5.1%, respectively, and the deformation amount was reduced to 0.31 mm, achieving the goal of optimal design.

Theoretical and Experimental Investigation on a Novel Cavitation-Assisted Abrasive Flow Polishing Method.

A novel polishing method is proposed to increase material removal rates through the acceleration of abrasive movements using micro-jets formed by spontaneous collapses of bubbles due to the cavitation in a special-shaped Venturi tube. The Venturi structure is optimized by numerical simulations. Process-related parameters for the optimal cavitation ratio are investigated for achieving maximum adaptation to polishing flat workpieces. Furthermore, this novel approach enhances processing efficiency by approximately 60% compared to traditional abrasive flow polishing. The processing method that employs cavitation bubbles within a special-shaped Venturi tube to augment the flow of abrasive particles holds significant potential for material polishing applications.

Stochastic geometry models for texture synthesis of machined metallic surfaces: sandblasting and milling

Training defect detection algorithms for visual surface inspection systems requires a large and representative set of training data. Often there is not enough real data available which additionally cannot cover the variety of possible defects. Synthetic data generated by a synthetic visual surface inspection environment can overcome this problem. Therefore, a digital twin of the object is needed, whose micro-scale surface topography is modeled by texture synthesis models. We develop stochastic texture models for sandblasted and milled surfaces based on topography measurements of such surfaces. As the surface patterns differ significantly, we use separate modeling approaches for the two cases. Sandblasted surfaces are modeled by a combination of data-based texture synthesis methods that rely entirely on the measurements. In contrast, the model for milled surfaces is procedural and includes all process-related parameters known from the machine settings.

Fabrication and manipulation for key elements of magnetic-driven speed-reduction micro-motor

The motion of magnetic-driven micro motor is controlled by external magnetic field, does not need any fuel which has good biocompatibility. However, its driving torque needs to be further improved. For it, a magnetic-driven micro-motor with speed-reduction function is proposed. The main elements for the micro-motor includes wave generator, central ring, and movable tooth frame which had to be fabricated with Electron beam lithography and vacuum evaporation coating technology. So, related processing parameters should be optimized to obtain high quality elements of the micro-motor. Here, a magnetic-driven micro-motor with speed-reduction function is proposed. Fabrication and manipulation techniques of the main elements for the micro-motor, such as wave generator, central ring, and movable tooth frame, are studied. Electron beam lithography, electron microscope, and atomic force microscopy (AFM) are applied to optimize the parameters of electron beam lithography. The optimized photolithography parameters are obtained, by which the micro movable tooth frame is successfully developed, and the photoresist molds of the wave generator and central ring is produced. Using vacuum evaporation coating technology, effect of evaporation rate on the quality of micro-parts is studied. The optimized evaporation rate is obtained, by which the nickel-based wave generator and copper-based center ring are successfully developed. The nickel-based wave generator and copper-based central ring are effectively peeled off from the substrate by ultrasonic oscillation technique. The effective manipulation of the wave generator and central ring is accomplished by AFM and piezoelectric-driven micro-probe.

Influence of pressure and retention time on briquette volume and raw density during biomass densification with an industrial stamp briquetting machine

Biomass densification is a key technology for economic and environmental use of biomass in bio economy. Thus, the aim of the study was to analyze and simulate the influence of process-related parameters of briquetting on the product quality. The densification of woody biomass was performed with an industrial stamp briquetting machine with a throughput of 60 kg/h. On the one hand, briquettes were produced using statistical methodologies by varying the pre-densification pressure (i.e., 13–40 MPa), main densification pressures (i.e., 100–200 MPa) and the retention time (i.e., 0–10 s). On the other hand, the pressure distribution in the forming mold was calculated numerically. The equations were solved iteratively. Subsequently, the data set of the statistical model was used to validate the numerical results. The investigation shows: (1) due to friction, pressure and density differences occur on the forming mold walls; (2) the retention time is the main influencing factor for biomass densification; (3) significant agreements between experimental and simulation data were possible. Based on the results, new forming molds for industrial biomass compaction could be developed. With a slightly conical briquette geometry, these could favor a more even pressure distribution and thus increase briquette stability.

Towards implementation of alloy-specific thermo-fluid modelling for laser powder-bed fusion of Mg alloys

Multi-physics thermo-fluid modeling has been extensively used as an approach to understand melt pool dynamics and defect formation as well as optimizing the process-related parameters of laser powder-bed fusion (L-PBF). However, its capabilities for being implemented as a reliable tool for material design, where minor changes in material-related parameters must be accurately captured, is still in question. In the present research, first, a thermo-fluid computational fluid dynamics (CFD) model is developed and validated against experimental data. Considering the predicted material properties of the pure Mg and commercial ZK60 and WE43 Mg alloys, parametric studies are done attempting to elucidate how the difference in some of the material properties, i.e., saturated vapor pressure, viscosity, and solidification range, can influence the melt pool dynamics. It is found that a higher saturated vapor pressure, associated with the ZK60 alloy, leads to a deeper unstable keyhole, increasing the keyhole-induced porosity and evaporation mass loss. Higher viscosity and wider solidification range can increase the non-uniformity of temperature and velocity distribution on the keyhole walls, resulting in increased keyhole instability and formation of defects. Finally, the WE43 alloy showed the best behavior in terms of defect formation and evaporation mass loss, providing theoretical support to the extensive use of this alloy in L-PBF. In summary, this study suggests an approach to investigate the effect of materials-related parameters on L-PBF melting and solidification, which can be extremely helpful for future design of new alloys suitable for L-PBF.

Life cycle assessment as a driver for process optimisation of cellobiose lipids fermentation and purification

PurposeCellobiose lipids (CL) are biosurfactants produced by various Ustilaginaceae species in aerobic fermentations. They show high potential for application as alternatives to conventional oleochemical- or petrochemical surfactants. To ensure their environmentally friendly performance, we aimed to assess CL production from a life cycle perspective at an early developmental stage to identify process steps that have the highest impact on the environment. With this information, optimisation approaches can be derived.Materials and methodsFollowing a cradle-to-gate approach, we modelled the CL fermentation and purification process based on experimental data from the lab scale and process simulation data at a 10 m3 scale. For LCA, the impact categories (IC) abiotic depletion potential (ADP), eutrophication potential, photochemical ozone creation potential, global warming potential, acidification potential, and the primary energy demand were calculated for all process steps. Based on the obtained results, process bottlenecks were identified, and alternative process scenarios varying the related process parameters were simulated. These were used to assess the environmental impact reduction potential (EIRP) of an optimised process and draw recommendations for experimental process optimisation.Results and discussionThe obtained results showed that the fermentation caused ~ 73% of ADP and more than 85% of all other ICs. The major contributor was the electricity consumption for continuous fermenter aeration. Thus, reducing the fermentation duration from the initial 14 to 5 days would result in a decrease in all investigated ICs of up to ~ 27–52%. An increase in CL concentration results in a decrease in all ICs of a similar magnitude due to the higher yield per batch at comparable energy and material consumption. Although the share of purification process steps to all ICs is overall relatively small, implementing foam fractionation for in situ product recovery showed an additional EIRP of 18–27% in all purification IC shares.ConclusionsThe conducted LCA showed that overall, more EIRP can be achieved by optimising fermentation process parameters compared to purification process steps. This is mainly due to the long fermentation duration and large energy consumption for fermenter aeration. This highlights the importance of using LCA as a driver for process optimisation to identify process steps with high EIRP. While some of the results are specific to CL, other obtained results can be transferred to other fermentations.

Examining lack of referrals to heart valve specialists as mechanisms of potential underutilization of aortic valve replacement

BackgroundRecent studies suggest that aortic valve replacement (AVR) remains underutilized. AimsInvestigate the potential role of non-referral to heart valve specialists (HVS) on AVR utilization. MethodsPatients with severe aortic stenosis (AS) between 2015 and 2018, who met class I indication for intervention, were identified. Baseline data and process-related parameters were collected to analyze referral predictors and evaluate outcomes. ResultsAmong 981 patients meeting criteria AVR, 790 patients (80.5%) were assessed by HVS within six months of index TTE. Factors linked to reduced referral included increasing age (OR: 0.95; 95% CI: 0.94-0.97; P < .001), unmarried status (OR: 0.59; 95% CI: 0.43-0.83; P = .002) and inpatient TTE (OR: 0.27; 95% CI: 0.19-0.38; P < .001). Conversely, higher hematocrit (OR: 1.13; 95% CI: 1.09-1.16; P < .001) and eGFR (OR: 1.01; 95% CI: 1.00-1.02; P = .003), mean aortic valve gradient (OR: 1.03; 95% CI: 1.01-1.04; P < .001) and preserved LVEF (OR: 1.59; 95% CI: 1.02-2.48; P = .04), were associated with increased referral likelihood. Moreover, patients assessed by HVS referral as a time-dependent covariate had a significantly lower two-year mortality risk than those who were not (aHR: 0.30; 95% CI: 0.23-0.39; P < .001). ConclusionA substantial proportion of severe AS patients meeting indications for AVR are not evaluated by HVS and experience markedly increased mortality. Further research is warranted to assess the efficacy of care delivery mechanisms, such as e-consults, and telemedicine, to improve access to HVS expertise.

Implementation of Grey Wolf, Multi-Verse and Ant Lion Metaheuristic Algorithms for Optimizing Machinability of Dry CNC Turning of Annealed and Hardened UNIMAX® Tool Steel

Advances in machining technology and materials science impose the identification of optimal settings for process-related parameters to maintain high quality and process efficiency. Given the available resources, manufacturers should determine an advantageous process parameter range for their settings. In this work, the machinability of a special tool steel (UNIMAX® by Uddeholm, Sweden) under dry CNC turning is investigated. The working material is examined under two states; annealed and hardened. As major machinability indicators, main cutting force Fz (N) and mean surface roughness Ra (μm) were selected and studied under different values for the cutting conditions of cutting speed, feed rate, and depth of cut. A systematic experimental design was established as per the response surface methodology (RSM). The experimental design involved twenty base runs with eight cube points, four center points in the cube, six axial points, and two center points in the axial direction. Corresponding statistical analysis was based on analysis of variance and normal probability plots for residuals. Two regression models referring to main cutting force and surface roughness for both the annealed and hardened states of the material were developed and used as objective functions for subsequent evaluations by three modern meta-heuristics under the goal of machinability optimization, namely multi-objective grey wolf algorithm, multi-objective multi-verse algorithm and multi-objective ant lion algorithm. All algorithms were found capable of providing beneficial Pareto-optimal solutions for both main cutting force and surface roughness simultaneously whilst regression models achieved high correlation among input variables and optimization responses.

Research Overview on Rectangular Tube Cross-Section Deformation in Rotary-Draw Bending Process

Rectangular tube bending process forming quality is not only affected by the tube material but also geometric dimensions will also be affected by bending mold and related process parameters. Cross-section deformation produced by the tube during the forming process becomes a major constraint to heightening the quality of the tube. The research work and process of cross-section deformation in the rotary-draw bending process (RDBP) of rectangular tubes in theory analysis, experiment research, and finite-element (FE) simulation in recent years is reviewed in this paper. The development trend of research in this field is also proposed.

Glulam beams adhesively bonded by birch plywood plates in moment-resisting beam-to-beam connections

The design of timber connections is of vital importance in timber structures. Bonded connections exhibit the advantages of lower cost, higher load-bearing capacity, and higher stiffness compared to conventional mechanical connections. However, the potential of the bonded connections has yet to be fully exploited, not only due to their sensitivity to the adhesive types and process-related parameters but also due to the lack of studies regarding the structural performance of the bonded connection in various loading conditions. In this paper, birch plywood plates were utilized to adhesively connect two glulam beam halves to create a longer span. Plywood made of birch was chosen because birch is highly resourced on the Eurasian continent, with its mechanical properties better than most softwoods. Specifically, glulam beams were connected by birch plywood plates at mid-span and then loaded in four-point bending. Four test series with two different bonding areas and birch plywood face grain orientations were carried out. The bonded region was designed as the weakest part to investigate the failure modes, moment capacity, bending stiffness, and moment-rotation angle relationships. Furthermore, numerical models were developed to predict the structural behaviors in the linear elastic stage, while analytical models were proposed and subsequently modified to predict the moment-carrying capacities. Both numerical and analytical models displayed satisfactory agreement with the test results.

An AFM-based approach for quantification of guest particle deformation during mechano-fusion

During the mechano-fusion process for dry particle coating, (hetero)-aggregates are formed consisting of host particles coated by smaller guest particles. During this process, the latter are exposed to intense particle–particle interactions and particle–wall impacts, which lead to deformation of their original shape. These deformations on the nano- and microscale can heavily influence the effective macroscopic properties of the resulting coated particles. We present a method for quantification of shape deformation based on measurements acquired by atomic force microscopy and apply it to guest particles during mechano-fusion. The 3D shape of guest particles is reconstructed by means of an ellipsoidal fit. Using these reconstructed shapes, we quantify the degree of deformation by comparing the aspect ratios of the ellipsoidal fits before and after mechano-fusion. Such a quantification enhances the understanding of how process-related parameters influence geometric descriptors of involved particles, which in turn impacts overall macroscopic properties of the material.

Optimization of laser beam parameters during processing of ASA 3D-printed plates

AbstractNew developments in manufacturing processes impose the need for experimental studies concerning the determination of beneficial process-related parameter settings and optimization of objectives related to quality and efficiency. This work aims to improve cutting geometry, surface texture, and arithmetic surface roughness average in the case of post-processing of filament material extrusion 3D-printed acrylonitrile styrene acrylate (ASA) thin plates by a low-power CO2 laser cutting apparatus. This material was selected owing to its unique properties for thin-walled customized constructions. Three parameters, namely focal distance, plate thickness, and cutting speed, were examined with reference to the Box-Behnken design of experiments (BBD) and regression modeling. Four responses were considered: mean kerf width, Wm (mm); down width, Wd (mm); upper width, Wu (mm); and average surface roughness Ra (μm) of cut surfaces. Different regression models were tested for their efficiency in terms of predicting the objectives with an emphasis on full quadratic regression. The results showed that a focal distance of 6.5 mm and 16 mm/s speed optimizes all quality metrics for the three plate thicknesses. The regression models achieved adequate correlation among independent process-related parameters and optimization objectives, proving that they can be used to improve the laser cutting process and support practical applications.

Enhanced dual-mode electrochemical zinc ion sensing by electric field-driven bi-directional mass transport

Electric field-driven bi-directional mass transport strategy was introduced for high accuracy and sensitive electrochemical (EC) zinc ion chip. The detection sensitivity and sensing accuracy of the EC sensor were significantly improved. The related process parameters including inter-electrode spacing and electrode absorbability were explored and surveyed. A limit of detection of 33.1 pM of chip was achieved for detecting zinc ion with excellent selectivity, stability, and flexibility, which was two orders of magnitude better than that without electric field. The mechanism of the EC chip was elucidated and discussed based on the experimental results. The real samples were detected by the chip integrating with smartphone-based portable system to prove the practical application. This work would provide new insights of the sensor for mobile environmental detection and biomedical monitoring.

Mechanical behavior of recycled carbon fiber epoxy and vinylester composites produced by resin infusion with flexible tooling technology (RIFT)

This research aims to define a technological process to design and manufacture high-performance components with innovative composite materials and to assess a line of recycling and recovery of processing waste. The material under study is a felt (non-woven fabric) of short carbon fibres produced by recycling composite material scraps. The activities focus on determining the most suitable production processes and the related process parameters that best lend themselves the uses of recycled carbon felt. Thus, two different laminates were manufactured, adopting epoxy and vinylester resinand the same recycled carbon withthe same stacking sequence. Consequently, the same thickness was obtained,andthe process feasibility and its limits were determined. In addition, the quasi-static and FIMEC tests were conducted to investigate their behaviour under tensile and flexural loading, respectively, and highlight theinfluence of the different matrices used. The results revealed the perfectly elastic behaviour of the material, the strong anisotropy for the epoxy sample and a significant difference in mechanical response in terms of strength and modulus

A grinding process method of solid end mills groove with segmented unequal helical angles by cutting edges offset and interference

Solid end mills with variable helical angles within a certain range can effectively mitigate cutting vibration and enhance the machining quality. However, the grinding process for these helical grooves is complex, and the existing disclosed process method cannot grind those helical grooves accurately. This study proposes a two-pass grinding method for the helical groove with variable helical angles. First, a cutting edge model with variable helical angles is established by edge offset to guide the grinding process. Second, to ensure the required cross-section parameters while avoiding overcutting and edge discontinuity, a novel optimization algorithm for determining the grinding wheel posture, and calculation rules of related process parameters for the two-pass grinding process are proposed. Finally, the verification is conducted and the results show that the maximum relative error of cross-section parameters is 1.254 % in simulation machining, which indicates the theoretical modeling of posture optimization and cutting edge are correct, and the two-pass grinding process is effective. Furthermore, this approach can be extended to grinding other complex structures with helical grooves.

Development of a new synthetic route of the key intermediate of riociguat

Herein, we describe a new synthetic route to prepare 1-(2-fluorobenzyl)-1H-pyrazolo[3,4-b]pyridine-3-carbonitrile (9), a key intermediate of riociguat (1). In this new route, 9 was obtained from commercially available methyl 2-chloronicotinate (28) as the staring material in four steps with an overall yield of 55%. The hydrazinolysis and intramolecular substitution were completed in one step to obtain 1H-pyrazolo[3,4-b]pyridin-3-ol (30). Regioselective N1-benzylation of 30 afforded 1-(2-fluorobenzyl)-1H-pyrazolo[3,4-b]pyridin-3-ol (31), whose structure was confirmed by 1H NMR, 13C NMR, MS and single-crystal X-ray crystallography. Pd-catalyzed cyanation of 1-(2-fluorobenzyl)-3-bromo-1H-pyrazolo[3,4-b]pyridine (32) was applied to prepare key intermediate 9. Compound 32 in our approach has not been previously reported in the literature. The related impurities and process parameters were studied. The new synthetic route provides an alternative method for the preparation of riociguat.

Manufacturing classification system for oral solid dosage forms of traditional Chinese medicines(Ⅳ): classification of hygroscopicity behaviors of capsules

Hard capsules of traditional Chinese medicine(TCM) have different degrees of hygroscopicity, which affects the stability and efficacy of drugs. In this paper, 30 kinds of commercially available TCM capsules were used as the research object. The hygroscopicity curves of capsule contents, capsule shells, and capsules were tested respectively, and the first-order kinetic equation was used for fitting. The results show that during the 24 h hygroscopicity process, the capsule shell can reduce the weight gain caused by the hygroscopicity of the contents by 0.80%-53.0% and the hygroscopicity rate of the capsule contents by 1.74%-91.3%, indicating that the capsule shell has a strong delay effect on the hygroscopicity of the contents of the TCM capsules. Seven physical parameters of the contents of 30 kinds of TCM capsules were determined, and 14 prescription process-related parameters were sorted out. A partial least squares model for predicting the hygroscopicity rate of the contents of TCM capsules(with shell) for 24 h was established. It is found that the hygroscopicity rate of the capsule shell is positively correlated with the hygroscopicity of the contents of TCM capsules(with shell), suggesting that the capsule shell with a low hygroscopicity rate is helpful for moisture prevention. In addition, the pre-treatment process route of the preparation and the type of molding raw materials affect the hygroscopicity. A larger proportion of the extract in the capsule content and a smaller proportion of the fine powder of the decoction pieces indicate stronger hygroscopicity of the capsule content. The 24 h hygroscopicity rate of 15% was used as the classification node of hygroscopicity strength, and the hygroscopicity rate constant of 0.58 was used as the classification node of hygroscopicity speed. The classification system of hygroscopicity behaviors of TCM capsules was established: the varieties with strong and fast hygroscopicity accounted for about 6.67%, while those with strong and slow hygroscopicity accounted for about 33.3%; the varieties with weak and fast hygroscopicity accounted for about 26.7%, while those with weak and slow hygroscopicity accounted for about 33.3%. The classification system is helpful to quantify and compare the hygroscopicity behavior of different TCM capsules and provides a reference for the quality improvement, moisture prevention technologies, and material research of TCM capsules.

FTIR-based prediction of collagen content in hydrolyzed protein samples

Fourier transform infrared spectroscopy (FTIR) is a powerful analytical tool that has been used for protein and peptide characterization for decades. In the present study, the objective was to investigate if FTIR can be used to predict collagen content in hydrolyzed protein samples. All samples were obtained from enzymatic protein hydrolysis (EPH) of poultry by-products providing a span in collagen content from 0.3% to 37.9% (dry weight), and the FTIR analysis was performed using dry film FTIR. Since nonlinear effects were revealed by calibration using standard partial least squares (PLS) regression, Hierarchical Cluster-based PLS (HC-PLS) calibration models were constructed. The HC-PLS model provided a low prediction error when validated using an independent test set (RMSE = 3.3% collagen), while validation using real industrial samples also showed satisfying results (RMSE = 3.2%). The results corresponded well with previously published FTIR-based studies of collagen, and characteristic spectral features for collagen were well identified in the regression models. Covariance between collagen content and other EPH related processing parameters could also be ruled out in the regression models. To the authors' knowledge, this is the first time that collagen content has been systematically studied in solutions of hydrolysed proteins using FTIR. This is also one of few examples where FTIR is successfully used to quantify protein composition. The dry-film FTIR approach presented in the study is expected to be an important tool in the growing industrial segment that is based on sustainable utilization of collagen-rich biomass.

Simultaneous production of high-quality CO2 and CH4 via multistage process using chitosan-based membranes

The use of biopolymers as membrane materials is a recent approach for reducing the environmental impact of CO2 separation processes. By considering previous process engineering tasks, it was concluded that no membrane currently provides sufficient purity and recovery to meet the requirements for the simultaneous direct separation of CO2 and CH4 in a single stage. The aim of this study is to simulate and optimise the separation of CO2 and CH4 from different sources using a simple multistage process, considering up to three stages. A chitosan biopolymer-based composite membrane with organic (ionic liquid) and different inorganic fillers in the selective layer was used to tune the selectivity and robustness of commercially available membranes. The process configuration utilized membrane units operating in series to enrich CO2 in the product stream from the permeate line, whereas the retentate line produced a CH4-enriched stream by mixing the retentate units of each stage. The target objectives were up to 95% purity and recovery of CO2 in the permeate outlet, corresponding to a recovery of CH4 higher than 97% in the retentate outlet stream of the multistage process. The decision variables included the permeance of each component, and thus the pair selectivity (CO2/CH4) and process-related parameters, such as the stage cut of each stage. Economic evaluation of the proposed three-stage separation process was performed for different process scales, from small installations to large plants. The total costs, the contribution of each term to the total costs, and the unitary costs were estimated for each operational scale, with reference to the feed flow rate based on the plant capacity. The lowest total cost was 0.3 € (Nm3)-1 for a large plant with a flow rate of 1000 Nm3 h−1.