Improvement In Material Removal Rate Research Articles

An energy concisions analytical modelling approach with experimental verification for cutting performance assessment in EDM of Ti-based superalloy

Electric discharge machining (EDM) is a stochastic process which is commonly engaged for cutting of Ti-based difficult-to-cut alloys. Experimental investigation in EDM is costly and requires significant amount of time due to the complex nature of the process. Moreover, the energy intensive nature is another criticism associated to this technique. Therefore, this research is focused on developing an energy conscious mathematical model of the process while considering the categorical parameters like type of dielectric, electrode and nano-powder along with pulse time ratio. Taguchi design of experiment (DOE) has been executed for the experimentation. The comprehensive analysis of the findings depicts transformer oil (TO) delivers a remarkable improvement in MRR and SEC in comparison to other dielectric choices. Furthermore, brass electrode stands out for achieving the best surface finish. When it comes to micro-additives, SiC exhibits substantial potential in increasing MRR, and graphite gives a better surface finish. The process has also been effectively modeled which helps to predict material removal rate (MRR), surface roughness (SR) and specific energy consumption with decent precision which is the key contribution of this study. 3D simulation for EDM illustrates that the features of the crater are defined by the liquefied region, whilst the dynamics of the mushy zone play a crucial role in controlling and characterizing the microstructure size progression. The confirmatory experimental results revealed that the use of optimized parametric combinations demonstrate 90.87% improvement in MRR, 52.07% reduction in SR and 96.19% decrease in SEC in contest to the responses’ values obtained at non-optimal settings.

A discharge plasma regulation method with spike current for electrical discharge machining

Improving material removal rate (MRR) has been one of the most important issues in electrical discharge machining (EDM). A major factor which hinders the improvement of MRR in EDM is the relatively low expulsion ratio of molten material. During a discharge process, a large portion of molten material cannot be expelled sufficiently from the molten pool but re-solidifies, ultimately resulting in a low machining efficiency. In this study, aiming at enhancing the expulsion ratio of molten material in EDM, a discharge plasma regulation method with a spike current is proposed. A novel discharge pulse shape, with a spike current aligned at pulse turn-off stage, is adopted. The transient behaviors of the discharge plasma when a spike current engaged are captured using a high-speed camera, and the morphologies of the corresponding discharge craters are also analyzed. A particle-in-cell with Monte Carlo collision simulation method is used to analyze the changes in particle state inside the plasma. It is found that the spike current applied at the stage when the plasma contracts to a smaller diameter is more conducive to facilitating molten material expulsion. The results of consecutive-pulse machining experiments verify that the proposed discharge plasma regulation method can increase MRR by at least 25.89 % for stainless steel.

Dynamic performance enhancement of machining center with epoxy granite base: Experiments and finite element simulations

Epoxy granite (EG) is used for machine building applications owing to excellent dynamic properties compared to cast iron (CI). Steel is preferred to reinforce with EG to improve the static stiffness of structures. The effects of addition of steel content on stiffness and damping properties of EG composite were assessed through a specimen level study. Subsequently, the base, which is a primary structure that affects the dynamics of the vertical machining center (VMC) was taken up for investigation. The novelty of the present work is the development of scaled down model of EG base with optimum reinforcement ratio to improve the dynamic response of VMC without compromising the static rigidity of the existing CI base. An experimental study was carried out to validate the assumption made in numerical analysis that EG is isotropic and homogeneous. The results of similitude relations revealed that the EG base exhibited sixteen times higher damping compared to CI base. The influence of EG base on the overall dynamics of VMC was assessed by performing pre-stressed finite element modal analysis and harmonic analysis. Upto seven-fold improvements in directional stiffnesses of VMC with the EG base were observed compared to VMC with CI base. The results of stability lobe diagram revealed a three-fold improvement in material removal rate for VMC with EG base compared to VMC with CI base. Thus, the proposed steel reinforced configuration of EG base has demonstrated a better dynamic performance of VMC without compromising static rigidity.

Effect of Al7075 and activated carbon reinforced composite on optimizing WEDM responses

This paper presents wire cut electrical discharge machining (WEDM) response characteristics of Aluminium 7075 (Al7075) reinforced with powdered activated carbon (PAC) composite. In recent days WEDM has become a significant machining process in targeting its benefits of contributing improved material removal rate (MRR) and low surface roughness (SR). This is due the rising need for intricate, accurate, and superior structural components, the WEDM process emerges as a formidable alternative to traditional machine tools. In this work Pulse-on time (Ton), pulse-off time (Toff), discharge current (IA) and servo speed rate (SS) are the variables to be given as input and machining responses such as MRR and SR are studied. From Analysis of Variance (ANOVA) study it is found that discharge current and servo speed is the significant parameters. The optimal desirability condition is obtained with input parameters Ip: 2000 mA; Ton: 8.9 μs; Toff: 25 μs and SS: 150 rpm for the precision machining. The optimum response parameters are found as MRR 10.46 mm3/min and SR 3.32 μm. Results shows that the model designed for the prediction of MRR produces an above 98.27% and the prediction of SR is above 97.17%. The error percentage among the experimental and predicted MRR and SR were estimated. Additionally confirmatory test is performed with optimal results achieved from response surface methodology (RSM) and desirability technique. Metallurgical tests like electron backscatter diffraction analysis (EBSD) and microstructure are conducted to confirm the surface properties and atomic force morphology (AFM) analysis is applied to clarify the structural features of machined composites. The results revealed that the variation of hard deflection is caused by depression of eroded materials on the top layers of machined surface.

Synergistic effect of abrasive friction and glycine on improving chemical mechanical polishing performance of single-crystal GaN substrate

With the rapid development of the third-generation semiconductor materials, the chemical mechanical polishing rate and surface quality of single-crystal gallium nitride (GaN) substrates have been a research hot-spot. In this work, the synergistic effect of abrasive friction and glycine (Gly) on improving the chemical mechanical polishing (CMP) performance of single-crystal GaN substrate is proposed and studied systematically. The results indicated that the polishing solutions with Gly have a 2.3-fold improvement in material removal rate (MRR) as well as scratch-free surface than that without Gly. The maximum MRR of the single-crystal GaN substrate is 129.4 nm/h with surface roughness (Ra) of 0.64 nm attained by using the polishing solutions containing only 3 wt% potassium persulfate (K2S2O8). In contrast, when Gly is added as a reaction reagent, which can be activated by abrasive friction, the maximum MRR is increased to 304.2 nm/h with Ra of 0.42 nm. Meanwhile, the epitaxial evaluation indicates that two-dimensional (2D) MoS2 grown on processed single-crystal GaN substrate has superior crystalline quality and optical properties. Finally, the polishing mechanism of the single-crystal GaN substrate using the mixed solutions of K2S2O8 and Gly is discussed. The proposed CMP method has potential applications in the semiconductor and microelectronics industries.

Multi-Objective Optimization in WEDM Process of Titanium Alloy (Ti-3Al-2.5V-2.0WC) using Desirability Approach

Recently, Titanium alloy (Ti-3Al-2.5V) reinforced with Tungsten Carbide (Ti-3Al-2.5V-2.0WC) developed using the microwave sintering process has plays a major role in mining industry. It has very good mechanical property and corrosion resistance. Due to its better strength and high melting point, it is difficult to machine in conventional machining process. Therefore, WEDM process give the solution to cut this high strength material in an effective manner. In this present work, the WEDM input variables such as Servo Voltage (SV), Pulse Time - On (PT-ON), Pulse Time – Off (PT-OFF) and Cutting Speed Percentage (CSP) are considered. L09 Orthogonal Array Matrix (OAM) is considered for experimental work. The output variables like Material Removal Rate (MRR) and Surface Roughness (SR) are considered to obtained the quality machining process. Multi objective optimization technique like Taguchi-Desirability Approach method is implemented to find the optimum input variables. The Improvement of MRR from 0.05978 g/min to 0.06420 g/min and SR from 3.812 μm to 3.452 μm are obtained using Desirability Approach.

Improving material removal rate and surface roughness in macro electrolyte jet machining of TC4 titanium alloy using tools with a converging-diverging Laval-type electrolyte channel

Improving material removal rate and surface roughness in macro electrolyte jet machining of TC4 titanium alloy using tools with a converging-diverging Laval-type electrolyte channel

Macro-electrolyte jet machining of TC4 titanium alloy using a rear-end tilt tool

Improving material removal rate and surface quality are the key issues in macro-electrolyte jet machining. The current density of the workpiece surface significantly influences material removal rate and surface quality. A novel tool with the rear-end tilted is proposed to increase the current density of the workpiece surface. The flow field simulation results demonstrate that, in comparison with standard tools, the tool with the rear-end tilted not only enables the rear-end contact with electrolyte but also enhances the rear-end electrolyte flow rate. The electric field simulation results showed that, in comparison with standard tools, the tool with the rear-end tilted enabled the rear-end to participate in the electrochemical dissolution of the workpiece surface and increased the current density of the workpiece surface. The experimental results show that the material removal rate of the workpiece is increased by 27 % and the surface roughness Ra is reduced from 6.71 μm to 2.52 μm by tools with a rear-end tilt angle of 15° compared with the standard tool. In addition, when a tool with a rear-end tilt angle of 15° is used to process the plane structure, the protrusion phenomenon of tool marks at the intersection of parallel trajectories with a step-over of 9.25 mm is the smallest, with a protrusion phenomenon of 0.092 mm.

Analysis and development of elliptical tool path in trochoidal milling

Trochoidal milling has been developed to extend the cutting tool life as compared to conventional milling. It is widely used in the machining of slots and corners of molds and dies. There are several tool paths typically used in trochoidal milling such as true, circular, variable-feed, and variable-step trochoidal tool paths. However, these paths suffer from low material removal rates, low surface qualities, high CPU processing times, and/or the requirement of high-dynamic machine tools. Elliptical trochoidal tool path showed its capability to improve the material removal rate, but the expected low surface quality of the produced slot. In this paper, the elliptical tool path will be analyzed analytically and experimentally. The effect of elliptical tool path on material removal rate, cutting forces, walls waviness, and surface roughness have been investigated. A novel linear elliptical-based tool path has been proposed to enhance the elliptical tool path performance by improving both material removal rate and surface quality. A Performance index has been utilized to evaluate the performance of these processes. An analytical model for the local maximum chip thickness in elliptical tool path has been conducted to correlate this path with the cutting forces. The slot walls waviness has been modeled based on the cutting tool path geometry and validated experimentally with error less than 11%. The experimental results showed that the elliptical tool path improved the material removal rate by 11%, with a slight reduction in the maximum resultant cutting force by 3%. On the other hand, the walls waviness and surface roughness have been increased by 45% and 38% respectively as compared to the typical true trochoidal tool path. The introduction of linear paths at the elliptical path sides in the linear-elliptical tool path improved the performance index about 18 times by improving the material removal rate, waviness, and surface quality by 5%, 300%, and 74% respectively, without a significant effect on cutting forces. Therefore, the novel linear-elliptical paths are promising tool paths in increasing the performance of trochoidal milling due to the improved material removal rate, walls waviness, and surface quality, without a significant effect on cutting forces, which will improve the process machinability and cost-effectiveness.

Chemical mechanical polishing of silicon carbide (SiC) based on coupling effect of ultrasonic vibration and catalysis

Polishing SiC is a difficult task due to its exceptional chemical stability and high hardness. While the strong catalytic performance resulting from the coupling effect of ultrasonic vibration and catalysis is well-known, there have been limited studies on its effectiveness for SiC chemical mechanical polishing. To address this gap, we present a novel approach that utilizes the coupling of ultrasonic vibration and catalysis for SiC polishing. The hydroxyl free radical (*OH) generated by coupling effect is analyzed using ultraviolet-visible spectrophotometry (UV–VIS) to screen for a catalyst that matches ultrasonic vibration and establish a high-performance catalytic coupling system. The use of ultrasonic vibration in SiC polishing results in a significant increase in catalytic efficiency, with a doubling effect observed. Additionally, the catalyst itself increases ultrasonic efficiency by 43.1 %, leading to a substantial improvement in material removal rate (MRR). We study the impact of the placement of the ultrasonic vibration device on MRR and evaluate the performance of the coupling system used for polishing. Also, we delved into the removal mechanism of SiC by utilizing XPS and nyquist plots. Our findings reveal a maximum MRR of 214.6 nm/h, which improves the efficiency of commercial slurry by 80.0 %. Furthermore, the proposed strategy increases the MRR of commercial slurry by more than 70 % in the time range of 0–1 h, 1–2 h, and 0–2 h. The surface roughness (Ra) measured by AFM using a scanning area of 1 × 1 µm2 at sub-angstrom scale (Ra=0.0627 nm) is achieved. This study significantly improves the polishing efficiency of commercial slurry and has great application prospects.

Atomic scale investigation of notch evolution on 4H-SiC under different cutting surfaces and environments

Due to the hardness and brittleness of silicon carbide, the surface defects of 4H-SiC are easily transferred to the machining stage. To better illustrate the influence of pre-existing notch on cutting process, the notch evolution on 4H-SiC under different cutting surfaces and environments is studied by molecular dynamics simulation. It is found that 0001 face 12¯10 basal slip is one of the most common slip systems of 4H-SiC and the basal slip is easy to start from the tip of notch. Water film can promote the evolution of notch and lead to deeper defective structures. When there is no water film, the notch will be filled with phase transformation atoms. Since the defects tend to generate and propagate along the basal plane of 4H-SiC, the subsurface damage caused by 011¯0 face cutting is much deeper. When cutting on 0001 surface, there will be massive spalling which can lead to a sharp increase in chip atoms. Thus, cutting on 0001 surface can not only reduce the depth of subsurface damage but also improve material removal rate. In addition, the basal slip is usually accompanied by long dislocation lines and more dislocation lines will be left when cutting on 011¯0 surface.

Influence of Silver-Coated Tool Electrode on Electrochemical Micromachining of Incoloy 825

Incoloy 825 alloy is often used in calorifiers, propeller shafts, and tank vehicles owing to the improved resistance to aqueous corrosion. The electrochemical micromachining process can be utilized to machine such an engineering material owing to higher precision and lower tool wear. In the present study, an investigation was performed to enhance the process of creating micro-holes using silver-coated copper tool electrodes. The sodium nitrate electrolyte was used under different levels of input parameters such as voltage, electrolyte concentration, frequency, and duty cycle with a view to improving material removal rate, conicity, overcut, and circularity. It was found that silver-coated copper tool electrode had a high material removal rate (MRR), better overcut, conicity, and circularity compared to uncoated copper tools in most cases, due to its high corrosive resistance and electrical conductivity. From SEM and EDS analysis, it was observed that better surface topography of the micro-holes is obtained with silver-coated copper tool electrode while machining Incoloy 825 alloy in the micromachining process.

Machining of Triangular Holes in D2 Steel by the Use of Non-Conventional Electrodes in Die-Sinking Electric Discharge Machining.

Electric discharge machining is relatively a slow process in terms of machining time and material removal rate. The presence of overcut and the hole taper angle caused by the excessive tool wear are other challenges in the electric discharge machining die-sinking process. The areas of focus to solve these challenges in the performance of electric discharge machines include increasing the rate of material removal, decreasing the rate of tool wear, and reducing the rate of hole taper angle and overcut. Triangular cross-sectional through-holes have been produced in D2 steel through die-sinking electric discharge machining (EDM). Conventionally, the electrode with uniform triangular cross-section throughout the electrode length is used to machine triangular holes. In this study, new designs of electrodes (non-conventional designs) are employed by introducing circular relief angles. For material removal rate (MRR), tool wear rate (TWR), overcut, taper angle, and surface roughness of the machined holes, the machining performance of conventional and unconventional electrode designs is compared. A significant improvement in MRR (32.6% increase) has been achieved by using non-conventional electrode designs. Similarly, the hole quality resulted by non-conventional electrodes is way better than hole quality corresponding to conventional electrode designs, especially in terms of overcut and hole taper angle. A reduction of 20.6% in overcut and a reduction of 72.5% in taper angle can be achieved through newly designed electrodes. Finally, one electrode design has been selected (electrode with 20 degree relief angle) as the most appropriate electrode resulting in better EDM performance in terms of MRR, TWR, overcut, taper angle, and surface roughness of triangular holes.

Effect of cations on the improvement of material removal rate of silicon wafer in chemical mechanical polishing

For obtaining a sub-nanometer surface, the material removal rate (MRR) is usually very low. It is challenging to achieve sub-nanometer surface with high MRR. To overcome this challenge, in this work, different cations are considered to improve the MRR during CMP for silicon (Si) wafer. When the concentration of NH4+ ions is 125 mmol/L, the MRR of Si wafer reaches 1687 Å/min, increasing 107.8 % compared with the controlled group. It is noted that nanometer silica abrasives remain at a good monodisperse state in CMP. The surface roughness Sa after CMP on a Si wafer is 0.744 nm under a measurement area of 868 × 868 µm2. COF data and X-ray photoelectron spectroscopy indicate that NH4+ ions reduce the electrostatic repulsion between silica nanoparticles and Si, whilst accelerating chemical reactions between Si and developed slurry. This work suggests a novel approach to fabricating sub-nanometer surface of Si wafer with high MRR, which is beneficial for the potential use in semiconductor and microelectronics industries.

MRR and TWR Study of Powder Mix EDM and Pure EDM Based on Response Surface Methodology

Powder-mixed electrical discharge machining (PMEDM) is the process of enhancing the output of the machined surface by combining dielectric fluid with various types of powders. This process is quickly gaining acceptance in the electrical discharge machining (EDM) sector. The purpose of this study is to determine whether a dielectric fluid containing tantalum carbide (TaC) powder can improve material removal rate (MRR) also lessen tool wear rate (TWR) during the subsequent EDM machining of stainless steel material. During the machining, the material removal rates, tool wear rate, and mathematical models of two different EDM mediums were examined. For the machining procedure, kerosene dielectric fluid containing TaC powder at a concentration of 25.0 g/L was used. The machining input variables were used peak current, pulse on time, and pulse off time. We determined how these variables affected the MRR and TWR of the copper-based EDMed electrode tools. During electrical discharge machining, the MRR for stainless steel (SUS 304) was increased by MRRPMEDM by 4.3 to 5.3% and TWRpEDM was reduced by 37.9% when TaC powder additive was used. Optimized results also show that TWR and maximum MRR can be achieved at 81.98% and 13.779mm3/min respectively with 83.50% desirability whenever the pulse on-time and pulse off-time are 6.20 µs and 6.50 µs respectively. The models are reliable and can be used to forecast the machining responses within the experimental region, it can be said. The MRR and TWR model for EDM with TaC powder additive (MRRPMEDM) identifies current as the most significant factor, followed by pulse on time and pulse off-time.

Investigations on material removal rate of reduced graphene oxide coated copper electrodes for electric discharge machining

ABSTRACT In the present work, the reduced graphene oxide (RGO) nanoparticles have been synthesised by modified Hummer’s technique. The RGO powder thus obtained was characterised by X-Ray diffraction analysis (XRD), Raman spectroscopy, scanning electron microscopy (SEM) and transmission electront microscopy (TEM). Raman spectra showed the D-band at Raman shift of 1354 cm−1 and G-band at 1606 cm−1 of RGO. TEM analysis exhibited the RGO structure in nanometres. The prepared nanoparticles were mixed with alcohol to form a paste and was coated on standard Copper electrode for experimentation on Electric Discharge Machine (EDM). The influence of process parameters like current, pulse on and pulse-off on the material removal rate were studied using L9 Orthogonal Array of Taguchi Technique using Minitab18.0. Substantial improvement in material removal rate at current of 20 amperes, pulse on time of 90 microseconds and pulse off time of 1 microsecond. It was also found that current and pulse off were significant factors that influenced the material removal rate.

Novel model of material removal rate on ultrasonic-assisted chemical mechanical polishing for sapphire

AbstractUltrasonic-assisted chemical mechanical polishing (UA-CMP) can greatly improve the sapphire material removal and surface quality, but its polishing mechanism is still unclear. This paper proposed a novel model of material removal rate (MRR) to explore the mechanism of sapphire UA-CMP. It contains two modes, namely two-body wear and abrasive-impact. Furthermore, the atomic force microscopy (AFM) in-situ study, computational fluid dynamics (CFD) simulation, and polishing experiments were conducted to verify the model and reveal the polishing mechanism. In the AFM in-situ studies, the tip scratched the reaction layer on the sapphire surface. The pit with a 0.22 nm depth is the evidence of two-body wear. The CFD simulation showed that abrasives could be driven by the ultrasonic vibration to impact the sapphire surface at high frequencies. The maximum total velocity and the air volume fraction (AVF) in the central area increased from 0.26 to 0.55 m/s and 20% to 49%, respectively, with the rising amplitudes of 1–3 µm. However, the maximum total velocity rose slightly from 0.33 to 0.42 m/s, and the AVF was nearly unchanged under 40–80 r/min. It indicated that the ultrasonic energy has great effects on the abrasive-impact mode. The UA-CMP experimental results exhibited that there was 63.7% improvement in MRR when the polishing velocities rose from 40 to 80 r/min. The roughness of the polished sapphire surface was Ra = 0.07 nm. It identified that the higher speed achieved greater MRR mainly through the two-body wear mode. This study is beneficial to further understanding the UA-CMP mechanism and promoting the development of UA-CMP technology.

Study on the effect of air and argon assisted short electric arc machining on Ti6Al4V titanium alloy

The use of an argon–water medium rather than air–water medium is proposed to increase the material removal rate (MRR) and decrease surface oxide production for short electric arc machining. To provide a more stable discharge state during high-temperature processing, this approach uses argon to reduce the production of highly resistant refractory materials (e.g. titanium oxide). For short-arc machining of Ti6Al4V titanium alloy, the effects of the voltage, milling depth, electrode speed and gas flow rate on the MRR, relative electrode loss rate and surface roughness were compared for air–water and argon–water mixtures. It was discovered that the milling depth and voltage had the greatest impact on the MRR, voltage and electrode rotational speed had the greatest impact on the relative tool electrode wear rate (REWR), and voltage had the greatest impact on the surface roughness. In contrast to the air–water mixture, the MRR with the argon–water working medium was as high as 9391 mm3/min, with a 13% improvement in MRR, as well as a smooth and flat surface of the machined workpiece. Nevertheless, the REWR increased to 2.46% and the surface roughness was at least 432 μm with the argon–water medium, increasing by 59 μm compared with the air–water medium. Moreover, the addition of argon reduced the types of surface compound on the workpiece and decreased the residual stress defects, including the recast layer, microcracks and holes.

Statistical investigation of the machining of aluminum LM-25 /SiC metal matrix composite

In the current study, various machining variables are investigated in relation to the abrasive mix electrical discharge machining (AMEDM) performance of aluminium LM25/SiC MMC. An originality of this experiment lies in the fact that silicon carbide abrasive mix EDM has been successfully applied to aluminium LM25 grade metal with 5% SiC reinforcement. The research was conducted with aluminium LM25/SiC MMCs with abrasive mixed dielectric fluid using Box-Behnken design (BBD) of response surface methodologies (RSM). The ANOVA has been performed to identify machining parameters that significantly influenced machining performance. The purpose of this article is to provide directions for optimizing the AMEDM parameters, such as voltage, pulse rate, and powder concentration, based on the material removal rate, wear rate, and roughness of the surface. It is found that discharge current contributes significantly to the improvement of material removal rate (99.23%), surface finish (98.01%) as well as the tool wear rate (40.56%), respectively. Which enhanced the performance characteristics of abrasive mix EDM.

Comparison of HSS (M35) and CrN tool performance in CNC drilling operation of AA3003-H14 material to maximize the material removal rate

• The performance comparison of HSS (M35) coated tool and CrN coated tool to improve material removal rate in the drilling of AA3003-H14. • Material removal rate of the drilled specimens are calculated without compromising the roundness quality, roundness error percentage is measured using imageJ software. • Statistical Analysis performed using SPSS software to check the significance value of obtained results. • Within the limits of this study, CrN coated tool performance was better compared to HSS (M35) in aspect of Material Removal Rate and Roundness Quality. The performance comparison in HSS (M35) tool and CrN tool coating to improve material removal rate in the drilling of AA3003-H14 plates as base material during the CNC drilling operation. In this study HSS M35 and CrN coated twist drill bits are used. Aluminum Alloy 3003-H14 is the specimen in which drilling operation is done. This study includes two groups of 20 specimens each in which drilling operation is done with both the tools. Spindle speed, feed and depth of cut were input factors as 2200, 200 and 10 respectively. On comparing the Material removal rate of AA3003-H14 after drilling done by HSS (M35) and CrN at speed and feed of 2200 and 200 is 165 and 190 respectively. Roundness error with HSS M35 and CrN twist drill tool were 0.0110 and 0.0074 respectively. The results were calculated and analyzed by SPSS software. The significance value obtained for both experimental and control groups was 0.006 (p < 0.05) for material removal rate and 0.019 (p < 0.05) for roundness error. Within the limits of this study, Material removal rate values are observed high in the CrN coated tool compared with the HSS M35 tool for the same input speed, feed and depth of cut without compromising the roundness quality.