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http://doi.org/10.22214/ijraset.2020.5042
May 2020
International Journal for Research in Applied Science & Engineering Technology (IJRASET) ISSN: 2321-9653; IC Value: 45.98; SJ Impact Factor: 7.429 Volume 8 Issue V May 2020- Available at www.ijraset.com
Influence of Machining Parameter on Concentricity of the Hole on VMC Machining using RSM (Central Composite Design) Dileep Panchal Asst. Professor, Department Of Mechanical Engineering, St’ Martins Engineering College, Hyderabad Abstract: In machining operation, work piece geometric dimensions and tolerance (GD&T) requirements is an important requirement for many applications. Thus, the choice of optimized cutting parameters is very important for controlling the required for concentricity of the hole requirements. The focus of present experimental study is to optimize the cutting parameters through work piece geometric dimensions and tolerance (GD&T) requirements as concentricity of the hole. This is an experiment carried out by employing a central composite design to develop a mathematical model in order to predict concentricity of the hole. After that the design of experiments (DOE) methodology by central composite design was used for optimizations (using Minitab 16, software) to find the optimum cutting parameters conditions for concentricity of the hole. The dissertation work is an experimental study of concentricity of the hole which was performed on VMC machine of EN8 and EN31 materials using carbide tool by varying the cutting parameters such as cutting speed and feed to determine optimum cutting parameters conditions for concentricity of the hole. After that work piece is testing on trimos instrument and getting the results those results analyzed in Minitab 16 software. Analysis of variance (ANOVA) was carried out for concentricity of the hole on EN8 and EN31 materials and their contribution rates were determined. Finally experimental observation shows the optimum parameters for concentricity of the hole and helps in saving the time along with required dimensional accuracy. Key words: - Concentricity of the hole, CCD, VMC and parameters. I. INTRODUCTION Concentricity is controlling a common datum axis between two or more holes on the work piece and which controls the tolerance zone. Concentricity resilience could be situations during which the axes of all cross-section components of an element’s surface of revolution are remain common to the axis of a datum plane. A concentricity tolerance identifies a cylinder-shaped resilience zone whose axis overlaps with a datum axis and inside which all cross-sectional axes of the characteristics being controlled lie. The resistance zone is similarly arranged about the datum axis for concentricity. The Concentricity necessitates that the middle purposes of the controlled component, no matter its size, be inside the tolerance zone.
Fig-1:- Concentricity of the Holes A. Objectives To investigate the influence of different machining parameters or variables of VMC on EN8 and EN31 materials through RSM approach, To check machine characteristics of roundness of EN8 and EN31 material on CMM or trimos measuring equipment’s and to examine the effect of process factors on dimensional accurateness and getting results. To advise best input factors for a given best output in form of dimensional accurateness.
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International Journal for Research in Applied Science & Engineering Technology (IJRASET) ISSN: 2321-9653; IC Value: 45.98; SJ Impact Factor: 7.429 Volume 8 Issue V May 2020- Available at www.ijraset.com II. METHODOLOGY “Methodology is the systematic, theoretical analysis of the methods applied to field of the study”
Fig-2.0:-Flow chart of methodology A. Material Selection for Machining Materials like EN8 and EN31 are selected because EN material has good properties like good mechanical properties, corrosion resistance and low carbon. Table-2.1.1: EN8 Material Chemical Composition:
Fig-2.1.1:- EN8 material
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International Journal for Research in Applied Science & Engineering Technology (IJRASET) ISSN: 2321-9653; IC Value: 45.98; SJ Impact Factor: 7.429 Volume 8 Issue V May 2020- Available at www.ijraset.com EN 31 is an outstanding high carbon mixture steel that provides a high measure of hardness with compressive strength and scraped area resistance. Table-2.1.2:EN31 Material chemical composition
Fig-2.1.2 EN31 material B. Machining Parameters On Concentricity Of Hole Here we consider only two factors. They are 1) Cutting Speed: Cutting speed is characterized as the speed at which the cutting edge of the device passes above the material. It is expressed in the meter per minutes.
Where, V= Cutting Speed, D= Diameter and N=Spindle Speed 2) Feed: It is the distance that the tool travels on the work or work goes to be away the tool finally at each rotation of the cutter. Feed is represented in mm/rev. Different feed for various machine are stable within ranges and typically depend on the depth of cut and the derived quality of the work. III. DESIGN OF EXPERIMENTS A. Generating the Design Matrix with DOE (Minitab V16) Design of experiments is used to identify out the relationship between varied variables which fits into the product and also helps to find the response of those variables on the standards and demonstration of the product. Experimental design additionally helps in enhancing efficiency. Within the experimentation, changes in variables are deliberately presented into the organization, so as to check the activities of the organization on the performance features i.e. output. The most productive method for enhancing the adjustments in variable is by statistical methodology. Testing can also be done by other techniques but statistical technique is the best route of experimentation. B. Selection of Parameters and their Levels Various different input parameters throughout the experiments are cutting speed and feed. The table below reveals domain of experiments containing the machining parameters selected and their particular levels. The experimental data has also been provided.
Machining parameters Cutting speed Feed
Notation V F
Table: 3.2 Domain of Experiment Unit Levels of parameters Level 1 Level 2 m/min 350 400 mm/rev 0.1 0.2
Level 3 450 0.3
Design matrix gained by using a running order of 13 numbers of tests considering above stated machining parameters shown below for different materials. Here two materials EN8 and EN31 materials are out lined in design matrix. It’s obtained from the Minitab V16 software with help of parameters.
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International Journal for Research in Applied Science & Engineering Technology (IJRASET) ISSN: 2321-9653; IC Value: 45.98; SJ Impact Factor: 7.429 Volume 8 Issue V May 2020- Available at www.ijraset.com C.
EN8 and EN31 Material design matrix sheet
IV. EXPERIMENTATION This experiment was conducted on the vertical machining center (VMC) and machining additionally performed on the vertical machining center (VMC). Every experiment on the work piece was conducted as per input factors as like cutting speed and feed.
Fig-4.0.1:-Experimental Setup on VMC machine
Fig-4.0.2:- After Experiment on VMC machine
In this experiment we selected two materials like EN8 and EN31 medium carbon steel and high carbon steel. Contour holes on the both work piece materials were made as per the design matrix.
Fig-4.0.3:- EN8 work piece material with contour holes
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International Journal for Research in Applied Science & Engineering Technology (IJRASET) ISSN: 2321-9653; IC Value: 45.98; SJ Impact Factor: 7.429 Volume 8 Issue V May 2020- Available at www.ijraset.com
Fig-4.0.4:- EN31 work piece material with contour holes A. Response Surface Methodology Response surface methodology (RSM) may be a collection of statistical methods and mathematical replicas that are suitable for modeling and enhancing the problems during which the maximum response is influenced by the freelance variables on dependent variables. The final aim of RSM in to enhance the correct relation between the variables and also the response. The RSM includes two approaches, they are 1) Central Composite Design (CCD) 2) Box Behnken Design (BBD) a) Central Composite Design (CCD): A central composite design is that the more generally utilized response surface designed test. Central composite designs are factorial or fractional factorial design with center points, which increase with a group of axial points (also called star points) and let you estimate curvature. You can use a central composite design to: i) Efficiently determine first- and second-order terms. ii) Model a response variable with curvature by additional center and axial points to a previously-done factorial design.
Fig-4.1:- Central Composite Design B. Trimos Trimos is the measuring instrument. Using this instrument we conducted experiments for getting exact results in the dimensional measurement and its dimensional accuracy. This instrument has a number of probes and that the appropriate selected diameter probe was selected and set to the instrument. Its measures inner diameter and outer diameter of the work piece and also finding the shift between the two holes and getting the results on display in this instruments.
Fig-4.2:- Trimos instrument using for our project
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International Journal for Research in Applied Science & Engineering Technology (IJRASET) ISSN: 2321-9653; IC Value: 45.98; SJ Impact Factor: 7.429 Volume 8 Issue V May 2020- Available at www.ijraset.com EN8 and EN31 dimension of work piece
V. RESULTS AND DISCUSSIONS In this machining operation having two necessary parameters like cutting speed and feed with facilitate of “response surface methodology” (RSM) and “central composite design” (CCD). ANOVA is utilized for capability of the model for response during this experimentation. ANOVA is arithmetical choice technique utilized for finding any variance average performance of experimented parameters. ANOVA analysis is completed by the Minitab version 16 software. In this chapter results gained from ANOVA using Minitab version 16 software is out lined by utilizing the software to getting the graphs and tables. A. Central Composite Design In this experiment, 2 factors are used for central composite design (CCD). The specifications are:Factors: 2, Replicates: 1, Base run: 13, Total run: 13, Base block: 1 and Total block: 1 B. Response Surface Regression The model relationship between a response variable and one or more predictors, using the regression investigation. A numerous regression analysis was shown on the verified information. Minitab delivers smallest square, incomplete minimum square then logistic regression process. Table-5.2:- Estimated regression coefficients for concentricity of hole for EN8 and EN31material: S = 0.00225699 PRESS = 0.000309382 R-Sq. = 94.28% R-Sq.(pred) = 50.53% R-Sq.(adj) = 90.19%
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International Journal for Research in Applied Science & Engineering Technology (IJRASET) ISSN: 2321-9653; IC Value: 45.98; SJ Impact Factor: 7.429 Volume 8 Issue V May 2020- Available at www.ijraset.com
S = 0.00348136 PRESS = 0.000601569 R-Sq. = 91.76% R-Sq.(pred) = 41.55% R-Sq.(adj) = 85.87% Using Minitab software the response superficial design may be investigated. Its gives a number of coefficients determined by regression coefficients along with SE coefficient and value for T test and also p value. The SE coefficient is considered as standard error of coefficient, which is utilized to build confidence intermission and execution hypothesis experimentation. T is the test static with student circulation and P-value is related with this test in statistics. P-values is chance to getting in test statistic results. Table-5.3:- Analysis of variance for concentricity of hole for EN8 and EN31 material
DOF = Degree of freedom. Seq SS = Sequential sum of square. Adj SS = Adjusted sum of square. Adj MS = Adjusted mean square. F = the value of fisher test. P = the probability value. ANOVA examines some process factors which are necessary to cause effect on the performance characteristics. This analysis gives necessary parameters and its performance in controlling the response of machining in dimensional accurateness.
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International Journal for Research in Applied Science & Engineering Technology (IJRASET) ISSN: 2321-9653; IC Value: 45.98; SJ Impact Factor: 7.429 Volume 8 Issue V May 2020- Available at www.ijraset.com C. Plot Plot refers to the sequence of events inside a story which affected other events through the principle of cause and effect They are two types of plot 1) Main Effect Plot: In the style of experiments and analysis of variance, a main impact is that the impact of associate variable on a variable quantity averaging across the amount of the other freelance variables. The term is often utilized in the context of factorial design and regression models to differentiate main effects from interaction effects. EN8 and EN31 material
Fig-5.4.1:- Main effects plot for concentricity of hole v/s cutting speed v/s feed
2) Interaction Plot Interaction could be a reasonable action that happens as two or more objects have an impact upon each other. The idea of a two-way impact is important within the concept of interaction, as against unidirectional causative impact. A closely connected term is interconnectivity, which deals with the interactions among system combinations of many straightforward interactions that cause surprising emergent phenomena. Interaction is totally different tailored meanings innumerous sciences. EN8 and EN31 material
Fig-5.4.2:- Interaction plot for concentricity of hole v/s cutting speed and feed
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International Journal for Research in Applied Science & Engineering Technology (IJRASET) ISSN: 2321-9653; IC Value: 45.98; SJ Impact Factor: 7.429 Volume 8 Issue V May 2020- Available at www.ijraset.com VI. CONCLUSION A. By this experiment observation it gives the best parameter for the concentricity of hole for EN8 material when cutting speed is 400m/min and feed rate is 0.3mm/rev respectively. B. EN31 material also shows better parameters for cutting speed 450m/min and feed rate 0.1mm/rev. This material is harder compared to EN8 materials. C. Here referring the design matrix and obtaining best input parameters and it’s effects on the dimensional accuracy, it also gives best dimensional accuracy. REFERENCES [1] [2] [3] [4] [5] [6] [7] [8]
“Elements of mechanical engineering” text book author K.P.Roy, S.K.Hajra Choudhury and A.K.Hajra Choudhury. “Elements of work shop technology” text book author S.K.Hajra Choudhury, A.K.Hajra Choudhury and Nirjhar Roy. “Production and costing” text book author G.B.Narang and V.Kumar. “An experimental study of cutting parameters on concentricity in CNC turning operation using design of experiment” Mr. P L Parmar1 1Mechanical Engineering, MEFGI-Faculty of Engineering. “Experimental Studies on Perpendicularity of Drilling Operation using DOE” B. P. Patel, Prof. (Dr.) P. M. George, Prof. (Dr.) V .J .Patel. P. M. Tadvi, R. S. Barot, V. H. Chaudhari, Dr. P. M. George,” Analyze Effect of Cutting Parameters on Geometric Tolerances in CNC Turning using Design of Experiment (2^3 and 3^3 Design) National Conference on Thermal, Fluid and Manufacturing Science January 20 – 21, 2012. A. Y. Mustafa and T. Ali, “Determination and optimization of the effect of cutting parameters and work piece length on the geometric tolerances and surface roughness in turning operation”, International Journal of the Physical Sciences Vol. 6(5), pp. 1074-1084, 4 March, 2011. “Study and Investigate Effect of Cutting Parameters on Flatness for Dual Plate Check Valve” Bhavin S. Modi, Dr. P.M. George Mechanical Engineering Department B.V.M. Engineering College, Saurin Sheth Mechatronics Engineering Department.
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