Showing papers on "Taguchi methods published in 2019"

A hybrid PSO–BFO evolutionary algorithm for optimization of fused deposition modelling process parameters

Abstract: Fused deposition modeling (FDM), a well known 3D printing technology is widely used in various sorts of industrial applications because of its ability to manufacture complex objects in the stipulated time. However, the proper selection of input process parameters in FDM is a tedious task that directly affects the part performance. Here, in this work, the research efforts have been made to optimize the FDM process parameters in order to find out the best parameter setting as per the mechanical and surface quality perspectives by using hybrid particle swarm and bacterial foraging optimization (PSO–BFO) evolutionary algorithm. Taguchi L18 orthogonal array was used for the development of acro-nitrile butadiene styrene based 3D components by considering layer thickness, support material, model interior and orientation as a process parameters. Further, the relationships among selected FDM process parameters and output responses such as hardness, flexural modulus, tensile strength and surface roughness were established by using linear multiple regression. Then, the effects of individual process parameters on selected response parameters were examined by signal to noise ratio plots. Finally, a multi-objective optimization of process parameters has been performed with hybrid PSO–BFO, general PSO and BFO algorithm, respectively. The overall results reveal that the layer thickness of 0.007 mm, support material type sparse, part orientation of 60 $${^\circ }$$ and model interior of high density helps in achieving desired performance level.

Impact of fused deposition modeling (FDM) process parameters on strength of built parts using Taguchi’s design of experiments

Abstract: The control of process parameters to customize a part has been a value-added ability related to additive manufacturing (AM). In this paper, parametric optimization of fused deposition modeling (FDM) process is performed using Taguchi design of experiments (DOE). Two sets of experiments were conducted on an industrial case study from the aerospace industry to assess the impact of FDM process parameters: layer thickness, shells, infill pattern, and infill percentage, on the compressive strength of the case study. A generic methodology was also proposed. Analysis of variance (ANOVA) and signal-to-noise (S/N) ratio analysis were performed to evaluate the importance of experimental error, finding the optimal combination of process parameters for maximizing the compressive strength, and assessing the robustness of the design. The paper concluded with the display of results, discussion, and conclusions drawn.

Optimization and reliability analysis to improve surface quality and mechanical characteristics of heat-treated fused filament fabricated parts

Abstract: Fused filament fabrication (FFF), an economic additive manufacturing (AM) method, is largely used for the fabrication of customized components (of medical, engineering, architectural, toy, artistic, etc. industries). However, the poor mechanical and surface properties are critical barriers limiting the growth of FFF. Therefore, a novel heat treatment approach has been utilized to improve the overall performance of printed parts. The parts were made with acrylonitrile-butadiene-styrene (ABS) with three infill densities (20, 60, and 100%) and annealing was carried out by changing the levels of temperature (105, 115, and 125 °C) and time duration (20, 25, and 30 min). The experimental design was conducted by Taguchi orthogonal array while the optimization was conducted using Taguchi S/N approach. The investigated responses were surface roughness, hardness, dimensional accuracy, tensile strength, flexural strength, and impact strength. Moreover, the reliability of the mechanical properties, with higher error (α > 5%), was verified by using the Weibull statistic to determine the survival rate of annealed FFF parts for functional applications. The adopted annealing approach was found to improve the physical and mechanical properties. The SEM analysis of fractured specimens revealed the type of failure (ductile or brittle). In recapitulation, the annealing process improved the quality characteristics of FFF parts.

Modeling and optimization of Wire-EDM parameters for machining of Ni55.8Ti shape memory alloy using hybrid approach of Taguchi and NSGA-II

Abstract: In the present research, Ni55.8Ti shape memory alloy has been machined by wire electric discharge machining (wire-EDM) process. The effects of input parameters such as spark gap voltage, pulse on-time, pulse off-time, and wire feed on productivity, i.e., metal removal rate (MRR) and surface quality, i.e., mean roughness depth (Rz), have been investigated. Empirical modeling and ANOVA study have been done after conducting 16 experiments based on Taguchi’s L16 design of experiment technique. Ranking and crowding distance–based non-dominated sorting algorithm-II (NSGA-II) is used for process optimization. The error percentage varies within ± 6% between experimental results and the predicted results developed by NSGA-II. It has been observed that the wire-EDM machining of Ni55.8Ti alloy at optimum parameters resulted in improved MRR —0.021 g/min—and surface quality with good surface finish (Rz—6.2 μm) and integrity as significant reduction in the formation of cracks, lumps, and deposited layers.

Optimization of parameters in laser powder deposition AlSi10Mg alloy using Taguchi method

Abstract: In this study, AlSi10Mg alloy were prepared by powder-delivery laser powder deposition (LPD) process. In order to obtain AlSi10Mg alloy with maximum density, LPD parameters were optimized using Taguchi method. Results were analyzed based on the signal-to-noise (S/N) ratios and analyses of variance (ANOVA). The optimal combination of parameters was laser power of 150 W, scanning speed of 400 mm/min, powder feeding rate of 0.78 g/min and shielding gas flow rate of 7 L/min. The dominant parameter was the laser power which contributes 49.43% to the relative density. Additionally, the regression equation was established based on the output parameter (relative density) and the four input process parameters, and validated by the obtained results. From the experiments, sample with density higher than 99% was obtained. The investigation will help to establish an efficient process for AlSi10Mg alloy fabricated by LPD.

Laser cladding of nanoparticle TiC ceramic powder: Effects of process parameters on the quality characteristics of the coatings and its prediction model

Abstract: In laser cladding process, the quality characteristics of the coatings are directly affected by laser cladding process parameters. In this work, in order to investigate the effects of the process parameters on the quality characteristics of the ceramic coatings on Ti6Al4V substrates, which were prepared by laser cladding using nanoparticle TiC powder as pre-placed material, five single factors (laser power, scanning speed, pre-placed powder thickness, laser spot diameter and multi-track overlapping ratio) and four interactions related to laser power were selected as influencing factors, and then multi-track cladding experiments with L27(313) orthogonal array designed by Taguchi method were carried out to obtain the geometric characteristics (coating thickness, coating width and height difference) and mechanical property (micro-hardness) of the coatings. Based on experimental results, the influence extents of all factors on quality characteristics were ranked by signal-to-noise (S/N) ratio, and the significances of all factors on quality characteristics were evaluated by using P-value from the analysis of variance (ANOVA). Then the effects of the significance factors on quality characteristic were analyzed in detail, and the optimal process parameters were selected. Finally, a prediction model based on support vector machine (SVM) was developed for the quality characteristics of the cladding coatings. The results showed that the pre-placed powder thickness, laser spot diameter and laser power were the most crucial process parameters. The prediction model based on SVM method can correctly describe the relations between cladding process parameters (input variables) and quality characteristics of coatings (output characteristics), with the correlation coefficient CC > 0.94. This research work gives a guideline for the selection of appropriate process parameters for laser cladding of high-quality coatings using nanoparticle TiC ceramic powder as starting material.

Taguchi’s methodology of optimizing turning parameters over chip thickness ratio in machining P/M AMMC

Abstract: Effect of turning parameters on chip generation during machining aluminum composite is studied in this work. Turning of Al–4%Cu–7.5%SiC composite material prepared through powder metallurgy procedure was chosen as the workpiece, machined using uncoated carbide insert TNMG 120404. Chips produced during machining were studied by measuring the thickness and were used along with uncut chip thickness to determine the chip thickness ratio. 99.85% pure aluminum was added with 4% volume fractions of copper and with silicon carbide particulates of 7.5%. To visualize the distribution of reinforcement phases in matrix, scanning electron microscope is used. Taguchi’s methodology of design of experiments was adopted for designing a L9 (Latin square) orthogonal array for experimental investigation, and from analysis of variance, cutting speed influencing the formation of chip by 64.13%, continuing with depth of cut by 35.26%, was identified. Confirmation test accomplished with ideal conditions produces a better chip condition.

Multi-objective optimization for sustainable turning Ti6Al4V alloy using grey relational analysis (GRA) based on analytic hierarchy process (AHP)

Abstract: Sustainable machining necessitates energy-efficient processes, longer tool lifespan, and greater surface integrity of the products in modern manufacturing. However, when considering Ti6Al4V alloy, these objectives turn out to be difficult to achieve as titanium alloys pose serious machinability challenges, especially at elevated temperatures. In this research, we investigate the optimal machining parameters required for turning of Ti6Al4V alloy. Turning experiments were performed to optimize four response parameters, i.e., specific cutting energy (SCE), wear rate (R), surface roughness (Ra), and material removal rate (MRR) with uncoated H13 carbide inserts in the dry cutting environment. Grey relational analysis (GRA) combined with the analytic hierarchy process (AHP) was performed to develop a multi-objective function. Response surface optimization was used to optimize the developed multi-objective function and determine the optimal cutting condition. As per the ANOVA, the interaction of feed rate and cutting speed (f × V) was found to be the most significant factor influencing the grey relational grade (GRG) of the multi-objective function. The optimized machining conditions increased the MRR and tool life by 34% and 7%, whereas, reducing the specific cutting energy and surface roughness by 6% and 2% respectively. Using Taguchi-based GRA by analytic hierarchy process (AHP) weights method, the benefits of high-speed machining Ti6Al4V through multi-response optimization were achieved.

Optimisation of mechanical stir casting parameters for fabrication of carbon nanotubes–aluminium alloy composite through Taguchi method

Abstract: The liquid metallurgical process route for synthesis of multiwalled carbon nanotube–A356 aluminium alloy (MWCNT-A356) composite is suitable for intricate designs and bulk production. In this work, MWCNT-CNT was fabricated through mechanical stir casting followed by thixoforming and modified by T6 (MT6) heat treatment. Hence, the optimisation and effect of variables such as amount of CNT, amount of wettability agent of Mg and mechanical stirring duration were investigated using a robust design of experiment (DOE), namely, Taguchi method, with two factorial levels. The signal-to-noise (S/N) ratio (‘larger is better’), hardness and ultimate tensile strength (UTS) were used as response variables. Results showed that the optimum hardness and UTS values of 106.4 HV and 277.0 MPa, respectively, were obtained from the nanoncomposite subjected to DOE run 4 and containing 0.5 wt.% MWCNT, 0.5 wt.% Mg and 10 min of mechanical stirring. The hardness (76.3%) and UTS (108.4%) improved compared with those of the as-cast A356 alloy. The transformation of the microstructures and the porosity of the as-cast after thixoforming and MT6 modification were also discussed. This work demonstrated the optimised mechanical stir casting parameters for MWCNT-A356 fabrication and the enhanced mechanical properties achieved by thixoforming and heat treatment.

Multi-objective optimization of energy consumption and surface quality in nanofluid SQCL assisted face milling

Abstract: Considering the significance of improving the energy efficiency, surface quality and material removal quantity of machining processes, the present study is conducted in the form of an experimental investigation and a multi-objective optimization. The experiments were conducted by face milling AISI 1045 steel on a Computer Numerical Controlled (CNC) milling machine using a carbide cutting tool. The Cu-nano-fluid, dispersed in distilled water, was impinged in small quantity cooling lubrication (SQCL) spray applied to the cutting zone. The data of surface roughness and active cutting energy were measured while the material removal rate was calculated. A multi-objective optimization was performed by the integration of the Taguchi method, Grey Relational Analysis (GRA), and the Non-Dominated Sorting Genetic Algorithm (NSGA-II). The optimum results calculated were a cutting speed of 1200 rev/min, a feed rate of 320 mm/min, a depth of cut of 0.5 mm, and a width of cut of 15 mm. It was also endowed with a 20.7% reduction in energy consumption. Furthermore, the use of SQCL promoted sustainable manufacturing. The novelty of the work is in reducing energy consumption under nano fluid assisted machining while paying adequate attention to material removal quantity and the product’s surface quality.

Influence of machining parameters on wire electrical discharge machining performance of reduced graphene oxide/magnesium composite and its surface integrity characteristics

Abstract: Taguchi coupled grey relation analysis is adopted to study the effects of machining parameters of Wire Electrical-Discharge Machining (WEDM) on magnesium metal matrix composite reinforced with Reduced Graphene Oxide(r-GO). An optimal combination of process parameter was expected to be finalized in this research to attain maximum Material Removal Rate (MRR) with a minimal surface roughness (Ra) value. The composite was fabricated through solvent based powder metallurgy route for varying percentage of r-GO. Experimental combination for WEDM of developed composite specimens were finalized to be L27 orthogonal array (OA) using Taguchi's method mainly based on the control factors namely reinforcement weight percentage (wt.%), pulse ON time (P1), pulse OFF time (P2) and wire feed rate (Wfd). ANOVA results revealed that wt.% and P1 are the most influencing parameters for MRR and Ra. Outputs scaleup that the developed regression model augments well with the experimental values. Using grey relation analysis (GRA) the optimal parameter was set and the final results obtained based on the optimal combination was found to be with a maximum MRR (18.38 mm3/min) and minimum Ra (3.29 μm). Traces of intermetallic formation are identified over the machined surface due to the action of machining parameters.

Prediction of surface roughness quality of green abrasive water jet machining: a soft computing approach

Abstract: The aim of this paper is to process modelling of AWJM process on machining of green composites using fuzzy logic (FL). An integrated expert system comprising of Takagi–Sugeno–Kang (TSK) fuzzy model with subtractive clustering (SC) has been developed for prediction surface roughness in green AWJM. Initially, the data base is generated by performing the experiments on AWJM process using Taguchi $$(\hbox {L}_{27})$$ orthogonal array. Thereafter, SC is used to extracts the cluster information which are then utilized to construct the TSK model that best fit the data using minimum rules. The performance of TSK–FL model has been tested for its accuracy in prediction of surface roughness in AWJM process using artificially generated test cases. The result shows that, predictions through TSK–FL model are comparable with experimental results. The developed model can be used as systematic approach for prediction of surface roughness in green manufacturing processes.

Integrated fuzzy AHP and fuzzy TOPSIS methods for multi-objective optimization of electro discharge machining process

Abstract: In the present work, the working of an electro discharge machining process was studied in which four factors, namely pulse on time, duty cycle, discharge current, and gap voltage, were considered to be the controllable parameters, each at three levels, for monitoring three responses, namely material removal rate, tool wear ratio, and tool overcut. Statistical design of experiments using Taguchi’s orthogonal array (OA) technique has been utilized to determine the optimum level of process parameters so that they are least affected by noise factors for obtaining a robust design of the parameters. Acknowledging the limitation that Taguchi’s OA technique can determine optimal setting of controllable parameters for one output or response at a time, integrated fuzzy AHP and fuzzy TOPSIS methods were used in the scheme of multi-response experiment so that Taguchi’s OA technique may be applied successfully for parametric optimization. The results show that none of the factors were highly significant although discharge current had the highest contribution (31.63%) among all.

Comparison and optimization of PVD and CVD method on surface roughness and flank wear in hard-machining of DIN 1.2738 mold steel

Abstract: This paper aims to examine the performance of the machining parameters used in the hard-turning process of DIN 1.2738 mold steel and identify the optimum machining conditions.,Experiments were carried out via the Taguchi L18 orthogonal array. The evaluation of the experimental results was based on the signal/noise ratio. The effect levels of the control factors on the surface roughness and flank wear were specified with analysis of variance performed. Two different multiple regression analyses (linear and quadratic) were conducted for the experimental results. A higher correlation coefficient (R2) was obtained with the quadratic regression model, which showed values of 0.97 and 0.95 for Ra and Vb, respectively.,The experimental results indicated that generally better results were obtained with the TiAlN-coated tools, in respect to both surface roughness and flank wear. The Taguchi analysis found the optimum results for surface roughness to be with the cutting tools of coated carbide using physical vapor deposition (PVD), a cutting speed of 160 m/min and a feed rate of 0.1 mm/rev, and for flank wear, with cutting tools of coated carbide using PVD, a cutting speed of 80 m/min and a feed rate of 0.1 mm/rev. The results of calculations and confirmation tests for Ra were 0.595 and 0.570 µm, respectively, and for the Vb, 0.0244 and 0.0256 mm, respectively. Developed quadratic regression models demonstrated a very good relationship.,Optimal parameters for both Ra and Vb were obtained with the TiAlN-coated tool using PVD. Finally, confirmation tests were performed and showed that the optimization had been successfully implemented.

Investigation of electrochemical post-processing procedure for Ti-6Al-4V lattice structure manufactured by direct metal laser sintering (DMLS)

Abstract: Additive manufacturing has become very popular nowadays to create complex geometries that cannot be achieved by any other manufacturing processes. The purpose of this study is to investigate and characterize the electrochemical polishing and chemical etching methods as a post-process treatment to improve the surface finish of lattice structures made from Ti-6Al-4V manufactured by direct metal laser sintering (DMLS). A lattice sample is designed with external and internal struts to compare the influence of the post-processing on different features. The post-processing parameters are studied via the Taguchi method. This work will provide critical information on the surface and geometrical characterization as well as the post-process treatment of a Ti-6Al-4V lattice. The metrological data will be analyzed to determine how the post-process treatment affects the surface finish, considering the final roughness and geometrical integrity of lattice samples. It is found that the material removal rate was more important at the edges, specifically on the external features. It was also confirmed that the average roughness is linked to the material removal for both processes. The more material is removed from the parts, the better the surface finish. It is also found that the etching process helps the electrochemical polishing go deeper inside the geometry.

Introduction to the Taguchi Method

Abstract: We now introduce a further powerful engineering tool: the Robustness concept. It is inextricably linked to the name of Genichi Taguchi, a Japanese engineer. Although his approach is based on what was outlined in the previous chapter on Design of Experiment, it contains strong innovation of those concepts. Significant improvements are proposed for three design phases: system design, parameters design and tolerance design. It is not possible to draw a comprehensive picture of the method here. Only the main concepts are introduced, leaving any more complex treatment of the method to specialized books. This method is a real improvement of the application of statistical methods to design applications. This chapter describes the basic concepts, among which the Quality Loss Function that better than other interpretations clarifies the term, often ambiguous, of quality. In this way, the link between robustness, reliability and design of quality becomes obvious. We tried to give emphasis to ideas more than to technicality, but a limited mathematical formalism is necessary.