Analysis of Spur Gear Cutting Using Milling Machine

Home , Gear cutting, Indexing head

International Journal For Technological Research In Engineering Volume 3, Issue 6, February-2016 ISSN (Online): 2347 - 4718

ANALYSIS OF SPUR GEAR CUTTING USING MILLING MACHINE

Sagar1, Mr. Neeraj Kumar2, Mr. Jagbir Sharma3 1Student of M.E, 2Assistant Professor, 3Workshop in charge Mechanical Dept., Panchkula Engineering College, Haryana.

ABSTRACT: Spur gears are the simplest type of the gear. completion period of the machining exercise, which Spur gears have teeth parallel to the axis of the wheel. Spur indirectly also determines the cost of producing the gears. In gears are the most commonly used for the transmission of cutting of the gear, most important is that machinability. power. The most common method of cutting the spur gears Machinability is defined that to cut the material how easily on milling machine is by form cutting. This is done by on a machine to get the desired shape with respect to tooling. taking a blank gear and rotating a cutter, with the desired tooth pattern, around its periphery. This ensures that the gear will fit when the operation is finished. While cutting the spur gears using the milling machine, the analysis of spur gear is very important. While analysis various parameter like pressure angle, cutting speed, feed rate, production time, tooth form, size of the teeth, pitch circle diameter, depth of cut and outside diameter. All the aspects are being calculated which is important while making the spur gears. Spur gears are cutting on milling machine utilized the various tooth cutters. The no of tooth cutters can be determined by the tooth count of the gear to be cut and also analysis the stress concentration in the spur gear while cutting. Figure 1 Spur Gear Keywords: Spur gear, milling machine, cutting tool, cutting Form milling is the process of machining special profile speed composed of curved and straight lines. It is done with milling cutter shaped to the profile to be cut. I. INTRODUCTION Gears are used for a wide range of industrial application. II. METHOD FOR GEAR CUTTING Gears used in aviation industries, textile looms, automobile, Gear cutting on a milling machine, the gear blank is mounted industrial machine, geared motors, agricultural machinery on a mandrel which is supported between the center of the etc. To meet the service conditions the geared should have dividing head and one more center at the other end. one tooth robust construction, reliable performance, high efficiency, space is cut by the milling cutter and a dividing head economy and long life. The gear should be fatigue free and /indexing head is used to index the job to the next required free from all stresses to avoid their failures. The gears should tooth space. The cutter is chosen according to the module (or be free from noise, chatter and should ensure high load DP) and number of teeth of the gear to the cut. This cutter is varying capacity at constant velocity ratio. Spur gears are the mounted on the milling arbor. Before the gear can be cut, it mostly used in all type of gear. It is used for the transmitting is necessary to have the cutter centered accurately relative to of power between two parallel shafts. In this type of gear, the the gear holding mandrel. One way is to adjust the machine teeth cut on the cylindrical face are parallel to the axis of the table vertically and horizontally until one corner of the cutter gear. In milling, a multi-toothed cutter, rotating at a fixed just touches the mandrel on one side. Both the dials are then position on the machine, shapes the work as it is traversed set to zero. The table is then adjusted for the cutter to just across the cutter. The work is firmly secured on the machine touch on the other side of the mandrel with vertical dial table which can be adjusted to set the depth of cut and can be showing zero. The reading of the horizontal feed screw is moves directions in the horizontal plane. In some machines, a read. This reading divided by two gives the central position vertical transverse also is possible manufacture of metallic of the mandrel relative to the cutter. When the table is set components using conventional machine tools, cutter tool centrally in this manner it should be locked in that position. wear, its effects on surface finish, and cutter tool failure The table is then fed vertically so that the blank just touches provide major limitations to the achievement of economic the cutter. The vertical dial is then set to zero. This is production.Form-milling the tooth of involute spur gear required to give the depth of cut on the job.With these involves specification of the cutting speed for the work piece settings the machine can be started and traversed along the material and feed rate of the milling cutter. The speed and axis of the job to cut the tooth over the whole width of the feed rate selection for such cutting has a strong link with the gear. Depth is increased slowly until it reaches the full depth

International Journal For Technological Research In Engineering Volume 3, Issue 6, February-2016 ISSN (Online): 2347 - 4718

of the tooth. With the depth setting the backlash of the gear B. Indexing Plate: can be controlled suitably and gear can be manufactured. Dividing plate is the most important part of the dividing head. The major role of the dividing plate is to key the dividing circle. The plate contains no of rings of holes. This means that one turn of the handle can be divided into the number of holes in the particular ring. Dividing plate having no of holes on the half of plate drilled on one side and other side to be drilled.The dividing plate is fitted properly all of the “zero” holes will be in line and will be vertically above the shaft of the handle. Usually, next to each of the zero holes, is stamped the number of holes in the ring

Figure 2: Milling Machine

III. PROCEDURE OF GEAR CUTTING While cutting the gear on a milling machine, it is important to know how to make the spur gear. One of the most common ways of making spur gears is by using a dividing head on a milling machine. The dividing head makes it possible to cut a gear with almost any number of teeth. It is possible to use either a horizontal milling machine or a vertical milling machine. Work piece to be held in dividing head.

A. DIVIDING HEAD Figure 4: Indexing Plate The dividing head is essentially a horizontal shaft with a worm wheel on it that can be driven round by means of a C. Holding the work piece: worm. The shaft has various means of holding a work piece. Work piece can be held in a chuck using with the help of This may seem very similar to a rotary table. It is different in dividing head. Whereas on a lathe if a chuck holds the that there is no table to mount the work piece on. It is workpiece slightly off center it is often still possible to turn possible to mount a center in the shaft or mount a chuck onto all the required surfaces so they are concentric to each other. it. Usually dividing heads are supplied with a tailstock. This This is not relevant when milling. If the workpiece has to be is essential when using a center with the dividing head. It can aligned accurately then it either has to be held between also be very useful for supporting the workpiece when using centers or centered accurately using a four-jaw chuck. Most the chuck. On all dividing heads the worm is turned by home machinists do not have horizontal milling machines means of a handle. Each turn of the handle can be divided by but have a vertical one. In this case the gear cutter is held on means of a dividing plate that contains a number of rings a stub arbor held in the vertical spindle’s socket. In this case, each with a different number of holes in it. The handle has a the cutter cuts into the workpiece in the middle of the front pin that can be moved to fit the holes in any one of the rings side. The cutters for gear cutting are designed for use on a of holes. Dividing heads are designed to divide the circle. horizontal arbor. If a vertical milling machine is being used They are not designed to turn by so many degrees though this then the same cutter is used but it is mounted on a stub arbor. can be done. This is then fitted to the vertical head. High speed cutter cut the material and makes the teeth on the material and soluble oil use for the Cooling of cutter and removes the dissipated heat.

IV. CUTTER OF CUTTING SPUR GEAR A cutter that was made for a tooth size would make any gear with that size tooth. But, unfortunately, for any given size of tooth, pressure angle etc. the shape of the tooth will vary depending upon the number of teeth on the gear being made. This means that to be able to cut a gear with any number of teeth but for a given size of tooth a set of eight cutters is required. In order to cope with this it is necessary to have a Figure 3: Dividing Head cutter for each of a range of teeth numbers.

International Journal For Technological Research In Engineering Volume 3, Issue 6, February-2016 ISSN (Online): 2347 - 4718

 Cutting Speed= (pi * Diameter * spindle speed) / 1000.  Feed = spindle speed * feed per tooth * no of flutes  Indexing Movement = 40 / no of teeth

Observation Reading

No of teeth 28 teeth Module 2.5 Pitch circle diameter 70mm Pressure angle 20 deg. Figure 5: High Speed Cutter Material Mild Steel Outside Diameter 75 mm V. SPUR GEAR PARAMETER Indexing Movement 1.428 There are still a few key features of gear we need and have to Working depth mm be defined. For gear of size having 28 teeth to mesh properly circular Pitch 0.7837mm with the other gear. There are several conditions that must be fulfilled: VII. CONCLUSION A. No of Teeth In present work steps involved in manufacturing engineering The number of teeth is important since this determines the of gear teeth have been explained using steps like alignment gearing obtained with other gear of this or other numbers of of mandrel on which work piece or job to be held, Work teeth. Spur gear made on a milling machine having 28 teeth piece size, cutter, center mark on job and teeth profile in proper manner so that they can mesh withanother gear generation. According to the manufacturing of the spur gear without rubbing and do not create wear and friction and work various kind of parameter have been calculated. These properly. parameter help the fresher and new student how to cut the B. Pitch Circle Diameter spur gear on the milling machine using form cutting Though a gear has an outside diameter this is not as technique. Various doubts are being easily solved. In this important as the pitch circle diameter. This is the distance paper, analysis that time taken for cutting spur gear tooth between the two centers of two identical gears meshed reduces with increase in the cutting speed and feed rate together. It is roughly the distance from the middle of a tooth respectively. on one side of the gear to the middle of a tooth on the other side. REFERENCES C. Outside Diameter [1] Khurmi. R. S and Gupta. J. B, a textbook of The gear will have an outside diameter. This is the size the machine design, 14thedition, India: Eurasia blank has to be turned down to. Since gears are usually Publishing house limited, 2014. defined by their tooth size and the number of teeth these set [2] Oladejo, K.A. and Oriolovo, K.T.,” Analysis of the outside diameter. Gear Milling at various speed, time and feed rate”, Outside diameter = (no of teeth +2)/ module Nigerian Journal of technology (NIJOTECH), D. Depth of Cut vol.34, No.1, January 2015, pp.150-155. The depth the cutter needs to cut is always marked upon the [3] Kumar. A, Jain. P. K and Pathak. P. M.,” Study of gear cutter. It includes an allowance of 10% at the bottom of Tooth Wear on Spur Gear Performance Parameters the cut so the top of one lot of teeth will not clash with the Using Reverse Engineering”, International bottoms of the other gear Conference on Production and Mechanical E. Pressure Angle Engineering (ICPME), Dec 2014,pp. 30-31, 2014 Where two gears touch each other the angle relative to a Bangkok, Thailand. normal on the pitch circle diameter to the tooth face at this [4] Rech, J. and Moissan, A., “Surface Hardened point can vary. In the past the fashion was for a pressure Steels”, International Journal Machine Tools and angle of 14.5º. The current fashion is for 20º. For special Manufacture, vol. 43, Issues 5, pp. 543-550, 2007. applications this can be even higher. [5] Ozel. C,” Research of production times and cutting of the spur gears by end mill in CNC milling VI. MATHEMATICAL FORMULAE’S AND TABLE machine”, International Journal of Advanced  PCD = module * no of teeth Manufacturing Technology 54(1):pp.203-213 ·  Diametric Pitch = no of teeth / pitch circle diameter April 2011.  Circular pitch = (pi * pitch circle diameter) / no of [6] Papaioannou.S.G,” Manufacture of High Precision teeth. Spur Gears with End Milling Cutters”, The American Society of Engineers, vol.10, pp-359-366,  Outside diameter =(no of teeth +2)/ module 1988.

International Journal For Technological Research In Engineering Volume 3, Issue 6, February-2016 ISSN (Online): 2347 - 4718

[7] Kumar. M. D,” Fabrication of multi milling process”, international journal of research in aeronautical and mechanical engineering”, Vol.2 Issue.2, February 2014, Pgs.: 105-111.

Sagar is pursuing Bachelor of Technology from Panchkula Engineering College Barwala in the Department of Mechanical Engineering. His research interest includes designing, manufacturing and production. It is my first research paper that I published in international level.

Student of Mechanical Engineering

Mr. Neeraj Kumar is working as assistant professor in the Mechanical Department at Panchkula Engineering College Haryana.Currently, he is also the Head of the department. He obtained his M.Tech in the area of thermal engineering from National Institute of technology Kurukshetra.He has published several research papers and articles in various reputed national and international journals and attend various conferences.

HOD of Mechanical Department

Mr. Jagbir Sharma is working as a workshop in charge in the Mechanical Department a Panchkula Engineering College Haryana. He had done ITI form Ambala. He had worked in various industries having 22 years experience in mechanical department and also in teaching.

Workshop In charge