APPLICATION OF CNC MILLING IN MANUFACTURING TURBINE BLADES

International Journal of Civil Engineering and Technology (IJCIET) Volume 8, Issue 5, May 2017, pp. 801 808, Article ID: IJCIET_08_05_089 Available online at http://www.iaeme.com/ijciet/issues.asp?jtype=ijciet&vtype=8&itype=5 ISSN Print: 0976-6308 and ISSN Online: 0976-6316 IAEME Publication Scopus Indexed APPLICATION OF CNC MILLING IN MANUFACTURING TURBINE BLADES A. Sai Kumar Department of Aeronautical Engineering, MLR Institute of Technology, Hyderabad, India M. Ganesh Department of Aeronautical Engineering, MLR Institute of Technology, Hyderabad, India G Hima Bindu Department of Mechanical Engineering, Malla Reddy Engineering College and Management Science, Hyderabad, India ABSTRACT The present work aims Modeling, Analysis and Manufacturing of Turbine Blade model by using CNC Milling Machine., Analysis by ANSYS Software and Manufacturing by CNC vertical machining centre. CNC Milling along with CAD/CAM technologies are being used in almost all the industries in manufacturing sector, In Order to improve the productivity at the same time with high precision of machining. The modeling of model is to be done by using the part programme with G- Codes, M-Codes and the part programme generates by the cam module. The machining of model is carried out in CNC vertical machining centre. A part from the live model, we also perform simple model analysis of a wing of the airplane and finding the natural frequencies and mode shapes. The wing will have a uniform cross section along its length. The wing fixed to the body of the aero plane at one end and hangs freely at the other end. The advantages of this project, comparing with conventional machines, found that, it is more flexible, high accuracy, good finish and also Complex shape. We can also read the results of analysis like deformed shapes, plotting the mode shapes, stresses, etc. Key words: CNC, Milling, CAD/CAM, Turbine Blades, etc. Cite this Article: A. Sai Kumar, M. Ganesh and G Hima Bindu, Application of CNC Milling in Manufacturing Turbine Blades. International Journal of Civil Engineering and Technology, 8(5), 2017, pp. 801 808. http://www.iaeme.com/ijciet/issues.asp?jtype=ijciet&vtype=8&itype=5 http://www.iaeme.com/ijciet/index.asp 801 editor@iaeme.com

A. Sai Kumar, M. Ganesh and G Hima Bindu 1. INTRODUCTION 1.1. Compressor Blades The axial-flow compressor compresses its working fluid by first accelerating the fluid and then diffusing it to obtain a pressure increase. The fluid is accelerated by a row of rotating airfoils (blades) called the rotor, and then diffused in a row of stationary blades (the stator). The diffusion in the stator converts the velocity increase gained in the rotor to a pressure increase. A compressor consists of several stages. One rotor and one stator make-up a Stage in a compressor. One additional row of fixed blades (inlet guide vanes) is frequently used at the compressor inlet to ensure that air enters the first- stage rotors at the desired angle. In addition to the stators, another diffuser at the exit of the compressor further diffuses the fluid and controls its velocity entering the combustors. Although the working fluid can be any compressible fluid, only air will be considered here. Figure 1 Stage of a Compressor 1.2. Blade and Cascade Since airfoils are employed in accelerating and diffusing the air in a compressor, much of the theory and research concerning the flow in axial compressors are based on studies of isolated airfoils. The nomenclature and methods of describing compressor blade shapes are almost identical to that of aircraft wings. Research in axial compressors involves several blades in a row to simulate a compressor rotor or stator. Such a row is called a Cascade. The compressor blades are shown in Figure 2. Figure 2 Compressor Blades When discussing blades, all angles, which describe the blade and its orientation, are measured with respect to the shaft (Z axis) of the compressor. The airfoils are curved, convex on one side and concave on the other, with the rotor rotating toward the concave side. The concave side is called the pressure side of the blade, and the convex side is called the suction http://www.iaeme.com/ijciet/index.asp 802 editor@iaeme.com

Application of CNC Milling in Manufacturing Turbine Blades side of the blade. The chord line of an airfoil is a straight line drawn from the leading edge to the trailing edge of the airfoil, and the chord is the length of the chord line. The camber line is a line drawn halfway between the two surfaces, and the distance between the camber line and the chord line is the camber of the blade. The camber angle θ is the turning angle of the camber line. The blade shape is described by specifying the ratio of the chord to the camber at some particular length on the chord line, measured from the leading edge. The aspect ratio AR is the ratio of the blade length to the chord length. The term hub-to-tip ratio'' is frequently used instead of aspect ratio. The aspect ratio becomes important when three-dimensional flow characteristics are discussed. The aspect ratio is established when the mass flow and axial velocity have been determined. The blade parameters are given in Figure 3 Figure 3 Blade Profile 2. PROBLEM DEFINITION Since the performance of the Turbine or Compressor depends on the airfoil shape and size of the blade, it is important to manufacture all the blades with same orientation and same dimensions. But, with the human limitations all the blades cannot be manufacture for with exact and similar dimensions. The major concerns with manual production of blades are More time requirement Added time for verification and Quality Check Less Accuracy More Labour This leads to inefficient working of the engine and sometimes results in failure of the engine. Hence, it there is a need to apply some reliable method which can improve the Production rate and Quality. 3. PROPOSED METHODOLOGY The work emphasizes on the use of Computers in the field of production i.e., CAD/CAM. The term CAD/CAM is a shortening of computer-aided design (CAD) and Computer-Aided manufacturing (CAM).It is the technology concerned with the use of digital computer to perform certain functions in design and production. This technology is moving in the direction of greater integration of design and manufacturing.cad/cam will provide the technology base for the computer-integrated factory of the future. http://www.iaeme.com/ijciet/index.asp 803 editor@iaeme.com

A. Sai Kumar, M. Ganesh and G Hima Bindu The CAD software consists of the computer programs to implement computer graphics on the system plus applications programs to facilitate the engineering functions of the user company. CAD/CAM software uses CAD drawing tools to describe geometries used by the CAM portion of the program to define a tool path that will direct the motion of a machine tool to machine the exact shape that was drawn. CAM uses Computer systems to plan, manage, and control the operations of a manufacturing plan through either direct to indirect computer interface with the plant s production resources. Figure 4 represents the mockup of the milling process using the GUI Interface. Figure 4 GUI Interface of CAM Software 3.1. CAD Advantages over Conventional Engineering Manufacturing of machine parts and components is carried out with the help of drawings. Computer aided design (CAD) is an important and powerful tool to create the drawings. Ease of Use Drawing Flexibility Modelling and drafting Accuracy Less time 4. MODELING CATIA is the leading product development solution for all manufacturing organizations, from OEMs, through their supply chains, to small independent producers. The range of CATIA capabilities allows it to be applied in a wide variety of industries, such as aerospace, automotive, industrial machinery, electrical, electronics, shipbuilding, plant design, and consumer goods, including design for such diverse products as jeweler and clothing. CATIA is the only solution capable of addressing the complete product development process, from product concept specification through product-in-service, in a fully integrated and associative manner. Based on an open, scalable architecture, it facilitates true collaborative engineering across the multidisciplinary extended enterprise, including style and form design, mechanical design and equipment and systems engineering, managing digital mock-ups, machining, analysis, and simulation. By enabling enterprises to reuse product design knowledge and accelerate development cycles, CATIA helps companies to speed-up their responses to market needs. http://www.iaeme.com/ijciet/index.asp 804 editor@iaeme.com

Application of CNC Milling in Manufacturing Turbine Blades In conjunction with ENOVIA and ENOVIA Smart Team for lifecycle management and decision support and DELMIA for manufacturing engineering, CATIA is a key component of collaborative PLM. Much beyond pure CAD software packages, which provide geometry modeling features for design-centric companies, CATIA delivers the keys to PLM for process-centric companies. The modeled blade in CATIA V5 is given in Figure 5 Figure 5 Blade modeled in CATIA V5 5. MANUFACTURING The part program provides the instructions to the CNC control to execute the machine operation. 5.1. Coordinate System of the Machine The information move the longitudinal slide in the spindle head direction is a very long one. Besides, in each language it would be different. That s why the traverse path movements in machine tools are described within the coordinate system. As shown in Figure 6 X Axis: movement of table. Y Axis: movement of saddle. Z Axis; movement of spindle +X movement: movement of the table to the left of the operator. -X movement: movement of the table to the right of the operator. -Y movement: movement of the table towards the operator. -Y movement: movement of the table away from the operator. -Z movement: movement of the spindle head up (away from the job) -Z movement: movement of the spindle head down (towards the job) http://www.iaeme.com/ijciet/index.asp 805 editor@iaeme.com

A. Sai Kumar, M. Ganesh and G Hima Bindu Figure 6 Milling Machine Coordinate System 5.2. Programming Method There are two methods to describe the path of motion in a CNC Machine Absolute Programming Method. Incremental Programming Method. In Absolute Programming method one point on work piece is taken as reference, or zero point and all other dimensions are represented with respect to that point. In incremental Programming Method the next point dimension in each block is referred with respect to the final point on the previous block. 5.3. Programming Methods Comparison Consider the tool moment as per the figure shown in Figure 7 Figure 7 Tool Movement http://www.iaeme.com/ijciet/index.asp 806 editor@iaeme.com

Application of CNC Milling in Manufacturing Turbine Blades The points are given in the Table 1 Table 1 Coordinate Points for the Tool Movement Path X Y a 0 3 b 2 0 c 0 2 Absolute System The path information given is always calculated from a definite starting point. Point O is the reference point. Incremental System The zero reference point for each information is the current position Slides Point O, A, B, C &D are new reference Points Based on the above study the circular interpolation or incremental system has been considered as the tool has to move in cyclic pattern to remove material. 6. RESULTS AND DISCUSSION A Model has been developed using the CNC machine and CAM software. The model generated is very accurate and very close to the dimensions given as input with a maximum variation of 1.1% to the actual given values. The image of the Fabricated Blade is given in Figure 8 Figure 8 Fabricated Blade of Compressor 7. FUTURE SCOPE This can be further employed in fabrication of base of the cascade where the blades are mounted and a complete stage can be manufactured with more precision. http://www.iaeme.com/ijciet/index.asp 807 editor@iaeme.com

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