Comparative assessment of standard and wiper insert on surface roughness in turning of Titanium alloy (Ti-6Al-4V)

Transcription

1 International Journal of Engineering Research and Technology. ISSN - Volume, Number (2) Comparative assessment of standard and wiper insert on surface roughness in turning of Titanium alloy (Ti-Al-V) Pravin A. Mane, Nilesh T. Mohite 2, Vinay S.Kale, 2, Assistant professor, Mechanical Engg. Department, D.Y.Patil college of engg., & Technology, Kolhapur. Maharashtra, India, Ashwin A. Desai Assistant professor, Mechanical Engg. Department, Dr.D Y Patil Technical Campus,Talsande,. Maharashtra, India, Abstract Titanium alloys are widely used in the engineering field, namely in the aerospace, automotive and biomedical parts, because of their high specific strength and exceptional corrosion resistance. However, the machinability of titanium alloys is difficult due to their low thermal conductivity and elastic modulus, high hardness at elevated temperature, and high chemical reactivity. This article reviews the state of the art of machinability of titanium alloys, and focuses on the analysis of the process details, namely the especial techniques for cutting improvement, machining forces, chip formation and cutting temperature. The influence of titanium properties on the machinability is also highlighted. Particular attention is given to the turning process of Ti-Al- V alloy. Keywords: cutting improvement, Machineability, Titanium alloys, Introduction Machining Machining is a process in which material is removed gradually from a work piece including metal cutting with single point and multipoint tools and grinding with abrasive wheels. It is the process in which a tool removes material from the surface of metal block, through relative movement and application of force. This process is most important since almost all the products get their final shape and size by metal removal, either directly or indirectly. The machining processes are commonly used by manufacturing industries in order to produce high quality and very complex products in a short time. These machining processes include large number of input parameters which may affect the cost and quality of the products. Selection of optimum machining parameters in such machining processes is very important to satisfy all the conflicting objectives of the process. [,2]. Figure: Schematic Representation of Machining Concept of Wiper Inserts Figure2: Concept of conventional and wiper inserts The wiper technology for turning is based on a carefully developed series of radii that make up the cutting edge. On a conventional insert, the nose of the edge is just one radius.

2 International Journal of Engineering Research and Technology. ISSN - Volume, Number (2) The wiper edge, however, is made up of a large, main radius complemented by several smaller radii. The long wiper edge should not misshape the surface nor generate unacceptable cutting forces. The wiper insert should also be as straightforward to set up and use as an ordinary insert. []. In turning with a single-point tool, the surface finish is determined by the feed rate and nose radius, as these are in a direct relationship to the profile height of the surface (Rmax). This means that the higher the feed, the rougher the surface generated by the edge of a given nose radius. Wiper inserts have changed this through the effect of their specially developed edges that smooth the scalloped tops that would otherwise have been created. An additional important feature is their improved chip-breaking capability. Wiper geometries are also designed to combine good chip control at low feeds and smooth chip breaking at high, productive feeds.[,]. Wiper insert in turning In turning, the development of new wiper insert is a strategy for productivity improvement. Manufacturers claim to improve surface finish two times over standard inserts. Alternatively, the feed rate can be increased at least by 2% without sacrificing surface finish requirement. A finish turning operation or sometimes usual grinding may not be required. A wiper insert s nose is slightly flattened. The geometry becomes a combination or a blend of radii.[]. The edge of the insert essentially traces a path around the edge of two overlapping circles, leaving the tip with a slightly elliptical shape. The blended radii knock off the high points created by the feed lines and provide a smoother finish without increasing the nose radius or reducing the feed. Wiper inserts are basically high feed tools for using with light depth of cut. The manufacturers claim the wiper inserts last longer than conventional inserts, even though they were not designed for it. []. Experimental Setup Workpiece Material: For our experiment Titanium Alloy is used as workpiece material. Table No. : Chemical composition of Titanium alloy Ti Al V Fe O % % % Max.2% Insert Specification: Figure: Insert Max.2% Table No. 2: Insert Nomenclature C N M G 2 MT 2 Insert Specification: CNMG 2 MT CNMG 2 WT Experimental Details We have done this work which aims to evaluate effect of wiper insert in turning on Titanium alloy. The major emphasis of this project is to study performance of wiper insert in turning of Titanium Alloy which has hardness more than HRC, the performance is evaluated in terms of tool wear, surface finish and quality of chips which are major parameters to describe the surface integrity. Number of experiments is conducted at different values of feed rates, speed and depth of cut by suitable grade of carbide. The cutting tool and workpiece surface are examined by appropriate measuring instrument like Surface Roughness Tester, Toolmaker s microscope keeping in view surface integrity, to decide how wiper inserts affects cutting forces, surface finish, and tool wear of Titanium Alloy. The results of machining with conventional inserts and wiper inserts will be compared to study surface integrity. According to the insert selection and for hard turning, the cutting parameters that are speed, feed and depth of cut are- Parameters Table No.: Process parameters Levels I II III Speed (N) (rpm) Feed (f) (mm/rev)...2 Depth of cut (d) (mm).. Types of inserts C W Design of Experiment: The design of experiment technique is tool, which permits us to carry out the modeling and analysis of the influence of process variables on the response variables. The response variable is an unknown function of the process variables, which are known as design factors. In turning operation, there are a large number of factor that can be considered as machining parameters. The depth of cut (DOC, mm), spindle speed (N, rpm) and feed rate (f, mm/rev) of cutting tool is the most widespread machining parameters taken by the researchers. Design of Experiments (DOE) techniques enables designers to determine simultaneously the individual and interactive effects of many factors that could affect the output results in any design. DOE also provides a full insight of interaction between design elements; therefore, it helps turn any standard design into a robust one. Simply put, DOE helps to pin point the sensitive parts and sensitive areas in designs that cause problems in Yield. Designers are then able to fix these problems and produce robust and higher yield designs prior going into production. DOE is

3 International Journal of Engineering Research and Technology. ISSN - Volume, Number (2) also very useful in getting information on the interactions between the elements in a design and how these interactions affect the variation in the output measure. Minitab software is used for design of experiment. Minitab is Statistical Analysis software that allows ease to conduct analyses of data. It is a statistical software package that was designed especially for the teaching of introductory statistics courses. It is our view that an easy-to-use statistical software package is a vital and significant component. Minitab is an interactive program. By this we mean that you supply Minitab with input data, or tell it where you re input data is, and then Minitab responds instantaneously to any commands you give telling it to do something with that data. Minitab has two main types of files, projects and worksheets. Worksheets are files that are made up of data; Projects are made up of the commands, graphs and worksheets. Designed experiments are often carried out in four phases: planning, screening (also called process characterization), optimization, and verification. For example creating, analyzing, and plotting experimental designs. []. Experimentation:. Prepared raw material having dimensions Ø mm is turned on CNC turning center. And the parameters obtained from the design of experiment are used for experiment. 2. From mm length of workpiece mm length is used for holding it into chuck. And 2 mm length is used for turning.. For each workpiece fresh corner of insert is used for analyzing the effect of changed parameters. Experimental Results Roughness Pattern Obtained By Roughness Tester: By Conventional inserts Design of Experiment (DOE) Parameters Table No.: Process Parameter Levels I II III Speed (N) (rpm) Feed (f) (mm/rev)...2 Depth of cut(d) (mm).. Types of inserts C W The data from above table is put into the orthogonal array which is formed by using Taguchi Design and these tables containing actual values of input parameters are used while performing Experiment. In our project there are three input parameters, all three parameters are having levels. So from the available designs in Minitab (Taguchi) we have chosen L array. The design is as follows: Table No.: Orthogonal Array of Taguchi L Sr. No. Speed Feed(mm/rev) DOC(mm) (rpm) N= rpm, feed=. mm, DOC=. mm N= rpm, feed=.2 mm, DOC=. mm N= rpm, feed=. mm, DOC=. mm N= rpm, feed=.2 mm, DOC= mm Figure: Roughness pattern by conventional inserts

4 International Journal of Engineering Research and Technology. ISSN - Volume, Number (2) By Wiper inserts: N= rpm, feed=. mm, DOC= mmn= rpm, feed=.2 mm, DOC=. mm N= rpm, feed=. mm, DOC=. mmn= rpm, feed=.2 mm, DOC=. m Figure: Roughness pattern by wiper inserts Roughness Values Table No.: Roughness values obtained by conventional inserts Exp t. No.. Spee d (rp m) 2... Feed (mm/re v) DO C (m m) al al al....2 Avg Table No.: Roughness values obtained by wiper inserts Spee DO Feed d C (mm/re (rp (m v) m) m) Exp t. No. al Analysis of Experimental Results al al Avg Anova for Surface Roughness Data The ANOVA and AOM results for surface roughness () data (Table) for conventional insert showed that the selected full factorial model was significant. Feed (P value=.) was the most significant parameter having maximum contribution. Speed and Depth of cut was other parameter which affected the surface roughness significantly but

5 International Journal of Engineering Research and Technology. ISSN - Volume, Number (2) contributed less than the feed. Speed and DOC are 2 nd & rd significant parameters respectively. Table No.: Analysis of Variance for, using Adjusted SS for Tests Sour D Seq Adj Adj ce F SS SS MS F P spee d feed doc Error 2... Total.2 feed doc Error 2... Total.22 S =.2 R-Sq =.2% R-Sq(adj) =.% Regression Equation = speed + 2. feed +. doc S =.22 R-Sq =.2% R-Sq (adj) =.% Regression Equation = speed +. feed +. doc Figure: an effect plot showing effect of various process parameters on surface roughness for wiper insert Figure: Mean effect plot showing effect of various process parameters on surface roughness for conventional insert From fig no., it is observed that Surface roughness is minimum at speed rpm and increases up to rpm feed. mm/rev and increases to.2 mm/rev and DOC mm and increases up to. mm. The ANOVA and AOM results from table no. for wiper insert showed that the selected full factorial model was significant. Feed (P value=.) was the most significant parameter having maximum contribution. Speed and Depth of cut was other parameter which affected the surface roughness significantly but contributed less than the feed. Speed and DOC are 2 nd & rd significant parameters respectively. Table No.: Analysis of Variance for, using Adjusted SS for Tests Source DF Seq SS Adj SS Adj MS F P From fig no., it is observed that Surface roughness is minimum at speed rpm, feed. mm/rev and increases to.2 mm/rev and DOC mm and increases up to. mm. From the ANOVA of surface roughness it is observed that only feed rate affects the surface roughness significantly. An increase in the feed rate increases the surface roughness, which is known from the fundamentals of metal cutting Where f is feed rate (mm/rev) and r is tool nose radius in mm. From above graph it is observed that the roughness value gradually increases within the feed range.-.2 and there is drastic increase in roughness value after. to.2. Along with feed rate speed and DOC are statistically significant. value is directly proportional to DOC up to. mm. Thereafter there is gradual increase in values as observed in above graph. From above graph it is observed that wiper insert gives minimum roughness value than conventional Insert. The geometry of the cutting edge has influence on the machined surface roughness as wiper insert has multi radii. The cutting speed N= rpm is higher level which gives minimum roughness value as compared to lower and medium levels of cutting speed. Statistically as observed speed is having least influence on surface roughness. speed

6 International Journal of Engineering Research and Technology. ISSN - Volume, Number (2) Anova for Tool Wear Data The ANOVA and AOM results for Tool Wear data (Table) for conventional insert showed that the selected full factorial model was significant. Feed (P value=.2) was the most significant parameter having maximum contribution. Speed and Depth of cut was other parameter which affected the surface roughness significantly but contributed less than the feed. DOC and Speed are 2 nd & rd significant parameters respectively. Table No.: Analysis of Variance for tool wear, using Adjusted SS for Tests Sourc D Seq SS Adj SS Adj MS F P e F speed Feed Doc Error Total. feed. DOC and feed are 2 nd & rd significant parameters respectively. Table No.: Analysis of Variance for tool wear, using Adjusted SS for Tests Source DF Seq SS Adj SS Adj MS F P speed feed doc Error Total.2 S =. R-Sq =.% R-Sq(adj) = 2.% Regression Equation Tool wear =.2 -.e- speed +.2 feed +.2 doc S =.2 R-Sq =.% R-Sq(adj) =.% Figure: Mean effect plot showing effect of various process parameters on tool wear for wiper insert From fig no., it is observed that Surface roughness is minimum at speed rpm, feed. mm/rev and increases to.2 mm/rev and DOC. mm and increases up to. mm. Figure: mean effect plot showing effect of various process parameters on tool wear for conventional insert Regression Equation Tool wear =.2 +.e- speed. feed +. doc From fig no., it is observed that Surface roughness is minimum at speed rpm and increases up to rpm, feed.2 mm/rev and DOC. mm and increases up to. mm. The ANOVA and AOM results from table no. wiper insert showed that the selected full factorial model was significant. Speed (P value=.) was the most significant parameter having maximum contribution. Depth of cut and feed rates other parameter which affected the surface roughness significantly but contributed less than the Tool Wear Measurement In this work, measurement of the wear on the flank surface carried out by using Tool maker s microscope. Sr. No. Table No.2: Measured values of tool Wear Type of insert Speed (rpm) Feed (mm/rev) DOC (mm) Tool wear(mm) C... 2 C.. C.2.. C.. C... C.2.. C...

7 International Journal of Engineering Research and Technology. ISSN - Volume, Number (2) C... C.2.2 W... W.. 2 W.2.. W..2 W... W.2.. W... W... W.2. For Tool wear S N r a t i o s o f. M e a n S i g n a l - t o - n o M a i n E f e c t s P l o t f o r S N r a t i o s f o r T o l W e a r D a t a M e a n s. : S m a i s e s p e e d d o c. r i s b e t e r l l e.. f e e d.. 2 S/N tios Plots For Surface roughness Figure2: S/N ratio plot showing effect of various process parameters on tool wear for conventional inserts M a i n E f e c t s P l o t f o r S N r a t i o s f o r S u r f a c e R o u g h n e s D a t a M e a n s s p e e d f e e d 2. MainEffects Plot for SNratios for Tool Wear DataMeans speed feed N r a t i o s S o f M e a n d o c o s 2. a t Nr 2. S o f a n 2. Me. doc S i g n a l - t o - n o i s e : S m a l e r i s b e t e r Signal-to-noi s e : S m a l e r i s b e t e r. Figure: S/N ratio plot showing effect of various process parameter on for conventional inserts Figure: S/N ratio plot showing effect of various process parameters on tool wear for wiper inserts d Surface Plots From ANOVA analysis we have observed that feed is the most significant process parameter for surface roughness value. Therefore the graph shows that with increase in feed the surface roughness value also get increases in proportion. And speed is second significant process parameter which shows gradual increase in roughness value from lower to higher values. For conventional inserts. Figure: S/N ratio plot showing effect of various process parameters on for wiper inserts Figure: Surface plot showing effect of speed & feed on

8 International Journal of Engineering Research and Technology. ISSN - Volume, Number (2) This surface plot shows that at the lower feed values the surface roughness values are less and with increase in feed there is increase in surface roughness values. Figure: Surface plot showing effect of speed & doc on This surface plot shows that at the lower speed and DOC values the surface roughness values are less. Figure: Surface plot showing effect of speed & doc on This surface plot shows that at the higher speed and lower DOC values the surface roughness values are less. Figure: Surface plot showing effect of feed& doc on This surface plot shows that at the lower feed and higher DOC values the surface roughness values are less. For wiper insert Figure: Surface plot showing effect of speed & feed on This surface plot shows that at the maximum speed and lower feed values the surface roughness values are less. Figure: Surface plot showing effect of speed & feed on This surface plot shows that at the medium feed and DOC values the surface roughness values are less. Conclusion In this study, performance of wiper insert in Hard turning of Titanium alloy has been evaluated in terms of surface roughness and Tool Wear. Conclusion is as follows: When multiple parameters are considered, it has been observed that feed is most influencing parameter. In this experiment it has been observed that in comparison with wiper insert and conventional insert value achieved by wiper insert (=. µ) is less. Hard turning with wiper insert can be used as alternative for grinding process. For single output parameter i.e. for single objective like Surface Roughness, Tool Wear, The techniques like ANOVA and AOM gives results as For surface roughness (), Feed (P value=.) is the most significant parameter having maximum contribution.

9 International Journal of Engineering Research and Technology. ISSN - Volume, Number (2) For Tool Wear, speed (P value=.) is the most significant parameter having maximum contribution. References [] Jagadale Amitkumar Hanamantrao, Jadhav B. R., Comparative Assessment of Wiper and Standard Insert On Surface Roughness In Hard Turning Of En- Steel, Proceedings Of th Irf International Conference, -, 2. [2] J. Guddata. b, R. M Saoubia, P. Alma, D. Meyerb, Hard turning of AISI 2 using PCBN wiper geometry inserts and the resulting surface integrity, Procedia Engineering 2, 2. [] K.Venkatesan, R.manujam, Vimal Saxena, chit Pandey, Performance Evaluation of Ordinary and Wiper Inserts in Dry Turning of Inconel Super Alloy using Grey-Fuzzy Algorithm A Hybrid Approach, th International & 2th All India Manufacturing Technology, Design and Research Conference - to -, 2. [] Tugrul Ozel, Neural network process modelling for turning of steel parts using conventional and wiper inserts, Int. J. Materials and Product Technology, Vol., Nos. /2, 2-2, 2. [] M. Dogra,V. S. Sharmab, J. Durejac, Effect of tool geometry variation on finish turning, Journal of Engineering Science and Technology Review -, 2. [] Nikunj Patel, Prof. R. K. Patel, Prof. U. J. Patel, Insert Selection for Turning Operation on CNC Turning Centre using MADM Methods, International Journal of Latest Trends in Engineering and Technology,-, 22. [] Jaroslava Fulemova, Zdeněk Janda, Influence of the Cutting Edge dius and the Cutting Edge Preparation on Tool Life and Cutting Forces at Inserts with Wiper Geometry, Procedia Engineering,, 2. [] J. Nithyanandam, Sushil LalDas, K. Palanikumar, Surface roughness analysis in turning of titanium alloy by nanocoated carbide insert, Procedia Materials Science,2 2, 2. [] V Krishnaraja, S Samsudeensadhama, R Sindhumathia, P Kuppanb, A study on high speed end milling of titanium alloy, Procedia Engineering,2 2, 2 2