Summer Training Report at TATA MOTORS

PROJECT REPORT ON SUMMER TRAINING IN TATA MOTORS, LUCKNOW SUBMITTED BY SUDHANSHU 1|Page

MECHANICAL ENGINEERING DEPARTMENT, SRMS CET,BAREILLY.

PROJECT REPORT TATA MOTORS, LUCKNOW PRODUCTIVITY IMPROVEMENT OF GLEASON NO.610 HYPOID GEAR MACHINE Submitted by SUDHANSHU

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Mechanical Engineering Department SRMS CET,BAREILLY Under the Guidance of Mr.TANUJ SONKER CX-CWP

CONTENTS ➢ Declaration ➢ Acknowledgement ➢ TATA MOTORS- An Introduction ➢ TATA Journey-Year by year ➢

Organisation Structure

➢ TATA MOTORS-Lucknow Plant ➢ What is a CROWN wheel 3|Page

➢ Gears Manufacturing and its uses ➢

Detailed Study of GLEASON NO.610

➢ Productivity Improvement ➢ My Role ➢ Overview

DECLARATION I hereby declare that the project work entitled: 1. PRODUCTIVITY IMPROVEMENT OF GLEASON NO.610 HYPOID GEAR MACHINE is an authentic record of my own work carried out at TATA MOTORS, (CX-CWP) , LUCKNOW as requirements of four week summer project , under the guidance of MR.TANUJ SONKER

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SUDHANSHU B.TECH.2nd year

Certified that the above statement made by the student is correct to the best of our knowledge and belief.

Mr.TANUJ SONKER Ms.JASNEET RAKHRA CX-CWP MANAGER,HR

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ACKNOWLEDGEMENT

Industrial training is a crucial period in engineering curriculum since it exposes a student to the real world which he or she is going to enter after the completion of the graduation. This is the period during which an engineer actually becomes an engineer by gaining the Industrial experience. I am very thankful to God who has given me the opportunity to get training in TATA MOTORS, LUCKNOW one of the most renowned organization of India. I would like to express my deep gratitude to my Project Head MR. TANUJ SONKER ,CX-CWP for having provided me with the wonderful & conductive environment to work in and realize what really industry is, he has been ever helpful and supportive. Last but not the least I would like to thank MS. JASNEET RAKHRA (Manager HR) for providing me the opportunity to add a new dimension to my personality. I will remain indebted to her for her generous ways of dealing with industrial trainees.

SUDHANSHU,B.Tech. 2nd year,SRMS CET,Bareilly 6|Page

TATA MOTORS ○ Tata Motors is a part of the Tata Group manages its share-holding through Tata Sons. The company was established in 1935 as a locomotive manufacturing unit and later expanded its operations to commercial vehicle sector in 1954 after forming a joint venture with Daimler-Benz AG of Germany. Despite the success of its commercial vehicles, Tata realized his company had to diversify and he began to look at other products. Based on consumer demand, he decided that building a small car would be the most practical new venture. So in 1998 it launched Tata Indica, India's first fully indigenous passenger car. Designed to be inexpensive and simple to build and maintain, the Indica became a hit in the Indian market. It was also exported to Europe, especially the UK and Italy. In 2004 it acquired Tata Daewoo Commercial Vehicle, and in late 2005 it acquired 21% of Aragonese Hispano Carrocera giving it controlling rights of the company. It has formed a joint venture with Marcopolo of Brazil, and introduced lowfloor buses in the Indian Market. Recently, it has acquired British Jaguar Land Rover (JLR), which includes the Daimler and Lanchester brand names.

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TATA JOURNEY –YEAR BY YEAR:

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1868: Jamsetji Nusserwanji Tata starts a private trading firm, laying the foundation of the TATA group. 1874: The Central India Spinning, Weaving and Manufacturing Company is set up, marking the Group's entry into textiles. 1902: The Indian Hotels Company is incorporated to set up the Taj Mahal Palace and Tower, India's first luxury hotel, which opened in 1903. 1907: The Tata Iron and Steel Company (now Tata Steel) is established to set up India's first iron and steel plant in Jamshedpur. The plant started production in 1912. 1910: The first of the three Tata Electric Companies, The Tata Hydro-Electric Power Supply Company, (now Tata Power) is set up. 1911: The Indian Institute of Science is established in Bangalore to serve as a centre for advanced learning. 1912: Tata Steel introduces eight-hour working days, well before such a system was implemented by law in much of the West. 1917: The Tatas enter the consumer goods industry, with the Tata Oil Mills Company being 8|Page

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established to make soaps, detergents and cooking oils. 1932: Tata Airlines, a division of Tata Sons, is established, opening up the aviation sector in India. 1939: Tata Chemicals, now the largest producer of soda ash in the country, is established. 1945: Tata Engineering and Locomotive Company (renamed Tata Motors in 2003) is established to manufacture locomotive and engineering products. Tata Industries is created for the promotion and development of hi-tech industries. 1952: Jawaharlal Nehru, India's first Prime Minister, requests the Group to manufacture cosmetics in India, leading to the setting up of Lakme. 1954: India's major marketing, engineering and manufacturing organization, Voltas, is established. 1962: Tata Finlay (now Tata Tea), one of the largest tea producers, is established. Tata Exports is established. Today the company, renamed Tata International, is one of the leading export houses in India. 1968: Tata Consultancy Services (TCS), India's first software services company, is established as a division of Tata Sons. 1970: Tata McGraw-Hill Publishing Company is created to publish educational and technical books. Tata Economic Consultancy Services is set up to provide services in the field of industrial, marketing, statistical and techno-economic research and consultancy. 9|Page

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1984: Titan Industries - a joint venture between the Tata Group and the Tamil Nadu Industrial Development Corporation (TIDCO) - is set up to manufacture watches. 1991: Tata Motors rolls out its millionth vehicle. (The two-million mark was reached in 1998 and the third million in 2003.) 1995: Tata Quality Management Services institutes the JRD QV Award, modelled on the Malcolm Baldrige National Quality Value Award of the United States, laying the foundation of the Tata Business Excellence Model. 1996: Tata Tele services (TTSL) is established to spearhead the Group's foray into the telecom sector. 1998: Tata Indica - India's first indigenously designed and manufactured car – is launched by Tata Motors, spearheading the Group's entry into the passenger car segment. 1999: The new Tata Group corporate mark and logo are launched. 2000: Tata Tea acquires the Tetley Group, UK. This is the first major acquisition of an international brand by an Indian business group. 2001: Tata-AIG - a joint venture between the Tata Group and American International Group Inc (AIG) marks the Tata re-entry into insurance. (The Group's insurance company, New India Assurance, was nationalized in 1956). The Tata Group Executive Office (GEO) is set up to design and implement change in the Tata Group and to provide long-term direction. 10 | P a g e

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2002: The Tata Group acquires a controlling stake in VSNL, India's leading international telecommunications service provider Tata Consultancy Services (TCS) becomes the first Indian software company to cross one billion dollars in revenues. Titan launches Edge, the slimmest watch in the world. Idea Cellular, the cellular service born of a tie-up involving the Tata Group, the Birla Group and AT&T, is launched. Tata Indicom, the umbrella brand for telecom services from the Tata Tele services stable, starts operations. 2003: Tata Motors launches City Rover – Indicas fashioned for the European market. The first batch of City Rovers rolled out from the Tata Motors stable in Pune on September 16, 2003. 2004: Tata Motors acquires the heavy vehicles unit of Daewoo Motors, South Korea. TCS goes public in July 2004 in the largest private sector initial public offering (IPO) in the Indian market, raising nearly $1.2 billion. 2005: Tata Steel acquires Singapore-based steel company NatSteel by subscribing to 100 per cent equity of its subsidiary, NatSteel Asia. 2009: Tata Motors launched Tata Nano, world’s cheapest family car.

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ORGANIZATION STRUCTURE (Lucknow Plant)

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TATA MOTORS-LUCKNOW PLANT 13 | P a g e

There are three divisions in TATA Motors, Lucknow: Training division The Training Center at the Lucknow plant aims at providing high quality Apprenticeship Training. In addition, the Centre provides both internal and external training, support to operators, supervisors and managers in areas like special skills and technology, safety, personnel practices etc. The Lucknow plant, after a major restructuring exercise, executed a smooth transition from functionbased to process-based structure. By this structure, process owners are required to meet stretched targets, and in order to do so, are required to encourage individual learning and development of employees. A structured process is being followed to establish and reinforce an environment that encourages innovation. Assembly division Lucknow Plant started with the assembly of Medium Commercial Vehicles (MCVs) to meet the demand in the Northern Indian market. However, in 1995, the unit started manufacturing bus chassis of Light Commercial Vehicles (LCVs) and SUMOs. The facilities for manufacturing the spare parts were set up and started supply of Crown wheel & pinion (CWP) in 1994. Subsequently, G-16 & G-18 Gear Parts started in 1998. With the availability of G-16 gear parts manufacturing facility, the Plant also started assembly of G-16 Gear Box to meet in-house requirement for SUMO vehicles in 14 | P a g e

the year 2000.Now TATA Motors Lucknow has started assembling of CNG MCV`s to meet the consumers demand. TATA Motors is also producing Rear Engine CV`s. Manufacturing Division In TATA Motors Lucknow Crown Wheel and Pinion are manufactured by various gear cutting process. Machining (grinding and heat treatment) of Gear Box parts is also done here. These gears are used in gear boxes or as spares. Now TATA Motors is assembling Gear Box of ACE (Newly launched small –CV) in Lucknow itself. The Manufacturing unit of Tata Motors at Lucknow is the latest manufacturing facility of Tata motors and is located towards East of Lucknow plant.

WHAT IS A CROWN WHEEL 15 | P a g e

A crown wheel is a type of circular gear wheel with teeth that extend perpendicular to the base. While a traditional gear features teeth that sit parallel to the edges of the base, a crown wheel's teeth sit on the surface of the wheel, forming a crown-like shape. Crown wheels are considered a type of beveled gear, which is the general term for all gears with teeth located on the surface of the wheel rather than the edges. The teeth on a beveled wheel may be placed at any angle to the surface, while the crown wheel teeth are distinguished by the fact that they are positioned at a 90-degree angle to the gear. These gears are often used along with a pinion to rotate a mechanical device. They are used in many automotive applications, as well as in industrial and manufacturing equipment. Many vehicles rely on crown wheel and pinion systems to create the vehicle's forward motion, or to rotate the axles. A crown wheel gear is also used with a pinion to operate a traditional mechanical clock. While standard gears line up edge to edge, crown wheels mesh at an angle with pinions or other gears. Rather than being located in the same plane, the two gears are positioned at an angle, or perpendicular to one another. This allows the teeth in the gears to fit together and transfer motion or force between various operating components. There are three basic types of crown wheel for buyers to choose from. Standard models have squared-off teeth that sit parallel to the top of the gear. This design results in a high level of vibration and noise when these gears are used. Spiral gears use teeth with angled 16 | P a g e

edges, resulting in quieter performance, but also in faster wear and more maintenance. Hypoid crown wheels are similar to spiral models, but work with an offset pinion to create better strength and performance. Users should select crown wheel gears carefully to match the needs of the application. The size and pattern of the teeth on the wheel must fit exactly with all adjacent gears or pinions. It is also helpful to choose higher quality gears, because are more precisely made to minimize noise and vibration. The material used to manufacture these gears is also a critical factor. If one gear is harder than the adjacent one, it will rapidly wear away the edges of the softer gear, shortening the life of the installation.

Figure 1USE OF CROWN AND PINION IN AN DIFFERENTIAL OF AN AUTOMOBILE 17 | P a g e

GEARS

A gear is a rotating machine part having cut teeth, or cogs, which mesh with another toothed part in order to transmit torque. Two or more gears working in tandem are called a transmission and can produce a mechanical advantage through a gear ratio and thus may be considered a simple machine. Geared devices can change the speed, magnitude, and direction of a power source. The most common situation is for a gear to mesh with another gear, however a gear can also mesh a non-rotating toothed part, called a rack, thereby producing translation instead of rotation. The gears in a transmission are analogous to the wheels in a pulley. An advantage of gears is that the teeth of a gear prevent slipping. When two gears of unequal number of teeth are combined a mechanical advantage is produced, with both the rotational speeds and the torques of the two gears differing in a simple relationship. In transmissions which offer multiple gear ratios, such as bicycles and cars, the term gear, as in first gear, 18 | P a g e

refers to a gear ratio rather than an actual physical gear. The term is used to describe similar devices even when gear ratio is continuous rather than discrete, or when the device does not actually contain any gears, as in a continuously variable transmission.

Comparison with other drive mechanisms The definite velocity ratio which results from having teeth gives gears an advantage over other drives (such as traction drives and V-belts) in precision machines such as watches that depend upon an exact velocity ratio. In cases where driver and follower are in close proximity gears also have an advantage over other drives in the reduced number of parts required; the downside is that gears are more expensive to manufacture and their lubrication requirements may impose a higher operating cost. The automobile transmission allows selection between gears to give various mechanical advantages.

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TYPES 1.External vs. internal gears

Internal gear An external gear is one with the teeth formed on the outer surface of a cylinder or cone. Conversely, an internal gear is one with the teeth formed on the inner surface of a cylinder or cone. For bevel gears, an internal gear is one with the pitch angle exceeding 90 degrees. Internal gears do not cause direction reversal. 2.Spur

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Spur gear Spur gears or straight-cut gears are the simplest type of gear. They consist of a cylinder or disk, and with the teeth projecting radially, and although they are not straight-sided in form, the edge of each tooth thus is straight and aligned parallel to the axis of rotation. These gears can be meshed together correctly only if they are fitted to parallel axles. 3. Helical

Helical gears Top: parallel configuration Bottom: crossed configuration Helical gears offer a refinement over spur gears. The leading edges of the teeth are not parallel to the axis of rotation, but are set at an angle. Since the gear is curved, this angling causes the tooth shape to be a segment of a helix. Helical gears can be meshed in a parallel or crossed orientations. The former refers to when the shafts are parallel to each other; this is the most common orientation. In the latter, the shafts are non-parallel.

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The angled teeth engage more gradually than do spur gear teeth causing them to run more smoothly and quietly. With parallel helical gears, each pair of teeth first make contact at a single point at one side of the gear wheel; a moving curve of contact then grows gradually across the tooth face to a maximum then recedes until the teeth break contact at a single point on the opposite side. In spur gears teeth suddenly meet at a line contact across their entire width causing stress and noise. Spur gears make a characteristic whine at high speeds and can not take as much torque as helical gears. Whereas spur gears are used for low speed applications and those situations where noise control is not a problem, the use of helical gears is indicated when the application involves high speeds, large power transmission, or where noise abatement is important. The speed is considered to be high when the pitch line velocity exceeds 25 m/s. A disadvantage of helical gears is a resultant thrust along the axis of the gear, which needs to be accommodated by appropriate thrust bearings, and a greater degree of sliding friction between the meshing teeth, often addressed with additives in the lubricant. For a crossed configuration the gears must have the same pressure angle and normal pitch, however the helix angle and handedness can be different. The relationship between the two shafts is actually defined by the helix angle(s) of the two shafts and the handedness, as defined: E = β1 + β2 for gears of the same handedness E = β1 − β2 for gears of opposite handedness 22 | P a g e

Where β is the helix angle for the gear. The crossed configuration is less mechanically sound because there is only a point contact between the gears, whereas in the parallel configuration there is a line contact. Quite commonly helical gears are used with the helix angle of one having the negative of the helix angle of the other; such a pair might also be referred to as having a right-handed helix and a left-handed helix of equal angles. The two equal but opposite angles add to zero: the angle between shafts is zero – that is, the shafts are parallel. Where the sum or the difference (as described in the equations above) is not zero the shafts are crossed. For shafts crossed at right angles the helix angles are of the same hand because they must add to 90 degrees. 4. Double helical

Double helical gears Double helical gears, or herringbone gear, overcome the problem of axial thrust presented by "single" helical gears by having two sets of teeth that are set in a V shape. Each gear in a double helical gear can be thought of as two standard mirror image helical gears 23 | P a g e

stacked. This cancels out the thrust since each half of the gear thrusts in the opposite direction. Double helical gears are more difficult to manufacture due to their more complicated shape. For each possible direction of rotation, there are two possible arrangements of two oppositely-oriented helical gears or gear faces. In one possible orientation, the helical gear faces are oriented so that the axial force generated by each is in the axial direction away from the center of the gear; this arrangement is unstable. In the second possible orientation, which is stable, the helical gear faces are oriented so that each axial force is toward the mid-line of the gear. In both arrangements, when the gears are aligned correctly, the total (or net) axial force on each gear is zero. If the gears become misaligned in the axial direction, the unstable arrangement generates a net force for disassembly of the gear train, while the stable arrangement generates a net corrective force. If the direction of rotation is reversed, the direction of the axial thrusts is reversed, a stable configuration becomes unstable, and vice versa. Stable double helical gears can be directly interchanged with spur gears without any need for different bearings. 5. Bevel

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Bevel gear A bevel gear is shaped like a right circular cone with most of its tip cut off. When two bevel gears mesh their imaginary vertices must occupy the same point. Their shaft axes also intersect at this point, forming an arbitrary non-straight angle between the shafts. The angle between the shafts can be anything except zero or 180 degrees. Bevel gears with equal numbers of teeth and shaft axes at 90 degrees are called miter gears. The teeth of a bevel gear may be straight-cut as with spur gears, or they may be cut in a variety of other shapes. Spiral bevel gear teeth are curved along the tooth's length and set at an angle, analogously to the way helical gear teeth are set at an angle compared to spur gear teeth. Zerol bevel gears have teeth which are curved along their length, but not angled. Spiral bevel gears have the same advantages and disadvantages relative to their straight-cut cousins as helical gears do to spur gears. Straight bevel gears are generally used only at speeds below 5 m/s (1000 ft/min), or, for small gears, 1000 r.p.m. 6. Hypoid

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Hypoid gear Hypoid gears resemble spiral bevel gears except the shaft axes do not intersect. The pitch surfaces appear conical but, to compensate for the offset shaft, are in fact hyperboloids of revolution. Hypoid gears are almost always designed to operate with shafts at 90 degrees. Depending on which side the shaft is offset to, relative to the angling of the teeth, contact between hypoid gear teeth may be even smoother and more gradual than with spiral bevel gear teeth. Also, the pinion can be designed with fewer teeth than a spiral bevel pinion, with the result that gear ratios of 60:1 and higher are feasible using a single set of hypoid gears. This style of gear is most commonly found in mechanical differentials.

7. Crown

Crown gear 26 | P a g e

Crown gears or contrate gears are a particular form of bevel gear whose teeth project at right angles to the plane of the wheel; in their orientation the teeth resemble the points on a crown. A crown gear can only mesh accurately with another bevel gear, although crown gears are sometimes seen meshing with spur gears. A crown gear is also sometimes meshed with an escapement such as found in mechanical clocks. 8. Worm

Worm gear Worm gears resemble screws. A worm gear is usually meshed with an ordinary looking, disk-shaped gear, which is called the gear, wheel, or worm wheel. Worm-and-gear sets are a simple and compact way to achieve a high torque, low speed gear ratio. For example, helical gears are normally limited to gear ratios of less than 10:1 while worm-and-gear sets vary from 10:1 to 500:1. A disadvantage is the potential for considerable sliding action, leading to low efficiency. Worm gears can be considered a species of helical gear, but its helix angle is usually somewhat large (close to 90 degrees) and its body is usually fairly long 27 | P a g e

in the axial direction; and it is these attributes which give it its screw like qualities. The distinction between a worm and a helical gear is made when at least one tooth persists for a full rotation around the helix. If this occurs, it is a 'worm'; if not, it is a 'helical gear'. A worm may have as few as one tooth. If that tooth persists for several turns around the helix, the worm will appear, superficially, to have more than one tooth, but what one in fact sees is the same tooth reappearing at intervals along the length of the worm. The usual screw nomenclature applies: a one-toothed worm is called single thread or single start; a worm with more than one tooth is called multiple thread or multiple start. The helix angle of a worm is not usually specified. Instead, the lead angle, which is equal to 90 degrees minus the helix angle, is given. In a worm-and-gear set, the worm can always drive the gear. However, if the gear attempts to drive the worm, it may or may not succeed. Particularly if the lead angle is small, the gear's teeth may simply lock against the worm's teeth, because the force component circumferential to the worm is not sufficient to overcome friction. Worm-and-gear sets that do lock are called self locking, which can be used to advantage, as for instance when it is desired to set the position of a mechanism by turning the worm and then have the mechanism hold that position. An example is the machine head found on some types of stringed instruments. If the gear in a worm-and-gear set is an ordinary helical gear only a single point of contact will be achieved. If medium to high power transmission is desired, the 28 | P a g e

tooth shape of the gear is modified to achieve more intimate contact by making both gears partially envelop each other. This is done by making both concave and joining them at a saddle point; this is called a cone-drive. Worm gears can be right or left-handed following the long established practice for screw threads. 9. Non-circular

Non-circular gears Non-circular gears are designed for special purposes. While a regular gear is optimized to transmit torque to another engaged member with minimum noise and wear and maximum efficiency, a non-circular gear's main objective might be ratio variations, axle displacement oscillations and more. Common applications include textile machines, potentiometers and continuously variable transmissions.

10. Rack and pinion

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Rack and pinion gearing A rack is a toothed bar or rod that can be thought of as a sector gear with an infinitely large radius of curvature. Torque can be converted to linear force by meshing a rack with a pinion: the pinion turns; the rack moves in a straight line. Such a mechanism is used in automobiles to convert the rotation of the steering wheel into the left-to-right motion of the tie rod(s). Racks also feature in the theory of gear geometry, where, for instance, the tooth shape of an interchangeable set of gears may be specified for the rack (infinite radius), and the tooth shapes for gears of particular actual radii then derived from that. The rack and pinion gear type is employed in a rack railway. 11. Epicyclic

Epicyclic gearing

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In epicyclic gearing one or more of the gear axes moves. Examples are sun and planet gearing (see below) and mechanical differentials. 12. Sun and planet

Sun (yellow) and planet (red) gearing Sun and planet gearing was a method of converting reciprocal motion into rotary motion in steam engines. It played an important role in the Industrial Revolution. The Sun is yellow, the planet red, the reciprocating crank is blue, the flywheel is green and the driveshaft is grey. 14. Harmonic drive

Harmonic drive gearing 31 | P a g e

A harmonic drive is a specialized proprietary gearing mechanism. 15. Cage gear A cage gear, also called a lantern gear or lantern pinion has cylindrical rods for teeth, parallel to the axle and arranged in a circle around it, much as the bars on a round bird cage or lantern. The assembly is held together by disks at either end into which the tooth rods and axle are set.

Nomenclature General nomenclature

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Rotational frequency, n Measured in rotation over time, such as RPM. Angular frequency, ω Measured in radians per second. 1RPM = π / 30 rad/second Number of teeth, N

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How many teeth a gear has, an integer. In the case of worms, it is the number of thread starts that the worm has. Gear, wheel The larger of two interacting gears. Pinion The smaller of two interacting gears. Path of contact Path followed by the point of contact between two meshing gear teeth. Line of action, pressure line Line along which the force between two meshing gear teeth is directed. It has the same direction as the force vector. In general, the line of action changes from moment to moment during the period of engagement of a pair of teeth. For involute gears, however, the tooth-to-tooth force is always directed along the same line—that is, the line of action is constant. This implies that for involute gears the path of contact is also a straight line, coincident with the line of action—as is indeed the case. Axis

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Axis of revolution of the gear; center line of the shaft. Pitch point, p Point where the line of action crosses a line joining the two gear axes. Pitch circle, pitch line Circle centered on and perpendicular to the axis, and passing through the pitch point. A predefined diametral position on the gear where the circular tooth thickness, pressure angle and helix angles are defined. Pitch diameter, d A predefined diametral position on the gear where the circular tooth thickness, pressure angle and helix angles are defined. The standard pitch diameter is a basic dimension and cannot be measured, but is a location where other measurements are made. Its value is based on the number of teeth, the normal module (or normal diametral pitch), and the helix angle. It is calculated as:

in metric units or

in imperial units.

Module, m 35 | P a g e

A scaling factor used in metric gears with units in millimeters who's effect is to enlarge the gear tooth size as the module increases and reduce the size as the module decreases. Module can be defined in the normal (mn), the transverse (mt), or the axial planes (ma) depending on the design approach employed and the type of gear being designed. Module is typically an input value into the gear design and is seldom calculated. Operating pitch diameters Diameters determined from the number of teeth and the center distance at which gears operate. Example for pinion:

Pitch surface In cylindrical gears, cylinder formed by projecting a pitch circle in the axial direction. More generally, the surface formed by the sum of all the pitch circles as one moves along the axis. For bevel gears it is a cone. Angle of action Angle with vertex at the gear center, one leg on the point where mating teeth first make contact, the other leg on the point where they disengage. 36 | P a g e

Arc of action Segment of a pitch circle subtended by the angle of action. Pressure angle, θ The complement of the angle between the direction that the teeth exert force on each other, and the line joining the centers of the two gears. For involute gears, the teeth always exert force along the line of action, which, for involute gears, is a straight line; and thus, for involute gears, the pressure angle is constant. Outside diameter, Do Diameter of the gear, measured from the tops of the teeth. Root diameter Diameter of the gear, measured at the base of the tooth. Addendum, a Radial distance from the pitch surface to the outermost point of the tooth. a = (Do − D) / 2 Dedendum, b Radial distance from the depth of the tooth trough to the pitch surface. b = (D − rootdiameter) / 2 37 | P a g e

Whole depth, ht The distance from the top of the tooth to the root; it is equal to addendum plus dedendum or to working depth plus clearance. Clearance Distance between the root circle of a gear and the addendum circle of its mate. Working depth Depth of engagement of two gears, that is, the sum of their operating addendums. Circular pitch, p Distance from one face of a tooth to the corresponding face of an adjacent tooth on the same gear, measured along the pitch circle. Diametral pitch, pd Ratio of the number of teeth to the pitch diameter. Could be measured in teeth per inch or teeth per centimeter. Base circle In involute gears, where the tooth profile is the involute of the base circle. The radius of the base circle is somewhat smaller than that of the pitch circle. 38 | P a g e

Base pitch, normal pitch, pb In involute gears, distance from one face of a tooth to the corresponding face of an adjacent tooth on the same gear, measured along the base circle. Interference Contact between teeth other than at the intended parts of their surfaces. Interchangeable set A set of gears, any of which will mate properly with any other. Helical gear nomenclature Helix angle, ψ Angle between a tangent to the helix and the gear axis. Is zero in the limiting case of a spur gear. Normal circular pitch, pn Circular pitch in the plane normal to the teeth. Transverse circular pitch, p Circular pitch in the plane of rotation of the gear. Sometimes just called "circular pitch". pn = pcos(ψ) Several other helix parameters can be viewed either in the normal or transverse planes. The subscript n usually indicates the normal. Worm gear nomenclature 39 | P a g e

Lead Distance from any point on a thread to the corresponding point on the next turn of the same thread, measured parallel to the axis. Linear pitch, p Distance from any point on a thread to the corresponding point on the adjacent thread, measured parallel to the axis. For a single-thread worm, lead and linear pitch are the same. Lead angle, λ Angle between a tangent to the helix and a plane perpendicular to the axis. Note that it is the complement of the helix angle which is usually given for helical gears. Pitch diameter, dw Same as described earlier in this list. Note that for a worm it is still measured in a plane perpendicular to the gear axis, not a tilted plane. Subscript w denotes the worm, subscript g denotes the gear. Tooth contact nomenclature

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Line of contact

Lines of contact (helical gear)

Face advance

Path of action

Arc of action

Line of action

Plane of action

Length of action

Limit diameter

Zone of action

Point of contact Any point at which two tooth profiles touch each other. Line of contact A line or curve along which two tooth surfaces are tangent to each other. 41 | P a g e

Path of action The locus of successive contact points between a pair of gear teeth, during the phase of engagement. For conjugate gear teeth, the path of action passes through the pitch point. It is the trace of the surface of action in the plane of rotation. Line of action The path of action for involute gears. It is the straight line passing through the pitch point and tangent to both base circles. Surface of action The imaginary surface in which contact occurs between two engaging tooth surfaces. It is the summation of the paths of action in all sections of the engaging teeth. Plane of action The surface of action for involute, parallel axis gears with either spur or helical teeth. It is tangent to the base cylinders. Zone of action (contact zone) For involute, parallel-axis gears with either spur or helical teeth, is the rectangular area in the plane of action bounded by the length of action and the effective face width. 42 | P a g e

Path of contact The curve on either tooth surface along which theoretical single point contact occurs during the engagement of gears with crowned tooth surfaces or gears that normally engage with only single point contact. Length of action The distance on the line of action through which the point of contact moves during the action of the tooth profile. Arc of action, Qt The arc of the pitch circle through which a tooth profile moves from the beginning to the end of contact with a mating profile. Arc of approach, Qa The arc of the pitch circle through which a tooth profile moves from its beginning of contact until the point of contact arrives at the pitch point. Arc of recess, Qr The arc of the pitch circle through which a tooth profile moves from contact at the pitch point until contact ends. Contact ratio, mc, ε

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The number of angular pitches through which a tooth surface rotates from the beginning to the end of contact.In a simple way, it can be defined as a measure of the average number of teeth in contact during the period in which a tooth comes and goes out of contact with the mating gear. Transverse contact ratio, mp, εα The contact ratio in a transverse plane. It is the ratio of the angle of action to the angular pitch. For involute gears it is most directly obtained as the ratio of the length of action to the base pitch. Face contact ratio, mF, εβ The contact ratio in an axial plane, or the ratio of the face width to the axial pitch. For bevel and hypoid gears it is the ratio of face advance to circular pitch. Total contact ratio, mt, εγ The sum of the transverse contact ratio and the face contact ratio. εγ = εα + εβ mt = mp + mF Modified contact ratio, mo For bevel gears, the square root of the sum of the squares of the transverse and face contact ratios. 44 | P a g e

Limit diameter Diameter on a gear at which the line of action intersects the maximum (or minimum for internal pinion) addendum circle of the mating gear. This is also referred to as the start of active profile, the start of contact, the end of contact, or the end of active profile. Start of active profile (SAP) Intersection of the limit diameter and the involute profile. Face advance Distance on a pitch circle through which a helical or spiral tooth moves from the position at which contact begins at one end of the tooth trace on the pitch surface to the position where contact ceases at the other end. Tooth thickness nomeclature

Tooth thickness

Thickness relationships

Chordal thickness

Tooth thickness measurement 45 | P a g e

over pins

Span Long and measuremen short t addendum teeth Circular thickness Length of arc between the two sides of a gear tooth, on the specified datum circle. Transverse circular thickness Circular thickness in the transverse plane. Normal circular thickness Circular thickness in the normal plane. In a helical gear it may be considered as the length of arc along a normal helix. Axial thickness In helical gears and worms, tooth thickness in an axial cross section at the standard pitch diameter. Base circular thickness

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In involute teeth, length of arc on the base circle between the two involute curves forming the profile of a tooth. Normal chordal thickness Length of the chord that subtends a circular thickness arc in the plane normal to the pitch helix. Any convenient measuring diameter may be selected, not necessarily the standard pitch diameter. Chordal addendum (chordal height) Height from the top of the tooth to the chord subtending the circular thickness arc. Any convenient measuring diameter may be selected, not necessarily the standard pitch diameter. Profile shift Displacement of the basic rack datum line from the reference cylinder, made non-dimensional by dividing by the normal module. It is used to specify the tooth thickness, often for zero backlash. Rack shift Displacement of the tool datum line from the reference cylinder, made non-dimensional by dividing by the normal module. It is used to specify the tooth thickness. Measurement over pins 47 | P a g e

Measurement of the distance taken over a pin positioned in a tooth space and a reference surface. The reference surface may be the reference axis of the gear, a datum surface or either one or two pins positioned in the tooth space or spaces opposite the first. This measurement is used to determine tooth thickness. Span measurement Measurement of the distance across several teeth in a normal plane. As long as the measuring device has parallel measuring surfaces that contact on an unmodified portion of the involute, the measurement will be along a line tangent to the base cylinder. It is used to determine tooth thickness. Modified addendum teeth Teeth of engaging gears, one or both of which have non-standard addendum. Full-depth teeth Teeth in which the working depth equals 2.000 divided by the normal diametral pitch. Stub teeth Teeth in which the working depth is less than 2.000 divided by the normal diametral pitch. Equal addendum teeth 48 | P a g e

Teeth in which two engaging gears have equal addendums. Long and short-addendum teeth Teeth in which the addendums of two engaging gears are unequal. Pitch nomenclature Pitch is the distance between a point on one tooth and the corresponding point on an adjacent tooth. It is a dimension measured along a line or curve in the transverse, normal, or axial directions. The use of the single word pitch without qualification may be ambiguous, and for this reason it is preferable to use specific designations such as transverse circular pitch, normal base pitch, axial pitch.

Base pitch Tooth pitch relationships Pitch Circular pitch, p

Principal pitches

Arc distance along a specified pitch circle or pitch line between corresponding profiles of adjacent teeth. Transverse circular pitch, pt Circular pitch in the transverse plane. 49 | P a g e

Normal circular pitch, pn, pe Circular pitch in the normal plane, and also the length of the arc along the normal pitch helix between helical teeth or threads. Axial pitch, px Linear pitch in an axial plane and in a pitch surface. In helical gears and worms, axial pitch has the same value at all diameters. In gearing of other types, axial pitch may be confined to the pitch surface and may be a circular measurement. The term axial pitch is preferred to the term linear pitch. The axial pitch of a helical worm and the circular pitch of its worm gear are the same. Normal base pitch, pN, pbn An involute helical gear is the base pitch in the normal plane. It is the normal distance between parallel helical involute surfaces on the plane of action in the normal plane, or is the length of arc on the normal base helix. It is a constant distance in any helical involute gear. Transverse base pitch, pb, pbt In an involute gear, the pitch on the base circle or along the line of action. Corresponding sides of involute gear teeth are parallel curves, and the base pitch is the constant and fundamental 50 | P a g e

distance between them along a common normal in a transverse plane. Diametral pitch (transverse), Pd Ratio of the number of teeth to the standard pitch diameter in inches.

Normal diametral pitch, Pnd Value of diametral pitch in a normal plane of a helical gear or worm.

Angular pitch, θN, τ Angle subtended by the circular pitch, usually expressed in radians. degrees or

radians

Backlash 51 | P a g e

Backlash is the error in motion that occurs when gears change direction. It exists because there is always some gap between the trailing face of the driving tooth and the leading face of the tooth behind it on the driven gear, and that gap must be closed before force can be transferred in the new direction. The term "backlash" can also be used to refer to the size of the gap, not just the phenomenon it causes; thus, one could speak of a pair of gears as having, for example, "0.1 mm of backlash." A pair of gears could be designed to have zero backlash, but this would presuppose perfection in manufacturing, uniform thermal expansion characteristics throughout the system, and no lubricant. Therefore, gear pairs are designed to have some backlash. It is usually provided by reducing the tooth thickness of each gear by half the desired gap distance. In the case of a large gear and a small pinion, however, the backlash is usually taken entirely off the gear and the pinion is given full sized teeth. Backlash can also be provided by moving the gears farther apart. For situations, such as instrumentation and control, where precision is important, backlash can be minimised through one of several techniques. For instance, the gear can be split along a plane perpendicular to the axis, one half fixed to the shaft in the usual manner, the other half placed alongside it, free to rotate about the shaft, but with springs between the two halves providing relative torque between them, so that one achieves, in effect, a single gear with expanding teeth. Another method involves tapering the teeth in the axial direction and providing for the gear to be slid in the axial direction to take up slack. 52 | P a g e

Shifting of gears In some machines (e.g., automobiles) it is necessary to alter the gear ratio to suit the task. There are several methods of accomplishing this. For example: • Manual transmission • Automatic gearbox • Derailleur gears which are actually sprockets in combination with a roller chain • Hub gears (also called epicyclic gearing or sunand-planet gears) There are several outcomes of gear shifting in motor vehicles. In the case of air pollution emissions, there are higher pollutant emissions generated in the lower gears, when the engine is working harder than when higher gears have been attained. In the case of vehicle noise emissions, there are higher sound levels emitted when the vehicle is engaged in lower gears. This fact has been utilized in analyzing vehicle generated sound since the late 1960s, and has been incorporated into the simulation of urban roadway noise and corresponding design of urban noise barriers along roadways. Tooth profile

Profile of a spur gear 53 | P a g e

Undercut A profile is one side of a tooth in a cross section between the outside circle and the root circle. Usually a profile is the curve of intersection of a tooth surface and a plane or surface normal to the pitch surface, such as the transverse, normal, or axial plane. The fillet curve (root fillet) is the concave portion of the tooth profile where it joins the bottom of the tooth space. As mentioned near the beginning of the article, the attainment of a non fluctuating velocity ratio is dependent on the profile of the teeth. Friction and wear between two gears is also dependent on the tooth profile. There are a great many tooth profiles that will give a constant velocity ratio, and in many cases, given an arbitrary tooth shape, it is possible to develop a tooth profile for the mating gear that will give a constant velocity ratio. However, two constant velocity tooth profiles have been by far the most commonly used in modern times. They are the cycloid and the involute. The cycloid was more common until the late 1800s; since then the involute has largely superseded it, particularly in drive train applications. The cycloid is in some ways the more interesting and flexible shape; however the involute has two advantages: it is easier to manufacture, and it permits the center to center spacing of the gears to vary over some range without ruining the constancy of the velocity ratio. Cycloidal gears only work properly if the center spacing is exactly right. Cycloidal gears are still used in mechanical clocks. 54 | P a g e

An undercut is a condition in generated gear teeth when any part of the fillet curve lies inside of a line drawn tangent to the working profile at its point of juncture with the fillet. Undercut may be deliberately introduced to facilitate finishing operations. With undercut the fillet curve intersects the working profile. Without undercut the fillet curve and the working profile have a common tangent. Gear materials

Wooden gears of a historic windmill Numerous nonferrous alloys, cast irons, powdermetallurgy and even plastics are used in the manufacture of gears. However steels are most commonly used because of their high strength to weight ratio and low cost. Plastic is commonly used where cost or weight is a concern. A properly designed plastic gear can replace steel in many cases because it has many desirable properties, including dirt tolerance, low speed meshing, and the ability to "skip" quite well. Manufacturers have employed plastic gears to make consumer items affordable in items like copy machines,

55 | P a g e

optical storage devices, VCRs, cheap dynamos, consumer audio equipment, servo motors, and printers. The module system Countries which have adopted the metric system generally use the module system. As a result, the term module is usually understood to mean the pitch diameter in millimeters divided by the number of teeth. When the module is based upon inch measurements, it is known as the English module to avoid confusion with the metric module. Module is a direct dimension, whereas diametral pitch is an inverse dimension (like "threads per inch"). Thus, if the pitch diameter of a gear is 40 mm and the number of teeth 20, the module is 2, which means that there are 2 mm of pitch diameter for each tooth. Manufacture

.

56 | P a g e

Gear are most commonly produced via hobbing, but they are also shaped, broached, cast, and in the case of plastic gears, injection molded. For metal gears the teeth are usually heat treated to make them hard and more wear resistant while leaving the core soft and tough. For large gears that are prone to warp a quench press is used.

GLEASON NO.610 HYPOID CUTTER MACHINE DESCRIPTION

GENERAL DESCRIPTION-TheNo.610 Universal Hypoid Gear Machine sets new standards in precision high speed roughing and finishing of medium and large non-generated hypoid and spiral bevel gears.The No.610 Machine offers many production and advantages where quantities are insufficient to justify separate roughing and finishing machines.Desinged primarily for use in the 57 | P a g e

truck,tractor and off the road equipment field,the No.610 accomodate gear members upto 20” in diameter and a minimum ratio of 2-1/4-1.maximum whole depth is 1.000”. When the work head is in the horizontal level- load position,the work can be rapidly and conveniently loaded.This feature provides the added benefit of safety.The work spindle is widely separated from the cutter,when the gears are mounted or removed. An overhead tieprovides a fixed relationship between cutter and work.When the work head is raised into the cutting position,the tie is hydraulically clamped.Hydraulic pressure on the clamp is maintained through the cutting cycle. A new hydraulic mechanism rigidly clamps the work spindle to the housing,providing increased rigidity during cutting and loading to improved surface finish and tooth spacing.The clamp is automatically released each time the work is indexed.In additionto the overhead tie and the work spindle clamp,rigidity is assured as the cutting forces are directed vertically downwards against the machine bed.When the work head is raised into cutting position,the rotating cutter contacts the work,so that the blades pass down the tooth slotlocated at the lowest point on the roughed

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gear.This design utilizes the weight of the machine in obtaining maximum rigidity.

Figure 2GLEASON 610 HYPOID CUTTER MACHINE

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CUTTING METHODS1.FORMATE-No generating motion is employed.Roughed out gears are finished accurately and quickly by the single cycle cutter,which rotates uniformly completing one tooth with each revolution.Indexing takes place in the large gap of the cutterand the machine stops automatically at the completion of the last tooth. Roughing is accomplished by a simple depth feed motion of the cutter into the work .indexing takes place when the cutter withdraws from the tooth slot.One tooth slot is roughed with ech revolution of the feed cam.The number of turns of the cutter depends on the depth of the tooth slot. 2.CYCLEX-For low production quantities,the CYCLEX method may be used to rapidly produce FORMATE,hypoid and spiral bevel gears in one operation from the solid. In this form of CYCLEX cutter,the roughing and semi-finishing blades are of gradually increasing height and the two finishing blades are located so that their top and cutting edges are slightly below those of the other blades. During the cutting cycle.the cutter makes a number of revolution for roughing operation,as the cutter is fed into the work by means of cam.Since the 60 | P a g e

finishing blades are set lower than the preceding blades they do not engage the work during this position of the cutting cycle. As the semi-finishing blades are passing through the tooth slot at full roughing depth,the cutter speed is reduced.The cutter is then quickly advanced,and the two finishing blades complete the tooth profile shape. The cutter is then rapidly withdrawn so that the roughing blades do not contact the work. Further withdrawal of the cutter provides clearance necessary for indexing. 3.HELIX FORM-As each blade of a HELIX FORM cutter passes through a tooth space,the cutter is advanced axially then quickly withdrawn, before the following cutter blade enters the tooth space. The combined motion makes the path of the cutter tip tangent to the root plane of the gear being cut. The cutter computes one tooth with each revolution. Indexing takes place when the large gap in the cutter is beside the blank. The HELIX FORM method of cutting produces gear tooth surfaces which are close to the true mathematical conjugacy with the mating pinion. It also minimises development.

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Figure 3CUTTING ON GLEASON NO.610

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Figure 4GLEASON 610

Figure 5CROWN MANUFACTURED ON GLEASON NO.610

63 | P a g e

Figure 6CROWN WHEEL

CUTTING CYCLE AUTOMATIC MODE ROUGHING AND CYCLEX-A blank is mounted on the work spindle and chucked manually. The cycle starts and the dual control buttons are activated, the work head raises to the cutting position, is hydraulically clamped for rigidity and the feed and coolant motor starts. The cutting cycle is controlled by the feed cam which feeds the cutter into the work. Indexing 64 | P a g e

and Chamfering is done during a dwell in the feed cam while the cutter is in the rear position. In the case of CYCLEX cutting set-in takes place at full depth as the two finishing blades pass through the cut. After all the teeth have been cut, the machine automatically stops, the work head unclamps and lowers to the loading positon.

HELIX FORM AND SINGLE CYCLE FINISHING-A roughed gear is mounted on the work spindle and chucked manually. The cycle starts and dual control buttons are activated, the work head raises to the cutting position, is hydraulically clamped for rigidity and the feed and coolant motors start. The cutter completes one tooth with each revolution and indexing take place in the large gap of the cutter. After all the tooth have been cut, the machine automatically stops , the work head unclamps and lowers to the loading position.

CONTROLS1.TEMPERATURE CONTROL LIGHT-The heaters in the hydraulic unit warm the oil when the hydraulic unit is running because the hydrostatic bearings for 65 | P a g e

the cutter spindle require warm oil. The heaters are set at the factory for 150 degrees fahrenheit and the thermostat cuts out when the temperature reaches 90. Light will come on and enable the machine to operate. 2.GROUND LIGHTS-These lights show if a wire has come loose somewhere and is touching the machine. Normally these lights each have a dull pink glow . If some wire becomes grounded, one light will dim and the other will brighten significantly. 3.FILTER LIGHT-If filter becomes clogged , this light will come on. The machine will be inoperative until this filter is cleaned. The machine does not stop in the middle of a cycle , but completes it and will not start the next. 4.AUTOMATIC PRODUCTION COUNTER-This counter is set by the operator to the number of pieces to be cut before the cutter is to be sharpened. 5.SHARPEN CUTTER LIGHT-This light comes on when the machine has cut the amount of blanks preselected on the production counter, signifying that the cutter should be sharpened. 6.MAIN LINE SWITCH-This switch connects and disconnects the machine with the input power supply.

66 | P a g e

7.CUTTER DISCONNECT SWITCH-Before changing a cutter, rotate this handle to the ‘lock’ position, then engage and secure the latch. 8.HYDRAULIC START BUTTON-After the main line switch is closed, depress this button to start the hydraulic, hydrostatic bearing and lubricating pump motors. 9.OVERSIZE BORE LIGHT-When this light is ‘ON’, it indicates the bore of the blank chucked on the arbor is too large and the arbor drawrod has travelled too far. This would make it unsafe to cut the part because there would not be proper workholding pressure . The light must be ’OUT’ to run the machine. 10.HYDRAULIC STOP MACHINE-Depress this button to stop all machine functions. In an emergency, it is more effective to depress this button than the cycle button. 11.GAGE CUTTER LIGHT-When ON , this light indicates that the cutter is at the full depth. This light must be ON when gaging the cutter for length. 12.LOAD POSITION LIGHT- This light is ON ,when the feed cam stop zone is adjacent to the cam follower. To begin an automatic cycle, this light must be ON.

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13.RESET BUTTON-It is necessary to depress this button prior to changing from a manual cycle to an automatic cycle(not vice versa). 14.AUTOMATIC LIGHT-When ON , this light indicates that an automatic machine cycle can be started by depressing the cycle start and the dual control button. 15.WORK SPINDLE LIGHT-This light comes ON when the work spindle revolves 360 degrees. A cam on the work spindle under the index plate contacts the 360 degrees switch. This indicates the work spindle has made one revolution and all the teeth are cut. If the index switch is OFF and the 360 degrees switch is contacted , the machine can be run during setup and not index off this position. 16.CYCLE START BUTTON-This button along with the dual control button is used to jog the machine from the main control panel when a manual mode is selected and remote jog switch is set to RUN. This button is also used to start an automatic cycle along with the dual control button when an automatic mode has been selected. 17.CYCLE STOP BUTTON-The machine can be stopped at any time during an automatic cycle with this button. 18.INDEX SWITCH-When ON , the machine can be run in an automatic cycle. 68 | P a g e

19.BRAKE SELECTOR SWITCH-When OFF, the feed cam and cutter spindle can be rotated by hand. The machine can only run with this switch in the ON position. 20.CUTTING METHOD SELECTOR SWITCH(CYCLEX MACHINE)-Change this switch setting when setting up to cut a new job, different type of cutter than previously used. Set to: a)Finish-for Single Cycle and HELIX FORM cutters, the main motor will run at slow speed. b)Rough-for TRIPLEX cutters, the main motor will run at high speed. c)Cyclex-for CYCLEX cutters , the main motor will run at high speed during the roughing portion of the cycle, and will run at low speed when in finishing portion of the cycle. 21.OUTSIDE CHAMFER SELECTOR SWITCH-This switch is used in setting up the outside chamfering tool and may only be used when in manual cycle mode. When the machine is to be operated in the automatic cycle mode, set this switch to OUT. 22.INSIDE CHAMFER SELECTOR SWITCH-This switch is used in setting up the inside chamfering tool and may only be used when in manual cycle mode. When the machine is to be operated in the automatic cycle mode, set this switch to OUT. 69 | P a g e

23.REMOTE JOG BUTTON-This button is used to enable the feed cam to be easily put on center must be set to JOG for this button to be operative, and will make operator station inoperative when set on JOG as a safety feature. 24.CUTTER ROTATION SWITCH-This switch allows the use of both left hand and right hand cutters . 25.MAIN MOTOR SPEED SWITCH-Set this switch to high speed when roughing and to low speed when finishing. 26.MANUAL CUTTER ROTATION-The cutter spindle may be rotated manually by rotating the upper speed pulley shaft when the brake is off. DO THIS ONLY WHEN THERE IS OIL PRESSURE TO THE HYDROSTATIC SPINDLE. The probable would be either the cutter spindle or its housing would be damaged. 27.DECHUCK CHUCK SELECTOR SWITCH-By turning this switch counter clockwise , the work holding equipment is dechucked. By turning this switch clockwise , the work holding equipment is chucked. 28.DUAL CONTROL BUTTON-This button is used in conjunction with the cycle start buttonto begin either a manual or auto cycle. Both buttons must be depressed at the same time. 70 | P a g e

CUTTER INFORMATION

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Figure 5CUTTER USED ON GLEASON NO.610

TRIPLEX,SINGLE CYCLE,CYCLEX and HELIX FORM cutters from 5”to 18” may be used on this machine. A marking screw , on the face of cutter head ,identifies the blade setup by giving the point width and point diameter of the setup. The blades are held in place in the slots by bolts. The last blade of each set is marked with the following information: the point width, set serial number, ordering number and the blades pressure angles.

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Figure 6CUTTING PROCESS OF CROWN

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Figure 7WORKING OF GLEASON NO.610

SPECIFICATIONS

GLEASON NO.610 HYPOID GEAR MACHINE A)CAPACITY:METRIC

ENGLISH

1.OUTSIDE CONE DISTANCE a)maximum

10”

254mm

b)minimum

2.75”

70mm

2.MAXIMUM GEAR PITCH DIAMETER 3.CUTTER DIAMETERS

20”

508mm

9” TO 18”

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4.WHOLE DEPTH 24.4mm

1.000”

5.ROOT ANGLE 6.FACE WIDTH

60 to 80 degrees 3”

7.EXTREME RATIO(MINIMUM)

76mm 2-1/4 to 1

8.NUMBER OF TEETH

20 to 75

B)WORK SPINDLE:1.DIAMETER OF TAPER HOLE AT LARGE END

3-27/64”

2.TAPER PER FOOT

1/2"

3.DEPTH OF TAPER

5/8”

C)SPEEDS AND FEEDS:1.CUTTER SPEED(feed per minute)FOR ROUGHING 8’-200’ 24m-61m 2.FEEDS(seconds per tooth)FOR ROUGHING

3-35

3.CUTTER SPEED(feed per minute)FOR FINISHING 61m

30’-100’

4.FEEDS(seconds per tooth)FOR FINISHING

3-9

D)ELECTRICAL EQUIPMENT:-

60Hz

1.MAIN MOTOR 2 SPEED(10HP/5HP) 1500/750 RPM

1800/900 RPM

2.HYDRAULIC MOTOR 3.COOLANT MOTOR 3000 RPM

24m-

50Hz

7-1/2HP1800 RPM 1500 RPM 2HP 3600 RPM

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4.CHIP CONVEYOR

1/4HP 1800 RPM

1500 RPM

5.HYDROSTATIC SPINDLE

1-1/2HP 1800 RPM 1500 RPM

E)MISCELLANEOUS:1.FLOOR SPACE 3000cm*2200cm

118”*86-1/2”

2.HEIGHT

70”

1780mm

a)net

16,500lbs

7,483kg

b) gross

17,500lbs

7,937kg

3.WEIGHT

TYPES OF CROWN WHEEL AND PINION MANUFACTURED AT TATA MOTORS AND THEIR PER DAY OUTPUT

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TYPE

OUTPUT

45/7

240

41/7

255

48/7

210

35/9

270

41/6

240

Graph showing per day output

JOB SPECIFICATION:-20Mn CR-5 CONSTITUENT S

PERCENTAGE

Carbon

0.17-0.22

Silicon

0.15-0.35

Manganese

1.0-1.4

Chromium

1.0-1.3 77 | P a g e

Iron

Rest

IMPROVING THE PRODUCTIVITY Metal cutting is the outwardly simple process of removing metal on a work piece in order to get a desired shape by using a tool, either by rotating the workpiece (as in a lathe) or by rotating the tool (as in a drilling machine). But behind this simple process lie numerous parameters that play their roles, from a small to a big way, in deciding many things in the act of metal cutting, including the speed of doing the job, the quality and accuracy of the finish, the life of the tool, the cost of production, and so on. Some parameters involved in the metal cutting process are in fact closely related with some other parameters in the metal cutting process; playing with one will have an influencing effect on another. Thus, even after several years of experience, process planning engineers may find difficulty in confidently declaring themselves as experts in metal cutting! . 78 | P a g e

1) Material machinability: The machinability of a material decides how easy or difficult it is to cut it. The material’s hardness is one factor that has a strong influence on the machinabilty. Though a general statement like a soft material is easier to cut than a harder material is true to a large extent, it is not as simple as that. The ductility of a material also plays a huge role. 2) Cutting Tool Material: In metal cutting, High Speed steel and Carbide are two major tool materials widely used. Ceramic tools and CBN (Cubic Boron Nitride) are the other tool materials used for machining very tough and hard materials. A tool’s hardness, strength, wear resistance, and thermal stability are the characteristics that decide how fast the tool can cut efficiently on a job. 3) Cutting speed and spindle speed: Cutting speed is the relative speed at which the tool passes through the work material and removes metal. It is normally expressed in meters per minute (or feet per inch in British units). It has to do with the speed of rotation of the workpiece or the tool, as the case may be. The higher the cutting speed, the better the productivity. For every work material and tool material combo, there is always an ideal cutting speed available, and the tool manufacturers generally give the guidelines for it. Spindle speed: Spindle speed is expressed in RPM (revolutions per minute). It is derived based on the cutting speed and the work diameter cut (in case of turning/ boring) or tool diameter (in case of drilling/ 79 | P a g e

milling etc). If V is the cutting speed and D is the diameter of cutting, then Spindle speed N = V /(Pi x D) 4) Depth of cut: It indicates how much the tool digs into the component (in mm) to remove material in the current pass. 5) Feed rate: The relative speed at which the tool is linearly traversed over the workpiece to remove the material. In case of rotating tools with multiple cutting teeth (like a milling cutter), the feed rate is first reckoned in terms of “feed per tooth,” expressed in millimeter (mm/tooth). At the next stage, it is “feed per revolution” (mm/rev). In case of lathe operations, it is feed per revolution that states how much a tool advances in one revolution of workpiece. In case of milling, feed per revolution is nothing but feed per tooth multiplied by the number of teeth in the cutter. To actually calculate the time taken for cutting a job, it is “feed per minute” (in mm/min) that is useful. Feed per minute is nothing but feed per revolution multiplied by RPM of the spindle. 6) Tool geometry: For the tool to effectively dig into the component to remove material most efficiently without rubbing, the cutting tool tip is normally ground to different angles (known as rake angle, clearance angles, relief angle, approach angle, etc). The role played by these angles in a tool geometry is a vast subject in itself. 7) Coolant: 80 | P a g e

To take away the heat produced in cutting and also to act as a lubricant in cutting to reduce tool wear, coolants are used in metal cutting. Coolants can range from cutting oils, water soluble oils, oil-water spray, and so on. 8) Machine/ Spindle Power: In the metal cutting machine, adequate power should be available to provide the drives to the spindles and also to provide feed movement to the tool to remove the material. The power required for cutting is based on the Metal removal rate – the rate of metal removed in a given time, generally expressed in cubic centimeters per minute, which depends on work material, tool material, the cutting speed, depth of cut, and feed rate. 9) Rigidity of machine: The rigidity of the machine is based on the design and construction of the machine, the age and extent of usage of the machine, the types of bearings used, the type of construction of slide ways, and the type of drive provided to the slides all play a role in the machining of components and getting the desired accuracies, finish, and speed of production. Thus, in getting a component finished out of a metal cutting machine at the best possible time within the desired levels of accuracy, tolerances, and surface finish, some or all the above parameters play their roles. As already mentioned in the beginning, each of the parameters can create a positive or negative impact on other parameters, and adjustments and compromises are to be made to arrive at the best metal cutting solution for a given job. 81 | P a g e

10)Process Cycle The time required to produce a given quantity of parts includes the initial setup time and the cycle time for each part. The setup time is composed of the time to setup the milling machine, plan the tool movements (whether performed manually or by machine), and install the fixture device into the milling machine. The cycle time can be divided into the following four times:

1.

2.

3.

4.

Load/Unload time - The time required to load the workpiece into the milling machine and secure it to the fixture, as well as the time to unload the finished part. The load time can depend on the size, weight, and complexity of the workpiece, as well as the type of fixture. Cut time - The time required for the cutter to make all the necessary cuts in the workpiece for each operation. The cut time for any given operation is calculated by dividing the total cut length for that operation by the feed rate, which is the speed of the cutter relative to the workpiece. Idle time - Also referred to as non-productive time, this is the time required for any tasks that occur during the process cycle that do not engage the workpiece and therefore remove material. This idle time includes the tool approaching and retracting from the workpiece, tool movements between features, adjusting machine settings, and changing tools. Tool replacement time - The time required to replace a tool that has exceeded its lifetime and therefore 82 | P a g e

become to worn to cut effectively. This time is typically not performed in every cycle, but rather only after the lifetime of the tool has been reached. In determining the cycle time, the tool replacement time is adjusted for the production of a single part by multiplying by the frequency of a tool replacement, which is the cut time divided by the tool lifetime.

My Role As a summer trainee, I was placed in the TRANSMISSION DEPARTMENT & was given the task of studying ,observing and analyzing the work being done in the TRANSMISSION FACTORY and to explore the possibilities of improving the productivity of GLEASON NO.610 HYPOID CUTTER MACHINE which was being used in CROWN manufacturing process. Thus,for increasing the productivity of the process being carried out at the TRANSMISSION FACTORY , I have sorted out following points:1. Change in the CROWN WHEEL material. 83 | P a g e

2. Change in the CUTTING TOOL material. 3. Change in the cutting speed and spindle speed. 4. Change in the cutting depth. 5. Change in the feed rate. 6. Change in the cutting tool geometry. 7. Cutting –with and without use of coolant. 8. Change in machine power. 9. Effecting the rigidity of machine. 10.Decreasing the process cycle time like: • Loading and unloading time of crown wheel • Cycle time • Idle time • Cutting Tool replacement time • Change in the machine setting Now we will have a look at each of the points as given above on the productivity of the machine.

1.

Change in the CROWN WHEEL material-The CROWN wheel material used at the present is 20Mn CR-5. But there are other options available for the CROWN wheel material that can be used such as 16MnCr5 and 42CrMo4v can used. The advantages of these materials over 20Mn Cr5 have been shown graphically as below:

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2.

Change in the CUTTING TOOL material-HSS is the cutting tool material that is widely used nowadays as a cutting tool material. But cutting tools of carbide ,cubic boron nitride(CBN) which has hardness of 50 Rc and cutting speed of 30310m/min etc.could be used which will be more advantageous and productive as a cutting tool material.HSS can also be used profitably by coating it with various materials like applying a copper coating or a TiN(Titanium Nitrate) coating on the cutting tool. The cutting speed and tool life of an cutting tool can be related by the TAYLOR’s equation as below: VTn=C

Where V=cutting speed in m/min T=tool life in min. C=cutting speed for a tool life of 1min.

n=Taylor’s exponent

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Tool material

Typical ‘n’ value

HSS

0.08-0.2

Cast alloy

0.1-0.15

Carbides

0.2-0.5

Ceramics

0.5-0.7

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Comparasion of these materials in the process of cutting can be viewed pictorially as below:

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3.

Change in the cutting speed and spindle speed-This option is presently not possible in the case of GLEASON No.610 Machine because of the rigidity of the machine. The GLEASON No.610 uses a pulley based system for the energy conversion , that is electrical energy to mechanical energy to supply rotational motion to the cutting tool which is as shown:

Driver pulley

Belt Idler pulley

Driven pulley

Fig.Pulley system used in GLEASON No.610 102 | P a g e

4.

Change in the cutting depth-This is another method to mprove the productivity and efficiency of the machine. Presently the machine works on the principle of indexing and renders a single cut each time. If we could decrease the cutting depth than it is possible that it would less strain on the cutter and also increase the cutter life which is presently changed after manufacturing around 350-

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400 pieces.

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Fig.vectorial representation of forces

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5. 6.

Change in the feed rate-This option is also not available with this machine due to its rigidity. Change in the cutting tool geometry- Cutting time can be significantly reduced by changing the geometry of the cutting tool.The various shapes and studies related to these shapes have been shown diagrammatically as below:

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Fig.shape of a cutter

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7.Cutting –with and without use of coolantPresently coolant is used in large scale in the process of cutting. This cause wide loss in the form of economic losses as the coolant oil that is recovered afterwards is very less in comparasion to the quantity that is being used. To minimize these losses techniques like dry cutting and of ice cooled cutters are used. In dry cutting process no coolant is used. This causes decrease in economic expenditure whereas in ice cutting technology the cutter is internally cooled which causes very less or minimal usage of coolant.Fette is now introducing to the world the idea of internally cooled gear cutters. The ICE cutters can be used for either wet or dry cutting. Although this tool is currently under study , there are enough benefits to introduce the product and concept to the market. The concept is quiet simple ; having coolant orifices projected at each cutting tooth with a central coolant line to keep the core temperature constant. The tool can operate in severe applications with outstanding results. One early test has shown a 40 percent increase in tool life on a test gear. This is quiet an exciting result , but the true savings be in the elimination of the chip welding to the part.

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8.Change in machine power-No change in power supplied to the machine is possible due to the rigidity of the machine. 9.Effecting the rigidity of machine-As there is minimal of option available for changing the rigidity of the machine as the machine mostly works on the mechanical process. So there is no space available for this option to come into effect. 10.Decreasing the process cycle time like: • Loading and unloading time of crown wheel • Cycle time • Idle time • Cutting Tool replacement time • Change in the machine setting I have calculated the production figures and the problems that occurred during one week of the production in all the shifts A,B and C and found out the following result: DATE

CROWN SHIFT type A

SHIFT B

SHIFT C

CAUSE

5/7/10

45/7

70

50

58

Cutter change in shift B

6/7/10

45/7

91

50

31

Unavailabilit y of material in shift B

7/7/10

45/7

32

13

0

Cutter changed in 114 | P a g e

shift A 8/7/10

41/6

2

60

55

Setting of machine changed

9/7/10

41/7

50

41

3

Chamfer tool breaks three times in shift C

10/7/10

41/7

23

30

65

House keeping done in shift B

11/7/10

41/7

70

70

65

Cutter changed in shift B and hydraulic oil filled in shift C

12/7/10

41/7

70

70

60

Cutter changed in shift B and hydraulic oil filled in shift C

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The cycle time for both rougher and finisher machine is around 4.2 minutes. That is both rougher and finisher finish one crown wheel in this estimated time. The cycle time of rougher and finisher also includes the loading and unloading time taken by the operator respectively, which is mostly around 1-1.5 minutes. Thus , the total estimated cycle time is approximately 5-5.5 minutes. Thus by minimizing the movement of operator the cycle time can be significantly brought down to 4.5-5 minutes. This reduction will have a positive impact on productivity. Many a times it is seen that the bottom neck machine which is the rougher machine is idle due to inefficiency of the operator and his extra movements. This time can also be significantly reduced if the operator gets the material directly on his working area. Presently the operator has to himself put the material on the conveyer belt located at a distance of about 150 metres. If this distance is reduced than the idle time of the bottom neck rougher machine will almost be negligible. There is also significant loss of time in the cutter changing and machine setting changing process. This time needs to be reduced.

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