Array Experimental Design Research Articles

Development of a hybrid model to estimate surface roughness of 3D printed parts

The research aims to develop a hybrid model to estimate the surface roughness of 3D printed parts, considering the significant process parameters and measurement uncertainties inherent in additive manufacturing (AM). The methodology involves a Taguchi L-27 orthogonal array design of experiments (DOE) to identify significant factors. This is followed by a deep dive analysis of the roughness profile and the modelling of the measurement process uncertainties. The ANOVA tests reveal that build orientation and layer height are critical contributors to surface roughness. However, it was evident from the experimental analysis that the layer height and build orientation shares a complex relation on surface roughness. The two novelties of this paper are: one, the development of a hybrid model of surface roughness by mathematically quantifying the staircase (step and stack) and corner geometry effects of the part geometry. Two, strengthening the model’s surface roughness prediction accuracy by incorporating the stylus flight and probe reachability measurement uncertainty functions. The final mathematical function was validated with multiple experimental data as well as literature data. The results show that the proposed model is robust to estimate the surface finish accurately at build orientations in the full range of 0–90 degree. The statistical analysis shows that the proposed model is capable of accurately predicting about 90 % variations in the data at different layer heights and build orientations. The proposed model is useful to accurately predict the surface finish of 3D printed parts, a priori, during the part design or before printing, thereby improving the surface quality of the AM parts.

Influence of design parameters on sustained drug release properties of 3D-printed theophylline tablets

The application of three-dimensional printing (3DP) in the pharmaceutical industry brings a broad spectrum of benefits to patients by addressing individual needs and improve treatment success. This study investigates the sustained release properties of 3DP tablets containing Theophylline (TPH), which is commonly used to treat respiratory diseases and recently having a comeback due to its potential in the treatment of conditions like Covid-19. Since TPH is a narrow therapeutic window (NTW) drug with serious side effects in the event of overdose, the release properties must be observed particularly closely. We employed a state-of-the-art single screw extrusion 3D printer, which is fed with granules containing the drug. By employing a Taguchi orthogonal array design of experiments (DOE), tablet design parameters and factor related process stability were sought to be evaluated fundamentally. Following this, examinations regarding tailored TPH dosages were undertaken and a relationship between the real printed dose of selected tablet designs and their sustained drug release was established. The release profiles were analyzed using different mathematical model fits and compared in terms of mean dissolution times (MDT). Finally, in-vivo/in-vitro correlation (IVIVC) and physiologically based pharmacokinetic (PBPK) modeling showed that a paradigm patient group could be covered with the dosage forms produced.

Tribological impact on borosilicate glass powder reinforced Al-MMC by variation of sliding velocity and the study of its machinability

Now-a-days, metal matrix composites based on pure aluminium are widely used as a replacement for a wide range of applications thanks to their high strength-to-weight ratio, ductility, and thermal conductivity. Micron-sized (10−3 mm) borosilicate (mixer of Silica (SiO2) and Boron Oxide (B2O3)) glass particles were used to create a dispersion in an aluminium matrix composite (Al7075- borosilicate glass MMC) utilizing a stir casting technique while in a liquid condition. The present study examines the effect of borosilicate glass particle content (0, 3, 6, and 9 wt%) and changes in sliding velocity (0.5, 1, 1.5, and 2 m s−1) on the wear behaviour of a composite rubbing against an EN31 steel disc at a constant load of 20N and a sliding distance of 1000 m. Analysis of wear showed that the presence of borosilicate glass increased the wear rate and countered the trend shown in the coefficient of friction. In a similar vein, the sliding velocity of the counter plate rotated faster resulted in a higher coefficient of friction and a higher wear rate. A reliable mathematical model is developed to find the best combination of machining parameters for Al7075-borosilicate glass metal matrix composite (MMC). This model will consider important performance measures like surface smoothness and material removal rate. The authors will also use a sophisticated statistical method called the Taguchi L9 orthogonal array design of experiments (DOE) to understand how different machining settings affect how easily the composite can be machined. By analyzing the results from the DOE, it can optimize the machining parameters for efficient and cost-effective processing. This work can lead to manufacturing innovation in the future.

Low binder content bricks: a regolith-based solution for sustainable surface construction on the Moon

This work proposes a composite construction material made by a blend of lunar regolith and thermoplastic binders in dry powder form. This solution offers advantages over regolith sintering or melting by requiring lower power consumption and simplifying the manufacturing process. However, its sustainability depends on minimizing the content of the binder material. Drawing from validated concepts used on Earth, such as polymeric concrete and compressed Earth bricks, this paper suggests that binder optimization can be achieved by simplifying and streamlining the manufacturing process, targeting parts with predefined shapes. Standardized elements like bricks or tiles ease production and assembly automation, especially when incorporating interlocking features, simplifying the payload concept transition. After drafting the process with a minimum number of basic steps, this work studies the effects of some process parameters to minimize the weight percentage of the matrix while maintaining reasonable mechanical properties. The compressive and the flexural strength are the targets of an orthogonal array Design of Experiment. Through comparison with reference values for civil engineering, the process demonstrates promising results within an organic phase as low as 10 wt%.

Comparative performance evaluation between ta-C and TiAlCrN coated tools during milling of additively manufactured CFRP composite

Due to the excellent strength-to-weight ratio and corrosion resistance properties, the application of carbon fibre-reinforced plastic (CFRP) composites is rising among various industries day-by-day. This research addresses the performance evaluation of tetrahedral amorphous hard carbon (ta-C) and TiAlCrN coated carbide tools during milling of additively manufactured CFRP composite under dry environment. Tool rotational (spindle) speed, feed and depth of cut are considered as the variable factors in order to evaluate the machining performance characteristics in milling operation concerning surface roughness (Ra), cutting force (Fc) and cutting temperature (T). Taguchi's L16 orthogonal array design of experiments was adopted to conduct the machining trials under various settings of process variables. The relative influence of the different types of coatings and different operating parameters on machined surface morphology in milling was analysed by scanning electron microscope. From the experimental results, a promising machining performance is noticed for TiAlCrN coated carbide end milling tool accomplished by physical vapour deposition technique in terms of all machining attributes compared to ta-C coated end milling tool due to superior wear resistance, surface hardness and bonding strength of coating material. Among the tools used, TiAlCrN coated carbide tools for CFRP milling application promises excellent machinability performances in terms of reduced cutting force, enhanced machined surface morphology as well as surface finish, and minimum cutting temperature. The mean value ratios for Ra ta-C/RaTiAlCrN, Fc ta-C/FcTiAlCrN and T ta-C/TTiAlCrN are 1.44, 1.24 and 1.21, respectively.

Design development of coal-based fly ash geopolymer brick using orthogonal array design of experiment

ABSTRACT The world produces billions of fired-clay bricks annually, but their manufacturing process adversely affects the environment. The present article investigates the alternative and sustainable approach for manufacturing coal-based fly ash geopolymer bricks by L9 orthogonal array design of experiment. Three factors and three levels were considered against a single response. The physical, mechanical, and thermal properties of bricks were evaluated and reported in the paper. The optimal ratio to produce fly ash geopolymer brick was 12 Molarity (M) NaOH solution, 2.5 alkaline solution ratio (ASR), and 60°C curing temperature (CT). The experiment’s confirmation and prediction were made and found within the limit. The significance of different levels of factors in enhancing the strength of brick specimens was analyzed using Analysis of Variance (ANOVA) through a General Linear Model. The results indicated that Molarity, ASR, and CT were the crucial factors in improving the strength of the brick specimens. Moreover, to investigate the morphology, mineralogy, phase structure, and thermal resistance of the brick specimens, microstructural properties such as Field Emission Scanning Electron microscopy (FESEM) – Energy dispersive spectra (EDS), X-Ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and Thermal Gravimetric Analysis (TGA) were carried out and reported in the paper.

Development and erosion wear analysis of polypropylene/Linz‐Donawitz sludge composites

AbstractIn the present investigation, a steel industry waste Linz–Donawitz (LD) sludge was added in different proportions with a polypropylene (PP) matrix and composite specimens were manufactured using the hand layup method. Experiments were performed to study the physical, mechanical, and erosion wear properties of the PP–LD sludge composites. This investigation also includes scanning electron microscopy (SEM), and x‐ray diffraction analysis of filler and composites. The erosion wear tests were carried out by Taguchi's experimental array design, where the effect of five control factors (impingement angle, filler content, erodent size, impact velocity, and erodent temperature) on erosion rate was analyzed. It was observed that filler content is the most influencing factor affecting were rate of the composites. At the maximum filler content of 20 wt%, the compressive strength and hardness increased to 85.71 MPa and 0.643 GPa, respectively. The tensile strength of the composites marginally decreased by 12.97% with the addition of 20 wt% filler. It was further observed that the flexural strength of the neat polymer decreased from 29.23 to 22.98 MPa with the addition of 20 wt% LD sludge. The SEM pictures of the eroded surface exhibited that the material removal is due to micro cracking and crack propagation.Highlights In this study, an industrial waste (LD sludge) is successfully used as a potential filler material in the PP matrix. Physical and mechanical properties of the PP‐LD sludge composites are analyzed. Effects of different parameters like filler content, impact velocity, impingement angle, erodent size and erodent temperature on the wear behavior are studied. Scanning electron microscopy is carried out so that a micro‐examination of the surfaces can be performed, as well as an assessment of the wear derbies.

Mechanical properties evaluation of FFF-printed ABS samples based on different process parameters combined with ANOVA and regression analysis

The fused fabrication process (FFF), is one of the most popular additive manufacturing technologies used for prototyping and production applications. On the other hand, poor mechanical characteristics significantly impact the application of FFF parts, and a variety of process parameters can influence the effectiveness of parts produced with FFF. Infill density, layer thickness, print speed, and extrusion temperature are the essential FFF parameters for fabricating parts and the dimensional integrity of printed specimens. This research aims to examine the functional performance of ABS fabricated through FFF. The study’s various variables include extrusion temperature (230°C, 240°C, and 220°C), feed rate (20, 35, and 50 mm/s), and layer height (0.1, 0.15, and 0.2 mm). Based on various combinations, elongation at break, energy, tensile strength, and compressive strength will be assessed. The measured lowest tensile and compressive strengths are 25.252 and 38.52 MPa, respectively, and highest tensile and compressive strengths are 33.96 and 185.94 MPa, respectively. As a result, changing the different process variables increases tensile strength by 34.49% and compressive strength by 382.71%. Fractography analysis is also performed to understand the failure modes of specimens, indicating pulling, necking, failure of raster’s, and voids for the considered specimens. To examine the dependency and relationship of the tensile and compressive strength on the process parameters, statistical analysis is performed using ANOVA, Taguchi’s L27 array design of experiment, and regression analysis. It indicates that layer height has the most significant influence on tensile and compressive strength, followed by extrusion temperature and feed rate.

Effects of machining parameters on H13 die steel using CNC drilling machine

In order to enhance the fitness of the product and in order to improve productivity in turning operations, greater amount of challenges have been faced. In this paper, we have made a comparative analysis of HSS and carbide coated HSS drills while machining with H13 steel plates. For the drilling operation, process parameters were analysed using the Taguchi design of experiments. The response performance characteristics of surface roughness of H13 die steel plates for the drilling settings, cutting speed (rpm), and feed rate (mm/min) is optimized. The design of the experiment was conducted using the Taguchi technique for the L18 orthogonal array, and an analysis of variance was observed. The effect of drilling settings on the quality of drilled holes is examined; variation in surface roughness for various levels of speed and feed and the different combinations of these levels will form an L18 orthogonal array design of experiment by Taguchi analysis. A total of 36 cutting tests were performed with two different drill bits; here three different cutting speeds of 300, 600, and 900 rpm were taken with a feed rate of 0.02, 0.04, and 0.06 mm/rev combinations. The response of SN ratio for surface roughness of HSS and carbide tool has been found out for different levels of speed and feed. From this Taguchi analysis, it is identified that the optimal parameter. As a result, the factors are analysed, and optimized parameters have been concluded for H13 material using HSS, and carbide tools were examined both statistically and experimentally. The carbide coated drill bit gives 60% better surface roughness value based on experimental data obtained. The surface roughness value based on experimentation for HSS tool was found to be 34.16% and carbide coated drill bit was 23.40%.

Taguchi optimization of YSZ/alumina/silica colloids for suspension plasma sprayed coating process

The stability of suspensions plays a key role in the water-based suspension plasma sprayed coating process. The effects of suspension parameters, such as the solid content and the type/content of dispersants on the suspension stability were studied in this work. In this regard, a Taguchi L9 array design of experiments was used to optimize submicron-sized YSZ/nano-sized alumina/silica additive suspensions with low viscosity, high steady-state turbidity, and inter-particle electrostatic charges. The optimal stable suspension with the viscosity of 4.2 cp, the zeta potential of 65 mV, and the Nephelometric Turbidity Units (NTU) of 3503 was used as the feedstock for suspension plasma spraying. Accordingly, a typical columnar coating morphology was obtained with the porosity of almost 19.3 vol%, which is a desirable feature for high-temperature applications. In conclusion, this study reflects the merit of the Taguchi design of experiments to optimize multicomponent thermal barrier coatings.

Drilling Strategies to Improve the Geometrical and Dimensional Accuracy of Deep through Holes Made in PA6 Alloy.

This article shows how different drilling strategies may affect the geometrical and dimensional accuracy of deep through holes. The tests were conducted on a three-axis direct-drive turning center. The holes were drilled in cylindrical PA6 aluminum alloy specimens 30 mm in length and 30 mm in diameter using 6 mm Ø VHM HPC TiAlN-coated twist drill bits. The cutting fluid was supplied to the cutting zone through the spindle. The experiments involved applying three strategies to drill deep through (5D) holes. The first required the workpiece to be fixed and the tool to perform both rotary and reciprocating motions. The second assumed that the workpiece performed the primary (rotary) motion whereas the tool moved in reciprocating motion. In the third strategy, the workpiece and the tool rotated in opposite directions and the tool also performed a reciprocating motion. The straightness, roundness, cylindricity, and diameter errors were the key output parameters in the analysis of the geometrical and dimensional accuracy of holes. The Taguchi orthogonal array design of experiment (DOE) was employed to determine the effects of the input (cutting) parameters (i.e., spindle speed and feed per revolution) and the type of hole making strategy on the hole errors by means of multi-factor statistical analysis ANOVA. The use of the highest spindle speed (n = 4775 rpm), the highest feed per revolution (fn = 0.14 mm/rev) and strategy I resulted in the lowest values of the output parameters (STR = 22.7 µm, RON = 8.6 µm, CYL = 28.2 µm, and DE = 9.9 µm). Strategy I was reported to be the most effective for hole drilling in PA6 aluminum alloy because, irrespective of the values of the process parameters used, three out of four output parameters, i.e., straightness, roundness and diameter errors, reached the lowest values.

EFFECT OF BUILD PARAMETERS ON PROCESS PERFORMANCES AND MECHANICAL PROPERTIES OF PRINTED PRODUCT IN FUSED DEPOSITION MODELLING METHOD

Fused deposition modelling performances are dominated by selection of process parameters. Multi objective optimisation is essential in ensuring excellent product mechanical properties, surface quality and resource efficiency. This paper presents a preliminary work based on Taguchi orthogonal array design of experiment, considering build orientation, printing angle and layer thickness as the input factors. The build orientation has a significant influence on tensile strength while the layer thickness on energy consumption and printing time. Adverse effects on the responses can be observed during the attempts. However, two factors optimisations were still achievable. Optimal settings should be suited based on final application and economical constraints. This study has established a groundwork of further studies in optimisation of quality of the method.

Efficient Synthesis of Quaternised Guar Gum using Tri‐alkylamine and Epichlorohydrin Condensate by Taguchi L9 Orthogonal Array

AbstractGlycidyltrimethylammonium chloride (GLYTAC) is an efficient quaternizing reagent, easy to synthesize, and causes lesser degradation to the polymer backbone than other reagents. Quaternization of guar gum was carried out using condensate of trimethylamine and epichlorohydrin as etherifying reagents adopting Taguchi's L9 orthogonal array design of experiment to optimize the reaction conditions to attain a higher degree of substitution (DS). The set of optimized levels of selected control factors are as follows; 2.5 mL and 1.2 g of condensate and sodium hydroxide respectively at 30 °C and time 6 h. The DS of the quaternized derivative prepared under optimized reaction conditions was determined as 0.046. The appearance of an additional signal at 3.06 ppm and 54.62 in 1H and 13C and the corresponding cross signal inHSQC (1H−13C) confirmed the synthesis of quaternized guar gum. The study demonstrated that Taguchi L9 orthogonal array is a reliable statistical approach for efficient and green synthesis of quaternized derivatives.

Statistical Analysis of Machining Parameters on Burr Formation, Surface Roughness and Energy Consumption during Milling of Aluminium Alloy Al 6061-T6.

Due to the increasing demand for higher production rates in the manufacturing sector, there is a need to manufacture finished or near-finished parts. Burrs and surface roughness are the two most important indicators of the surface quality of any machined parts. In addition to this, there is a constant need to reduce energy consumption during the machining operation in order to reduce the carbon footprint. Milling is one of the most extensively used cutting processes in the manufacturing industry. This research was conducted to investigate the effect of machining parameters on surface roughness, burr width, and specific energy consumption. In the present research, the machining parameters were varied using the Taguchi L9 array design of experiments, and their influence on the response parameters, including specific cutting energy, surface finish, and burr width, was ascertained. The response trends of burr width, energy consumption, and surface roughness with respect to the input parameters were analyzed using the main effect plots. Analysis of variance indicated that the cutting speed has contribution ratios of 55% and 47.98% of the specific cutting energy and burr width on the down-milling side, respectively. On the other hand, the number of inserts was found to be the influential member, with contribution ratios of 68.74% and 35% of the surface roughness and burr width on the up-milling side. The validation of the current design of the experiments was carried out using confirmatory tests in the best and worst conditions of the output parameters.

Experimental optimization of electrical discharge coatings using conventional electrode

In the last few years, researchers around the world are working to develop procedures that will allow coating a conductive material on another conductive base material using Electrical Discharge Machine (EDM). This process helps to extend the usage of EDM for the purpose of hard coatings. In this study, 24 experiments were conducted to coat copper on titanium alloy substrate by varying the coating input process parameters and surface treatments and output responses such as material deposition rate (MDR) and electrode wear rate (EWR) were calculated. Wherever it is necessary, L9 orthogonal array design of experiments was implemented and all the coatings were taken for characterization with scanning electron microscope (SEM). With this characterization, surface morphology, coating thickness, coating-base material interface and surface crack density were studied to select one optimum coating for each case. Selected three coatings were considered for further characterization viz., phase analysis with X-ray diffraction (XRD) and surface topography with Atomic Force Microscopy (AFM). Phase obtained were Cu and TiZn16 which were further heat treated to stabilize. Line and area profiles from surface roughness analysis was obtained and parameters such as min and max, peak and valley, Ra, Rq, Rz were evaluated.

Mechanical characteristics and failure morphology of FFF-printed poly lactic acid composites reinforced with carbon fibre, graphene and MWCNTs

Fused Filament Fabrication (FFF) is the most prevalent additive manufacturing technique, which involves extruding a softened thermoplastic filament through the nozzle of a heated extruder. For improving the mechanical properties of the FFF-printed PLA parts one of the options is to add reinforcing material, such as carbonaceous materials or metal particles. The present study deals with analysing and comparing mechanical properties of carbon fibre reinforced poly lactic acid (CF-PLA), graphene reinforced PLA (Gr-PLA) and multi walled carbon nano tubes reinforced PLA (MWCNTs-PLA) composites by FFF. The selected process parameters used in this study are raster angle (0°, 45°, 90°), feed rate (20 mm/s, 40 mm/s, 60 mm/s) and layer height (0.1 mm, 0.15 mm, 0.2 mm) and based on different combinations, elongation at break, modulus and tensile strength are examined. MWCNTs-PLA exhibits overall maximum tensile strength, 37.438 MPa with 15.384% elongation at break for layer height 0.1 mm, raster angle 0° and feed rate 20 mm/s as compared to other selected specimens. Fractography analysis is also done to better understand the failure modes of specimens. To examine the dependency of the tensile strength on the process parameters, ANOVA, Taguchi’s L9 array Design of Experiment (DOE) is utilized indicating that layer height has the highest contribution of 56.713% for Gr-PLA, but raster angle has the highest contribution of 54.899% and 76.16% for CF-PLA and MWCNTs-PLA, respectively. This work will help in better understanding of how different parameters effects the material properties for PLA composites.

Taguchi design-based synthesis and structural analysis of Cassia galactomannan hydroxypropyl derivative

Hydroxypropylation is a significant industrial process for diverse applications of polysaccharides. In the present study hydroxypropylation of Cassia gum derived from ruderal Cassia tora species was investigated using Taguchi's L'16 orthogonal array design of experiments. The optimized reaction conditions comprised: reaction temperature 50 °C, time 240 min, sodium hydroxide (0.015 mol), propylene oxide (0.0755 mol) and 60% aq. propane-2-ol. The maximum hydroxypropyl content, 8.43 and 7.71% were achieved using chromic acid titration and 1H NMR spectroscopic analysis respectively in the optimized product. The chemical shift values of substituted hydroxypropyl groups for methyl, methine and methylene protons at 0.98, 3.87 & 3.41 ppm along with respective carbons at δ 18.23, 69.41 & 79.13, and other assignments, 1H and 13C signals, were confirmed by COSY and HSQC correlation spectral analysis. The substituted hydroxypropyl groups, C 6 of the β-D-1, 4-linked-Manp unit, were established at 66.18 ppm.

Optimization of NSM-CFRP reinforcement on pre-cracked RCB using Taguchi method: Numerical Analysis

In the current paper, different methods of repairing a pre-cracked reinforced concrete beam (RCB) were reviewed and described briefly. Afterward, the near-surface mounted (NSM) technique was used to simulate reinforcement of a pre-cracked RCB using carbon fiber reinforced polymer (CFRP) laminated layer. To do this end, Firstly, based on previous experimental and analytical studies the limitations of the dimensions were specified, and then using Minitab software, Taguchi L9 orthogonal array design of experiment (DoE) was applied to optimize the number of simulations and find the best dimensions for the reinforcement. Subsequently, ABAQUS software was used to analyze the flexural behavior of the NSM-CFRP Pre-cracked RCB. Finally, Force-deflection curves were exported from the simulation results and the best reinforcing pattern was selected

Parametric optimization of traveling wire electrochemical discharge machining (TW-ECDM) process for aspect ratio during machining of borosilicate glass

Glass owing to its transparency, chemical resistance, and high strength to weight ratio has gained importance in various advanced applications including MEMS, lab-on-chip devices, microfilters, micropumps, microvalves, microfluidics, and so on. The borosilicate glass serves as the substrate of microdevices due to its good surface integrity, corrosion, and thermal shock resistance but the micromachining of glass due to its brittleness and non-conductivity had been posing serious challenges with accuracy and precision. A recently developed hybrid non-conventional machining technique called electrochemical discharge machining (ECDM) has emerged as a successful tool for cutting these materials. The present paper discusses the effect of voltage, electrolyte concentration, and inter-electrode gap on the aspect ratio of machined micro slots on borosilicate glass with the help of TW-ECDM set up using Taguchi L9 array design of experiments. The results show the voltage has emerged as the main effecting factor followed by electrolyte concentration and inter-electrode gap. Using this novel process micro slots having an aspect ratio of up to 28 have been machined successfully.

Effect of slicing parameters on surface roughness of fused deposition modeling prints

The effect of fused deposition modeling (FDM) slicing parameters on the surface roughness of FDM prints have been evaluated by using Taguchi based L9 orthogonal array design of experiments. Polylactic acid (PLA) feedstock filament has been used for the fabrication of specimens. The critical input parameters considered for the experimentation were layer thickness, raster angle and infill pattern. The surface roughness of the FDM prints was measured along two axis (i.e. X and Y axis). Surface roughness along X axis lies in the range of 3.18 µm to 9.210 µm, whereas along Y axis, it remains in the range of 3.133 µm to 9.512 µm. The average value lies in the range of 4.444 µm to 7.180 µm. The specimen prepared with the combination of process parameters such as layer thickness 0.16 mm, raster angle 60° and cubic infill pattern has the surface roughness 3.254 µm (along X axis) and 5.755 µm (along Y axis), with a composite desirability of 0.762.