HSS Drill Research Articles

Influence of HSS drill coatings on surface finish and cylindricity of AA6061/C/ZrO2 composite in CNC drilling operations under dry conditions

Abstract This study aims to evaluate the effect of HSS drill tool coatings, namely single-layer TiN, single-layer AlCrN, and double-layer AlTiN + TiSiXN (Durana), on the surface roughness and cylindricity of AA6061 (90 wt%)/C (5 wt%)/ZrO2 (5 wt%) hybrid composite material processed by the stir casting method. The fabricated sample was examined for the uniform particle distribution of reinforcements using Scanning Electron Microscope. The drilling operation was carried out on the fabricated in a CNC machining center by setting the spindle speeds of 800, 1200, and 1600 rpm, depths of cut of 0.5, 1, and 1.5 mm, and feeds of 50, 100, and 150 mm/rev. An orthogonal array (L27) designed by Taguchi’s method was used as the design of the experiment for the optimization of the best cutting parameters and coating. Surface roughness and cylindricity errors were determined for the 27 experimental runs. Field emission scanning electron microscopic (FESEM) examination and Energy Dispersive Spectroscopy (EDS) were used to analyze the surface integrity and elemental composition, respectively. The results revealed that Durana had a significant effect on the surface substrate with minimum surface roughness (Ra) of 1.666 μm and obtained the minimum cylindricity error for the parameters of depth of cut 0.5 mm, spindle speed of 1200 and feed of 100 mm rev−1.

Evaluation of drilling by induced delamination of hybrid biocomposites reinforced with natural fibers: A statistical analysis by RSM

Studying the drilling of a hybrid jute/palm composite material offers significant contributions to sustainable material development. Incorporating renewable jute and palm fibers represents an innovative, eco-friendly approach compared to synthetic composites. This research aims to optimize drilling parameters to reduce defects and evaluate the performance of different drilling tools, crucial for industrial applications. Drilling is performed via three different types of drills bit: High-Speed Steel, HSS-Co5 coated high-speed steel with 5% cobalt, and carbide. The drilling process involves adjusting the feed and rotational speed. Response Surface Methodology (RSM) was used to select drilling settings by validating experimentally obtained data and predicting the behavior of the structure based on cutting circumstances. The findings indicated that the most effective cutting parameters for minimizing delamination are achieved using the HSS drill bit, namely at lower feed and rotational speeds. Delamination remains below the threshold of 1.106 when the feed is 0.04 mm/rev and the rotational speed is 1592 rpm. The analysis of the results obtained using the response surface methodology indicates that the R2 coefficient for cylindricity is 0.96%. In contrast, the rate of delamination is 0.79% and the rate of circularity is 0.89%.

A Comparative and Experimental Study of Parametric Influence on Drilling Process of Hybrid AMMC

Abstract: To aim for the highest quality product quality and a high metal removal rate, metal cutting is crucial. The primary obstacle to attaining optimal quality and high production is the short tool life. The hybrid aluminum metal matrix AA 6082, with reinforcement consisting of titanium dioxide (7.5%) and cenosphere (2.5%), was optimized using the Modified Taguchi optimization method for simultaneous minimization and maximization of surface roughness (Ra), machining time, and material removal rate. The surface finish was affected by different types of geometrical precision values of the CNC drilling process parameters in order to both minimize and maximize the responses. The experiments, including call for the machining of hybrid AMMC and the use of an HSS drill bit, will be performed using a CNC with different process parameters. The L16 orthogonal array will be used for the examinations, and each experiment will be run under a distinct set of circumstances, including feed, speed, and pecking. Using the TAGUCHI design, the optimal geometrical and machining parameters were determined from the experimental output responses, and significant influences were discovered for the corresponding specific output responses.

Investigation of Delamination in The Drilling of PLA Specimens With Different Lattice Structures

In this study, it was aimed to investigate the effects of processing parameters and different lattice structures on delamination in the drilling of lattice structures. In this context, cylinder PLA (Polylactic acid) parts designed in four different (gyroid, I-WP, nevoius and diamond) lattice structures were produced on a 3D printer and drilled from the centre point with a 5 mm HSS drill. After drilling, entrance and exit hole images were taken with a digital microscope and delamination, burr and circularity around the hole were analysed. According to the results obtained, the lowest delamination at the entrance of the hole was measured in the Gyroid and I-WP lattice structure at the exit. There was no burr at the hole entrance of the specimens. It is seen that the specimen with the lowest value in terms of burr at the hole exit, entrance and exit circularity deviation is Nevoius lattice structure.

Vanadis 4E’nin Kaplamalı Matkaplarla Delinmesinde; Aşınma, Yüzey Pürüzlülüğü ve Talaş Oluşumunun İncelenmesi

Vanadis 4E is a versatile powder metallurgical tool steel widely used in today's market with high wear resistance and excellent yield properties. Drilling operations applied to materials are one of the operations commonly used in the machining industry. In drilling operations, coated or uncoated drills are used, which may vary according to the material used. This study applied drilling operation to Vanadis 4E powder metallurgical steel with TiN-coated HSS drills. In the study, Drills with diameters of 5, 8.5, and 10.5 mm, cutting speeds of 22, 23, and 24 m/min, and feed rates of 0.10, 0.12, and 0.14 mm/tooth was used. Nine experiments were carried out using the Taguchi L9 orthogonal array. After the experiments, the material was cut from the holes, and the roughness values were measured from the inner surfaces of the holes. In addition, hardness measurements were made from the material surfaces around the holes. The wear conditions of the drills used in the experiments were examined with an optical microscope after the experiment. The formations after each experiment were also examined. The best roughness value was obtained with the 5 mm diameter drill in the 1st experiment, the best roughness value was obtained in the experiments carried out with the 8.5 mm diameter drill in the 6th experiment, and the best roughness value was obtained in the 7th experiment for the 10.5 mm diameter drill. When the wear in the drills was evaluated, it was observed that the side surface and radial wear occurred.

Machining aerospace aluminium alloy with cryo-treated and untreated HSS cutting tools

ABSTRACT In this study, effects of drilling parameters and cryogenic treatment, which were applied to the cutting tool (M35 HSS drill bit), on the burr width, surface roughness (Ra), chip formation and tool wear were investigated in drilling of AA2024-T3 aluminium alloy under dry drilling conditions. In this context, the drilling parameters determined based on the Taguchi experimental design were employed, and also, the analysis of variance (ANOVA) and regression analysis were performed. The spindle speed (1500, 3000 and 4500 rev/min), feed rate (100, 150 and 200 mm/min) and cutting tool (cryo-treated and untreated M35 HSS tools) were selected as machining parameters. In terms of average burr width, the performance of the cryo-treated (DC&T) HSS drill bit was 28.91% (for the highest value) and 46.96% (for the lowest value) better than that of the untreated (UT) HSS drill bit. According to Ra values, the performance of DC&T HSS drill bit was 13.29% (for highest value) and 12.01% (for lowest value) better than that of UT HSS drill bit. The flank wear (VB) of UT HSS drill bit was found to be approximately four times greater than the flank wear of DC&T HSS drill bit.

Machining fiber-reinforced glass-epoxy composites with cryo-treated and untreated HSS cutting tools of varying geometries

Depending on the expanding application areas of glass fiber reinforced composite materials, quality machining of such materials also receives increasing interest. However, since the cutting tools used for machining such composites generally have standard geometric properties, both the life of the cutting tool and the quality of the machined composite workpiece are adversely affected by. In this study, the performance and the most optimum drilling geometries of untreated (UT) and cryo-treated&tempered (DCT&T) HSS cutting tools used for machining of fiber-reinforced glass-epoxy composites were investigated. Moreover, Taguchi experimental design was employed to reduce the number of experiments, and also the analysis of variance (ANOVA) and regression analysis were performed. Furthermore, XRD analysis and microhardness tests were applied to UT and DCT&T HSS cutting tools. From the highest and lowest delamination factor (Fd) values obtained using UT and DCT&T HSS drills, it was understood that DCT&T HSS drills achieved better results by 0.8% and 0.7%, respectively. According to average surface roughness (Ra) values obtained, the performances of DCT&T HSS drills were 14.76% (for the highest Ra value) and 2.69% (for the lowest Ra value), better than UT HSS drills. When the highest and lowest cutting force values were compared, it was seen that the cutting force values obtained using DCT&T HSS drills were 24.54% and 16.15% less than the cutting force values obtained using UT HSS drills, respectively. According to the S/N ratios for the cutting forces, the most optimum geometries of the cutting tool were found to be 128° point angle, 33° helix angle and 8° clearance angle, respectively. With respect to S/N ratios for Fd values, the most optimum geometries of the cutting tool were found to be 118° point angle, 26° helix angle and 8° clearance angle, respectively. Based on S/N ratios for Ra values, the most optimum geometries of the cutting tool were found to be 128° point angle, 26° helix angle and 8° clearance angle, respectively. On the other hand, as a result of the regression analysis, R2 values obtained over 90% show that the regression models are quite successful. Besides, it was observed (from SEM and thermal camera images) that the epoxy resins in the chips produced at high spindle speeds melted because of high temperature, which indicated that the integrity of the composite workpieces started to deteriorate.

Experimental Assessment of Hole Quality and Tool Condition in the Machining of an Aerospace Alloy

This paper deals with an experimental investigation of hole quality in Al2024-T3, which is one of the aerospace alloys used in aircraft fuselage skin due to its high level of resistance to fatigue crack propagation. The experiments are conducted with 6 mm uncoated carbide and HSS drill bits using a CNC machine under dry conditions and different drilling parameters. The characteristics of the hole quality are investigated in terms of its perpendicularity, cylindricity, circularity and hole size. An ANOVA (analysis of variance) and Pareto charts are used to analyze the effects of the drilling parameters on the hole quality. The hole quality is also assessed using a digital microscope to observe the formation of hole burrs. Moreover, scanning electron microscopy is also used to investigate the inside-hole surface defects. Further investigations are carried out using optical microscopy to inspect the post-drilling tool condition at high drilling parameters. The results show that hole quality reduces as the feed rate and spindle speed increase. However, from the ANOVA results and Pareto charts, the influence of the feed rate on the hole quality is found to be insignificant. At the same time, the type of drill bit material shows the highest percentage of contribution affecting the hole quality, following the spindle speed. The HSS drill bit shows more adhesion and built-up edges than the uncoated carbide drill bit. There were more burrs formed at the hole edges when the holes were drilled with uncoated HSS drill bits. In the same way, the SEM analysis reveals more surface deformation and damage defects inside the hole walls of holes drilled using the uncoated HSS drill bit.

Performances of cryo-treated and untreated cutting tools in machining of AA7075 aerospace aluminium alloy

The quality of drilled holes in aluminium alloys used in the aerospace industry is vital to ensure high-precision structural integrity. For this reason, optimum selection of cost-effective cutting tools and cutting parameters is of great importance. Nowadays, due to their high cost and supply difficulties, there is a great interest in improving the performance of traditional HSS cutting tools as an alternative to ceramic, carbide and coated cutting tools. HSS cutting tools are widely used in different industries due to their cost-effectiveness and suitability to improve tool performance. In this research, the performances of cryo-treated (DC&T) and untreated (UT) HSS cutting tools used in dry machining of AA7075 aluminium alloys were investigated. Thanks to DC&T processes applied to HSS cutting tool, improvements have occurred in its microstructure. The hardness value of HSS cutting tool increased by 6.89% with the effect of DC&T processes applied. When the highest and lowest Ra values obtained using DC&T and UT HSS cutting tools were compared, it was seen that DC&T HSS cutting tool performed better by 11.05% and 25.91%, respectively. It has been determined that the hole surface quality of the aluminium workpiece machined with DC&T and UT HSS drills is negatively affected by the increase in spindle speed and feed rate. The highest S/N ratios calculated according to Ra values of holes drilled on aluminium workpieces using DC&T and UT HSS cutting tools were found to be -7.12 dB (2.27 μm) and -9.62 dB (3.03 μm), respectively. In the ANOVA analysis, it was determined that the most effective parameters on Ra values were spindle speed (70.62%), tools (18.19%) and feed rate (9.98%), respectively. In the regression analysis, R2 value for Ra values was calculated as 98.30%. High R2 value result shows that the model developed is quite successful in estimating Ra values.

Investigation of wear mechanism in drilling of PPA composites for automotive industry

Drilling is one of the most widely used processes in manufacturing and assembling parts used in the automotive industry.Drill bits wear out due to increased forces and temperatures during the drilling process. Drill wear is one of the most important problems when drilling conventional or composite materials. This reduces the quality of the hole and degrades the drill. In this study, the wear mechanism during drilling of PPA composites used in the automotive industry was investigated. Therefore, TiN-coated HSS drills were utilized in the tests. A TiN-coated HSS drill with a diameter of 5 mm and a tip angle of 118° was used to perform the drilling test. Drilling tests were performed in dry conditions on a 3-axis CNC milling machine. Three cutting speeds of 15, 20 and 25 m/min and feed rates of 0.05, 1.0 and 1.5 mm/rev were selected for the drilling conditions. Scanning Electron Microscopic (SEM) images and Energy Dispersive Spectrum (EDS) analysis were used to study the wear mechanism. As a result of the investigation, the mechanisms of abrasive wear and adhesive wear were identified. Drills also showed flank wear, corner rounding, chipping, and coating flaking.

Recognition of drilling-induced defects in Fiber Reinforced Polymers using Machine Learning

The machining of Fiber Reinforced Polymers (FRP) is accompanied by specific defects such as delamination, uncut fibers, and others. Such defects are unique in their shape and size for different FRP types, used tools, and applied cutting conditions. Therefore, defect recognition and quantification remain a central challenge in the quality control of FRP components from an accuracy and time balance perspective. The study presents the implementation of Machine Learning techniques for automated recognition of the hole defects resulting from drilling Flax/PLA biocomposites using HSS drills with various cutting data. The paper discusses the effectiveness and stability of the developed solution.

Wear resistance analysis of HSS drill bits P6M5 and special round carbide drill bits VK8 for drilling alloyed steels and alloys

This paper analyses tool life and accuracy of made holes. As a result of experiments, the revealed variation coefficients reach high values - k=0.61, which indicates significant instability of the machining process of holes. In order to verify this assumption, a series of test measurements of the geometry of the gauge plugs used in the workshop were taken.

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%.

Effects of Drilling Parameters on Drilling of PEEK-CF30 Thermoplastic Material: Thrust Force, Surface Roughness and Delamination

Bu çalışmada, Poli-eter-eter-keton (PEEK)-CF30 kompozit malzemenin kaplamasız HSS matkapla delinmesinde oluşan itme kuvveti, yüzey pürüzlülüğü ve delaminasyon faktörünün kesme parametrelerine göre değişimleri araştırılmıştır. Delme deneyleri üç farklı kesme hızı (40, 80, 120 m/dk) ve ilerleme miktarı (0.1, 0.15, 0.2 mm/dev) kullanılarak kuru işleme şartlarında yapılmıştır. Delmede oluşan itme kuvvetleri Kistler dinamometre ve ekipmanlarıyla ölçülmüş ve elde edilen sonuçların aritmetik ortalaması alınarak analiz edilmiştir. Delik yüzeyinde oluşan pürüzlülük ile delik çıkışında oluşan delaminasyon hasarları ölçülmüştür. İlerleme miktarının artmasıyla itme kuvvetinde %3-%25’lik artış olurken, kesme hızının artmasıyla itme kuvvetlerinde %9-%28 aralığında artışlar görülmüştür. Kesme hızındaki azalma ve ilerleme miktarındaki artışla birlikte yüzey kalitesinde iyileşme olurken, delaminasyon faktöründe artış görülmüştür. En düşük yüzey pürüzlülüğü 40 m/dk kesme hızı ve 0.2 mm/dev ilerlemede 1.18 µm, en yüksek yüzey pürüzlülüğü 120 m/dk kesme hızı ve 0.1 mm/dev ilerlemede 2.96 µm olarak elde edilmiştir.

Optimizing to Minimize Thrust Force in Drilling Carbon Fiber Reinforced Plastic Composites with HSS Drill Bit Using Taguchi-Pareto Particle Swarm Optimization Method

In this study, a robust method of Taguchi-Pareto (TP) coupled with particle swarm optimization (PSO) is proposed to minimize the thrust force in the drilling of carbon fiber reinforced plastic composites. Taguchi-Pareto is used against Taguchi (T) to emphasize the prioritization scheme essential for deploying the resources to parameters. Besides, and differently from earlier studies, particle swarm optimization is integrated with the Taguchi-Pareto to optimize the structure further. A further result is placed in the fitness function of the PSO to cultivate the velocity and position vectors. In the TP-PSO, the Pareto scheme is introduced to prioritize the factors based on the 80-20-rule. The Taguchi method yielded a feasible optimal parametric setting. The TPSO and TPPSO attained minimum thrust force in four and seven iterations, respectively. Furthermore, the PSO, TPPSO, and TPSO hold the first, second, and third positions, respectively. Results suggest that the proposed robust TPPSO offers an important indicator of optimization of the thrust force while drilling carbon fiber reinforced plastic composites using existing datasets. The usefulness of this effort is to help drilling operators and process engineers undertake energy-saving decisions.

Effect of temperature on surface roughness in friction stir drilling of AL-6061 with varied drill tools

Friction stir drilling is a sheet metal hole-making technology that is the most cost-effective and high-production method for sheet metal fastenings. Fastening or attaching sheet metals, in particular, is widely employed in all manufacturing and industrial applications. However, due to the small structural steel gauge, these metal clasps should be seen as a major manufacturing issue. The effects of drilling settings on average temperature (T) and surface roughness (Ra) in friction stir drilling of Al-6061 with HSS and tungsten carbide drills were examined in this work. Three different drills and three distinct degrees of cutting parameters were used in the machining studies (feed rate, depth and cutting speed). Furthermore, it was demonstrated that increasing Ra machining with various drill tools by varying temperature, speed, and feed rate. The optimal surface roughness was calculated at various temperatures, and the correctness of the optimization was checked using grey rational analysis.

Comparison of coated and uncoated HSS drill bit on surface roughness, material removal rate and dimensional accuracy of SS410 stainless steel

Stainless Steel 410 (SS410) is 12% chromium martensitic steel which can be heat treated to obtain wide range of mechanical properties. Due to its high corrosion resistance and excellent combination of toughness and strength, it is used for furnace parts, steam turbine buckets, blades, pump, nozzle, automotive parts, aerospace application etc. Considering the challenges in machining of this material, drilling experiments were conducted on SS410 to analyse the effect of various parameters. Coatings always have a positive influence on the tool. It helps to reduce friction in the cut, reducing heat build-up in the drill bit, as well as improving the flow of material out of the drilling point. It also delivers protection against corrosion, rust and water damage. The AlTiN coating provides exceptional oxidation resistance and extreme hardness. This coating works well in very demanding cutting tool applications, especially when tools are being pushed to the max. This paper reports on the investigation of performance of Al-Ti-N coated and uncoated HSS drill bits when drilling SS410. Machining characteristics studied in this investigation include Material Removal Rate (MRR), Surface Roughness (Ra), Ovality. Drilling tests were carried out as per Taguchi’s L16 array using process parameters such as Speed (30, 40, 50, 60 m/min), Feed (F) (0.05, 0.075, 0.1, 0.125 mm/rev) and point angle (P) (100, 110, 120, 130 degree). Comparison of the performance of coated and uncoated drill bits showed that coated drill bits have higher performance than uncoated. By using coated drills surface Roughness and Ovality values of drilling are reduced to an extend of 48.5% and 2%. Material removal rate value is also improved to an extend of 23%.

Investigation of thrust force in drilling polyphthalamide (PPA) composites

In this study, the drilling process is explored on 30% glass fiber reinforced PPA composite to investigate the influence of drilling parameters on thrust force. HSS, TiN coated HSS and carbide twist drills with 5 mm diameter and 118° point angle are used to perform the drilling tests. The drilling tests were carried out in dry conditions on the 3-axis CNC milling machine. Three different cutting speeds such as 15, 20, and 25 m/min and feed rate such as 0.05, 1.0, and 1.5 mm/rev were selected as drilling conditions. Experimental results indicated that the thrust force increases with increasing the feed rate and in contrast the force decreases with increasing the cutting speed. Statistical Analysis of Variance (ANOVA) method was used to determine the effects of drilling parameters and interactions on the thrust force. According to the analysis, drill materials play the most important role on the thrust force. In addition, mathematical models were developed using the multi-linear regression method. The optical microscope and Scanning Electron Microscopic (SEM) images were used to examine the drilled hole surface of the PPA composite material. According the images of the drilled hole surfaces indicated the existence of matrix crack, fiber pull-out, and shearing of fibers. In order to obtain the best surface quality (in terms of delamination factor and surface roughness) and minimum thrust, it is recommended to use carbide drill bits at the lowest feed rate and highest cutting velocity cutting conditions.

Factor Selection in Drilling Unidirectional Carbon Fiber Reinforced Plastic Composite Plates with The HSS Drill Bit Using Analytic Hierarchy Process

The present state of competition within the plastic composite industry calls for efficiency to be competitive. However, in the drilling of carbon-fiber-reinforced plastic (CFRP) composites, the process engineer still lacks knowledge of the priority of parameters as parameters are chosen at random, and resources are deployed without justification on their importance and strength. Consequently, production crises and productivity losses persist. In this article, the analytic hierarchy process (AHP) method is deployed to evaluate the weights of criteria in a CFRP composite drilling operation. The establishment of the decision, alternatives, and criteria is accomplished, and pairwise comparisons are conducted to allow the computation of the importance weight of each criterion. The weight is then established. The proposed approach was illustrated with experimental data from the literature with a plastic drilling case. Six criteria were chosen as crucial in determining the drilling parameters of CFRP composites. The results reveal the following: thrust force (0.413), torque (0.253), eccentricity (0.151), surface roughness (0.115), delamination at entry (0.037) and delamination at exit (0.030). In a validation exercise to ascertain the consistency of the analysis, a consistent analysis was obtained. The novelty of the article is using the AHP approach on the drilling of CFRP composites. Practically, these results impact operator training, indicating that attention should be focused on thrust force control. The industrial applications of CFRP composites include the basic structures of automobiles, ships, and airplanes.

Performance evaluation of the minimum quantity lubrication with Al2O3- mixed vegetable-oil-based cutting fluid in drilling of AISI 321 stainless steel

Abstract Due to increased awareness of ecological and health related problems, the researchers are actively searching for renewable and biodegradable cutting lubricants. Vegetable oils with solid lubricants are being explored as a potential source of environmentally helpful lubricants due to good combination of biodegradability, renewability and fabulous lubrication performance. Although sunflower oil poses good cooling capability, yet its application has not been explored extensively in drilling. Therefore, in this research work minimum quantity lubrication (MQL) technique with Al2O3-mixed vegetable-oil-based cutting fluid was implemented. The main objective of this experiment is to analyze the performance of various coolant-lubricant environments (dry, flood, pure MQL and nanofluid MQL) with regard to drilling forces, surface roughness, drill tip temperature and tool wear mechanism in the drilling of AISI 321 stainless steel by using HSS drill tools. In the MQL conditions, coolant supply rate and air pressure are fixed at 120 mL/hr and 6 bar respectively. In addition to explore the cooling capabilities of sunflower oil, nano-Al2O3 were added to the sunflower oil to prepare different concentration (0.5 wt.%, 1.0 wt.% and 1.5 wt.%) nanofluids. Results indicated that MQL drilling with Al2O3-mixed vegetable-oil-based cutting fluid achieved much better performance as compared to the dry, wet and pure MQL drilling. Thrust force, torque, surface roughness and drill tip temperature approximately reduced 44 %, 67 %, 56 % and 26 % respectively at the 30th hole under nanofluid MQL drilling (with 1.5 wt.% of aluminium oxide nanoparticles) as compared to flood conditions. Moreover, tool wear rate reduced significantly while machining under NFMQL conditions. Better results of nanofluid MQL drilling may be attributed to the fact that NFMQL is capable for producing higher cooling effect due to the lubrication characteristics of nanoparticles.