Taguchi Orthogonal Array Research Articles

Non-contact surface roughness evaluation of milling surface using CNN-deep learning models

ABSTRACT Machining quality control is a bottleneck operation as human inspectors and expensive equipment is needed in most operations. Automated quality assurance in the manufacturing industry has the potential to replace humans and lower the cost of the machined product. This paper presents the analysis of end-milled machined surfaces backed with experimental and deep learning model investigations. The effects of machining parameters like spindle speed, feed rate (table feed), depth of cut, cutting speed, and machining duration were investigated to find machined surface roughness using Taguchi orthogonal array. Following standard DOE, surface roughness and machined surface image were recorded for each machining experiment and categorized into four classes, viz. fine, smooth, rough, and coarse, based on the roughness value (Ra). The machined surface images were used to develop CNN models for surface roughness class prediction. Further, comparative studies among the five popular optimizers were performed. The results showed that the CNN model with the ‘Rectified Adam’ optimizer performed better amongst the optimizer pool, with the training and test accuracy of 96.30% and 92.91%, respectively. The proposed CNN model features a highly accurate and slim structure, potentially substituting human quality control procedures that employ expensive surface roughness measuring devices.

Calibration of UAV flight parameters for pavement pothole detection using orthogonal arrays

Visual inspection for road damages demands significant human effort. Automating these inspections would reduce costs and errors. Using photogrammetry to generate 3D models of roads has become popular thanks to advances in cameras and image processing techniques. Using UAVs, these models depend on images' capturing parameters such as height, overlap, and camera angle over the studied infrastructure. Traditionally, these flight parameters are defined on a trial-and-error basis without any systematic procedure. To fill this gap, the application of Taguchi's orthogonal arrays to calibrate the main flight parameters is proposed. To evaluate this methodology, the area and volume of pavement potholes were reconstructed from 3D models generated with UAV photographs. This article contributes with a methodology for developing 3D models and replicable for other types of infrastructure. Moreover, the results obtained allow defining a flight and image capture strategy adequate to the quality requirements of the modelling, optimising time and resources.

To predict the surface roughness of Black ABS component with variable parameters by applying the Taguchi method

The objective of this research is to find the best combination factor values for minimizing surface roughness in test materials using Fused Deposition Modelling (FDM), specifically targeting Acrylonitrile Butadiene Styrene (ABS). However, the research community has given less attention to the surface quality with adequate process parameters as a result. This research aims to close that gap. The Design of Experiment (DOE) method is utilized in this study to evaluate how particular characteristics such as orientation, infill density, and nozzle diameter impact the surface roughness of Ultimaker 2 + produced products. Taguchi Orthogonal array was used to produce the specimens to restrict the number of experiments and give different combinations of these three elements and their levels at each experiment. The outcomes were based on both practical and ANOVA data. The surface roughness tester of the contact type used in this experiment was Mitutoyo Surface SJ-210. And minimum surface roughness was achieved using less infill percentage, nozzle diameter, and horizontal orientation of test specimen.

Investigation of Cold Extrusion of Aluminum AA 2024 Alloy using Finite Element Analysis

In recent years, the interest in modeling extrusion processes has resulted in the development of several analytical and numerical methodologies. The present work optimizes cold extrusion process variables (Die angle (DA), Ram speed (RS), Coefficient of friction (CoF)) on extrusion force, displacement, damage and time for the Aluminum AA 2024 alloy material. DEFORMTM-3D software is used to carry out numerical simulations and to study the behavior of the Aluminum AA 2024 billet during the plastic deformation over the conical die. The die/ container and ram (top die) are considered as rigid bodies and the room temperature is maintained during the extrusion process. The simulations are conducted as per L27 Taguchi orthogonal array. The obtained results are analyzed in ANOVA. An optimization using multiple variables is performed by grey relational analysis (GRA). The highest grey relational grade (GRG) is obtained for experiments conducted at DA level 2, RS level 2, and CoF level 3 (minimum extrusion force, damage and time) and (maximum displacement) is achieved by GRA. Systematically, the influence of the ram speed, coefficient of friction, and die angle are examined. The damage factor is considerable at 30° DA under the ram speed of 3mm/min.

Process intensification for the enhancement of growth and chlorophyll molecules of isolated Chlorella thermophila: A systematic experimental and optimization approach

In our current work, we have optimized six physicochemical parameters (light intensity, light period, pH, inoculum size, culture period, and salt concentration) toward growth and chlorophyll synthesis using isolated fresh water microalgae Chlorella thermophila [contains ∼6% (w/w on dry biomass basis) chlorophyll]. Here, both experimental and computational [Taguchi orthogonal array (TOA), artificial neural network (ANN), and genetic algorithm (GA)] approaches were employed for the process intensification. Results revealed that the content of biomass and chlorophyll were enhanced by 118% and 95%, respectively, with productivity enhancement of 30% for biomass and 61% for chlorophyll from the optimization of physicochemical parameters. Further, optimum light intensity was found to be 128 µmol m−2 s−1 after conducting experiments in optimized chemical and physicochemical conditions, contributing to the enhancement of productivity of 46% for biomass and 106% for chlorophyll. Urea was found to be the most effective nitrogen source with an increase of 70% and 160% biomass and chlorophyll productivity, respectively. Moreover, sucrose as a carbon source contributed to an increase of 97% and 264% biomass and chlorophyll productivity.

Optimizing biocatalytic potential of Dipodascus australiensis M-2 for degrading lignin under laboratory conditions

In present research, a potent fungal strain was isolated from paper mill effluent (black liquor) in order to investigate its potential for the biodegradation of lignin. Two step strategy was used to screen most efficient fungal strain having ability to growin MSM-black liquor medium and to degrade alkali lignin.The results of initial screening indicated that the strain M-2 produced comparatively higher ligninolytic zone on MSN agar plates supplemented with black liquor (BL) and alkali ligninase compared to the other isolates.The results of 18S rRNA gene sequencing revealed that strain M-2 showed ≥ 99% sequence homology with Dipodasceus australiansis.The process for the biodegradation of lignin was optimized using Taguchi Orthogonal Array design. Under optimized conditions of pH 9, 40 °C and 4% inoculum, a maximum of 89% lignin was degraded with 41% color reduction after 8 days of incubation period by Dipodasceus australiansis M-2. The pH and temperature were found to be significant terms with the p-values of 0.002 and 0.001 respectively. The laccase activity of the Dipodascus australiensis was found to be maximum of 1.511 U/mL. The HPLC analysis of lignin biodegradation indicated sharp transformation of peaks as compared to the control. Our results suggested that the strain Dipodascus australiensis M-2 possess excellent lignin degradation and color reduction capability and can be applied in waste treatment systems for pulp and paper mill effluent. In present work we are reporting first hand information regarding biodegradation of lignin by a potent strain of Dipodascus australiensis and statistical optimization of the bioprocess.

Kinetics and antimicrobial activity of gallic acid by novel bacterial co-culture system using Taguchi’s method and submerged fermentation

A tannase-positive Bacillus gottheilii M2S2 and Bacillus cereus M1GT were co-cultivated for the production of gallic acid using tannic acid as the sole carbon source through submerged fermentation. Taguchi orthogonal array of design of experimental methodology was used to estimate the influence and significance of tannic acid concentration, glucose concentration, agitation speed, and inoculum size on the gallic acid production in a shake flask. Among all the factors, agitation speed contributed the highest for gallic acid production (28.28%), followed by glucose concentration (21.59%), inoculum size (19.6%), tannic acid concentration (19.54%), and pH (11.09%). Validation experiments were executed at the found optimized conditions which resulted in a 6.36-fold increase in gallic acid yield compared to unoptimized conditions. Further, the kinetics of growth, tannic acid degradation, and gallic acid yield were evaluated at the optimized conditions. The kinetic parameters Y x/s, Y p/s, and Y p/x were determined as 0.292 mg of cells/mg of tannic acid, 22.2 µg of gallic acid/mg of tannic acid, and 70.76 µg of gallic acid/mg of cells with a growth rate of 0.273 h −1 after 24 h of fermentation. Finally, the antimicrobial activity of the product gallic acid was investigated against food-borne pathogenic E. coli, S. aureus, and Serriatia marcescens and showed a zone of inhibition of 2 cm, 1.6 cm, and 1.3 cm, respectively, using the agar disc diffusion technique. Thus, the cost-effective bioproduct gallic acid proved to be potentially effective to control food poisoning diseases and preserve foodstuff.

SELECTING OPTIMAL PROCESS PARAMETERS OF Al2O3/C COMPOSITE USING GRA WITH PCA AND TAGUCHI’S QLF APPROACH

The aim of this study is to find the controlled factors affecting the mass density of the combined Al2O3/Cu. All experiments were carried out using powder metallurgy. Experiments were carried out with four controllable powder processing parameters, namely milling time, compaction pressure, sintering temperature, and holding time. The L18 mixed-level Taguchi Orthogonal Array was used for experimental because it is the basis for the analysis of the Taguchi method. In this research, statistical analysis is carried out using GRA with PCA and Quality Loss Function. The result was the best model based on the Quality Loss Function, because the method has the biggest determination coefficient value is 99,97% where the results is better than GRA with PCA. From the main effect table study, the optimal combination of parameters for response: mass density and hardness are A2B3C3D2 powder metallurgical process parameters, namely milling time of 360 minutes, compacting powder of 200 MPa, sintering of 7000C, and holding time of 20 minutes. The ANOVA results show that the compaction pressure has the most influential parameter that affects the response. The percentage contribution of compaction pressure is 87.09%. Based on ANOVA, the R-squared value is 99.97%, which means the tested factor variables can explain the density of the Al2O3/Cu composite by 99.70%. Therefore, only 18 experimental trials are needed to discover the reality of what will happen in the process.

Statistical optimization of hydrogen production from bio-methanol steam reforming over Ni-Cu/Al2O3 catalysts

Hydrogen has emerged its importance for decarbonization to approach net-zero emissions in 2050. This study aims to develop three highly-porous Ni-Cu/Al2O3 catalysts (Ni-to-Cu weight ratio = 10 %, 20 %, and 30 %) for hydrogen production from the steam reforming of “Green” methanol (or bio-methanol). The prepared catalysts require no organic templates, thereby efficiently reducing unnecessary costs. With Taguchi orthogonal array design and analysis of variance (ANOVA), the impacts of selected operating factors on hydrogen productivity under ultrasonic sprays are investigated. The results reveal that the carrier gas flow rate is the most influential factor in H2 yield at the steam-to-methanol molar ratio (S/C) of 1.5, whereas the temperature is the most impactful factor at S/C = 2.0. The regression between the Taguchi effect value and the ANOVA F value develops a strong linear relationship. The optimal experimental conditions of Ni-Cu(30 %)/Al2O3, reaction temperature of 300 °C, N2 flow rate of 1,000 mL⋅min−1, and S/C = 2.0, achieve 100 % methanol conversion, 39.74 vol% H2 concentration in the product gas, and 2.93 mol⋅(mol CH3OH)-1 H2 yield. Thes data also show superior performance compared to those in the literature. In long-term stability tests, the prepared catalysts also exhibit high stability and effectiveness commensurate with commercialized Cu-based catalysts.

Microstructural and compaction characteristics of tropical black clay soil subgrade modified with lead-zinc mine tailings

Lead–Zinc Mine tailings (LZMT) are wastes generated after the extraction of lead and zinc from mined mineral ore, whose disposal mechanism is gradually becoming environmentally unfriendly. For effective recycling of LZMT, this present study utilized a combination of LZMT and Portland limestone cement (PLC) to improve the compaction and microstructural characteristics of tropical black clay soil (TBCS) for use in pavement design and construction. The LZMT and PLC were added to the expansive soil in varying proportions with mix ratios generated from Taguchi orthogonal array. The result obtained for the compaction characteristics showed that the maximum dry density (MDD) increased significantly when a combination of 20% LMZT and 4% PLC were blended with the expansive soil. The increase in the MDD was attributed to the formation of cementitious compounds. In addition, the optimum mix ratio obtained from the unconfined compressive strength of the TBCS, was used for the evaluation of the pore structure characteristics which included porosity, tortuosity and permeability. The result obtained from the analysis that was implemented with a combination of fractal geometry and Bradley and Roth adaptive thresholding image segmentation technique, indicates the possibility of a slight reduction in the strength properties of the modified soil due to its high level of porosity. Also, the permeability and tortuosity values obtained from the present study suggest a slight increase in the permeability of the modified soil-additive mixtures which may not be unconnected to the occurrence of pozzolanic reaction that resulted in the agglomeration and flocculation of the LZMT-PLC modified TBCS. Furthermore, microstructural analysis was executed on the modified TBCS and LZMT using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The result from the FTIR analysis indicates the pozzolanic character of LZMT in the presence of Si–O and Al–O tension bond with the bonds around 1000 cm−1 wavenumber, while the SEM analysis reveals the formation of a cementitious compound in the modified expansive soil-LZMT-PLC mixture.

Taguchi Grey Relational Analysis for Multi-Response Optimization of Bacillus Bacteria Flocculation Recovery from Fermented Broth by Chitosan to Enhance Biocontrol Efficiency.

Degradation of environment is a challenge to crop production around the world. Biological control of various plant diseases using antagonistic bacteria is an encouraging alternative to traditionally used chemical control strategies. Chitosan as a well-known natural flocculation agent also exhibits antimicrobial activity. The goal of this study was to investigate a dual nature of chitosan in flocculation of Bacillus sp. BioSol021 cultivation broth intended for biocontrol applications. Experiments were performed based on L18 standard Taguchi orthogonal array design with five input parameters (chitosan type and dosage, pH value, rapid and slow mixing rates). In this study, the grey relational analysis was used to perform multi-objective optimization of the chosen responses, i.e., flocculation efficiency and four inhibition zone diameters against the selected phytopathogens. The results have indicated a great potential of a highly efficient method for removal of the Bacillus bacteria from the cultivation broth using chitosan. The good flocculation efficiency and high precipitate antimicrobial activity against the selected phytopathogens were achieved. It has been shown that multiple flocculation performance parameters were improved, resulting in slightly improved response values.

Taguchi method and Box-Behnken design approach for process parameter optimization of magnetite (Fe3O4) coating developed on stainless steel 410 grade by hot alkaline treatment

The blackening of materials is widely used in the automobile industry, defense applications, aerospace applications, and solar applications. Methods such as electroless chemical process, conversion coating, physical vapor deposition, chemical vapor deposition, and diamond-like carbon are some of the commonly employed techniques to produce black coatings on various metals. Hot aqueous alkaline treatment is a chemical conversion coating process. In this study, hot alkaline treatment is used to blacken surgical equipment made of stainless steel 410, which is a novel approach. The effect of process variables such as immersion time, salt solution temperature, and wt% of sodium dichromate on the anti-reflective property of ferrous ferric oxide (magnetite, Fe3O4) coating has been optimized using the Taguchi method and response surface methodology. The experiments were designed using a Taguchi orthogonal array and a Box-Behnken design. The influences of coating parameters on average percentage reflectance were quantified by the signal-to-noise ratio, main effect plot, analysis of variance, and two-dimensional and three-dimensional plots. The comparison of experimental and confirmatory tests shows that both procedures optimized the parameters successfully. The lowest average percentage reflectance value of 8.013% was obtained at 56.976 min immersion time, 124.998°C salt solution temperature, and 348.689 g/l wt% of sodium dichromate in the composition by Box-Behnken design methodology.

Effect of alumina particulate and E-glass fiber reinforced epoxy composite on erosion wear behavior using Taguchi orthogonal array

This article includes the erosion wear behavior of alumina (Al2O3) and E-glass fiber reinforced epoxy composites. The erosion wear was conducted on air jet erosion tester. Alumina was reinforced with a variation of 0–20 wt%. Five formulations were made: L1, L2, L3, L4, and L5. The reinforcement content, impact velocity, discharge, and impingement angle as machine control factors were employed for the erosion wear. Taguchi (L25) orthogonal array was used to determine erosion wear. From the Taguchi analysis, the minimum erosion rate was recorded at 10 wt% of reinforcement content, 30 m/s of impact velocity, 1 gm/min of discharge, and 45°of impingement angle. The impact velocity was found the most influential parameter affecting the erosion rate from the ANOVA analysis, with a percentage contribution of 41 %. From the investigation of the scanning electron microscope, the result shows that Al2O3 particles have more interaction with polymer matrix and good stress transfer properties.

Multi-Response Optimisation of Automotive Door Using Grey Relational Analysis with Entropy Weights

Tail-welded blanks (TWBs) are widely used in automotive bodies to improve the structural performance and reduce weight. The stiffness and modal lightweight design optimisation of TWBs for automotive doors was performed in this study. The finite element model was validated through physical experiments. An L27 (312) Taguchi orthogonal array was used to collect the sample points. The multi-objective optimisation problem was transformed into a single-objective optimisation problem based on the grey relational degree. The optimal combination of structural design parameters was obtained for a tail-welded door using the proposed method, and the weight of the door structure was reduced by 2.83 kg. The proposed optimisation method has fewer iterations and a lower computational cost, enabling the design of lightweight TWBs.

Effect of Build Parameters on Process Energy Consumption and Material Usage in Fused Deposition Modelling Method

Fused deposition modelling (FDM) process is one of popular 3D printing technologies, especially on printing polymer materials for a rapid prototyping. The process is well known for its resource saving, with no tooling cost required and minimum energy demand. However, the challenge is that the process performances are highly influenced by selection of parameters. From literature, consideration on material usage and process energy demand in FDM processes is still limited. This study used an L9 Taguchi orthogonal array design in investigating effect of build orientation, printing speed and layer thickness on process energy consumption and total material usage in FDM processes. The p-values from ANOVA analysis revealed that only layer thickness and build orientation had significant effect on the outputs. In minimising material usage, the strategy is to select the correct build orientation to avoid need of support structure. For reducing energy demand, optimum layer thickness needs to be determined by considering other factors such as mechanical properties and surface roughness. This study provides preliminary findings which will benefit FDM users in using resources efficiently. Further studies are required to complement the findings from the aspects of mechanical and physical properties of the printed products.

Parameter Screening and Optimization for a Polycaprolactone-Based GTR/GBR Membrane Using Taguchi Design.

Our objective was to determine and optimize the significant parameters affecting mechanical properties and mean fiber diameter (MFD) of a novel GTR/GBR membrane composed of polycaprolactone (PCL) and chicken eggshell membrane (ESM). For this, we prepared electrospun membrane specimens (n = 16) with varying concentrations of PCL, ESM, nano-hydroxyapatite (HAp), and altered electrospinning parameters as generated by DOE++ software. After the determination of MFD and mechanical properties for all specimens, Taguchi orthogonal array L8 design was used to screen significant factors affecting the MFD and mechanical properties. PCL wt%, ESM wt%, HAp wt%, applied voltage (AV), flow rate (FR), and spinneret-collector distance (SCD) were the independent variables investigated. The response variables analyzed were MFD, tensile strength (TS), and elastic modulus. ANOVA outlined ESM wt%, HAp wt%, AV, FR, SCD, and an interactive effect between PCL wt% and AV to be the significant factors affecting modulus values of an electrospun PCL/ESM membrane (p < 0.05). Furthermore, concentrations of PCL and ESM were the significant factors affecting MFD (p < 0.05) and there were no significant factors affecting the TS values. Optimization using DOE++ software predicted that the maximal TS of 3.125 MPa, modulus of 278.168 MPa, and MFD of 882.75 nm could be achieved.

Optimization of mannanase hydrolysis of steamed palm kernel cake to improve nutritional quality

Palm kernel cake (PKC), an abundant and healthy feed alternative to soybean meal and yellow corn, has been used in animal diets. The use of PKC in monogastric nutrition is limited due to its high fibre content. Although it has been demonstrated that steamed PKC is easily digestible by mannanase, the impact of the operation variables is unknown. Steamed PKC was enzymatically hydrolyzed to improve its efficient when used as feed by multi-response criteria based on the Taguchi orthogonal array. On the basis of a L9 orthogonal array, nine experimental runs were carried out. The percentage of substrate, incubation duration, and enzyme units were optimized, focusing on protein and carbohydrate content. The predicted and experimental results of optimal conditions to produce steamed PKC hydrolysate based on the Nine Taguchi design were 20%, 6 h, and 750 units. Optimum conditions yielded reducing sugar, total sugar, and protein release at 655.85 mg/mL, 875.75 mg/mL, and 1,631.86 mg/mL, respectively. Protein content was considerably decreased during pepsin digestion in all runs when compared to raw PKC. The chemical analysis of steam hydrolysate demonstrated that B. amyloliquefaciens NT6.3 mannanase increased the amount of neutral detergent soluble (NDS) components while decreasing non-starch polysaccharide components. This study identified the optimal conditions for improving the functionality of steamed PKC for efficient use as a feedstuff.

Process Parameter Optimization for 3D Printed Investment Casting Wax Pattern and Its Post-Processing Technique

This research paper aims to improve the quality of 3D printed parts made of the wax filament by implementing the Taguchi orthogonal array process optimization method. The manufactured parts can be used as cost-effective investment casting patterns. With the Taguchi method, it was concluded that the nozzle temperature has the most effect on the dimensional accuracy of printed parts. In addition, thermal, mechanical, and rheological characterization were performed on the wax filament, revealing several important findings. For instance, the rheological studies identified the low viscosity of melted wax at printing temperatures. This resulted in the rough surface of the printed parts. To improve the surface roughness, a post-processing procedure was implemented using a white spirit as a surface smoothing agent.

Crystal violet removal from aqueous solutions using dry bean pods husks powder – optimization and desorption studies

Abstract In this study the Taguchi method was used to establish the optimal conditions for the adsorption of crystal violet dye on an adsorbent obtained from dry bean pods husk. Six factors, at three level, were considered in establishing the L27 Taguchi orthogonal array. The ANOVA analysis was performed to calculate the each factor percentage contribution on the dye removal efficiency. A desorption study was carried out to evaluate the regeneration possibility of the used adsorbent. The removal efficiency ranged from 5.91 to 94.48 % depending on the controllable factors combination set by Taguchi design. The results showed that the factor with the highest percentage contribution on the dye removal efficiency was the ionic strength (48.85 %). The correlation between the predicted values of the dye removal efficiency with those obtained experimentally indicate a good accuracy of Taguchi approach.

Systemic Optimization and Validation of RP-HPLC Method for the Estimation of Ritonavir from Hybrid Polymeric Nanoparticles in Rat Plasma

Background: Hybrid polymeric materials have been in research focus owing to their outstanding progression in drug targeting. A new Quality by Design approach by RP-HPLC was developed and validated for the estimation of hybrid polymeric nanoparticles of Ritonavir in rat plasma. Objective: The main objective of the present study was to develop and validate a simple, robust, and accurate method by QbD approach for the detection of hybrid polymeric nanoparticles of Ritonavir (RTV) in plasma. Methods: The mobile phase consisting of a mixture of Acetonitrile: HPLC grade water (60:40 v/v), 1.0 ml/min flow rate and UV detection at 240 nm. Critical Analytical Attributes (CAAs) were screened and selected by Taguchi orthogonal array model. Box-Behnken's three-level, the 3- factorial design, was employed to create and analyze a "Design Space" (DoE). This design was statistically analyzed by ANOVA, contour-plot, and 3D response surfaces plots, which demonstrated that the model was statistically significant. The developed method was validated as per the ICH guidelines Q2 (R1). Results: The developed method showed excellent linearity between 100 and 600 ng/mL with good regression (R2&gt;0.998), LOD (10 ng/mL) and LOQ (30 ng/mL). The validation results of the tested parameters were found within the acceptable limit. Conclusion: From the study, it was concluded that QbD driven bioanalytical method is suitable for the in-vitro and in-vivo estimation of RTV from bulk as well as from hybrid polymeric nanoparticles formulation.