Average Surface Roughness Values Research Articles

Optimization of machining parameters for abrasive water jet drilling of carbon fiber-reinforced polymer composite material using Taguchi method

Purpose The aim of this paper is to optimize the machining parameters to obtain the smallest average surface roughness values during drilling of the carbon fiber-reinforced polymer (CFRP) composite material with abrasive water jet (AWJ) and analyze the damage of the delamination. Design/methodology/approach CFRP composite material had been fabricated having fiber orientations frequently used in the aerospace industry (0°/45°/90°/−45°). Three different stand-off distances (1, 2 and 3 mm), three different water pressures (1,800, 2,800 and 3,800 bar) and three different hole diameters (4, 8 and 12 mm) were selected as processing parameters. The average surface roughness values were obtained, and delamination damage was then analyzed using Taguchi optimization. Drilling experiments were performed using the Taguchi L27 orthogonal array via Minitab 17 software. The signal/noise ratio was taken into account in the evaluation of the test results. Using the Taguchi method, the control factors giving the mean surface roughness values were determined. Analysis of variance was performed using the experimental results, and the effect levels of the control factors on the average surface roughness were found. Findings It was found that water pressure and hole diameter had a higher effect on average surface roughness, while water pressure and stand-off distance were effective on delamination. Practical implications Owing to their excellent thermal and mechanical properties, the CFRP composite materials show greater potential for their applications in aircraft and aerospace industry. Originality/value The novel approach is to reduce cost and spent time using Taguchi optimization as a result of AWJ drilling the material in this fiber orientation ([0°/45°/90°/−45°]s, which is often used in the aerospace industry).

Study of leukosapphire surface morphology change by argon ion beam at small grazing angle

Subject of Research. The paper presents the results of experimental study on the specific features of argon ion beam effect on a sapphire surface at small grazing angles. Mechanically ground and defective epipolished leucosapphire plates with 20 × 20 × 1.2 mm in size were used as experimental samples. The initial surface roughness of the polished samples was 0.250–1 μm and of the epipolished ones was 5–10 nm. Method. The ion beam deposition setup was used for research. It includes the ion source of CLAN-53M type with ion neutralizer. The ion source generates ion flux with energies in the range of 150–1500 eV, with an output ion current density up to 4 mA/cm2, with ion current from 10 to 80 mA. The studies were carried out at different technological parameters of ion-beam polishing: the ion energy and the angle between the sapphire surface and the ion beam axis α. Main Results. We have determined effects of sapphire surface morphology change both with preservation and change in the overall roughness level, and the effect of surface structuring during processing in two projections with the formation of flat peaks with a diameter of 2 μm. The experiment results have shown that the maximum efficiency (the highest value is a change in the arithmetic average surface roughness) during ion-beam polishing is observed at α equal to 15° and the ion beam energy of 400 eV. When α value changes from 25 to 30°, an oriented change of the surface morphology from the symmetrically ordered surface microrelief to an asymmetric one occurs. At the same time, the flat sides do not bleed much, and the effect of steep shadow smoothing of the local microrelief is observed with retention of the same general roughness level. After the sample surface processing with ion beam at the first stage of the experiment, it was re-processed at 90° angle relative to the previous treatment, which led to cross-spraying of the shadow sections and the design of gentle peaks with a diameter of about 2 μm (effect of the substrate surface structuring). Practical Relevance. After the ion-beam polishing of epipolished sapphire substrate samples, smoothing of the highest surface irregularities is observed, and the average arithmetic value of surface roughness has decreased from 5.7 nm to 0.9 nm for the polished sample.

Experimental and Statistical Investigation of Surface Roughness in Turning of AISI 4140 Steel

In this study, AISI 4140 tempering steel with 48 HRc hardness was machined on CNC lathe with different cutting parameters and cooling environment. The Taguchi L9 test design was developed based on the three-level cutting speed, feed, chip depth and cooling environment parameters. The average surface roughness (Ra) values were measured in experiments made according to the L9 test design. Chip form occurring during turning is photographed. The Signal/Noise (S/N) ratios of the Taguchi experiment design in the Minitab program have been determined. According to the experimental results, the most significant effect on the Ra from the four factors was found in the hand made by the depth of cut. In ANOVA analysis, it was respectively determined that depth of cut, cutting speed, feed rate and cooling environment affected 95% confidence in Ra value. It has been found that the repeat experiments for the optimum parameters yielded about 90% accuracy compared to the Taguchi estimate.

CNC milling of EVA foam with varying hardness for custom orthotic shoe insoles and process parameter optimization

CNC milling strategy of EVA foam with varying hardness to provide a high degree of surface roughness of orthotic shoe insoles is presented in this work. Machining parameters (tool path strategy, spindle speed, feed rate, and step over) in addition to hardness material and wide tolerance insoles were optimized using a hybrid approach of Taguchi-Response Surface Methodology (TM-RSM). The aim of this research was to develop mathematical models and determine the optimum machining parameters which could be applied for the CNC milling of EVA foam as the insoles. Experiments were performed on a CNC milling machine with a standard milling cutter and run under dry coolants. The effects of the six parameters on the average values of surface roughness were initially analyzed by an S/N ratio of TM. Optimal conditions were established from the TM and then used to determine the optimum values in RSM modeling. The final results indicate the significant improvement of percentages (0.24% and 4.13%) in the surface roughness of the insoles obtained with TM-RSM as compared to the TM analysis. It is envisaged the present study would add to the understanding of production for orthotic shoe insoles through CNC milling.

Anodization of a Medical-Grade Ti-6Al-7Nb Alloy in a Ca(H2PO2)2-Hydroxyapatite Suspension

The electrochemical parameters used for surface treatments should be individually determined for each titanium alloy. In this paper, the parameters for the anodization of a medical-grade Ti-6Al-7Nb alloy in hydroxyapatite suspensions were determined. It was found that formation of a favorable porous oxide layer occurred for the plasma electrolytic oxidation process in a Ca(H2PO2)2 solution with 150 g/dm3 hydroxyapatite particles at 350 V and 450 V. The differences in the morphology, chemical and phase composition caused variability in the average surface roughness (up 4.25 μm) and contact angle (strongly hydrophilic) values. Incorporation of the hydroxyapatite ceramic particles into formed TiO2 layer also influenced the layer thickness and adhesion of the layers to the substrate. The oxide layers formed on the Ti-6Al-7Nb alloy were between 5.19 and 31.4 μm in thickness with an average range of approximately 8–15 μm. The formation of a ceramic layer under controlled electrochemical parameters allows the design of a bioactive surface of implants for bone tissue. The hydroxyapatite particles may promote the osseointegration process. Thus, in this study, the formation of ceramic composites on medical-grade Ti surfaces is presented and discussed.

SURFACE ROUGHNESS OF BULK-FILL RESIN-BASED COMPOSITE RESTORATIVE MATERIALS AFTER IMMERSION IN PROBIOTIC MILK

Background: Dentists often restore posterior cavities caused by caries using the latest resin-based composite; i.e. bulk-fill resin-based composite. Probiotic milk may affect the surface roughness because the acid content may induce degradation of filler components resulted in roughness on the surface of bulk-fill resin-based composite. Objective: This study aims to determine the surface roughness of bulk-fill resin-based composite restorative materials after immersion in probiotic milk for 10 hours and 20 hours. Method: The study applied true experimental method using pretest and posttest with control group design. The research sample was obtained using simple random sampling. This study employed 8 samples which were included in 4 treatments. Thus, the total number of samples used was 32 samples. Results: The average value of surface roughness in group I was 0.2675 µm, group II was 0.4138 µm, group III was 0.0900 µm and group IV was 0.0938 µm. The results of One-Way ANOVA parametric test revealed p value = 0.000 (p < 0.05) and presented that the immersion of bulk-fill resin-based composite in probiotic milk for 20 hours obtained the highest average surface roughness value compared to the immersion in distilled water and probiotic milk for 10 hours. Conclusion: There is an increase in surface roughness of bulk-fill resin-based composite restorative material after immersion in probiotic milk for 10 hours and 20 hours.

INVESTIGATION OF POLISHING ABILITIES OF UNDERGRADUATES AND POSTGRADUATES BY USING VARIOUS SYSTEMS ON COMPOSITE MATERIALS

Background: The purpose of dental education is to enable students to gain the knowledge and skills to provide the best service to their patients upon graduation. In order to achieve this, students need to work with a sufficient number of cases and use current materials throughout their education. Aim: The aim of this in vitro study, conducted in 2017, was to examine the surface roughness of two types of composites prepared with different polishing systems, constructed by either undergraduate or doctoral students. Methods: Bulk-fill (Filtek Bulk Fill Posterior) and nano-hybrid (Ceram.x One Universal) composites were polished using single-step (OneGloss Set) and multi-step (Sof-Lex System) systems. The finishing and polishing procedures were performed by ten dental undergraduate students and ten doctoral students. Average surface roughness values (Ra, µm) were measured using a profilometer. Data were analyzed using the Wilcoxon signed-rank test (? = 0.05). Results: No statistically significant differences in Ra values were noted between operators with different levels of experience. Surface roughness was higher in the samples prepared using the single-step system than in those prepared using the multi-step system for both sample types tested in this study. Conclusion: Practitioner ability does not affect the performance of polishing systems. Regardless of the composite type, the single-step polishing system produces rougher surfaces than the multi-step system.

Surface roughness effect on droplet impact characterization: Experimental and theoretical study

In this paper, the effect of surface roughness on the both normal and inclined droplet impact is investigated experimentally by image processing. The impingement of water droplets with 2.9 mm diameter and 1m/s velocity impacting on three types of stainless steel surfaces with respective arithmetic average surface roughness values of 2.24 μm (Smooth), 6.04 (Medium) and 30.2 (Rough) is examined using a high-speed camera. The dynamic behavior of the impact including droplet deformation, the maximum spreading diameter and length, contact angle and the number of fingers are studied. Experimental results demonstrate that rough surfaces not only prevent secondary droplet formation but also decrease the number of fingers formed around the droplet in the normal droplet impact. Considering the inclined droplet impact scenarios, the asymmetric spreading of droplet on inclined surfaces avoids the secondary droplet formation by decreasing the fluid kinetic energy. In the inclined impact, fingers are formed around the droplet perimeter like the normal impact. The only difference between impacts onto the inclined surfaces is a gradual decrease of the number of fingers by increasing the incline angle. The experimental results are compared with those of the analytics available in the literature for the normal droplet impacts. Next, a simple analytical model for droplet impact on an inclined surface is developed; the predictions from this model was also compared to those of measurements. Calculated values from the analytical models agreed well with experimental data for both normal and inclined impact scenarios.

Comparison Between Microstructure, Wear Behavior, and Corrosion Resistance of Plasma-Nitrided and Vacuum Heat-Treated Electroless Ni–B Coating

In the present study, electroless nickel–boron coating was deposited on AISI 4140 steel and post-treated under two different conditions. One of the treatments was carried out under a vacuum condition at 400 °C for 4 h, and the other post-treatment was plasma nitriding in an atmosphere comprising 25% N2–75% H2, at 400 °C, for 4 h. The coated samples were characterized by means of XRD, FESEM, and EDS. The average values of microhardness and surface roughness of the coatings were reported subsequently. The friction and wear behavior of the specimens were studied by pin-on-disk method, and the worn surface of the samples was studied through FESEM and EDS. Potentiodynamic polarization and EIS tests were used to evaluate the corrosion resistance of the specimens. Both post-treatment processes increased the toughness and adhesion of the coatings. Higher wear resistance and lower friction coefficient were achieved in plasma-nitrided sample. On the other hand, the more negative corrosion potential and higher corrosion rate were obtained for the plasma-nitrided sample.

Effect of CBN grain friability in hardened steel plunge grinding

Nowadays, modern technology allows engineers to create tools with more adequate properties depending on the application. Currently, a lot of components require dimensional and geometric precision with tolerances increasingly tight. Grinding is the most suitable machining process in many cases and is currently applied in large scale in the machining business. Since it is a complex process due to its stochastic nature, there is a wide-open field of study and data collection to obtain the most efficient combination of tool/workpiece material depending on what is desired, always seeking improvements and optimization of the process. Besides this, a new parameter that can recently be considered to select the grinding wheel is the abrasive grains’ friability level within cubic boron nitride (CBN) material. Since there is scarce information about the influence of this specific parameter in the performance of the wheel, this work aims to fill this gap. This work analyzes the cylindrical grinding of the AISI 4340 steel using two types of vitrified-bonded CBN grinding wheels. Their only significant distinction is the difference in the abrasive grains’ friability. The performance of each wheel was analyzed taking into account the results obtained from the parameters’ surface roughness, roundness error, micro hardness, acoustic emission, and average power. Regarding the average surface roughness, the more friable wheel produced values of 0.31, 0.40, 0.44, and 0.53 μm, respectively, for the 0.25, 0.50, 0.75, and 1.00 mm/min feed rates. On the other hand, the average surface roughness values obtained from the workpieces ground with the less friable wheel were: 0.22, 0.29, 0.35, and 0.40 μm, respectively, for the 0.25, 0.50, 0.75, and 1.00 mm/min feed rates. This means that when using the less friable abrasive grain, the surface roughness is better, which suggests that in the friability range analyzed, the use of a less friable wheel produces workpieces with better quality.

Biomechanical evaluation between orthodontic attachment and three different materials after various surface treatments: A three-dimensional optical profilometry analysis

To determine the best bonding method of orthodontic attachment among monolithic zirconia, feldspathic porcelain, hybrid porcelain, and the impact of surface-conditioning methods using a three-dimensional optical profilometer after debonding. 56 feldspathic porcelain, 56 monolithic zirconia, and 56 hybrid porcelain samples were divided into four surface treatment subgroups: (1) hydrofluoric (HF) acid etch + silane, (2) Al2O3 sandblasting + silane, (3) silicoating (SiO2), and (4) diamond bur + silane. The specimens were tested to evaluate shear bond strength (SBS). Residual composite was removed after debonding. Three-dimensional white-light interferometry was used to obtain quantitative measurements on surface roughness. The highest SBS value was found for the HF acid-etched feldspathic porcelain group. The average surface roughness values were significantly higher in all material groups in which diamond bur was applied, while roughening with Cojet provided average surface roughness values closer to the original material surface. Variations in structures of the materials and roughening techniques affected the SBS and surface roughness findings.

Experimental investigation on novel drilling strategy of CFRP laminates using variable feed rate

This study focused on the influences of drilling parameters on hole quality and thrust force in drilling of carbon fiber-reinforced polymer (CFRP) composite laminates via variable feed rate. Drilling experiments were carried out by using three different cutting speeds, feed rates and the qualities of tungsten carbide drill. Scanning electron microscopy and coordinate measurement machine were used for hole surface damage and diameter analyses, and also a portable instrument and 3D optical profilometer were utilized for surface roughness measurement. It was identified that thrust force (Fz), delamination factor (Fd) and average surface roughness (Ra) values attained in drilling processes by variable feed rate are lower than those of constant feed rate with average of 14%, 3% and 18%, respectively. Besides, the hole diameter (D) values obtained with variable feed rate in hole exit were higher than those of constant feed rate. Moreover, the higher Fz values were obtained with diamond-coated and TiAlN-coated drills than those of uncoated drill with 55% and 77%, respectively. The interactive influences of drilling parameters on machinability factors were evaluated via analysis of variance, and then, the most significant parameter was specified as the feed rate for Fd, just as the drill quality for Fz, Ra and D. According to the experimental and statistical results, we suggested that the novel drilling strategy is a significant alternative for the step hole and conventional drilling of CFRP laminates.

Modeling and Spark Erosion Drilling Process Optimization of Inconel 718 Using RSM Technique

Electrical discharge machining with rotary tool is known as electric discharge drilling (EDD) which is being widely used for machining the difficult-to-cut materials like super alloy, ceramics and composite materials. Present research work has been introduced to find the impact of four influencing input factors discharge current (C), pulse off time ([Formula: see text]), pulse-on time ([Formula: see text]) and drill speed (S) on the response, tool wear rate (TWR), metal removal rate (MRR) and Centre line average value of surface roughness (Ra). The spark erosion drilling was performed on the Inconel 718 with rotating copper electrode. The major performances characteristics material removal rate (MRR), tool wear rate (TWR), and surface roughness (SR) are to be evaluated with consultation of Response Surface Methodology (RSM) techniques. The central composite rotatable design (CCRD) has been reported to plan the experimental design and developing the model for prediction of data within the range of investigation. ANOVA test was also carried out to check the adequacy for development of models. It has been evaluated that discharge current, [Formula: see text], and [Formula: see text] have been found as most significant factors that effects on the performance measures. The models have 86.02, 84.29, and 83.15% values of correlation coefficient (R2) for MRR, TWR and Ra whereas the adjusted R2 (R2 adj) are 73.80%, 70.55%, and 68.41% for MRR, TWR and SR, respectively.

Influence of working environment and built orientation on the tensile properties of selective laser melted AlSi10Mg alloy

AlSi10Mg alloy was fabricated by Selective Laser Melting (SLM) using two different atmospheres, argon and nitrogen, both in vertical and horizontal built directions. The influence of work environment and anisotropy are studied in this work by keeping all other process parameters including shielding gas pressure constant. The meso-structural features revealed scan tracks and melt pool layers while the microstructural features have showed cellular structure with α-Al matrix and its boundary made up of the eutectic mixture of Al and Si. These cells were approximately of 500 nm size as revealed by TEM analysis. The grain morphology and texture were studied using EBSD analysis. The XRD analysis revealed similarity in the phases formed in samples built under argon and nitrogen environment. Both the horizontal as well as vertical built samples contain elongated grains with 〈100〉 direction oriented along the built direction and 〈100〉 fibre texture in the XY plane. Tensile test results showed the maximum strength of 385 ± 5 MPa was exhibited by vertically built sample under nitrogen environment while the lowest strength of 338 ± 2 MPa was exhibited by horizontally built sample under argon environment. Surface roughness and porosity measured in all the conditions exhibited minor variation in the average surface roughness and porosity area fraction values. Among the samples tested under same built orientation, the variation in strength is approximately 5% higher in nitrogen environment while among the samples tested under same working environment, the variation in strength is approximately 7.5% higher in vertically built samples. This states that the influence of working environment on strength is lesser than that of the built orientation. The materials exhibited brittle failure with inclined fracture profile, fracture morphology with pores, river patterns and inter-cellular fracture plus approximately 4.5% elongation in all the tested samples, implied isotropic elongation behaviour. The samples built under both the work environments exhibited the similarity in defect structure, microstructure and nearly isotropic behaviour in mechanical properties. It inferred that nitrogen could be preferred over argon as shielding gas in SLM for its cost effectiveness.

Effect of tangential misalignment in ultrasonic burnishing

Ultrasonic burnishing is a surface finishing process that produces fine surface roughness, improved geometrical accuracy, high compressive residual stresses and increased hardness. The method is suitable for finishing dies or other double curvature surfaces and it does not require changing of the fixturing setup after a machining process. The method has not however become commonly used in industry, because the technology has not been extensively tested. Technological parameters in ultrasonic burnishing includes the surface speed, distance between consecutive passes (or in machining terms, feed) and contact force. Ultrasonic burnishing is based on forging at an ultrasonic frequency of over 20,000 impacts per second and there is no material removal associated with the process. The technological parameters have been tested and recommended values have been recorded for some common work materials. One important parameter is the tangential alignment of the burnishing tool in regard to the workpiece surface normal. This parameter is easy to control in turning operations or with planar surfaces, but with a double curved surface the control of the angle is more difficult. All the previous research has been done on cylindrical or planar workpiece and therefore the tangential misalignment or the sensitivity of the surface integrity regarding the tangential misalignment has not been studied. This paper investigates the effect of the tangential misalignment of the burnishing tool and the effect on surface integrity. The results show that ultrasonic burnishing is suitable method for finishing workpiece surfaces even with inclined tool angle. The ultrasonic burnishing produced a beneficial surface integrity state on the workpiece surface with hardened material and improved surface quality. The surface micro-hardness increased by 1.4-6.7 %. At the same time, the average surface roughness (Ra) values decreased by 50-85 % depending on the misalignment angle.

A comparative study on the surface finish achieved during face milling of AISI 1045 steel components using eco-friendly cutting fluids in near dry condition

This paper elucidates the effect of near dry machining (NDM) on the surface quality achieved during face milling of AISI 1045 steel components using the conventional emulsified mineral oil cutting fluid and emulsified cutting fluid prepared from eco-friendly non-edible unrefined oils such as castor oil, cottonseed oil and neem oil. This work was completed in a FANUC arrangement CNC vertical machining centre (VMC) with three TiN coated carbide inserts of 0.4 mm nose radius adjusted into a face milling cutter of 25 mm in diameter. The machining parameters considered in this investigation are number of passes, depth of cut, spindle speed and feed rate. The experiments were planned based on Taguchi's L9(34) orthogonal array. The surface roughness of the machined components is measured using a surface roughness tester and subsequently, a mathematical model was developed for the average surface roughness values through regression analysis for all the machining conditions. The significance of the selected machining parameters and their levels of surface roughness are found by analysis of variance (ANOVA). The results revealed that machining under near dry condition using eco-friendly cutting fluids provides better product surface quality than the conventional cutting fluid.

Modelling and Simulation Based Surface Characterization of Reverse- µEDM Fabricated Micro Pin-fins

Cross-sectional profile and surface quality of micro-fins of a heat sink play a significant role in the transmission of heat from microelectronic and MEMS devices subjected to intense heating. Several processes are available for the fabrication of such pin-fins, Reverse micro electro discharge machining (RµEDM) among them is one of the most promising. A wide range of parameters associated with this process provides varying competence for surface roughness. An effectively modeled and simulated surface, thus, may serve as a database for an operator to study the effect of parameters for the desired surface. A single discharge model is developed to study the volume removal by each discharge pulse to achieve the goal. ANSYS finite element code is used to simulate the process to find the volume of the crater for further prediction of average surface roughness values. The model’s predictions are compared with experimental results for verifying the approach and presented a good agreement with them.

Effects of mechanical polishing treatments on high cycle fatigue behavior of Ti-6Al-2Sn-4Zr-2Mo alloy

In this study, high cycle fatigue (HCF) behavior of Ti-6Al-2Sn-4Zr-2Mo (wt.%) (Ti-6242) alloy sheets subjected to mechanical polishing treatments (MPTs) were investigated at room temperature. The effects of surface roughness and residual stress induced by the MPTs (cold rolling polishing (CRP), sandpaper polishing (SP) and nylon cloth polishing (NCP)) were studied. Results indicate that the fatigue limits of Ti-6242 alloy sheets polished by CRP, SP and NCP were 632.6, 593.0 and 639.0 MPa, respectively. The average surface roughness (Ra) values of the Ti-6242 alloy sheets for CRP, SP and NCP were 0.36, 0.31 and 0.18 μm, respectively. Top surface tensile residual stress (TRS), surface and deep subsurface TRS and top surface compressive residual stress (CRS) were induced by CRP, SP and NCP, respectively. HCF behavior of the Ti-6242 alloy sheets was dominantly influenced by deep subsurface residual stress induced by the MPTs, whereas the effects of surface roughness and top surface residual stress were negligible.

An investigation on surface roughness of aluminium metal matrix composites cut by abrasive waterjet

Abrasive waterjet cutting is a new, growing technology and is used to cut difficult to cut materials. Surface roughness of abrasive waterjet cut materials is an important output parameter. In this study an attempt is made to investigate the average surface roughness value of aluminium 6061 and its composites along the depth of penetration. Trapezoidal shaped aluminum-silicon particulate metal matrix composites manufactured by stir casting method with 5, 10 and 15 weight percentage of silicon carbide particles reinforced in aluminum 6061 alloy are cut by abrasive waterjet employing #80 mesh size. The average surface roughness value is increasing as the depth of penetration increases in aluminium 6061 base material and its composites. Also, it increases with the increase in percentage of silicon carbide particles in the metal matrix composites. The waterjet pressure and traverse speed of the jet has a significant effect of average surface roughness of cut samples.

Evaluation of hard coating materials performance on machinability issues and material removal rate during turning operations

The potential of various varieties of hard outer surface coats of carbide inserts on surface roughness, material removal rate (MRR) and flank wear, are scrutinized based on an experimental study using standard orthogonal array L16(4^3 × 2^1). For this motive, AISI 304 austenitic stainless steel is turned applying five divergent varieties of coated carbide inserts over a gamut of cutting parameters that include cutting speed, feed depth of cut and nose radius. Among the selected coated carbide inserts, turning by physical vapour deposition (PVD) coated with TiAlN-TiN layers cemented carbide insert obtained the lowest average surface roughness value (1.06 µm) and the lowest average flank wear value (0.1580 mm). The maximum average MRR (29248.9 mm3/min) is obtained by chemical vapour deposition (CVD) [Ti (C, N) + Al2O3] layer cemented carbide coated tool. It is found out that the fundamental theoretical tendency of surface roughness values in respect of feed rate is different from the experimental values. Further, the most significant factors affecting the machinability issues and MRR are identified using analysis of variance (ANOVA). Reasonably accurate mathematical models are developed for prediction of machinability issues and MRR within limits.