Combined Effects Of Process Parameters Research Articles

An Investigation to Study the Effect of Process Parameters on the Strength and Fatigue Behavior of 3D-Printed PLA-Graphene.

3D printing, an additive manufacturing process, draws particular attention due to its ability to produce components directly from a 3D model; however, the mechanical properties of the produced pieces are limited. In this paper, we present, from the experimental aspect, the fatigue behavior and damage analysis of polylactic acid (PLA)-Graphene manufactured using 3D printing. The main purpose of this paper is to analyze the combined effect of process parameters, loading amplitude, and frequency on fatigue behavior of the 3D-printed PLA-Graphene specimens. Firstly, a specific case study (single printed filament) was analyzed and compared with spool material for understanding the nature of 3D printing of the material. Specific experiments of quasi-static tensile tests are performed. A strong variation of fatigue strength as a function of the loading amplitude, frequency, and process parameters is also presented. The obtained experimental results highlight that fatigue lifetime clearly depends on the process parameters as well as the loading amplitude and frequency. Moreover, when the frequency is 80 Hz, the coupling effect of thermal and mechanical fatigue causes self-heating, which decreases the fatigue lifetime. This paper comprises useful data regarding the mechanical behavior and fatigue lifetime of 3D-printed PLA-Graphene specimens. In fact, it evaluates the effect of process parameters based on the nature of this process, which is classified as a thermally-driven process.

Ultrasound-assisted dilute acid hydrolysis for production of essential oils, pectin and bacterial cellulose via a citrus processing waste biorefinery

An orange peel waste biorefinery was developed employing a design of experiments approach to optimize the ultrasound-assisted dilute acid hydrolysis process applied for production of useful commodities. Central composite design-based response surface methodology was used to approximate the combined effects of process parameters in simultaneous production of essential oils, pectin and a sugar-rich hydrolyzate. Application of a desirability function determined the optimal conditions required for maximal production efficiency of essential oils, pectin and sugars as 5.75% solid loading, 1.21% acid concentration and 34.2 min duration. Maximum production yields of 0.12% w/w essential oils, 45% w/w pectin and 40% w/w sugars were achieved under optimized conditions in lab- and pilot-scale facilities. The hydrolyzate formed was applied in bacterial cellulose fermentations producing 5.82 g biopolymer per 100 g waste. Design of experiments was efficient for process analysis and optimization providing a systems platform for the study of biomass-based biorefineries.

Effect of process parameters on flexural strength and surface roughness in fused deposition modeling of PC-ABS material

Fused deposition modeling (FDM) is one of the most commonly used additive manufacturing (AM) technologies, which has found application in industries to meet the challenges of design modifications without significant cost increase and time delays. Process parameters largely affect the quality characteristics of AM parts, such as mechanical strength and surface finish. This article aims to optimize the parameters for enhancing flexural strength and surface finish of FDM parts. A total of 18 test specimens of polycarbonate (PC)-ABS (acrylonitrile–butadiene–styrene) material are printed to analyze the effect of process parameters, viz. layer thickness, build orientation, and infill density on flexural strength and surface finish. Empirical models relating process parameters with responses have been developed by using response surface regression and further analyzed by analysis of variance. Main effect plots and interaction plots are drawn to study the individual and combined effect of process parameters on output variables. Response surface methodology was employed to predict the results of flexural strength 48.2910 MPa and surface roughness 3.5826 µm with an optimal setting of parameters of 0.14-mm layer thickness and 100% infill density along with horizontal build orientation. Experimental results confirm infill density and build orientation as highly significant parameters for impacting flexural strength and surface roughness, respectively.

Synthesis and Process Parameter Optimization of Biodiesel from Jojoba Oil Using Response Surface Methodology

Jojoba seed is an attractive alternative energy source in Saudi Arabia due to its high adaptability to harsh weather, saline water, desert, and hot temperature. In the present study, cold-pressed jojoba oil is used for the synthesis of biodiesel. In addition to that, this research work carried out a detailed optimization study of process parameters using response surface methodology. An empirical model is developed and employed for the optimization of process parameters. The study also investigates the significance of process parameters on biodiesel yield from the jojoba seed. Results show that the molar ratio of methanol to oil is the most significant input parameter, followed by the reaction time and NaOH concentration. The developed model was further validated using experimental results. The study also examined the combined effects of process parameters on process optimization. The maximum yield conditions are 15.99 molar ratio of methanol to jojoba oil, 15-min reaction time, and 1.5 wt% NaOH concentration.

Effect of Process Parameters on Defects, Melt Pool Shape, Microstructure, and Tensile Behavior of 316L Stainless Steel Produced by Selective Laser Melting

Previous studies have revealed that laser power and energy density are significant factors affecting the quality of parts manufactured by selective laser melting (SLM). The normalized equivalent density E0* and dimensionless laser power q*, which can be regarded as a progress on the understanding of the corresponding dimensional quantities, are adopted in this study to examine the defects, melt pool shape, and primary dendrite spacing of the SLM-manufactured 316L stainless steel, because it reflects the combined effect of process parameters and material features. It is found that the number of large defects decreases with increasing E0* due to enough heat input during the SLM process, but it will show an increasing trend when excessive heat input (i.e., utilizing a high E0*) is imported into the powder bed. The q* plays an important role in controlling maximum temperature rising in the SLM process, and in turn, it affects the number of large defects. A large q* value results in a low value of absolute frequency of large defects, whereas a maximum value of absolute frequency of large defects is achieved at a low q* even if E0* is very high. The density of the built parts is greater at a higher q* when E0* remains constant. Increasing the melt pool depth at relatively low value of E0* enhances the relative density of the parts. A narrow, deep melt pool can be easily generated at a high q* when E0* is sufficiently high, but it may increase melt pool instability and cause keyhole defects. It is revealed that a low E0* can lead to a high cooling rate, which results in a refined primary dendrite spacing. Relatively low E0* is emphasized in selecting the process parameters for the tensile test sample fabrication. It shows that excellent tensile properties, namely ultimate tensile strength, yield strength, and elongation to failure of 773 MPa, 584 MPa, and 46%, respectively, can be achieved at a relatively low E0* without heat treatment.

Combined influences of process parameters on microorganism-derived dissolved organic nitrogen (mDON) formation at low temperatures: Multivariable statistical and systematic analysis

Regulation of process parameters is a cost-effective approach to control microorganism-derived dissolved organic nitrogen (mDON) formation in low-temperature biological wastewater conditions. However, the integrated influence of multiple parameters in this process is poorly defined. In this study, mathematical methodology was used to evaluate the combined effects of hydraulic retention time (HRT), solids retention time (SRT), and mixed liquor suspended solids (MLSS) on mDON formation at 8 °C. This study also systematically explored how multiple combinations of those three parameters affected mDON chemodiversity (fluorescent properties and molecular compositions), microbial compositions, and specific relationships between mDON molecules and microbial species in activated sludge systems. Results showed that combined effects significantly controlled the mDON formation at 8 °C (P < .05). The systematic analysis suggested that the multi-parameter effects modulated the distribution of different mDON compositions and shaped the microbial communities. Most bacterial phyla as the generalist and a few as the specialist were displayed in 2487 pairs of strong microbe-mDON connections (|r| ≥ 0.6, P < .05). Moreover, network analysis on microbe-mDON relationships identified the network centers as crucial media in terms of combined effects of process parameters on mDON formation. Our results provide comprehensive insight on the roles of multi-parameter covariation influences in regulating the high complexity of mDON traits and microbe-mDON linkages, thereby highlighting the necessity to focus on the combined effects of process parameters for effective and correct controlling strategies on mDON concentrations.

Multi response optimization in WEDM of H13 steel using hybrid optimization approach

Surface roughness and material removal rate (MRR) are important technological parameters which describe quality of machined surfaces and productivity of machining process. Surface roughness and MRR are significantly influenced by many interactive process parameters dynamically but those are difficult to quantify adequately in any machining process. Wire electrical discharge machining (WEDM) is one of the advanced machining processes which used thin wire as cutting tool for creating intricate features on machined parts. In WEDM, optimizing surface roughness(Ra) and material removal rate (MRR) combinedly by controlling process variables namely pulse on time, pulse off time, wire feed, voltage gap, etc, is difficult task and much needed area of research. In the present work, investigation is made to study and optimize the surface roughness of H13 steel in WEDM. L16 orthogonal array of Taguchi methodology has been used to conduct the experiments. Analysis of variance (ANOVA) has been applied on experimental data to determine the significance of input parameters on surface roughness and MRR. Mathematical relationships are developed to correlate the machining parameters and output responses: surface roughness and MRR. Contour plots have been drawn to illustrate the combined effects of process parameters on output responses. Multi-objective jaya optimization algorithm (MJOA) applied on developed mathematical equations to predict the multi-responses simultaneously. From the study, it is stated that hybridTaguchi method, RSM and MJOA is useful for studying, modeling and optimizing the multiple responses: surface roughness and MRR, simultaneously in WEDM of H13 steel.

The effect of melamine formaldehyde impregnation and hot-pressing parameters on the density profile of densified poplar wood

The vertical density profile (VDP) of thermo-hydro-mechanically (THM) densified wood is a result of the combined effect of process parameters and properties of unmodified wood. The effect of thermosetting resins on VDP of THM densified wood has not been extensively studied. The aim of this study was to determine the combined effect of methylated melamine–formaldehyde (MF) resin impregnation along with thermal compression at 150 °C on the VDP of poplar wood acquired by X-ray densitometry. Four different stress levels were applied: 0, 10, 20 and 30 kg/cm2. Control specimens (without MF) were also impregnated and densified under the same conditions. The results showed that the use of MF increased the density compared to control specimens for the respective CR level. The increase in CR resulted in a linear decrease in WPG values as a result of the MF loss during pressing. Due to the bulking effect of cell walls, thermal compression resulted in higher CR for control than for MF-treated specimens. In the case of uncompressed specimens, MF-treated specimens showed slight density peaks near the surfaces probably due to migration of MF solution from the core to the heated surfaces of the specimens. MF-impregnated specimens generally showed a more uniform density profile since the differences between maximum density and minimum density were smaller than the control ones. Peak width did not seem to be affected by CR for MF-treated specimens. Maximum density was not formed in the outer surface of the specimens but was measured in deeper regions as CR increased. This trend was clearer for control specimens than for MF-impregnated ones.

Uncertainty Error Analysis on Micro Hardness of Al6061-B4C Surface Composites Produced by Friction Surfacing

Friction surfacing is a confined surface modification process of depositing a layer of a consumable tool (Mechtrode) over the base plate (Substrate). This solid-state surfacing opts for dissimilar material and erosion resistant coatings. It is also utilized for localized repairing of worn-out components. In the present study, the hardness of the coated material is compared with the substrate. In this experiment, the Al-B4C composite consumable rod is prepared with Aluminium 6061 alloy and 3, 6, 9, 12 and 15 weight % of B4C by stir casting and coated over the Aluminium 6061 alloy plate. The 25-run experiment is conducted for the combination of the rotational speed, traverse speed and axial load. The combined effect of process parameters and the increase in weight % of B4C results in the change in hardness. The hardness of the coating is enhanced by 65% than the substrate. The uncertainty analysis revealed that it has a good correlation with the hardness standard value and also it has an error of 5%. The ANOVA analysis concluded that the rotational speed and the weight percentage of the reinforcement improved the microhardness of the coating.

Multivariate Parametric Analysis for the Determination of Kinetic Rate Constants in 2‐(difluoromethoxy)ethyl Acrylate Atom‐Transfer Radical Polymerization

AbstractPoly(2‐(difluoromethoxy)ethyl acrylate), synthesized via ATRP, enables the synthesis of amphiphilic block copolymers that can self‐assemble into spherical micelles quite easily. The new monomer used, 2‐(difluoromethoxy)ethyl acrylate (DFMOEA), presents great potential to lead the development of new advanced materials with partially fluorinated segments, since it is easily synthesized, and the polymers derived may present unique characteristics. Currently, few studies detail the polymerization kinetics of this class of monomers with thorough information on the influence of operational and kinetic parameters on the synthesis. This research develops a deterministic modeling to simulate the synthesis of poly‐DFMOEA via ATRP. A multivariate parametric analysis is performed to evaluate the combined effect of process parameters on the polymerization kinetics and on the properties. A statistical modeling is obtained with a mathematical simplicity that allows the determination of the parameters by adjusting curves to the experimental data of literature. The estimated parameters are used to compare the monomer conversion, molar mass, and dispersity with the experimental data using deterministic modeling. The good adjustment obtained confirms the feasibility of using the methodology proposed. Simulations of different reagent ratios suggest the use of high concentration of catalyst to obtain polymers with ideal characteristics for future applications in self‐assembled materials.

Optimization of lead removal in exhausting Manilkara zapota based activated carbon: application of response surface methodology

ABSTRACT The present study demonstrates the removal of lead ion from aqueous solution by the adsorption process using Manilkara zapota tree wood-based activated carbon (MZTWAC) as an adsorbent. The MZTWAC was characterized using a scanning electron microscope and Fourier transform infrared spectroscopy. XRD analysis was carried on MZTWAC. Batch adsorption studies were designed and performed to evaluate the adsorption property of MZTWAC for the removal of lead from an aqueous solution based on the central composite design with response surface methodology. The experiments were focused on the individual and combined effects of process parameters, namely, lead concentration, pH and adsorbent dose on the uptake of lead from aqueous solution. A quadratic polynomial equation was established between the adsorption capacity of the activated carbon and the parameters influencing the adsorption with a coefficient of determination R 2 = 0.9792. The analysis of variance gauged the significance of process parameters and the optimization of process variables was attained by desirability function. There was a noticeable indication of the strong connotation of lead adsorption with Langmuir (R 2 = 0.9911) and Freundlich (R 2 = 0.8368) isotherm models. The D-R isotherm model indicated that physisorption occurred in the adsorption of lead by MZTWAC. The pseudo-second-order adsorption kinetic model (R 2 = 0.9973) perfectly fitted into the present study.

Frictional behaviour of AA7050/B&lt;SUB align="right"&gt;4C&lt;SUB align="right"&gt;p hybrid composites

In this work, AA7050 aluminium alloy reinforced with SiCp was fabricated through the liquid stir casting technique. The influence of % reinforcement, sliding speed, applied load and sliding distance on friction coefficient was investigated using a pin on disc equipment with tests based on the design of experiments. The results revealed that the friction coefficient increases with an increase in % reinforcement. Sliding speed, load and distance follow the similar trend that is at saddle point it registers maximum and after that COF decreases with an increase in any of the above-said parameters. The result showed that the presence of a mechanical mixed layer reduces the coefficient of friction and it's broke down leads to an increase in friction factor. The presence of mechanical mixed layer was confirmed through EDAX analysis. A mathematical model for friction coefficient was developed using response surface methodology and the combined effect of process parameters was thoroughly analysed.

Continuous twin screw wet granulation: The combined effect of process parameters on residence time, particle size, and granule morphology

In this study, a set of 24 experiments was designed to understand the combined effect of different process parameters, i.e. material feed rate, liquid-to-solid (L/S) ratio, screw speed, and screw configuration on the residence time distribution, granule morphology, and particle size distribution in twin screw wet granulation of microcrystalline cellulose. It was shown that residence times were longer at higher L/S and lower screw speeds. However, the most dominant effect on mean residence time had screw configuration, with longer residence times observed with increasing complexity of the screws employed. Scanning electron microscopy and laser diffraction measurements showed accordingly that the most important quality attribute affecting size of granules is L/S ratio. The relationships between input and output parameters observed for our low throughput setup generally match those concerning higher throughput granulators described in literature.

Combined effect of process parameters during aluminothermic reaction process on the microstructure and mechanical properties of in situ Al/TiB2 composite

Al/TiB2 particle reinforced composites were processed through aluminothermic reaction process using potassium hexafluorotitanate (K2TiF6) and potassium tetrafluoroborate (KBF4) salts as precursors and Al (A380) alloy as a matrix material, with different processing conditions such as addition time (AT) of precursors (10 min, 20 min, 30 min), holding time of melt (HT) (20 min, 30 min, 40 min) and melt temperature (700 °C, 750 °C, 800 °C, 850 °C). The combined effect of the process parameters of aluminothemic reaction on the formation of TiB2, size and distribution of TiB2 particles in the microstructure and the mechanical properties of Al/TiB2 composite were studied. The formation of TiB2 particles were confirmed from XRD pattern. The microstructures showed uniform distribution of TiB2 particle in Al matrix in the processing condition: addition time (20 min), holding time (30 min) and melt temperature (800 °C). The hardness and ultimate tensile strength of composite have improved 57%, 59% respectively in this condition. The resultant properties were correlated to the microstructure and process parameters. Coarser particles were formed at a lower addition time (10 min) and holding time (20 min) of precursors with all the processing temperatures.

Two-step process for production of methyl ester from rubber seed oil using barium hydroxide octahydrate catalyst: Process optimization

Synthesis of rubber oil methyl ester (ROME) employing a two-step procedure, esterification using homogeneous catalyst followed by transesterification with heterogeneous catalyst was studied. The acid value of extracted RSO was reduced from 24 mg KOH/g to 2 mg KOH/g during esterification using 1.5 wt% catalyst loading (H2SO4) and 15:1 methanol to oil molar ratio for 2 h reaction time at 30 °C. Transesterification of esterified RSO with heterogeneous barium hydroxide octahydrate catalyst (Ba(OH)2·8H2O) was performed using conventional and ultrasonic techniques. Ultrasonic technique results in the increased yield of ROME compared to conventional process. The effect of catalyst Ba(OH)2·8H2O dehydration on the yield of ROME was also investigated in detail. The results showed that methyl ester conversion is not influenced by calcinations of catalyst. Highest transesterification yield was obtained with non-calcinated Ba(OH)2·8H2O compared to calcinated catalyst. But, within the studied calcinations temperature range, 400 °C showed significantly higher ROME conversion compared to 800 °C. BET analysis confirms lower surface area formation at 800 °C compared to other calcinated conditions. Central composite design (CCD) using response surface methodology (RSM) was adopted to design the experimental matrix and to optimize the combined effect of process parameters, reaction time (5–15min), catalyst loading (CL) (4–6wt%) and methanol to oil molar ratio (MR) (6:1–9:1) on ROME conversion. A second order model equation with p-value <0.05 was obtained to predict the conversion using the input parameters. Maximum conversion (∼97%) was achieved at CL of 5.38 wt% with MR of 8.09:1 in 13.20 min.

Experimental study and prediction of the diameter of melt-electrospinning polypropylene fiber

Firstly, the effects of the spinning temperature, spinning voltage, tip-to-collector distance and ambient temperature on the diameter of melt-electrospinning polypropylene (PP) fibers were studied. The results showed that with the increase of the spinning temperature, spinning voltage and tip-to-collector distance, the fiber diameters first decreased and then increased. However, when the ambient temperature increased, the fiber diameters increased gradually. Secondly, based on the previous results, the response surface methodology (RSM) was used to investigate the combined effects of processing parameters on fiber diameters and establish a second-order polynomial equation to predict the fiber diameter. The results showed that the effect order of four factors on fiber diameter was as follows: spinning temperature > tip-to-collector distance > ambient temperature > spinning voltage. Moreover, the fiber diameter predicted by response surface analysis fitted well with the experimental result. Finally, three layer melt-electrospinning PP webs with different fiber diameters were online compounded with conventional non

Free surface electrospinning: investigation of the combined effects of process parameters on the morphology of electrospun fibers

In this study, three different free surface electrospinning methods: Splashing electrospinning, spiral coil electrospinning and rotary wires electrospinning methods were explored and compared in terms of fiber morphology (diameter fiber and its distribution) and process parameters. It was found that higher voltage values between 45 kV to 60 kV were necessary for Splashing electrospinning method while voltage values ranged between 50 kV to 70 kV and voltage values between 40 kV and 60 kV were enough for spiral coil and straight wires electrospinning methods, respectively. The real impact of process parameters and the evaluation of the influence of combined various processing parameters on electrospun fiber were undertaken. The results analysis demonstrates that two combined parameters based investigation can help provide insight into how to control and improve the design of the electrospinning process. The fiber diameter and its distribution can be effectively minimized either by controlling the processing parameters to a certain level. The nonlinearity relationship existing between electrospinning process parameters and nanofiber diameter and its distribution has been illustrated. It has also been observed that electric field plays a crucial role in the successful free surface electrospinning.

An experimental investigation and optimization of friction stir welding process for AA6082 T6 (cryogenic treated and untreated) using an integrated approach of Taguchi, grey relational analysis and entropy method

Friction stir welding is a solid state welding in which two metal parts are joined without melting with the help of frictional heat generated between the work material and non-consumable tool. Because of the poor microstructure, cracks, porosity and residual stresses in fusion welding of aircraft aluminium alloys, friction stir welding is highly attractive for joints in aircraft structures. In the present work, using Taguchi’s design of experiment method, combined effect of process parameters namely tool rotation speed, welding speed (or traverse speed of tool), tool pin profile and tool shoulder diameter have been investigated for the ultimate tensile strength and percentage elongation of friction stir welded joints of AA6082 alloy. Two similar sets of experiments were performed to prepare the friction stir welded joints; first samples of AA 6082-T6 (solution heat treated and artificially aged) were friction stir welded and second cryogenic treated AA6082 alloy were friction stir welded . A comparison in the optimal conditions of two sets of experiments has also been presented. In tempered aluminium alloy, three process parameters namely tool rotation, weld speed and tool shoulder diameter are significantly affecting ultimate tensile strength, while all four parameters are significant for percentage elongation. The influence of cryogenic treatment has also been noticed on two response characteristics. An integrated approach of Taguchi method, grey relational analysis and entropy measurement method have been utilized to obtain an optimal single setting of process parameters for two response characteristics. For the friction stir welded joint of AA6082-T6 (without cryogenic treatment), a single optimal setting of process parameters was obtained corresponding to tool rotation: 1200 r/min, weld speed: 35 mm/min, tool pin profile, threaded cylindrical and tool shoulder diameter: 16 mm. Similarly, the single optimal setting for cryogenic treated aluminium alloy (AA6082) was obtained corresponding to tool rotation: 1200 r/.min, weld speed: 35 mm/min, tool pin profile, cylindrical and tool shoulder diameter: 14 mm.

Analysis and optimization of hard turning operation using cubic boron nitride tool

The present work concerns an experimental study of hard turning of AISI 52100 bearing steel, with CBN tool. The combined effects of process parameters (cutting speed, feed rate, depth of cut and cutting time) on performance characteristics (tool wear, surface roughness, cutting forces and metal volume removed) are investigated using ANOVA analysis. The relationship between process parameters and performance characteristics through the response surface methodology (RSM) are modeled. Moreover, Grey-Taguchi method, composite desirability function and genetic algorithm are used as multi-objective optimization approaches to find the process parameters values that optimize simultaneously the performance characteristics. The results show that the cutting speed exhibits maximum influence on abrasive tool wear. The depth of cut affects strongly the cutting forces; however, it has a negligible influence on surface roughness. The cutting time has a considerable effect on all performance characteristics. Though the optimization approaches predicted near similar results, the GA technique seems to be the most advantageous approach. Finally, the proposed experimental and integrated approaches bring reliable methodologies to model, to optimize and to improve the hard turning process. They can be extended efficiently to study other machining processes.

Free surface electrospun fibers: The combined effect of processing parameters

In this study, a free surface electrospinning experimental setup was developed based on rotating spiral copper wire electrode and used as the spinneret. The scheme was investigated by varying processing parameters including polymer solution concentration, distance between the electrode and the collector, applied voltage between the electrode, and the collector and wire electrode diameter. An average of fiber diameter ranged between 202 and 543 nm and a relative standard deviation ranged between 11.0 and 26.9% were obtained. The combined effects of processing parameters on the resulting fiber morphology were investigated. The analysis shows that in a multiple variable process like electrospinning, the interaction between the different processing parameters played an important role, rather than one parameter separately in obtaining desired nanofibers. Knowing the relative combined effects of processing parameters on fiber morphology should be useful for process control and prediction of electrospun fiber quality as it has been demonstrated in this study. POLYM. ENG. SCI., 54:189–197, 2014. © 2013 Society of Plastics Engineers