Cutting Speed

 

 

 

 

 

 

 

 

 

 

Cutting Speed

 

 

 

 

 

 

 

 

 

Acknowledgments

Throughout the course of this project, I have interacted with many people who have influenced the development of my professional work as well as my personal growth. I would like to thank the following person:

My supervisor, Alan Jowitt, for his guidance and support to accomplish the final specialization project. His patience, knowledge, and instructions helped me a lot in completing my project. I did enjoy and benefited from the regular intellectual discussions that we had every week during this year.

Finally, I should mention my appreciation and respect to my project partner Ahmed Alsaloum for the time, hearing and support the weight of this paper during the most last year study period; we were working as a good teamwork.

 

 

 

 

 

 

 

 

 

 

 

 

 

1. Abstract

Many materials are used as cutting tools in the present day modern industry. Several factors affect the characteristics of the final machined product; it is therefore imperative to know these factors to be able to regulate them to produce the best results. The cutting trail or rather the degree of surface roughness is used to determine the quality of the product. It is therefore a very vital quality attribute and therefore setting cutting parameters to optimize the smoothness becomes a crucial machining process. The focus of this research paper is to determine how speeds of cutting tools affect the chip thickness ratio. The findings of the paper aims at relating the above factors required for best machining outcome. Cutting speed seems to be the one of the most vital factors affecting machining quality. These are the aims of the paper…identifying how this factor specifically affect chip thickness ratio. Cutting speed, denoted by V refers to the largest cutting tool relative velocity; V = D1N, where D represents the work piece diameter. Depth of Cut (d) represents the penetration distance of the cutting tool into the work piece; d = (D1-D2)/2 and finally, speed of cut can be defined as the speed (or rate) that the material moves alone the cutting edge of the cutting tool. The study is carried on the same materials owing to the various qualities displayed by different tool materials. In determining facts under this study, the material type and a host of other factors are kept constant.

 

 

 

 

 

 

2. Background

Obtaining an optimal machining condition is every engineer’s greatest desire; for instance surface roughness determines the properties of a products functional attributes such as heat transmission, surface friction, light reflection and resistance to fatigue. Whatever the machining outcome it may be the focus of wanting a high quality product remains unchanged. That is for the tool to have a high metal removal rate; for the product to be made with great accuracy; to have an appropriate surface finish and lastly, to have a long tool life. The formation of the chip comes as on because of the tearing effect of the material by the tool (Montagometry and Runger, 1994). As chips are removed, there will be new surfaces are exposed and another chips created again with continuous machining process. Material with a certain thickness is sheared and goes as a chip of thickness along the rake face of the tool and extensive deformation has taken place from an Aluminum work piece.

The following diagram (Fig.2.1) can illustrate this: –

Some chips come up as discontinuous chips which is formed by a series of rupture occurring approximately perpendicular to the tool place surface’ each chip element passing off along the tool face the chip element’ and that may adhere loosely to each other and becomes a little longer. A better surface been obtained since the chips split up into small segments the friction between the tool and the chips reduces, and these chips are suitable to collect’ handle and dispose off.

In the form of small segment, the chip thickness ratio as determined by the orthogonal cutting model is expressed by the equation; r=t_o/t_c is illustrated by fig.2.3 below: –

Where;

r = chip thickness ratio

t_o = thickness of the chip before chip formation, and

t_c = chip thickness after separation

The chip formation is highly related to the material’s type of the work peice, and there are more other factors have an effect on the chip form like cutting forces, cutting speed, tool geometry, vibrations and temperature.

Chip formation might have adverse special effects on metal work piece quality when the chip breaks against it (C), and it may cause breaking if chip hammering will be in cutting edge (B) as its shown in Fig 2.4. Because of that, controlling chip formation is important and so avoids some of the damages that can happen to the tool or work piece.

Fig 2.4: Three ways to break a chip, (Black, 1996)

A mixture of many factors can manage chip formation. One of the factors that influence the chip formation is the tool geometry, the nose radius affects the chip width and flow direction as shown in Fig 2.5 the radius of the nose have an effect on the chip width and flow direction as shown in Fig 2 also angle entering affects on the length of the chip. The formation of the chip is smoother and softer with angles between (45^o-60^o) for instance (Black, 1996).

Fig 2.5: The effect of nose radius on chip form, (Black, 1996)

Moreover, cutting speed, depth of cut and feed rates highly effect the chip thickness and formation, and each work piece material has got its specific design values.

In this project Aluminum material was chosen as the Aluminum cutting has been a topic of huge interest for the industrial productions and scientific investigate worldwide. It is obvious the observed that chip morphology below changeable cutting speeds are different in the Aluminum cutting, and this is mostly because the differences in crack propagation and initiation as well as differences in the feed rate in the cutting sector. In this research, an investigational consider of cutting speed and chip thickness is been carried out for pure orthogonal cutting in an average cutting speeds between 7.065 to 111.47 m/min. The effect of cutting speed on the level of chip thickness is analyzed.

3. Initial Research

This research determines that cutting tools normally works in a transient surface…the surface to be cut by the tool positioned between the machined surface and the surface to be machined. Practical machining procedure shows that a tool will cut the transient surface marked on the tools previous pass. Choudhury and El-Baradie (1999) takes note of the depth of cut, denoted by d_cw relative to uncut chip thickness, denoted by t_1. The book further explains that with a low cutting feed, then this equation will apply d_cw>t₁. Increasing the cutting feed will reverse the equation in which the uncut chip thickness will be greater than the depth of cut. On a broader view, this paper determines that several indices that influence machining output.

Experiments have been done on this topic of relating cutting speed with dry feed rate and it show that as faster the cutting speed as the chip thickness is thicker. The experiment used Pure Orthogonal cutting method.

 

 

3.1 Pure Orthogonal Cutting and Oblique Cutting Methods

The deformation style and forces of strain present in the primary shear zone bring about the difference between the properties and characteristics of chips. These forces result from the frictional interaction between the cutter and the chip in the secondary shear zone. A machining process, which is the interaction between the tool and the work piece, presents a complex interactive equation of stress, strain and temperature.

Orthogonal machining refers to a process in which the edge of the tool is positioned parallel to the uncut work piece surface and at the same time perpendicular to the cutting direction. This means that the cutting and advancing velocities are both positioned orthogonal to the edge of the tool. This method of machining results into a two-dimensional problem since it forms a single plane deformation (Shih and Yang, 1993). Orthogonal machining uses a wedged-shaped tool, which is forced into the workpiece leading to the formation of chips by shear deformation along the shear plane. This type of machining has two main geometrical elements; clearance angle and rake angle. The former provides a clearance between the tool flank and the working surface, while the latter determine the direction of chip flow. In this method, the chip flows over the surface of the tool rake…at right angle to the principle cutting edge. Oblique machining allows for post-production processing that shapes up the product into the desired shape (Shih and Yang, 1993, pp.353-6).

Oblique machining on the other hand presents a system in which the tool cutting edge is inclined to some angle to the cutting direction, thus produces a three-dimensional problem. The direction of chip flow therefore is at an angle normal to the cutting edge, which in turn is inclined to an angle λ (inclination angle) to the feed. The direction of chip flow is at an angle β (chip flow angle) to the feed. The principle cutting force and the chip geometry in oblique machining are determined by the rake angle, which is given by β_e (Srenskowski, 2005)

3.2 Orthogonal “pure” Cutting Method Advantages:

The decision to settle on orthogonal “pure” cutting method is because it is not only cheap, but also less complex as in orthogonal cut; the work piece is a flat plate (it can be a thin tube as well) and is machined by a wedge-shaped tool using a rake angle of  and a relief angle of . The work piece is moving at a cutting speed of V with a depth of cut to. The method helps in showing the amount of cutting forces involved that are necessary for the desired deformation. Another advantage that engineers stand to get by using this method in this experiment over other empirical and analytical methods is the capability represents the properties of the cutting tool materials and the work piece as a function of temperature, strain, frictional coefficient, strain rate and stress. The method therefore is appropriate to understand the mechanisms of chip formation as well as the transient stresses and strains obtained during machining (Ozel and Altan, 2000).

4. Methodology:

Given that aluminum is a material with good quality mechanics, very common also in the machine-tool industry, this experimental work was carried out on specimens of Aluminum 1350 using a conventional lathe; Table 2 describes the chemical composition of aluminum.

Alloy	Si	Fe	Cu	Mn	Mg	Cr	Zn	Ti	V
1350	0.10	0.40	0.05	0.01	–	0.01	0.05	0.02+Ti

 

The experiment involved three different speed 7.065 m/min, 28.26 m/min and 111.47 m/min. Work piece description:

 

4.1 Tools and instruments

• A1 tube 6063
• Tool is 20 RAKE. (See a appendix A)
• 10 Clearance, (See appendix B)
• Workshop turning machine.

4.2 Experimental procedure

1. The work piece was placed and fixed in the turning machine.
2. Work piece properties:
   6063. Material: Aluminium 6063.
   6064. Geometry: OD 55mm tube.
3. Fixing the cutting tool on the turning cutting machine.
4. The lathe was adjusted to cutting parameter as following:
   7. Three cutting speeds: 7.065, 28.26, 11.47 m/min
   8. Dry Feed rate
5. The turning machine was turned on.
6. Cutting working piece begin and chip was produced
7. Collecting chips and measure chip thickness .

 

5. Result and Discussion

5.1 Result:

Result table 1 for the thickness of the work piece after the cutting operation:

Experiment Number	Speed	Average Chip thickness
1	7.065 m/min Chip produced at highest speed shows rough work piece surface and chip surface as well.	0.40 mm
2	28.26 m/min Chip produced at highest speed shows dull work piece surface and chip surface.	0.47 mm
3	111.47 m/min Chip produced at highest speed shows smooth shiny work piece surface and chip surface.	0.66 mm

5.2 Discussion:

It is obvious that in all the three cutting speeds experiments, the chip thickness tend to be thicker slightly with shiny surface as the cutting speed increased. That can be illustrated by the effect of heat that generated in the share-cutting zone. Therefore, continues chip was produced with highest cutting speed experiment. Moreover, as the cutting speed was decreased from 111.47 m/min to 28.26 m/min the cut chips tend to be less length than the higher speed with dull surface, and that because of the less heat was generated in the cutting shear zone. Lastly, decreasing the cutting speed to 7.065 m/min generate thinner discontinues chips with a slightly rough surface.

The information of the cutting force is the elementary power to the cut assessments in the experiment. In order to determine the mechanical output in relation to a machine or a tool, it is critical to identify and understand the cutting power. Cutting power information would enable the experiment to have relevant data on the cutting forces. The cutting forces are crucial towards determination of the organs of the tool. This is a revelation towards prediction of the deformations of the pieces. This takes section of the precision of the material aspect or machining. The precision is in the form of auto-excited vibrations or indirect means of cutting. Cutting force with reference to the mechanical properties of relevant material of the chip is susceptible to offer information in relation to the machinability of the tool and the work piece. CWT completion is possible within the cutting process with the aim of determining ranges of the parameters that subscribes to cutting.

This enhances the quality of the criteria or the cost function in relation to the thermal softening adopted by the industry. Metal cutting reflects usual process in relation to manufacturing. The process is crucial in the process of removing unwanted materials from the work piece. It is also critical towards obtaining suitable dimensions for the chips to be applied for unique requirements. Numerous studies have been conducted in relation to the machining process because of its economic and technical benefits or importance. These studies aim at improving the quality, enhancing the productivity levels, and reducing the cost of the manufacturing process. Chip alloys are very fascinating materials applicable in the industrial setup. This is with reference to the strength-on-weight ratio and the resistance to corrosion reflected at high temperatures. Despite the essence of these features, the material is limited in its utilization because of the poor machinability. The essence of lower thermal conductivity limits the evacuation of heat that is generated in the process of cutting thus the effect of temperature rise of the material. This differentiates alloys from other materials. It is evident that saw-tooth chips are prone to occur in relation to the cutting speed. The formation of chips leads to decrease in the life of the material, degradation of the surface of the work piece, and reduces the accuracy of the process. These aspects make it vital to examine the cutting process of alloys in relation to the machinery performance. The process would lead to enhancement abilities with the aim of improving the life of the tool, component surface, and dimensional control. These developments would enhance the productivity levels in relation to the manufacturing process.

Increase in temperature leads to loosening of the molecules within the metal components thus increase in size. The generation of heat is because of the thermal conductivity or friction. The process of increase in size due to heating or cutting at greater speed is known as the expansion. This accounts for the increase in the size of the chips at higher speed due to expansion. The decrease in cutting speed results into reduction of the size due to minimal conductivity of heat or friction. The chips undergo contraction to reduce the lengths in comparison to cutting at higher speed. Decreasing of the cutting speed is also responsible for generation of thinner chips that are discontinuous in nature. The chips also displays rough surfaces to depict the essence of minimal heat generated during cutting at lower speed. The process of generation of heat at this stage is minimal to facilitate smooth cutting thus the development of rough surfaces in relation to the chips. This indicates that the cutting speed is vital towards achievement of quality chips in accordance with the requirements or functions of the work piece.

In the event of relatively low temperatures during the cutting, the aluminum has the opportunity to undergo thermal softening. Thermal softening is referred to as the capacity of the specimen or apparatus to undergo degradation in relation to strength or hardness. It is also the ability of the apparatus to experience stress relaxation. This is the process of reduction in the stress levels to develop elastic strain transformation towards the formation of plastic strain under constrained apparatus. This experience might result to the failure of the surface of the specimen and apparatus. The thermal softening is applicable in the illustration of the decrease or increase in the lengths of the aluminum during the experiment.

Since the chips have higher thermal conductivity, there is increase in length at high temperature. This is because to influence in relation to the molecules of the chips thus expansion process. High temperature loosens the molecules thus initiating the expansion process. Low temperature has minimal effects on the molecules or particles of the chips thus decrease in size. This is because of contraction that follows expansion process. The chips decrease in length because of contraction in the essence of low temperatures. Low and temperature result from the increase or decrease in the cutting speed. Cutting speed is essential for the development of friction force thus the opportunity to illustrate the influence of thermal softening and thermal conductivity. Since the alloys are effective thermal conductors, it is ideal to note that in high cutting speed, the process develops greater temperature levels. This result from the friction forces thus the softening and expansion of the chips. Decrease in the cutting speed would reduce elements of friction forces thus the minimal ability to continue expansion process. This result into contraction thus decreases in the length of the chips. Further decrease in the cutting speed would result into formation of rough surfaces in relation to the chips. This is because no heat is generated to influence the molecules. The reduction in temperature illustrates the deformation of the chips during the experiment.

6. Further Research

6.1. Plastic Deformation of Chips to Primary and Secondary Shear

Metal machining involved chip production, which in itself is a plastic deformation, which has to be eliminated from the finished product. The tool cutting speed, V towards the direction of the primary motion at a time in which the tool inclination angle is γ_o (rake angle), which ranges from -6^o up to +15^o. This angle influences the degree of resultant, temperature, chip thickness and plastic deformation. During a metal cutting process, formation of chips occurs in what is referred to as primary (between the cut and the chip) and secondary shear zones (along the surface of the cutting tool) (Altintas, 2000).

Moreover, the secondary deformation zone may be divided into two regions, the sticking region and the sliding region, figure (…..). In the sticking region, the work piece materials adheres to the tool and shear occurs within the chip, the frictional force is high and so is the heat generation.

http://www.sciencedirect.com/science/article/pii/S0924013607000866

FIGURE (….) Definition of the primary and the secondary deformation zone and the sliding and sticking region.

Altintas (2000) further uses the following expressions to explain the chip formation process in details; Taking a chip thickness compression ration to be Ẩ_h, which is expressed by: –

Ẩ_h = h_ch/h_d

In which h_ch = chip thickness and,

h_d = chip depth

The thickness of the chips got upon machining, denoted by Ẩ_h = >1.

The chip compression ratio, Ẩ_h represents the degree of plastic deformation possible during chip formation.

The following are the three cutting conditions observed during any metal cutting process:-

Cutting Velocity, V: – the speed at which the tool travels relative to the work piece, it is expressed                                in m/ min or m/s. (in the experiment done, it was realized that chip thickness                                    increased with cutting velocity)

Depth of Cut, d: – the axial projection length of the active edge of the cutting tool; it is expressed                                  in mm. This distance is assumed to be equal to the actual width of cut, h_D in                               orthogonal cutting

Feed, f: – the cutting tool relative movement on the working surface during the machining           process                        Feed, f is considered to be equal to the cut thickness, h_D in orthogonal cutting. It is                                expressed in terms of mm/min in case of drilling or milling and in form of mm tr^-1                         when in a turning process.

6.2 Types of chips and chip formation:

Between the 1930s and 1940s people starts the study of chip metrology. After that since various Scientifics study worldwide of the industrial and manufacturing productions, (automotive, companies aeronautic orthopedics) have made a variety of chip classifications, relaying on cutting speed, microstructure, feed rate, cutting angle, depth of cut.

There are three types of chips that result from a machine cutting process, namely: continuous chips, discontinuous chips and continuous chips with built-up edge.

The type of chips formed indicate different cutting conditions; for instance continuous chips show that there is a high possibility of either one or all of the following three factors…negative or small rake angle, work material very brittle or and low speed or coarse feed. However, longer continuous chips present removal and handling problems in practical machining operation, and it’s got narrow shear zone, also a secondary shear zone and excellent surface finish.

Continuous chips figure 6.2.1.

http://eng.sut.ac.th/metal/images/stories/pdf/07_Machining%20of%20metals

A discontinuous chip on the other hand may be as a result of large positive rake angles, high speed or fine feed, and or brittle material, which cannot withstand the high shear strains imposed in the machining progression without fracture.

Discontinuous chips figure 6.2.2.

http://eng.sut.ac.th/metal/images/stories/pdf/07_Machining%20of%20metals

Lastly, a continues chip with built up edge which appears as a long ribbon with rough dull surface are developed by working at low speeds (below 0.5m/s) and at negative or small rake angles. The shape of built up edge is due to work hardening in the secondary shear zone at low cutting speed (since heat is transferred to the tool).

Continuous chip with built up edge figure 6.2.3

http://eng.sut.ac.th/metal/images/stories/pdf/07_Machining%20of%20metals

Materials such as aluminum, mild steel and cast iron tend to develop this type of chip more often due to their hardened surface (Mkaddem and Whitfield, 2008).

6.3 Considerations for Proper Cutting Conditions

Considering the three points mentioned above, this paper recommends that in order to get a good end result on the material being worked on, the worker must lay a lot of emphasis on the following: cutting velocity, V, depth of cut, d and feed, f . These three factors to a greater extent influence the final product of the machining process, particularly the external appearance of the surface. This paper proposes that working at low speed is never desirable, cutting speed should therefore be kept relatively high so that feed and depth alteration during the process is made easy and uniform due to proper chip control (Liu and Guo, 2000). Liu and Guo add that another very important factor to be considered for a good machining outcome is the material used in machining. For instance an alloy of lead and steel has been found to make the best result. In machining, such steels are referred to as free-machine steels. It is also has been found out that by working on a very hard material, the resultant chips will be quite discontinuous. Discontinuous chips are considered favorable, mainly because of the following: –

• They are easy to handle and dispose
• They can be cleared from the working area with less trouble
• They are considered less dangerous to the operator
• They are less destructive to the surface of the work piece and cutting tool

In order to produce discontinuous chips, the following principle methods should be considered: –

• Use of proper chip breakers
• Good selection of work material properties
• Proper selection of desirable cutting conditions

 

Feed rate and chip thickness ratio reveal that at low feed rates, chips are never formed with every tool pass. This paper also determines the influence of feed rate on the surface appearance (cutting trail). It holds it that at lower feed rates, the surface appearance becomes smoother and it depends only on nose radius; the opposite is true for increased feed rate. An increased skewness shows significant high feed rates and this changes from material to material. The following table shows the level of effect of feed rate on roughness indices (surface appearance—cutting trail) for copper and steel (Viktor and Shevets, 2004).

7. Further Analysis:

Further analysis to the chip characteristics at different feed rates resulted to the following pictorial representations of chip morphology at different feeding rates: –

Fig. 12: Feed rate = 0.106 mm/rev “Aluminum”

Fig. 7.1: feed rate = 0.160mm/rev

Fig. 7.2: f = 2.32 mm/rev “Aluminum”

Fig.7.3: f= 3.19 mm/rev

Chips appear to be helical in shape in case of a normal feed rate; increasing the feed rate lowers the chips’ plastic flow that in turn makes them to acquire ribbon-like shapes. This can therefore leads to a conclusion that the rate of feed equals to the uncut chip thickness; its ratio with chip thickness is referred to as the cutting ratio, which increases with feed rate. This determination is a proof to the theory that at plastic flow is high at lower feeding rate and vice versa. Low feed rates also results into chip carlings, besides this, it should be noted that increased side flow appears mainly at low feed rate (Childs et al, 2008).

The more controlled the tool movement is, the better will be the outcome of the product surface. Having a regulated feed rate and tool speed ensures that dimensional accuracy is maintained and a good surface finish obtained. Childs (2008) also warns that though accuracy is easily obtainable at lower speeds, extremely slow operation is uneconomical and therefore an optimum speed should be set. These two factors are very important in setting cutting trails.

Getting to know the working cutting trail helps the engineer to keep cutting force and material removal rate at a constant pace so as to achieve what Yao and Gupta (2004) would refer to as a “Pythagorean-hodograph curve” (p.2152). This path should be predicted prior to starting a machining process in order to get best machining results. Prediction of the trail is not marked, but is based on setting optimum speed and feed rate obtained after a test analysis. Abouelatta and Madi (2001) suggests that by keeping some of the machining parameters constant.

The quality of an end-milled product is therefore dependent on many factors, the ones mentioned in this paper are need to be considered if a good product desired. The Industrial Technology is faced with the dire need to improve not only the quality of the products, but also significantly reduce the production coat and solve time constraints. This being the truth of the matter, this research paper was focused on determining the degree by which two factors considered to be the most important in influencing the quality of the end-product…feed rate and tool speed. The experimental results will be utilized to create an approach strategy of implementing desirable design parameters for optimum results: optimum surface roughness (cutting trail) and chip thickness ratio.

 

This project has determined that not only the chip ratio and cutting trails are affected by cutting distance and feed rate, but the entire cutting condition during machining. The analytical research paper has results, which can be interpreted to mean that setting optimum cutting parameters is vital for best results. The cutting speed and feed have therefore come across as vital factors to be considered during machining due to their strong relationship with the product final characteristics. However when used to determine the state of the final product, some factors need to be kept constant like in a controlled experiment. For instance, material type, tool diameter, cutting condition (wet or dry) and cutting depth. They factors must therefore be considered during cutting, not forgetting other host of parameters influencing product character. All tools regardless of the materials in which they are made do have optimum cutting speeds and feed rates…these when followed will bring most desirable results; recommended chip thickness ratio and cutting trails. Calculating the spindle speed is done by employing the below formula: –

N = (CS × 1000) / πd

Where,

N   = spindle speed in RPM

CS = cutting speed in m/min

D   = work piece diameter

Feed as used in this paper referred to the distance the tool covers per work piece revolution. According to the research, it has been determined that feed depends on the amount of surface finish needed.

Conclusion

Conclusively, this paper manages to set design parameter rates (cutting speed) with results, which can systematically be applied to achieve optimum characteristics. Application of the rates recommended by this paper will ensure that the product liability is boosted and the defects on the final product are kept to their minimum to come up with a superior quality product. The study however shows results of only two factors (influence of feed rate and cutting speed on chip thickness ratio and cutting trail), it can be used to determine the degree of influence of a number of other factors influencing product quality. Taking into account the three points mentioned above, in order to get a good end result on the material being worked on, the worker must lay a lot of emphasis on the following: cutting velocity, V, depth of cut, d and feed, f . These three factors largely influence the final product of the machining process, particularly the external appearance of the surface. There are three types of chips that result from a machine cutting process, namely: continuous chips, discontinuous chips and continuous chips with built-up edge. As the cutting speed was decreased from 111.47 m/min to 28.26 m/min the cut chips tend to be less length than the higher speed with dull surface, and that because of the less heat was generated in the cutting shear zone. Lastly, decreasing the cutting speed to 7.065 m/min generate thinner discontinues chips with a slightly rough surface.

 

 

 

 

 

 

 

 

 

 

References

Abouelatta, B. and Madi. J. (2001). “ Surface roughness prediction based on cutting parameters           and tool vibration in turning operations ”, Journal of Materials Processing Technology,     118, pp.269-77

Childs. C., Sekiya. K., Tezuka. R., Yamane. Y., Dornfeld. D., Lee, E., Min. S. and Wright, K. (2008). “Surface finishes from turning and facing with round nosed tools ”, Annals of        CIRP, V-57, pp.89-92.

Black, S. C. (1996). Principles of engineering manufacture. New York: Halsted Press.

 

Choudhury, A. and El-Baradie, M. (1999). ‘Machinability assessment: Factorial Design of        Experiment Coupled With Response, Surface methodology’, Journal of Materials   Processing and Technology 95; 30-39.

Montagometry, C. and Runger, C. (1994). Applied Statistics and Probability for Engineers. Wiley: New York.

Viktor, A and Shevets. S. (2004). “The Assessment of plastic deformation in metal cutting”,      Journal of Materials Processing Technology, 146(2). pp.193-202.

Yao, Z. and Gupta, S. (2004). ‘Cutter path generation for 2.5D milling by combining multiple    different cutter path patterns’. International Journal of Production Research,       42(11):2141-2161.

Altintas, Y. (2000). “Fundamental of Metal machining, Machine Tools, Vibrations and CNC     Designs”. Cambridge University Press.

Liu, R. and Guo, B. (2000). “Finite Element Analysis of the Effect of Sequential Cuts and Tool  chips Friction on Residual Stresses in the Machined Layer Int. J. Mech. Sci.., 42: 1069   86.

Mkaddem, A. and Whitfield, C. (2008). “Computer Based Modeling of Popular machining       Operations for Force and Power Predictions”. Palermo Italy. pp.65-9

Ozel, T. and Altan, T (2000). “Determination of work piece flow stress and friction at the chip   tool contact for high-speed cutting. Int. J. Mach. Tools Manufac., 40 (1): 133–52.

Shih, J. and Yang T. (1993). “Experiment on Finite Element Predictions of Residual Stresses    Due to Orthogonal Metal Cutting “. International Journal for Numerical Methods in       Engineering; Vol: 36; p. 346-54.

Srenskowski, Moon. (2005). “A Finite Element Model of Orthogonal Metal Cutting”. ASME> Journal of Engineering for Industry. Vol107; pp.346-54.