The use of coating materials to enhance the performance of cutting tools is not a new concept. Coatedhard metals have brought tremendous increase in productivity since their introduction in 1969 and had an immediate impact on the metal cutting industries .Due to their significantly higher hardness, carbide-cutting tools are more widely used in the manufacturing industries today than high-speed steels. Coated and uncoated carbides are widely used in the metal working industry and provide the best alternative for most turning operations . Due to their heat resistance, cemented carbides can be used in very hot applications and all types of PVD and CVD processes can be used to deposit coatings .The combined substrate-coating properties determine the important properties such as wear, abrasion resistance and adhesion strength of a coating. A hard wear resistant coating can not perform well unless complimented by a hard and tough substrate. Thus, a hard coating deposited on a soft substrate leads to poor properties . Physically and chemically vapour deposited coatings offer today a powerful alternative to improve further the cutting performance of the cutting materials.
The various methodologies and strategies that are adopted by researchers in turning optimization and different techniques used by the researchers in turning process are follows Singh et al  investigated the effects of cutting parameters like spindle speed, feed and depth of cut on surface finish and material removal rate of EN-8 on CNC Lathe by using CNMG120408 insert with Taguchi approach. The results found were, spindle speed contributed 63.90%, depth of cut contributed 11.32% and feed rate contribution was 8.33% for Ra. Adinarayana et al  studied optimization of power consumption in turning operations using CVD cutting tool on AISI 4340 alloy Steel with speed, feed and depth of cut as control parameters. Result obtained was, power consumption is increase with increase in cutting speed, feed rate and depth of cut. Singh et al  investigated the effects of cutting parameters like spindle speed, feed and depth of cut on surface finish and material removal rate on EN-8 under turning conditions on CNC lathe by using carbidetool. Response Surface Methodology has applied to optimize cutting parameters. Result found was that speed and depth of cut are put negligible effect on the surface roughness and feed rate shown increasing trend. Suresh et al  studied that performance of multilayer hard coatings on cemented carbide substrate using CVD for machining of hardened AISI 4340 steel using Taguchi approach in turning process by cutting speed, feed and depth of cut as a controlled factor and power consumption as performance
Turning is a process of removing unwanted material from a rotating work piece to obtain a desired shape and size of component. Hardturning deals with turning materials with a hardness of above 45 HRC, typically in the hardness range of 58 to 68 HRC . Hardturning operation is performed with coatedcarbide, cermet, ceramic, PcBN and PCD tools. In recent years, application of single-layercoated and multi- layered coated cutting tools are used for machining hardened materials to improve the tribological conditions at the tool-workpiece interface and at the tool-chip interface. In these days, the manufacturers are more concentrate on final product accuracy and quality rather than tool wear or cutting force . Today 85% of carbide cutting inserts used in industry are coated, to obtain better results and great number of coating materials and methods are also available. By practical approach the type of tool wear mechanism should be identified and a suitable coating on cutting insert has to be selected by correlating the coating materials and their performance before choosing a cutting insert .
Carbide cutting tools are very popular in metal cutting industry for the cutting of various hard materials such as, alloy steels, die steels, high speed steels, bearing steels, white cast iron and graphite cast iron. In the past few decades there had been great advancements in the development of these cutting tools. Coating is also used on cutting tools to provide improved lubrication at the tool/chip and tool/work piece interfaces and to reduce friction, and to reduce the temperatures at the cutting edge. During machining, coatedcarbide tools ensure higher wear resistance, lower heat generation and lower cutting forces, thus enabling them to perform better at higher cutting conditions than their uncoated counterparts. The use of coated tools are becoming increasingly demanding among the other tool materials. More than 40% of all cutting tools are coated in modern industry today.
Due to the continuous developments in cutting tools materials are being investigated to determine the potential of using them for use in extreme conditions as in hardturning. Coatedcarbide cutting tools one of the tools are using to machining hard material such as stainless steel. At the same time investigation of uncoatedcarbide inserts still conducted to determine the potential of using in cutting of hared material due to the their low cost compare to the coated inserts. In the past few years, different efforts focusing on optimization of cutting parameters in turning machining with energy-related studies of machine tools have been conducted. Nevertheless, very little work has been done in evaluation the performance of cutting tools based on minimum energy consumption and production cost considerations. In this article, study is the evaluate of the performancecoated and uncoated carabid insert in hardturning process of AISI 316 based on Multi- Cutting Tool Criteria problem of tool cost, energy cost and time life of tools.
Typical wear pattern of samples is seen in SEM micrographs, after turning at a cutting speed of 60 m/min. By visual examination, it is found that on sample A, local flank wear so called notch wear on the main and minor cutting edges also non uniform abrasive wear seen. Notching is mainly caused by a fracture process, it happens when excessive localized damage occurs at the flank and rake face simultaneously. The notch will cause poor surface finish, further, it leads to fracture wear. Where as for sample B wear was smooth, which does not lead to any catastrophic tool failure. Iron has good wettability and solubility for tungsten carbide. Addition of an iron enhances the fusion of tungsten carbide particles, which increases the overall strength of sample as compared to the sample without iron.
, this will lead the designers of machine tools to verify their calculations on the basis of important constraints. The system is known as the pin-on-disk system, which is unfortunately not able to simulate the contact conditions in cutting, since the conditions (temperature, pressure) are not real and . The phenomena occurring at the interface of the tool-chip (secondary shear zone) and at the interface of the toolworkpiece may be identified by the new tribometer in order to achieve a precise modeling using finite element methods In order to characterize some materials developed by Ascométal within the LTDS, and particularly the friction coefficient between cutting tool and machined metal, the exchange of heat flow, tool wear, quality of machined surface, series of tests on an axial tribometer have been carried out (Fig 1). The tribological phenomena at the interface tool / machined surface / chip are very complex to model and yet they are the key behavior of the tool, including its resistance to wear. The present work lays out experimental results on the TiN and AlTiN wear behaviour when applying an agressive machining on 42CrMo4 and 27MnCr5 steels. In addition, surface quality degradation, cutting force and heat flow evolution are related to the tool wear.
Looking for a better productivity of metal cutting is therefore a major concern of researchers. Steels with improved machinability; various coatings of cutting tools, machining at high speeds, the study of tribological interface tool-chip-workpiece, constantly improve product quality and productivity. The main purpose is to participate in the development of new ways of machining or new techniques of programming and control to improve productivity. Depending on the machining conditions, the wear process of cutting tools can affect one, two or all active faces of the tool  and . This can lead to inaccurate tolerances of the machined parts. The wear of cutting tools can occur through erosion, abrasion, adhesion and diffusion  and . Such problems, essentially of tribological, nature vary considerably from one family to another family of steels. Materials characterization is essential in developing new products of steels  and . Therefore, it is necessary to develop an accurate
Similar findings for the natural-frequency data and resonance were pointed out by Khanfir at al. . In order to validate the experimental results, a finite-element analysis was performed, and as in , ANSYS software was used. The workpiece was modeled as a beam element, and the cutting tool was represented with combined elements that include spring rigidity and damping . Both supports are considered rigid in the first analysis, while in the second analysis the chuck was considered as an elastic support with high rigidity, to be able to predict the backlash in the chuck. Using the calculated rigidity of the cutting tool, the results of the natural frequencies for different locations of cutting tool in contact with the workpiece were obtained. These results and the results for the workpiece without any contact with the cutting tool are shown in Table 3. The natural-frequency data for one elastic support, including contact with the cutting tool, corresponds (shadowed cell in Table 3) with frequency Preglednica 2. Lastne frekvence komponent strunice
Titanium composites are utilized broadly as a part of aviation industry such as aerospace in view of their excellence mix of high specific strength (strength-to- weight ratio), which is retained at hoisted temperature, their excellent resistance to corrosion at high temperature and their fracture resistant characteristics (Ezugwu and Wang, 1997). Some common qualities of aerospace super alloys are austenitic lattice which advances rapid work hardening, reactivity with cutting device materials under atmospheric conditions which has a tendency to build-up-edge and weld onto cutting tools, low heat conductivity which weakens the surface quality and vicinity of abrasive carbide in their microstructures (Che Haron et al., 2001; Ezugwu, 2005).
clamped by screw on an Aluminum supporting tool. The 8.0 mm carbide cutting tool will run over the panel which is fixed on machine. Table-2 and Table-3 show the chemical and physical composition of carbide cutting tool. The general information of JFRP panel and the panel properties are described on Table-4 and Table-5. Tool wear values were collected after 600 mm distance travelled which is illustrated in Figure-3. Response surface methodology was used to conduct the experiment. To get better result of tool wear Central Composite Design (small type) was selected and Table-2.6 shows the input variable for machining.
In industry, machining operation such as turning, milling, drilling and grinding commonly use especially in manufacturing industry. There is a need to produce high volumes of product in order to ensure their companies always achieve their target. The optimization of machining process for the achievement of high responsiveness of production is the key factor. However, it can cause wear on cutting tool which is a result of physical contact between cutting tool and workpiece that remove small parts of the material from cutting tool. Tool wear can cause catastrophic failure of the tool that causes significant damage to the workpiece and even to machine tool after a certain limit. As getting inspiration from this kind of situations, this project consist the research of the tool wear and in the meantime includes the investigation of wear mechanism. It is necessary to compare the cutting performance in both cases of wet and dry cutting to know which techniques are better to machine AISI 1045.
In this investigation, a new mathematical model based on the mechanics and dynamics of the drilling mechanism is improvised for the exaggeration of cutting force and hole quality. A new technique is also explained in order to obtain cutting coefficients directly from a group of comparatively simple calibration tests. It is easy to stimulate the cutting forces for different cutting conditions in the process of planning stage using only the model. In the structural dynamic model measured frequency functions of spindle and tool system are integrated into model to obtain hole profile. Kadam M. S et.al  presented a paper on “Experimental analysis and comparative performance of coated and uncoated twist drill bit dry machining”. A practical research was carried out to check the effect of input machining parameters feed rate, cutting speed, point angle and diameter of drill bit on CNC machine under dry condition. The change in torque, chip load and machining time are obtained through series of research according to equations of response. The comparative study of single layer Titanium Aluminium Nitride (TiAlN) and High speed steel tool for EN31 steel under dry condition is done. The report describes Analysis of Variance to validate of established mathematical models for depth analysis of finish drilling process parameters on torque, machine time and chip load.
In addition, much cutting force models have been developed to predict the machining parameter. Most focus mainly on dry conditions even though coolants are widely used in practical machining. Beside, research for modeling of MQL conditions is scarce and not really established. As for FEM simulation of machining, the main problem is to determine the boundary conditions at the tool-chip interface. The use of coolants in machining makes it very difficult to determine the friction coefficient at the tool-chip interface. Hence, a better understanding of friction modeling is required in order to produce more realistic finite element models of machining process. The contact behavior between the chip and the tool is critical due to its effect on the toolperformance. Furthermore, the coolant method will not only affect the friction coefficient but also the heat transfer coefficient between the tool and workpiece combination.
Substrate independent measures for the onset of failure are obtained if critical track widths are considered instead of critical loads. The composite scratch hardness can be written as the product of the track width independent substrate scratch hardness and a track width dependent function b(w) that depends on the coating properties, but that is substrate independent. The volume law of mixtures model by Burnett and Rickerby, originally intended to describe the composite Vickers hardness cannot be used for the scratch hardness. Upon loading a coated specimen in the scratch test, the hardening of the specimen due to the presence of the coating increases with increasing load until chipping of the coating occurs.
The results showed excellent resistance to coatedtool crater and flank wear when CVD multilayer coated tools are compared to uncoated tools 9 . Sarıkaya et al. investigated the machinability of Haynes 25 under three cutting methods (dry, conventional cooling and lubrication, and minimum lubrication). As a result, when the MQL method was applied with high pressure, the amount of oil used was reduced while the machinability of the material was improved 10 . Ramkumar et al. discussed the effect of post-weld heat treatment on the fusion region microstructure and mechanical properties of Inconel —————
The achivement of high quality, in terms of workpiece dimensional accuracy, surface finish, high production rate, less wear on the cutting tools, economy of machining in terms of cost saving and increase the performance of the product with reduced enviornmental impact are the main and effective challenges of modern metal cutting and machining industries 1 . Traditionally, hardened steels are machined by grinding processdue to their high strength and wear resistance properties but grinding operations are time consuming and limited to the range of geometries to be produced. In recent years, machining the hardened steel in turning which uses a single point cutting tool has replaced grinding to some extent for such application. This leads to reduced the number of setup changes, product cost and ideal time without compromising on surface quality to maintain the competiveness 2,3 . The improve technological process, proper tool selection, determination of optimum machining parameters (cutting speed, feed, depth of cut, etc.) or tool geometry (nose radius, rake angle, edge geometry, etc.) are
The characteristics of the enco alloys cause high temperature (1000°C) and stresses ( 3450 MPa) in the cutting zone leading to accelerated flank wear, chattering and notching, depending on the tool material and cutting conditions used Ezugwu et al (1991).The material results in high temperature stress and a thick adhering layer at the tool-work interface during machining. The toughness results in difficulty in chip breaking during the process. These difficulties lead to high tool wear less material remove rate (MRR) and poor surface finish. The metallurgical damage to the workpiece due to the very high cutting forces which also gives rise to work hardening, surface tearing and distortion in finally machined components due to induced stresses. Rahman et al (1997) Choudhury et al (1998). The tendency to form a BUE during machining and the presence of hard abrasive carbides in their microstructure also deters machinability. The combination of high speed cutting and dry cutting for difficult-to-cut aerospace materials is the growing challenge to deal with the economic, environmental and health aspects of machining. Added advantages of dry machining are non-pollution of atmosphere or of water, no residue of lubricant on machined components and no residue of lubricant on evacuated chips which reduces disposal costs and the associated energy consumption. D. Dudzinski et al (2004).
Abstract— Hardturning is characterized by development of high temperatures at the cutting zone, which impairs the surface quality of the final product. Thus, an effective control of heat generated at the cutting zone is essential to ensure workpiece surface quality. Cutting fluids are generally used to avoid this. However, cutting fluids are being restricted due to their direct influence to human health and environment. New alternative approaches are in process to alleviate the problems associated with dry and wet hardturning. This study deals with an investigation of molybdenum disulphide as a solid lubricant as an alternative to the cutting fluids to reduce friction and thereby improve the surface finish of bearing steels. Experiments have been conducted using central composite rotatable design, to study the effect of molybdenum disulphide lubricant on surface roughness while hardturning bearing steel. Results indicate that there is a considerable improvement in the performance of hardturning of bearing steels using molybdenum disulphide as a solid lubricant when compared with dry hardturning in terms of surface roughness
Isabel, A., Barreiro, F. J., Norberto, L., Lacalle, L. De, & Martínez-pellitero, S. (2012). Behavior of austenitic stainless steels at high speed turning using specific force coefficients. International Journal Advance Manufacturing Technology, (62), 505–515. http://doi.org/10.1007/s00170-011-3846-9