Taguchi Orthogonal Array Design Research Articles

Encapsulation of Lactiplantibacillus plantarum CRD7 in sub-micron pullulan fibres by spray drying: Maximizing viability with prebiotic and thermal protectants

Pullulan was used as the wall material for microencapsulation of L. plantarum CRD7 by spray drying, while isomalto-oligosaccharides (IMO) was used as prebiotic. Also, the effect of different thermal protectants on survival rate during microencapsulation was evaluated. Taguchi orthogonal array design showed that pullulan at 14 % concentration, IMO at 30 % concentration and whey protein isolate at 20 % rate were the optimized wall material, prebiotic and thermal protectant, respectively for microencapsulation of L. plantarum. FESEM images revealed that the spray-dried encapsulates were fibrous similar to those produce by electrospinning, while fluorescence microscopy ascertained that most of the probiotic cells were alive and intact after microencapsulation. The adsorption-desorption isotherm was of Type II and the encapsulate had specific surface area of 1.92 m2/g and mean pore diameter of 15.12 nm. The typical amide II and III bands of the bacterial proteins were absent in the FTIR spectra, suggestive of adequate encapsulation. DSC thermogram showed shifting of melting peaks to wider temperature range due to interactions between the probiotic and wall materials. IMO at 30 % (w/w) along with WPI at 20 % concentration provided the highest storage stability and the lowest rate of cell death of L. plantarum after microencapsulation. Acid and bile salt tolerance results confirmed that microencapsulated L. plantarum could sustain the harsh GI conditions with >7.5 log CFU/g viability. After microencapsulation, L. plantarum also possessed the ability to ferment milk into curd with pH of 4.62.

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.

Optimization of Welding Parameters for Minimizing Defects and Porosity in Electric Arc Welding of Mild Steel Grade Fe 500 Using of Taguchi Method

Abstract: Electric arc welding is a widely used technique in industrial applications for joining metals, including mild steel grade Fe 500. However, the process is susceptible to defects such as porosity, which can compromise the integrity and quality of welds. In this study, we investigate the optimization of welding parameters to minimize defects and porosity in electric arc welding of mild steel grade Fe 500, utilizing the Taguchi method. The Taguchi method, known for its efficiency in optimization studies, is employed to systematically identify the most influential welding parameters and their optimal levels. Through a series of experiments based on the Taguchi orthogonal array design, we vary parameters such as current amperage, voltage, and electrode size to explore their effects on weld quality. The experimental results reveal significant insights into the relationship between welding parameters and defect formation. By analyzing signal-to-noise ratios and ultimate tensile strength, we quantify the effects of parameter variations on weld quality. The Taguchi analysis enables us to identify the optimal combination of welding parameters that minimizes defects and porosity while maximizing weld strength.

Integrated optimization of common rail direct injection diesel engine input parameters with linseed biodiesel: A hybrid approach using grey relational analysis and genetic algorithm techniques

In the pursuit of improved productivity and efficiency, the search for alternative fuels that reduce dependence on fossil fuels is of utmost importance. This research study aims to investigate the influence of process parameters, namely blend percentage, fuel injection pressure, exhaust gas recirculation (EGR) rate, and engine load, on various engine performance parameters such as torque, brake thermal efficiency (BTE), brake mean effective pressure (BMEP), hydrocarbon emissions (HC), and mechanical efficiency. The experiments are conducted following the Taguchi orthogonal array (L25) design of experiments. Additionally, grey relational analysis, a multi-objective optimization technique, is applied to identify the optimal levels of the process variables that optimize all the response parameters. The optimal values obtained through grey relational analysis are determined as 0% blend, 600 bar fuel injection pressure, 12% EGR rate, and 12 kg engine load. Moreover, the Genetic Algorithm-based Multi-Objective Genetic Algorithm (MOGA) is employed for multi-objective optimization of the engine input variables, yielding optimal levels of 19.45% blend, 594.35 bar fuel injection pressure, 14.12% EGR rate, and 12 kg engine load. Furthermore, multivariable regression models are developed to predict the response variables within the experimental domain. These models are validated through a confirmation test. The findings of this study provide insights into the optimization of process variables for enhanced engine performance, with the developed models serving as valuable tools for future predictions and optimization.

Preparation and optimization of an eggshell membrane-based biomaterial for GTR applications

ObjectivesGuided Tissue Regeneration (GTR) is a popular clinical procedure for periodontal tissue regeneration. However, its key component, the barrier membrane, is largely collagen-based and is still quite expensive, posing a financial burden to the patients as well as healthcare systems and negatively impacting the patient’s decision-making. Thus, our aim is to prepare a novel biomimetic GTR membrane utilizing a natural biomaterial, soluble eggshell membrane protein (SEP), which is economical as it comes from an abundant industrial waste from food and poultry industries, unlike collagen. Additive polymer, poly (lactic-co-glycolic acid) (PLGA), and a bioceramic, nano-hydroxyapatite (HAp), were added to improve its mechanical and biological properties. MethodsFor this barrier membrane preparation, we initially screened the significant factors affecting its mechanical properties using Taguchi orthogonal array design and further optimized the significant factors using response surface methodology. Furthermore, this membrane was characterized using SEM, EDAX, and ATR-FTIR, and tested for proliferation activity of human periodontal ligament fibroblasts (HPLFs). ResultsOptimization using response surface methodology predicted that the maximal tensile strength of 3.1 MPa and modulus of 39.9 MPa could be obtained at membrane composition of 8.9 wt% PLGA, 7.2 wt% of SEP, and 2 wt% HAp. Optimized PLGA/SEP/HAp membrane specimens that were electrospun on a static collector showed higher proliferation activity of HPLFs compared to tissue culture polystyrene and a commercial collagen membrane. SignificanceFrom the results observed, we can conclude that SEP-based nanofibrous GTR membrane could be a promising, environment-friendly, and cost-effective alternative for commercial collagen-based GTR membrane products.

Chemometrics Assisted Formulation of Glimepiride Nanosuspension for Solubility Enhancement in Diabetic Therapy—A Systematic Approach

AbstractGlimepiride (GLM), a third‐generation sulfonylurea oral hypoglycemic medication, is used to treat type II diabetes. Admittedly, it has a low bioavailability, a relatively short half‐life (t1/2), and high toxicity. To address the issue, a nanosuspension of poorly soluble GLM is designed using a Quality‐by‐Design (QbD) method, to enhance its solubility. Prospective risk factors are identified and assessed using Critical Material Attribute (CMAs) and Critical Processing Parameter (CPPs) to evaluate the targets by Taguchi orthogonal array (OA) design and to study the effects of formulation and process variables on dependent variables. The amount of Polyvinylpyrrolidone (PVP) (X2), agitation time (X5), and concentration of Poloxamer (X7) are found as significant parameters (p < 0.05), and are further optimized using the Box Behnken Design as response surface methodology model. The optimized GLM nanosuspension 1) has mean particle size (PS), zeta potential, viscosity (VS), and percentage cumulative drug release (CDR%) of 258.17 nm, −25.2 mV, 1.087cPs, and 98.52%, respectively. The pattern of drug release is fitted to Non‐Fickian kinetics. The study results in an economic and efficient nano formulation with enhanced solubility.

Microbial bioethanol production from Agave tequilana leaves juice sugars: Process variable optimization and kinetic modeling

This study focuses on the valorization of Agave tequilana leaves through bioethanol production from juice sugars. Optimal cultivation conditions were determined using a Taguchi orthogonal array design to maximize bioethanol production by Saccharomyces cerevisiae BEL6 61003. The optimal conditions included reducing sugars at 120 g/L, air flow at 0.5 vvm; agitation at 300 rpm, and pH at 4.5. Under these conditions, the maximum bioethanol concentration reached 43.26 ± 2.20 g/L, with a productivity (rP) of 2.4 ± 0.12 g/L·h and a yield of 43 %. A mathematical model was developed to describe the dynamics of the fermentation process under optimal conditions, comparing the kinetic equations of Moser-Boulton and Moser-Loung. The simulations strongly fit the experimental data, with coefficient of determination (R2) values reaching 0.96 for both models. The selection of the best model was assessed using the Akaike Information Criterion (AIC), favoring the Moser-Boulton equation as the more effective model.

Unlocking the potential of Tunisian dam sediment: optimizing zeolite X synthesis via Taguchi and Box-Behnken methods for sustainable resource recovery and versatile applications.

The Tunisian Lebna dam sediment was utilized to create the zeolite faujasite type Na-X. The aim of this investigation is to optimize the yield of Na-X zeolite using alkaline fusion hydrothermal treatment. Taguchi orthogonal array design was employed with nine trials to explore operating parameters including fusion temperature and time, activator type, and sediment type. The efficiency of alkaline fusion was evaluated using acid solubility. After dissolving the optimal alkali-fused sample in water, the Box-Behnken plan was used to identify the influence of L/S ratio, crystallization temperature, and time on zeolite Na-X yield. Rietveld analysis identified the mineral phases in the sediment as quartz (82.0%), calcite (8.8%), kaolinite (6.0), and illite (1.2%). With a NaOH activator, 850°C fusion temperature for 30min, 15 L/S ratio, and 75°C crystallization temperature for 4days, highly crystalline zeolite Na-X was created. FTIR, TGA, N2 adsorption-desorption isotherm, and X-ray diffraction were used to thoroughly describe this sample. The findings reveal the substantial zeolitization potential of the raw Lebna dam sediment, resulting in a high yield of zeolite Na-X.

Investigation of The Use of Calcium Naphthalene Sulfonate as A Binder in Magnesite Spinel Brick Production and Determination of Optimum Conditions

Refractory materials are indispensable for industries working with high temperatures. Magnesite spinel refractory bricks are used in the cement industry, and calcium lignosulfonate is used as a binder in their production. Due to forest fires and similar reasons in recent years, there is a problem in the supply of calcium lignosulfonate raw materials. In this study, research was conducted on alternative binders to be used in the production of magnesite spinel bricks and the optimum conditions for production with the selected binder were determined. Some of the binders are calcium naphthalene sulfonate, sodium naphthalene sulfonate, magnesium oxide, magnesium sulfate, and molasses. As a result of preliminary tests, it was observed that the most successful results were obtained with calcium naphthalene sulfonate. The optimum conditions for the production of magnesite spinel refractory bricks using calcium naphthalene sulfonate were found by the Taguchi method. As parameters, seawater sintered magnesite in 4 different fractions (A: 3-5 mm, B: 1-3 mm, C: 0-1 mm and D: Powder) and Sinter Spinel in 2 different fractions (E: 3-5 mm and F: 1-3 mm) in total, 6 parameters were selected and an L16 (44x22) Taguchi orthogonal array design was created for this. Volume weight, water absorption, porosity, and strength tests were performed on the samples obtained. Accordingly, taking into account the strength values, the optimum conditions were determined as A1, B1, C2, D4, E1 and F2. Under these conditions, the estimated strength value was calculated as 84.24 N/mm2 and the experimental value was 83.85 N/mm2.

Multi objective optimization of EDM process parameters for HCHCr steel

Electric discharge machining (EDM) or spark machining involves controlled erosion of electrically conducting materials by an interrupted, repetitive electric spark creating discharge between the cathode- tool and anode- work-piece, separated by a dielectric fluid medium. The objective of this work is to study the influence of machining characteristics during EDM of high carbon and high chromium steel (HCHCr) with copper electrode. EDM of HCHCr steel is conducted according to Taguchi orthogonal array (OA) design of experiment to evaluate the material removal rate (MRR), tool wear rate (TWR) and surface finish (Ra).The experiments are conducted on die-sinking EDM with varying current, voltage, and pulse-on-time to measure the above responses. Finally, the multi objective optimization technique namely principal component analysis (PCA) is used for optimizing the process parameters. The experimental results indicate the optimum parameters as: current 9 Amps, pulse-on time 15 µs and pulse-off time 10 µs.

The use of low-pressure cold plasma optimization for microbial decontamination and physicochemical preservation of strawberries

Strawberries are highly perishable products due to the presence of elevated water levels, thereby necessitating postharvest treatments to enhance physicochemical quality (PQ) and shelf-life. Although several studies have focused on the development of cold plasma processes as postharvest treatments, the effect of the processing parameters remains unexplored. Therefore, this study aimed to assess the use of low-pressure cold plasma (LP-CP) for microbial decontamination and physicochemical preservation of strawberries using Taguchi orthogonal array design (OAD). The results showed that optimizing LP-CP treatment power, exposure time, and reactor pressure delayed the deterioration rates of strawberries by approximately 10–60 %. Total plate count (TPC) showed that LP-CP treatment with 90 W for 90 s at 0.076 Torr was the optimum condition for microbial decontamination. Color change (CC) was optimally inhibited with 90 W for 60 s in 0.076 Torr. Meanwhile, the optimum condition for maintaining electrolyte leakage (EL) was 30 W for 30 s at 0.076 Torr. Optimal ascorbic acid (AA) content and antioxidant capacity (DPPH) were obtained at 30 W for 30 s in <0.756 Torr. LP-CP processing parameters of power (up to 59–96 %) had the most significant contribution (p < 0.05), followed by time (up to 29 %) and pressure (up to 10 %). Based on the results, reducing microbial contamination preserved the surface color of strawberries. Lowering LP-CP power input, exposure time, and reactor pressure was suggested to enhance the membrane integrity and antioxidant properties of the samples. The results of this study could promote green industrialization of strawberries by reducing waste and improving process efficiency to achieve sustainable development.

Cysteine-coated Magnetite Nanoparticles for the Removal of Carmoisine Edible Dye from Aqueous Medium.

In this study, cysteine-coated magnetite nanoparticles (Fe3O4@Cys MNPs) were synthesized by chemical method and applied as a recoverable and efficient adsorbent for the removal of carmoisine dye from aqueous solutions. The synthesized MNPs were characterized by FT-IR, XRD, SEM, and TEM studies. The effect of various experimental parameters on the dye removal efficiency was studied using Taguchi orthogonal array design (L16 array). Under the optimum conditions (pH = 2, stirring time = 30 min, adsorbent amount = 0.1 g and without salt addition), more than 92% of carmoisine was removed from the aqueous solutions. The kinetic studies showed rapid adsorption dynamics by a pseudo-second-order kinetic model, confirming that diffusion controls the adsorption process. Dye adsorption equilibrium data were fitted well to the Freundlich isotherm, and the synthesized adsorbent showed high removal efficiency. The obtained results showed that the synthesized MNPs act as a reusable adsorbent for carmoisine removal with an easy procedure.

Adsorption of phenol using adsorbent derived from Saccharum officinarum biomass: optimization, isotherms, kinetics, and thermodynamic study

The present research shows the application of Taguchi's design of experiment approach to optimize the process parameters for the removal of phenol onto surface of Saccharum officinarum biomass activated carbon (SBAC) from an aqueous solution to maximize adsorption capacity of SBAC. The effect of adsorption parameters viz. adsorbent dose (m), temperature (T), initial concentration (C0) and mixing time (t) on response characteristics i.e., adsorption capacity (qt) has been studied at three levels by using L9 orthogonal array (OA) which further analyzed by variance analysis (ANOVA) for adsorption data and signal/noise (S/N) ratio data by using ‘larger the better’ characteristics. Using ANOVA, the optimum parameters are found to be m = 2 g/L, C0 = 150 mg/L, T = 313 K and t = 90 min, resulting in a maximum adsorption capacity of 64.59 mg/g. Adopting ANOVA, the percentage contribution of each process parameter in descending order of sequence is adsorbent dose 59.97% > initial phenol concentration 31.70% > contact time 4.28% > temperature 4.04%. The phenol adsorption onto SBAC was best fitted with the pseudo-second-order kinetic model and follows the Radke-Prausnitz isotherm model. Thermodynamic parameters suggested a spontaneous, exothermic nature and the adsorption process approaches physisorption followed by chemisorption. Hence the application of Taguchi orthogonal array design is a cost-effective and time-efficient approach for carrying out experiments and optimizing procedures for adsorption of phenol and improve the adsorption capacity of SBAC.

Experimental Investigation of the Water Droplet Evaporation on Inclined Surfaces by Taguchi and ANOVA Optimization Analysis

Abstract We experimentally investigated the evaporation characteristics of a sessile water droplet on a glass substrate with different surface roughness levels. The influence of five parameters is evaluated for the evaporation process: substrate temperature (30 °C, 45 °C, and 60 °C), surface roughness (P0, P600, and P60), droplet volume (3, 5, and 8 µL), water droplets initial temperature (30 °C, 40 °C, and 60 °C), and inclination angle (0 deg, 45 deg, and 75 deg) of the glass substrate. The Taguchi orthogonal array design of L27 is utilized to establish minimal candidate trial points for experimental works, and more trials have been conducted to quantify the effects accurately. Then, analysis of variance (ANOVA) has been used to evaluate the evaporation times for the sessile droplets. The results indicate that evaporation times decrease with rising substrate temperatures, increasing substrate inclination angle, and increasing initial water droplet temperatures. In contrast, evaporation times rise with increasing surface roughness and droplet volumes. After evaluation of the ANOVA analysis, surface roughness levels and droplet volumes are considered the most influential parameters after substrate temperatures, which is the most effective parameter on the evaporation times. On the other hand, initial water droplet temperatures and substrate inclination angle are less effective considering droplet evaporation times. A linear regression fit was derived via ANOVA analysis for the evaporation time, and the best mean deviation was found to be 10% from the experiments. The experimental outcomes were compared to previous research, and correlations were derived. The proposed correlation has given good results considering experimental and literature data.

Analysis of the mechanical properties of the single layered braid reinforced thermoplastic pipe (BRTP) for oil & gas industries

Reinforced thermoplastic pipes (RTPs) are instantly being broadly scrutinized as a feasible surrogate for metallic pipes due to their superior corrosion resistance, low weight, and low maintenance worth, they have three primary layers inner, outer, and reinforcement. Process parameters for manufacturing reinforced layers are critically essential to enhancing the mechanical performance of RTPs. However, limited comparative research on the impact of braiding parameters on RTP’s mechanical characteristics appears to be publicly available. Therefore, this study examines how these variables affect the mechanical characteristics of braid RTP. This new class of braid RTP is constructed of an HDPE liner pipe, over-wrapped with a single braid layer of resin glass fiber. L9 Taguchi orthogonal array design for experiments was used to create specimens. Furthermore, specimens were subjected to tensile and compression to assess their mechanical properties. Epoxy and ±75 were the most promising parameters in achieving the highest number of tensile and compression properties among choices of thermoplastic polymer matrices and braid angles, respectively. ANOVA suggested that both parameters are significant and significantly impact the mechanical properties of the prototype braid RTP. Also, A1B3 is considered the best combination for producing braid RTP with higher mechanical performance; no notable interaction among factors was found.

Unlocking the hidden value of industrial by-products: Optimisation of bioleaching to extract metals from basic oxygen steelmaking dust and goethite

In this study, the potential of bioleaching to extract valuable metals from industrial by-products, specifically basic oxygen steelmaking dust (BOS-D) and goethite was investigated. These materials are typically discarded due to their high zinc content and lack of efficient regeneration processes. By using Acidithiobacillus ferrooxidans, successful bioleaching of various metals, including heavy metals, critical metals, and rare earth elements was achieved. The Taguchi orthogonal array design was used to optimise the bioleaching process, considering four variables at three different levels. After 14 days, the highest metal extraction for the BOS-D (11.2 mg Zn/g, 3.2 mg Mn/g, 1.6 mg Al/g, 0.0013 mg Y/g, and 0.0026 mg Ce/g) was achieved at 1% solid concentration, 1% energy source concentration, 1% inoculum concentration, and pH 1.5. For goethite, the optimal conditions were 1% solid concentration, 4% energy source concentration, 10% inoculum concentration, and pH 2 resulting in a extraction of 26.6 mg Zn/g, 2.1 mg/g Mn, 1.8 mg Al/g, 0.01 mg Co/g, 0.0022 mg Y/g. These findings are significant, as they demonstrate the potential to extract valuable metals from previously discarded industrial by-products. The extraction of such metals can have substantial economic and environmental implications, while simultaneously reducing waste in the metallurgical industry. Furthermore, the preservation of initial concentration of iron in both BOS-D and goethite residues represents a significant step towards implementing more sustainable industrial practices.

The effect of tread patterns on slip resistance of footwear outsoles based on composite materials in icy conditions

Introduction: Falls on icy surfaces are the leading cause of injuries for outdoor workers. Footwear outsole material and geometrical design parameters are the most significant factors affecting slips-and-falls. Recently, composite materials have been incorporated into outsoles to improve traction, yet the best design parameters are not fully understood. Method: In this effort, based on Taguchi orthogonal array design, 27 outsole prototypes were fabricated with different tread pattern features using our patented composites and tested in a simulated winter condition. Results: An analysis of variance (ANOVA) showed that surface area (p = 0.041, Contribution = 15.63%) was the only factor significantly affecting the slip-resistance of our prototypes. The best performance was observed for the maximized surface area covered by our composite material with circular and half circular plugs laid obliquely, mostly in the forefoot area. Practical Applications: These findings suggest that some tread design features of composite-based footwear have a great role in affecting slip-resistance properties of composite-based footwear.

Green extraction of phospholipids from ghee residue using pulsed electric field processing: Process optimisation and analysis of structural and compositional parameters

Process parameters were optimised using Taguchi orthogonal array design for extraction of phospholipids (PLs) from ghee residue (GR) with pulsed electric field (PEF) assistance. For higher PL yield and antioxidant activity, process voltage and time were observed to be significant factors. Optimised conditions were determined as 60 kV/cm voltage at 7.5 (v/w) solvent (water)‐to‐solid ratio for 5 min. Physical disruption of GR matrix due to PEF treatment was established through scanning electron micrographs. Lipidomic profile of the extract ascertained through liquid chromatography‐mass spectrophotometry (LC–MS) revealed multiple species of phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol and phosphatidylserine in the resultant extract.

Optimization of Process Parameters for End Milling Operation on EN-31 Using Taguchi-Grey Relation

A material with exceptional levels of abrasion resistance, compressive strength, and hardness is known as bearing steel, also known as EN-31 high-grade carbon alloy steel. It has several uses, including the bulk manufacturing of roller bearings, taps, gauges, ejector pins, swaging dies, etc. The lowest surface roughness (Ra) and highest material removal rate (MRR) are sought for this alloy steel in order for it to be used successfully in a range of applications. In the experiment, a L9 Taguchi orthogonal array design was used to CNC end mill EN-31 steel using a bullnose end mill carbide tool with inserts. This study presents a way for enhancing process factors such as cutting speed, depth of cut, feed rate, and tool corner radius that result in desirable output responses. Taguchi and Taguchi-Grey analyses are used to show the best input values that reduce surface roughness and increase MRR. The lowest level of surface roughness could be attained using the operating parameters of 3000 rpm cutting speed, 500 mm/min feed rate, 0.25 mm depth of cut, and 1.00 mm tool corner radius, while the highest level of material removal rate could be attained using 3000 rpm cutting speed, 2500 mm/min feed rate, 0.25 mm depth of cut, and 1.00 mm tool corner radius.

Effect of Drilling Parameters and Tool Geometry on the Thrust Force and Surface Roughness of Aerospace Grade Laminate Composites.

Carbon fiber-reinforced plastics (CFRPs) have been specially developed to enhance the performance of commercial and military aircraft because of their strength, high stiffness-to-density ratios, and superior physical properties. On the other hand, fasteners and joints of CFRP materials may be weak due to occurring surface roughness and delamination problems during drilling operations. This study's aim is to investigate the drilling characterization of CFRPs with different drilling parameters and cutting tools. Drilling tests were performed with the Taguchi orthogonal array design (L18: 2^1 3^3). Tests were conducted with three levels of cutting speed (15, 30, 45 m/min), three levels of feed rate (0.05, 0.1, 0.2 mm/rev), two levels of drill diameter (3 and 5 mm), and three different types of drills (two twist drills with a point angle of 138° and 120° and one brad drill). Thrust forces were recorded during drilling tests, and afterwards surface roughness and hole delamination were measured. Obtained results were analyzed with Taguchi and two-way ANOVA. The general tendency was that low cutting speed, high feed rate, and small diameter drill caused an increase in thrust force. Surface roughness decreases with increasing tool diameter, decreasing feed, and cutting speed. Delamination factors of the samples dropped depending on decreasing thrust force levels. Remarkably, it is possible to control the delamination factor values via better surface quality. The brad drill and larger point angle have a negative effect on the drilling quality of CFRPs. According to all results, the cutting speed of 45 m/min and feed rate of 0.05 mm/rev using a type II drill having a 120° point angle and 5 mm diameter (12th trial) and the cutting speed of 30 m/min and feed rate of 0.05 mm/rev using a type II drill having a 120° point angle and 3 mm diameter (2nd trial) were determined as optimum drilling conditions.