39178405 summer training report at tata motors

8/6/2019 39178405 Summer Training Report at TATA MOTORS

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PROJECT REPORTON SUMMER TRAINING INTATA MOTORS, LUCKNOW

SUBMITTED BYSUDHANSHU

MECHANICAL ENGINEERING DEPARTMENT,SRMS CET,BAREILLY.


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CONTENTS

Declaration

Acknowledgement

TATA MOTORS- An Introduction

TATA Journey-Year by year

Organisation Structure

TATA MOTORS-Lucknow Plant

What is a CROWN wheel

Gears Manufacturing and its uses

Detailed Study of GLEASON NO.610

Productivity Improvement

My Role

Overview


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DECLARATION

I hereby declare that the project work entitled: 1.PRODUCTIVITY IMPROVEMENT OF GLEASON NO.610

HYPOID GEAR MACHINE is an authentic record of myown work carried out at TATA MOTORS, (CX-CWP) ,

LUCKNOW as

requirements of four week summer project , under theguidance of MR.TANUJ SONKER

SUDHANSHU B.TECH.2 nd 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 RAKHRACX-CWP MANAGER,HR


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ACKNOWLEDGEMENT

Industrial training is a crucial period in engineeringcurriculum since it exposes a student to the real worldwhich he or she is going to enter after the completion of

the graduation. This is the period during which anengineer 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 TATAMOTORS, LUCKNOW one of the most renowned

organization of India. I would like to express my deepgratitude 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 andsupportive. Last but not the least I would like to thank

MS. JASNEET RAKHRA (Manager HR) for providing methe opportunity to add a new dimension to my

personality. I will remain indebted to her for hergenerous ways of dealing with industrial trainees.

SUDHANSHU ,B.Tech. 2nd year,SRMS CET,Bareilly


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TATA MOTORS

Tata Motors is a part of the Tata Group manages itsshare-holding through Tata Sons . The company wasestablished in 1935 as a locomotive manufacturing unitand later expanded its operations to commercial vehiclesector in 1954 after forming a joint venture with Daimler-

Benz AG of Germany. Despite the success of itscommercial vehicles, Tata realized his company had todiversify and he began to look at other products. Basedon consumer demand, he decided that building a smallcar would be the most practical new venture. So in 1998it launched Tata Indica , India's first fully indigenouspassenger car. Designed to be inexpensive and simple tobuild and maintain, the Indica became a hit in the Indianmarket. It was also exported to Europe, especially the UKand Italy. In 2004 it acquired Tata Daewoo CommercialVehicle, and in late 2005 it acquired 21% of Aragonese Hispano Carrocera giving it controlling rights of thecompany. It has formed a joint venture with Marcopolo of Brazil, and introduced low-floor buses in the IndianMarket. Recently, it has acquired British Jaguar LandRover (JLR), which includes the Daimler and Lanchesterbrand names.


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TATA JOURNEY YEAR BY YEAR:

1868 : Jamsetji Nusserwanji Tata starts a privatetrading firm, laying the foundation of the TATAgroup.

1874: The Central India Spinning, Weaving andManufacturing Company is set up, marking theGroup's entry into textiles.

1902: The Indian Hotels Company is incorporatedto 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 TataSteel) is established to set up India's first iron andsteel plant in Jamshedpur. The plant startedproduction 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 establishedin Bangalore to serve as a centre for advancedlearning.

1912: Tata Steel introduces eight-hour workingdays, well before such a system was implemented bylaw in much of the West.

1917 : The Tatas enter the consumer goods industry,with the Tata Oil Mills Company being established tomake soaps, detergents and cooking oils.

1932: Tata Airlines, a division of Tata Sons, isestablished, opening up the aviation sector in India.

1939: Tata Chemicals, now the largest producer of soda ash in the country, is established.


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1945: Tata Engineering and Locomotive Company(renamed Tata Motors in 2003) is established tomanufacture locomotive and engineering products.

Tata Industries is created for the promotion and

development of hi-tech industries. 1952: Jawaharlal Nehru, India's first PrimeMinister, requests the Group to manufacturecosmetics in India, leading to the setting up of Lakme.

1954: India's major marketing, engineering andmanufacturing organization, Voltas, is established.

1962: Tata Finlay (now Tata Tea), one of the largesttea producers, is established. Tata Exports isestablished. Today the company, renamed TataInternational, is one of the leading export houses inIndia.

1968: Tata Consultancy Services (TCS), India's firstsoftware services company, is established as adivision of Tata Sons.

1970: Tata McGraw-Hill Publishing Company iscreated to publish educational and technical books.

Tata Economic Consultancy Services is set up toprovide services in the field of industrial, marketing,statistical and techno-economic research andconsultancy.

1984: Titan Industries - a joint venture between the Tata Group and the Tamil Nadu IndustrialDevelopment Corporation (TIDCO) - is set up tomanufacture watches.

1991: Tata Motors rolls out its millionth vehicle.

(The two-million mark was reached in 1998 and thethird million in 2003.) 1995: Tata Quality Management Services institutesthe JRD QV Award, modelled on the MalcolmBaldrige National Quality Value Award of the UnitedStates, laying the foundation of the Tata BusinessExcellence Model.


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1996: Tata Tele services (TTSL) is established tospearhead the Group's foray into the telecom sector.

1998: Tata Indica - India's first indigenouslydesigned and manufactured car is launched by

Tata Motors, spearheading the Group's entry intothe passenger car segment. 1999: The new Tata Group corporate mark and logoare launched.

2000: Tata Tea acquires the Tetley Group, UK. Thisis the first major acquisition of an internationalbrand by an Indian business group.

2001: Tata-AIG - a joint venture between the TataGroup and American International Group Inc (AIG) -marks the Tata re-entry into insurance. (TheGroup's insurance company, New India Assurance,was nationalized in 1956). The Tata Group ExecutiveOffice (GEO) is set up to design and implementchange in the Tata Group and to provide long-termdirection.

2002: The Tata Group acquires a controlling stakein VSNL, India's leading internationaltelecommunications service provider TataConsultancy Services (TCS) becomes the first Indiansoftware company to cross one billion dollars inrevenues. Titan launches Edge, the slimmest watchin the world. Idea Cellular, the cellular service bornof a tie-up involving the Tata Group, the Birla Groupand AT&T, is launched. Tata Indicom, the umbrellabrand for telecom services from the Tata Teleservices stable, starts operations.

2003: Tata Motors launches City Rover Indicasfashioned for the European market. The first batchof City Rovers rolled out from the Tata Motors stablein Pune on September 16, 2003.

2004: Tata Motors acquires the heavy vehicles unitof Daewoo Motors, South Korea. TCS goes public in

July 2004 in the largest private sector initial public


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offering (IPO) in the Indian market, raising nearly$1.2 billion.

2005: Tata Steel acquires Singapore-based steelcompany NatSteel by subscribing to 100 per cent

equity of its subsidiary, NatSteel Asia. 2009: Tata Motors launched Tata Nano, worldscheapest family car.


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TATA MOTORS-LUCKNOWPLANT

There are three divisions in TATA Motors, Lucknow:

Training division

The Training Center at the Lucknow plant aims atproviding high quality Apprenticeship Training. Inaddition, the Centre provides both internal and externaltraining, support to operators, supervisors and managersin areas like special skills and technology, safety,

personnel practices etc. The Lucknow plant, after a major restructuring exercise,executed a smooth transition from function-based toprocess-based structure. By this structure, processowners are required to meet stretched targets, and inorder to do so, are required to encourage individuallearning and development of employees. A structuredprocess is being followed to establish and reinforce anenvironment that encourages innovation.

Assembly division

Lucknow Plant started with the assembly of MediumCommercial Vehicles (MCVs) to meet the demand in theNorthern Indian market. However, in 1995, the unitstarted manufacturing bus chassis of Light CommercialVehicles (LCVs) and SUMOs. The facilities for

manufacturing the spare parts were set up and startedsupply 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 manufacturingfacility, the Plant also started assembly of G-16 Gear Boxto meet in-house requirement for SUMO vehicles in the

year 2000.Now TATA Motors Lucknow has started


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assembling of CNG MCV`s to meet the consumersdemand. TATA Motors is also producing Rear EngineCV`s.

Manufacturing DivisionIn TATA Motors Lucknow Crown Wheel and Pinion aremanufactured by various gear cutting process.Machining (grinding and heat treatment) of Gear Boxparts is also done here. These gears are used in gearboxes or as spares. Now TATA Motors is assembling GearBox of ACE (Newly launched small CV) in Lucknowitself. The Manufacturing unit of Tata Motors at Lucknow

is the latest manufacturing facility of Tata motors and islocated towards East of Lucknow plant .


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WHAT I S A CROWN WH EE

A crown wheel is a type of circular gear wheel with teeththat extend perpendicular to the base. While a traditionalgear features teeth that sit parallel to the edges of thebase, a crown wheel's teeth sit on the surface of thewheel, forming a crown-like shape. Crown wheels areconsidered a type of beveled gear, which is the generalterm for all gears with teeth located on the surface of thewheel rather than the edges. The teeth on a beveledwheel may be placed at any angle to the surface, while

the crown wheel teeth are distinguished by the fact thatthey are positioned at a 90-degree angle to the gear.

These gears are often used along with a pinion to rotate amechanical device. They are used in many automotiveapplications, as well as in industrial and manufacturingequipment. Many vehicles rely on crown wheel andpinion systems to create the vehicle's forward motion, orto 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 wheelsmesh at an angle with pinions or other gears. Ratherthan being located in the same plane, the two gears arepositioned at an angle, or perpendicular to one another.

This allows the teeth in the gears to fit together andtransfer motion or force between various operatingcomponents.

There are three basic types of crown wheel for buyers tochoose from. Standard models have squared-off teeththat sit parallel to the top of the gear. This design resultsin a high level of vibration and noise when these gearsare used. Spiral gears use teeth with angled edges,resulting in quieter performance, but also in faster wear


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a nd o a in n a n poid o n h l are s i ilart o s pi ra l m od e ls, b t w or k wit h a n o set pinion t o createbetter stre n t h a nd perf orma n ce.

Users s ho ld se lect cr own wh ee l gears carefu ll t o matc h t h e n ee ds of t h e a ppli cat ion . Th e s i e a nd patter n of t h eteet h on t h e w h ee l must f it e xact l wit h a ll a djace n t gearsor pinion s. It is a ls o h e lp fu l t o choo se hi gh er qua litygears, because are m ore prec ise l y ma de t o m ini m i enoi se a nd vib rat ion . Th e mater ia l use d t o ma n ufacturet h ese gears is a ls o a cr it ica l fact or. If on e gear is h ar dert h a n t h e a djace n t on e, it w ill ra pidl y wear away t h e e dgesof t h e s ofter gear, s ho rte nin g t h e life of t h e in sta llat ion .

F i ur 1 SE F CROWN AND PI NION IN ANDIFF E R E NT IA OF AN A TOMO BI E


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GEARS

A gea r is a rotat in g mac hin e part h a vin g cut teeth , orcogs , w hi ch mesh wit h a no t h er t oo t h ed part in order t o tra n sm it t orque . T wo or m ore gears w orkin g in ta nd emare ca lled a transmission a nd ca n p rod uce a mec h a ni ca l

a dva n tage t h roug h a gear rat io a nd t h us may becon s id ere d a s im ple mac hin e. Geare d devices ca n ch a n get h e s pee d , mag ni tu de, a nd di rect ion of a po wer s ource .

Th e m ost c omm on s ituat ion is f or a gear t o mes h wit h a no t h er gear, ho we ver a gear ca n a ls o mes h a non-rotat in g t oo t h e d part, ca lled a rac k , t h ere b y p rod uc in gtra n s lat ion in stea d of r otat ion .

Th e gears in a tra n sm iss ion are a n a logous t o t h e wh ee ls

in a pu lley . A n a dva n tage of gears is t h at t h e teet h of agear p re ven t s lippin g.

Wh en tw o gears of u n equa l n um ber of teet h arecom bin ed a mec h a ni ca l a dv a n tage is prod uce d , w it h bo t h t h e rotat ion a l s pee ds a nd t h e t orques of t h e tw o gearsdi ffer in g in a s im ple re lat ion s hip .

In tra n sm iss ion s w hi ch offer mu lt ipl e gear rat ios, suc h

as bi cyc les a nd cars, t h e term gea r , as in f irst gear , referst o a gear rat io rat h er t h a n a n actua l ph ys ica l gear. Th eterm is use d t o descr ibe s im ilar devices e ven wh en gearrat io is con t in u ous rat h er t h a n discrete , or w h en t h edevice do es no t actua ll y c on ta in a n y gears, as in acon t in u ous l y var ia ble tra n sm iss ion .


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Comparison with other drive mechanisms

The definite velocity ratio which results from having teethgives gears an advantage over other drives (such astraction drives and V-belts ) in precision machines suchas watches that depend upon an exact velocity ratio. Incases where driver and follower are in close proximitygears also have an advantage over other drives in thereduced number of parts required; the downside is thatgears are more expensive to manufacture and theirlubrication requirements may impose a higher operating

cost. The automobile transmission allows selection betweengears to give various mechanical advantages.


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TY PES

1 Ext e r al vs. i t e r al gea r s

In ter n a l gear

An external gear is on e w it h t h e teet h f orme d on t h eouter surface of a cy lind er or c on e. C onv erse l y, a n internal gear is on e w it h t h e teet h f orme d on t h e inn ersurface of a cy lind er or c on e. F or beve l gears, a n in ter n a l gear is on e w it h t h e pi tc h a n gle e xcee din g 90 degrees.In ter n a l gears do no t cause di rect ion re versa l.

2 .S ur

Sp ur gear

Spu r gears or straight-c u t gears are t h e s im plest ty pe of gear. Th ey c on s ist of a cy lind er or di s k , a nd wit h t h eteet h project in g ra di a ll y, a nd a lt ho ug h t h ey are no tstra igh t-s ide d in f orm, t h e e dge of eac h t oo t h t h us isstra igh t a nd a lign ed para lle l t o t h e a xis of r otat ion . Th ese


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gears ca n be mes h ed t oget h er c orrect l y onl y if t h ey aref itte d t o para lle l a xles.

3 . H el i al

He lica l gears Top para lle l con f igurat ion Bott om: cr osse d con f igurat ion

H elical gears offer a ref in eme n t over s pur gears. Th elea din g e dges of t h e teet h are no t para lle l t o t h e a xis of rotat ion , but are set at a n a n gle. Sin ce t h e gear is cur ved ,t hi s a n glin g causes t h e t oo t h s h a pe t o be a segme n t of ah e lix. He lica l gears ca n be mes h ed in a p arallel or

crossed or ien tat ion s. Th e f ormer refers t o wh en t h es h afts are para lle l t o eac h ot h er; t hi s is t h e m ostcomm on or ien tat ion . I n t h e latter, t h e s h afts are non-para lle l.

Th e a n gled teet h en gage m ore gra dua ll y t h a n do s purgear teet h caus in g t h em t o ru n m ore sm oo t hl y a nd qu iet l y. W it h para lle l h e lica l gears, eac h pa ir of teet h f irstma ke c on tact at a s in gle poin t at on e s id e of t h e gear

wh ee l; a m ovin g cur ve of c on tact t h en gr ows gra dua ll yacr oss t h e t oo t h face t o a ma ximum t h en rece des u n t il t h e teet h brea k con tact at a s in gle poin t on t h e oppo s ites ide. I n s pur gears teet h su dd enl y meet at a lin e c on tactacr oss t h e ir e n t ire w id t h caus in g stress a nd noi se. Sp urgears ma ke a c h aracter ist ic w hin e at hi gh s pee ds a nd ca n no t ta ke as muc h t orque as h e lica l gears. W h ereas


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spur gears are used for low speed applications and thosesituations where noise control is not a problem, the useof helical gears is indicated when the application involveshigh speeds, large power transmission, or where noise

abatement is important. The speed is considered to behigh when the pitch line velocity exceeds 25 m/s.

A disadvantage of helical gears is a resultant thrust alongthe axis of the gear, which needs to be accommodated byappropriate thrust bearings , and a greater degree of sliding friction between the meshing teeth, oftenaddressed with additives in the lubricant.

For a crossed configuration the gears must have thesame pressure angle and normal pitch, however the helixangle and handedness can be different. The relationshipbetween the two shafts is actually defined by the helixangle(s) of the two shafts and the handedness, asdefined:

E = 1 + 2 for gears of the same handedness

E = 1 2 for gears of opposite handedness

Where is the helix angle for the gear. The crossedconfiguration is less mechanically sound because there isonly a point contact between the gears, whereas in theparallel configuration there is a line contact.

Quite commonly helical gears are used with the helixangle of one having the negative of the helix angle of theother; such a pair might also be referred to as having aright-handed helix and a left-handed helix of equalangles. The two equal but opposite angles add to zero:the angle between shafts is zero that is, the shafts are pa r allel . Where the sum or the difference (as described inthe equations above) is not zero the shafts are c r ss ed .


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F or s h afts crossed at r igh t a n gles t h e h e lix a n gles are of t h e same h a nd because t h ey must a dd t o 90 degrees.

4 . D ou le h el i al

Dou ble h e lica l gears

Dou ble h e lica l gears, or herringbone gear , overc ome t h ep robl em of a xia l t h rust p rese n te d b y "s in gle" h e lica l gearsb y h a vin g tw o sets of teet h t h at are set in a V s h a pe.Eac h gear in a do u ble h e lica l gear ca n be t ho ug h t of astw o sta nd ar d m irr or image h e lica l gears stac ke d . Thi sca n ce ls out t h e t h rust s in ce eac h h a lf of t h e gear t h rusts

in t h e oppo s ite di rect ion . D ou bl e h e lica l gears are m oredi ff icu lt t o ma n ufacture due t o t h e ir m ore c om pli cate d s h a pe.

F or eac h po ss ibl e di rect ion of r otat ion , t h ere are tw o po ss ibl e arra n geme n ts of tw o oppo s ite l y-o r ien te d h e lica l gears or gear faces. I n on e po ss ible or ien tat ion , t h eh e lica l gear faces are or ien te d s o t h at t h e a xia l f orcege n erate d b y eac h is in t h e a xia l di rect ion away fr om t h e

ce n ter of t h e gear; t hi s arra n geme n t is u n sta ble. I n t h esec ond po ss ibl e or ien tat ion , w hi ch is sta ble, t h e h e lica l gear faces are or ien te d s o t h at eac h a xia l f orce is t owar d t h e m id-lin e of t h e gear. I n bo t h arra n geme n ts, w h en t h egears are a lign ed correct l y, t h e t ota l (or net ) a xia l f orce on eac h gear is zer o. If t h e gears b ec ome m isa lign ed in t h ea xia l di rect ion , t h e u n sta ble arra n geme n t ge n erates a n et


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f orce f or di sassem bl y of t h e gear tra in , w hil e t h e sta blearra n geme n t ge n erates a n et c orrect ive f orce. If t h edi rect ion of r otat ion is re verse d , t h e di rect ion of t h e a xia l t h rusts is re verse d , a sta ble c on f igurat ion bec omes

u n sta ble, a nd v ice v ersa .S ta ble do u ble h e lica l gears ca n be di rect l y in terc h a n ge d wit h s pur gears w it ho ut a n y n ee d f or di ffere n t bear in gs.

5 . Be v el

Be ve l gear

A beve l gear is s h a ped lik e a r igh t c ircu lar c on e wit h m ost of its t ip cut off. W h en tw o beve l gears mes h t h e irimag in ary vert ices must occu p y t h e same poin t. Th e irs h aft a xes a ls o in tersect at t hi s poin t, f orm in g a n ar bi trary non- stra igh t a n gle betwee n t h e s h afts. Th ea n gle betwee n t h e s h afts ca n b e a n yt hin g e xce p t zer o or180 degrees. Be ve l gears w it h equa l n um bers of teet h a nd s h aft a xes at 90 degrees are ca lled miter gears .

Th e teet h of a beve l gear may be stra igh t-cut as w it h s pur gears, or t h ey may be cut in a var iety of ot h ers h a pes. Sp iral be v el gear teet h are cur ved a lon g t h e

t oo t h s len gt h a nd set at a n a n gle, a n a logous l y t o t h e wayh e lica l gear teet h are set at a n a n gle c om pare d t o s purgear teet h . Zerol be v el gears h a ve teet h whi ch are cur ved a lon g t h e ir len gt h , but no t a n gled . Spi ra l beve l gearsh a ve t h e same a dva n tages a nd disa dva n tages re lat ive t o t h e ir stra igh t -cut c ous in s as h e lica l gears do t o s purgears. S tra igh t beve l gears are ge n era ll y use d onl y at


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s pee ds be low 5 m/s ( 1000 ft/m in) , or, f or sma ll gears,1000 r. p .m.

6 . Hy oi

Hy poid gear

Hy poid gears resem bl e s pi ra l beve l gears e xce p t t h e s h afta xes do no t in tersect. Th e pi tc h surfaces a pp ear c oni ca l but, t o com pen sate f or t h e offset s h aft, are in facth y per boloid s of re volut ion . Hy poid gears are a lm osta lways des ign ed t o op erate w it h s h afts at 90 degrees.De pendin g on whi ch s ide t h e s h aft is offset t o, re lat ive t o t h e a n glin g of t h e teet h , c on tact betwee n h y poid gearteet h may be e ven sm oo t h er a nd m ore gra dua l t h a n with s pi ra l beve l gear teet h . A ls o, t h e pinion ca n be des ign ed wit h fewer teet h t h a n a s pi ra l beve l pinion , w it h t h eresu lt t h at gear rat ios of 60 :1 a nd hi gh er are feas ibl eus in g a s in gle set of h y poid gears. Thi s sty le of gear ism ost c omm onl y f ou nd in mec h ani ca l di ffere n t ia ls.


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7 . C ro

Cr own gear

C rown gears or contrate gears are a part icu lar f orm of beve l gear w ho se teet h project at r igh t a n gles t o t h e pl a n eof t h e w h ee l; in t h e ir or ien tat ion t h e teet h resem ble t h epoin ts on a cr own . A cr own gear ca n onl y mes h accurate l y w it h a no t h er beve l gear, a lt ho ug h cr own gearsare s omet imes see n mes hin g w it h s pur gears. A cr own gear is a ls o s omet imes mes h ed wit h a n esca peme n t suc h as f ou nd in mec h a ni ca l clocks.

8 . W or

Worm gear

W orm gears resem ble screws . A w orm gear is usua ll ymes h ed wit h a n or din ary lookin g, di s k- s h a ped gear,whi ch is ca lled t h e gear , wheel , or worm wheel .


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Worm-and-gear sets are a simple and compact way toachieve a high torque, low speed gear ratio. For example,helical gears are normally limited to gear ratios of lessthan 10:1 while worm-and-gear sets vary from 10:1 to

500:1. A disadvantage is the potential for considerablesliding 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 90degrees) and its body is usually fairly long in the axialdirection; and it is these attributes which give it its screwlike qualities. The distinction between a worm and ahelical 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 asfew as one tooth. If that tooth persists for several turnsaround the helix, the worm will appear, superficially, tohave more than one tooth, but what one in fact sees isthe same tooth reappearing at intervals along the lengthof the worm. The usual screw nomenclature applies: aone-toothed worm is called s ng le hr ead or s ng le s a r ; aworm with more than one tooth is called u ltiple th r ead or m u ltiple s ta r t . The helix angle of a worm is not usuallyspecified. Instead, the lead angle, which is equal to 90degrees minus the helix angle, is given.

In a worm-and-gear set, the worm can always drive thegear. However, if the gear attempts to drive the worm, itmay or may not succeed. Particularly if the lead angle issmall, the gear's teeth may simply lock against theworm's teeth, because the force componentcircumferential to the worm is not sufficient to overcomefriction. Worm-and-gear sets that do lock are called self locking , which can be used to advantage, as for instancewhen it is desired to set the position of a mechanism byturning the worm and then have the mechanism hold


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t h at po s it ion . A n exam pl e is t h e mac hin e h ea d f ou nd on s ome ty pes of str in ge d in strume n ts .

If t h e gear in a w orm -a nd- gear set is a n ordin ary h e lica l gear onl y a s in gle poin t of c on tact w ill be ac hi eved . If me dium t o hi gh po wer tra n sm iss ion is des ire d , t h e t oot h s h a pe of t h e gear is m odi f ied t o ac hi eve m ore in t imatecon tact b y ma kin g bo t h gears part ia ll y e nv e lop eac h ot h er. Thi s is don e b y ma kin g bo t h con ca ve a nd joinin gt h em at a sa ddl e poin t ; t hi s is ca lled a c o e - ri v e .

Worm gears ca n be r igh t or left -h a nd e d f ollo win g t h e lon gesta bli s h ed p ract ice f or screw t h rea ds.

9 . N o - c ir c u la r

Non- c ircu lar gears

Non- c ircu lar gears are des ign ed f or s pec ia l pur po ses.Whil e a regu lar gear is op t im ize d t o tra n sm it t orque t o a no t h er e n gage d mem ber w it h m ini mum noi se a nd weara nd ma ximum eff ic ien cy , a non- c ircu lar gear's ma in obj ect ive m igh t be rat io var iat ion s, a xle di s placeme n tosc illat ion s a nd m ore. C omm on a ppli cat ion s in clu dete xt ile mac hin es, po te n t iometers a nd con t in u ous l yvar ia bl e tra n sm iss ion s.


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10 . R a c k and p in io n

Rac k a nd pinion gear in g

A rac k is a t oo t h ed bar or r od t h at ca n be t ho ug h t of as asect or gear w it h a n in f ini te l y large ra di us of cur vature.

To rque ca n be c onv erte d t o lin ear f orce b y mes hin g arac k wit h a pinion : t h e pinion tur n s; t h e rac k m oves in astra igh t lin e. Suc h a mec h a ni sm is use d in aut om obil esto conv ert t h e r otat ion of t h e steer in g wh ee l in t o t h e left -t o-r igh t m ot ion of t h e t ie r od (s ). Rac ks a ls o feature in t h et h eory of gear ge ometry, w h ere, f or in sta n ce, t h e t oo t h s h a pe of a n in terc h a n gea ble set of gears may be s pec if ied f or t h e rac k (in f ini te ra dius ), a nd t h e t oo t h s h a pes f or

gears of part icu lar actua l ra dii t h en der ived fr om t h at. Th e rac k a nd pinion gear ty pe is em plo ye d in a rac k ra ilway .

11 . E p i c y c l i c

Epi cyc lic gear in g


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In epi cyc lic gear in g on e or m ore of t h e gear a xes m oves.Ex am ples are su n a nd pla n et gear in g (see be low) a nd mec h a ni ca l di ffere n t ia ls.

12 . Su n and p lane t

Su n (ye llow) a nd pla n et (re d) gear in g

Su n a nd pla n et gear in g was a met hod of c onv ert in grec ip r oca l m ot ion in t o r otary m ot ion in steam e n gin es . Itpl aye d a n im po rta n t r ole in t h e Ind ustr ia l Revolut ion .

Th e Su n is ye llow, t h e pl a n et re d , t h e rec ip r ocat in g cra nk is bl ue, t h e f l yw h ee l is gree n a nd t h e d r ives h aft is grey.

14 . H a r o n ic d ri v e

Harm oni c d r ive gear in g

A harmonic dri v e is a s pec ia lize d prop r ietary gear in gmec h a ni sm.


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15 . C age gea r

A cage gear , a ls o ca lled a lantern gear or lantern p inion h as cy lind r ica l rod s f or teet h , para lle l t o t h e a xle a nd arra n ge d in a c irc le ar ou nd it, muc h as t h e bars on arou nd bi r d cage or la n ter n . Th e assem bl y is h e ld t oget h erb y di s ks at e it h er e nd in t o whi ch t h e t oo t h rod s a nd a xleare set.

No en c la tur e Gene r al n o en c la tur e

Ro tat ion a l freque n cy , n

Measure d in rotat ion over t ime, suc h as RPM.


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Angular frequency ,

Measured in radians per second . 1 RPM = / 30rad/second

Number of teeth, N

How many teeth a gear has, an integer . In the caseof worms, it is the number of thread starts that theworm 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 twomeshing gear teeth.

Line of action, pressure lineLine along which the force between two meshinggear teeth is directed. It has the same direction asthe force vector. In general, the line of actionchanges from moment to moment during the periodof engagement of a pair of teeth. For involute gears ,however, the tooth-to-tooth force is always directed

along the same linethat is, the line of action isconstant. This implies that for involute gears thepath of contact is also a straight line, coincidentwith the line of actionas is indeed the case.

Axis


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Axis of re volut ion of t h e gear; ce n ter lin e of t h e s h aft.

Pitc h poin t, p

Poin t w h ere t h e lin e of act ion cr osses a lin e joinin gt h e tw o gear a xes.

Pitc h c irc le, pi tc h lin e

C irc le ce n tere d on a nd per pendi cu lar t o t h e a xis,a nd pass in g t h roug h t h e pi tc h poin t. A p re def in ed di ametra l po s it ion on t h e gear w h ere t h e c ircu lart oo t h t hi ckn ess, pressure a n gle a nd h e lix a n gles are

def in ed .Pitc h di ameter, d

A pre def in ed di ametra l po s it ion on t h e gear w h eret h e c ircu lar t oo t h t hi ckn ess, p ressure a n gle a nd h e lix a n gles are def in ed . Th e sta nd ar d pi tc h di ameter is a bas ic dime n s ion a nd ca nno t bemeasure d , but is a locat ion wh ere ot h er

measureme n ts are ma de. Its va lue is base d on t h en um ber of teet h , t h e no rma l m od u le ( or no rma l di ametra l pi tc h) , a nd t h e h e lix a n gle. It is ca lcu late d as:

in metr ic u ni ts or in im per ia l u ni ts.

Mod u le, m

A sca lin g fact or use d in metr ic gears w it h u ni ts in m illimeters w ho 's effect is t o enl arge t h e gear t oo t h s ize as t h e m od u le in creases a nd re duce t h e s ize ast h e m od u le decreases. M od u le ca n be def in ed in t h e


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no rma l (m n ), t h e tra n s verse ( m t ), or t h e a xia l pl a n es(m a ) dependin g on t h e des ign a pp roac h em plo ye d a nd t h e ty pe of gear be in g des ign ed . M od u le isty pica ll y a n inp ut va lue in t o t h e gear des ign a nd isse ldo m ca lcu late d .

Operat in g pi tc h di ameters

D iameters determ in ed fr om t h e n um ber of teet h a nd t h e ce n ter dista n ce at w hi ch gears op erate. Ex am plef or pinion :

Pitc h surface

In cy lind r ica l gears, cy lind er f orme d b y p roject in g api tc h circ le in t h e a xia l di rect ion . M ore ge n era ll y, t h esurface f orme d b y t h e sum of a ll t h e pi tc h c irc les ason e m oves a lon g t h e a xis. F or beve l gears it is acon e.

An gle of act ion

An gle w it h verte x at t h e gear ce n ter, on e leg on t h epoin t w h ere mat in g teet h f irst ma ke c on tact, t h eot h er leg on t h e poin t w h ere t h ey di se n gage.

Arc of act ion

Segme n t of a pi tc h c irc le su b te nd ed b y t h e a n gle of act ion .

Pressure a n gle,

Th e c om pleme n t of t h e a n gle betwee n t h e di rect ion t h at t h e teet h exert f orce on eac h ot h er, a nd t h e lin e


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joining the centers of the two gears. For involutegears, 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 isconstant.

Outside diameter, D o

Diameter of the gear, measured from the tops of theteeth.

Root diameter

Diameter of the gear, measured at the base of thetooth.

Addendum, a

Radial distance from the pitch surface to theoutermost point of the tooth. a = (D o D ) / 2

Dedendum, b

Radial distance from the depth of the tooth trough tothe pitch surface. b = (D r oo tdiamete r ) / 2

Whole depth, h t

The distance from the top of the tooth to the root; itis equal to addendum plus dedendum or to workingdepth plus clearance.

ClearanceDistance between the root circle of a gear and theaddendum circle of its mate.

Working depth


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Depth of engagement of two gears, that is, the sumof their operating addendums.

Circular pitch, p

Distance from one face of a tooth to thecorresponding face of an adjacent tooth on the samegear, measured along the pitch circle.

Diametral pitch, p d

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 theinvolute of the base circle. The radius of the basecircle is somewhat smaller than that of the pitchcircle.

Base pitch, normal pitch, p b

In involute gears, distance from one face of a toothto the corresponding face of an adjacent tooth on thesame gear, measured along the base circle.

Interference

Contact between teeth other than at the intendedparts of their surfaces.

Interchangeable set

A set of gears, any of which will mate properly withany other.

Helical gear nomenclature


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Helix angle,

Angle between a tangent to the helix and the gearaxis. Is zero in the limiting case of a spur gear.

Normal circular pitch, p n

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". p n = p cos( )

Several other helix parameters can be viewed either inthe normal or transverse planes. The subscript n usuallyindicates the normal.

Worm gear nomenclature

Lead

Distance from any point on a thread to thecorresponding point on the next turn of the samethread, measured parallel to the axis.

Linear pitch, p

Distance from any point on a thread to thecorresponding point on the adjacent thread,measured parallel to the axis. For a single-threadworm, lead and linear pitch are the same.

Lead angle,

Angle between a tangent to the helix and a planeperpendicular to the axis. Note that it is thecomplement of the helix angle which is usually givenfor helical gears.


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Pitc h di ameter, d w

Same as descr ib ed ear lier in t hi s list. N ote t h at f or aworm it is st ill measure d in a pl a n e per pendi cu lar t o

t h e gear a xis, no t a t ilte d pla n e.Su bscr ip t w deno tes t h e w orm, su bscr ip t g deno tes t h egear.

T oot h c o n t a c t n o en c la tur e

L in e of c on tactPat h of act ion L in e of

act ion Pla n e of act ion

L in es of c on tact(h e lica l gear ) Arc of act ion

Len gt h of act ion

L im itdiameter

Face a dva n ce Zon e of act ion

Poin t of c on tact

An y poin t at w hi ch tw o t oo t h p rof iles t ouc h eac h ot h er.


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Line of contact

A line or curve along which two tooth surfaces aretangent to each other.

Path of action

The locus of successive contact points between apair of gear teeth, during the phase of engagement.For conjugate gear teeth, the path of action passesthrough the pitch point. It is the trace of the surfaceof action in the plane of rotation.

Line of action The path of action for involute gears. It is thestraight line passing through the pitch point andtangent to both base circles.

Surface of action

The imaginary surface in which contact occursbetween two engaging tooth surfaces. It is thesummation of the paths of action in all sections of the engaging teeth.

Plane of action

The surface of action for involute, parallel axis gearswith either spur or helical teeth. It is tangent to thebase cylinders.

Zone of action (contact zone)

For involute, parallel-axis gears with either spur orhelical teeth, is the rectangular area in the plane of action bounded by the length of action and theeffective face width .


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Path of contact

The curve on either tooth surface along whichtheoretical single point contact occurs during the

engagement of gears with crowned tooth surfaces orgears that normally engage with only single pointcontact.

Length of action

The distance on the line of action through which thepoint of contact moves during the action of the toothprofile.

Arc of action, Q t

The arc of the pitch circle through which a toothprofile moves from the beginning to the end of contact with a mating profile.

Arc of approach, Q a

The arc of the pitch circle through which a toothprofile moves from its beginning of contact until thepoint of contact arrives at the pitch point.

Arc of recess, Q r

The arc of the pitch circle through which a toothprofile moves from contact at the pitch point untilcontact ends.

Contact ratio, m c,

The number of angular pitches through which atooth surface rotates from the beginning to the endof contact.In a simple way, it can be defined as ameasure of the average number of teeth in contact


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dur in g t h e per iod in whi ch a t oo t h comes a nd goesout of c on tact w it h t h e mat in g gear.

T ra n s verse c on tact rat io, m p ,

Th e c on tact rat io in a tra n s verse pl a n e. It is t h e rat io of t h e a n gle of act ion t o t h e a n gu lar pi tc h . F orinvol ute gears it is m ost di rect l y ob ta in ed as t h erat io of t h e len gt h of act ion t o t h e base pi tc h .

Face c on tact rat io, m F ,

Th e c on tact rat io in a n a xia l pla n e, or t h e rat io of

t h e face w id t h t o t h e a xia l pi tc h . F or beve l a nd h y poid gears it is t h e rat io of face a dva n ce t o c ircu lar pi tc h .

To ta l con tact rat io, m t ,

Th e sum of t h e tra n s verse c on tact rat io a nd t h e facecon tact rat io.

= +

m t = m p + m F

Modi f ie d con tact rat io, m o

F or beve l gears, t h e square r oo t of t h e sum of t h esquares of t h e tra n s verse a nd face c on tact rat ios.

L im it diameter

D iameter on a gear at w hi ch t h e lin e of act ion in tersects t h e ma ximum ( or m ini mum f or in ter n a l pinion) a dd end um c irc le of t h e mat in g gear. Thi s isa ls o referre d t o as t h e start of act ive prof ile, t h e start


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of c on tact, t h e e nd of c on tact, or t h e e nd of act ivep rof ile.

S tart of act ive prof ile ( SAP)

In tersect ion of t h e lim it diameter a nd t h e invol utep rof ile.

Face a dva n ce

D ista n ce on a pi tc h c irc le t h roug h whi ch a h e lica l ors pi ra l t oo t h m oves fr om t h e po s it ion at w hi ch con tact beg in s at on e e nd of t h e t oo t h trace on t h e

pi tc h surface t o t h e po s it ion wh ere c on tact ceases att h e ot h er e nd .

T oot h t h i c k ne ss n o e c la tur e

Too t h t hi ckn ess Thi ckn ess

re lat ion s hip s

Cho r da l t hi ckn ess

Too t h t hi ckn essmeasureme n tover pin s

Sp a n measureme n t

L on g a nd s ho rta dd end umteet h

C ircu lar t hi ckn ess


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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 helicalgear it may be considered as the length of arc alonga normal helix.

Axial thickness

In helical gears and worms, tooth thickness in anaxial cross section at the standard pitch diameter.

Base circular thickness

In involute teeth, length of arc on the base circlebetween the two involute curves forming the profileof a tooth.

Normal chordal thickness

Length of the chord that subtends a circularthickness arc in the plane normal to the pitch helix.Any convenient measuring diameter may beselected, not necessarily the standard pitchdiameter.

Chordal addendum (chordal height)Height from the top of the tooth to the chordsubtending the circular thickness arc. Anyconvenient measuring diameter may be selected, notnecessarily the standard pitch diameter.


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Profile shift

Displacement of the basic rack datum line from thereference cylinder, made non-dimensional by

dividing by the normal module. It is used to specifythe tooth thickness, often for zero backlash.

Rack shift

Displacement of the tool datum line from thereference cylinder, made non-dimensional bydividing by the normal module. It is used to specifythe tooth thickness.

Measurement over pins

Measurement of the distance taken over a pinpositioned 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 pinspositioned in the tooth space or spaces opposite thefirst. This measurement is used to determine tooththickness.

Span measurement

Measurement of the distance across several teeth ina normal plane. As long as the measuring device hasparallel measuring surfaces that contact on anunmodified portion of the involute, the measurement

will be along a line tangent to the base cylinder. It isused to determine tooth thickness.

Modified addendum teeth

Teeth of engaging gears, one or both of which havenon-standard addendum.


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Fu ll-d ep t h teet h

T eet h in whi ch t h e w or kin g de p t h equa ls 2 .000 divid ed b y t h e no rma l di ametra l pi tc h .

S tu b teet h

T eet h in whi ch t h e w orkin g dep t h is less t h a n 2 .000 divid ed b y t h e no rma l di ametra l pi tc h .

Equa l a dd end um teet h

T eet h in whi ch tw o en gag in g gears h a ve equa l a dd end ums.

L on g a nd s ho rt -a dd end um teet h

T eet h in whi ch t h e a dd end ums of tw o en gag in ggears are u n equa l.

Pit c h n o en c la tur e

Pit c h is t h e dista n ce betwee n a poin t on on e t oo t h a nd t h e c orres pondin g poin t on a n a djace n t t oo t h . It is adi me n s ion measure d a lon g a lin e or cur ve in t h etra n s verse, no rma l, or a xia l di rect ion s. Th e use of t h es in gle w ord p itch wit ho ut qua lif icat ion may beam bi gu ous, a nd f or t hi s reas on it is p refera bl e t o uses pec if ic des ign at ion s suc h as tra n s verse c ircu lar pi tc h ,no rma l base pi tc h , a xia l pi tc h .

Pitc h Too t h pi tc h Base pi tc h re lat ion s hip s

Pr in c ip a l pi tc h es

C ircu lar pi tc h , p


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Arc distance along a specified pitch circle or pitchline between corresponding profiles of adjacentteeth.

Transverse circular pitch, p t Circular pitch in the transverse plane.

Normal circular pitch, p n , p e

Circular pitch in the normal plane, and also thelength of the arc along the normal pitch helixbetween helical teeth or threads.

Axial pitch, p x

Linear pitch in an axial plane and in a pitch surface.In helical gears and worms, axial pitch has the samevalue at all diameters. In gearing of other types,axial pitch may be confined to the pitch surface andmay be a circular measurement. The term axialpitch is preferred to the term linear pitch. The axial

pitch of a helical worm and the circular pitch of itsworm gear are the same.

Normal base pitch, p N, p bn

An involute helical gear is the base pitch in thenormal plane. It is the normal distance betweenparallel helical involute surfaces on the plane of action in the normal plane, or is the length of arc onthe normal base helix. It is a constant distance inany helical involute gear.

Transverse base pitch, p b, p bt


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In a n invol ute gear, t h e pi tc h on t h e base c irc le ora lon g t h e lin e of act ion . C orres pondin g s id es of invol ute gear teet h are para lle l cur ves, a nd t h e basepi tc h is t h e c on sta n t a nd fu nd ame n ta l di sta n cebetwee n t h em a lon g a c omm on no rma l in atra n s verse pla n e.

D iametra l pi tc h (tra n s verse ), P d

Rat io of t h e n um ber of teet h t o t h e sta nd ar d pi tc h di ameter in in ch es.

Norma l diametra l pi tc h , P nd

Va lue of diametra l pi tc h in a no rma l pla n e of ah e lica l gear or w orm.

An gu lar pi tc h , N, An gle su b te nd ed b y t h e c ircu lar pi tc h , usua ll yexp resse d in ra di a n s.

degrees or ra di a n s


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Backlash

Backlash is the error in motion that occurs when gearschange direction. It exists because there is always somegap between the trailing face of the driving tooth and theleading face of the tooth behind it on the driven gear, andthat gap must be closed before force can be transferredin the new direction. The term "backlash" can also beused to refer to the size of the gap, not just thephenomenon it causes; thus, one could speak of a pair of gears as having, for example, "0.1 mm of backlash." Apair of gears could be designed to have zero backlash,but this would presuppose perfection in manufacturing,

uniform thermal expansion characteristics throughoutthe system, and no lubricant. Therefore, gear pairs aredesigned to have some backlash. It is usually provided byreducing the tooth thickness of each gear by half thedesired gap distance. In the case of a large gear and asmall pinion, however, the backlash is usually takenentirely off the gear and the pinion is given full sizedteeth. Backlash can also be provided by moving the gearsfarther apart.

For situations, such as instrumentation and control,where precision is important, backlash can be minimisedthrough one of several techniques. For instance, the gearcan be split along a plane perpendicular to the axis, onehalf fixed to the shaft in the usual manner, the other half placed alongside it, free to rotate about the shaft, butwith springs between the two halves providing relativetorque between them, so that one achieves, in effect, asingle gear with expanding teeth. Another methodinvolves tapering the teeth in the axial direction andproviding for the gear to be slid in the axial direction totake up slack.


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S h i ti ng o gea r s

In s ome mac hin es (e.g., aut om obil es ) it is n ecessary t o a lter t h e gear rat io t o su it t h e tas k . Th ere are se vera l met hod s of acc om pli s hin g t hi s. F or e xam pl e:

y Ma n ua l tra n sm iss ion y Aut omat ic gear box y Dera illeur gears whi ch are actua ll y s p rockets in

com bin at ion wit h a roller c h a in y Hu b gears (a ls o ca lled epicyc lic gear in g or su n- a nd-

pl a n et gears )

Th ere are se vera l outc omes of gear s hi ft in g in m ot orvehi c les. I n t h e case of a ir poll ut ion em iss ion s, t h ere arehi gh er poll uta n t em iss ion s ge n erate d in t h e lower gears,wh en t h e e n gin e is w or kin g h ar der t h a n wh en hi gh ergears h a ve bee n atta in ed . I n t h e case of vehi cle noi seem iss ion s , t h ere are hi gh er s ou nd leve ls em itte d wh en t h e vehi c le is e n gage d in lower gears. Thi s fact h as bee n ut ilize d in a n a l yz in g vehi cle ge n erate d s ou nd s in ce t h elate 1960 s, a nd h as bee n in cor po rate d in t o t h e

s imu lat ion of ur ba n roa dway noi se a nd corres pondin gdes ign of ur ba n noi se barr iers a lon g r oa dways.

T oot h p ro i le

Prof ile of a s pur gearUnd ercut

A prof ile is on e s id e of a t oo t h in a cr oss sect ion betwee n t h e outs ide c irc le a nd t h e r oo t c irc le. Usua ll y a p rof ile ist h e cur ve of in tersect ion of a t oo t h surface a nd a pl a n e or


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surface normal to the pitch surface, such as thetransverse, normal, or axial plane.

The fillet curve (root fillet) is the concave portion of thetooth profile where it joins the bottom of the tooth space.

As mentioned near the beginning of the article, theattainment of a non fluctuating velocity ratio isdependent on the profile of the teeth. Friction and wearbetween two gears is also dependent on the tooth profile.

There are a great many tooth profiles that will give aconstant velocity ratio, and in many cases, given anarbitrary tooth shape, it is possible to develop a tooth

profile for the mating gear that will give a constantvelocity ratio. However, two constant velocity toothprofiles have been by far the most commonly used inmodern times. They are the cycloid and the involute. Thecycloid was more common until the late 1800s; sincethen the involute has largely superseded it, particularlyin drive train applications. The cycloid is in some waysthe more interesting and flexible shape; however theinvolute has two advantages: it is easier to manufacture,

and it permits the center to center spacing of the gears tovary 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 arestill used in mechanical clocks.

An undercut is a condition in generated gear teeth whenany part of the fillet curve lies inside of a line drawntangent to the working profile at its point of juncturewith the fillet. Undercut may be deliberately introducedto facilitate finishing operations. With undercut the filletcurve intersects the working profile. Without undercutthe fillet curve and the working profile have a commontangent.


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Gea r m a t e ri al s

Wood en gears of a hi st or ic wind m ill

Numer ous non ferr ous a llo ys, cast ir on s, po wder -meta llurgy a nd even plast ics are use d in t h ema n ufacture of gears. H owe ver stee ls are m ost c omm onl yuse d because of t h e ir hi gh stre n gt h t o we igh t rat io a nd low c ost. Plast ic is c omm onl y use d wh ere c ost or we igh tis a c on cer n . A p rop er l y des ign ed pl ast ic gear ca n re placestee l in ma n y cases because it h as ma n y des ira blep rop ert ies, in c lu din g di rt t olera n ce, low s pee d mes hin g,a nd t h e a bili ty t o "s kip " qu ite we ll. Ma n ufacturers h a veem plo ye d pl ast ic gears t o ma ke c on sumer items

aff or da ble in items lik e c op y mac hin es, op t ica l st oragedevices, VC Rs, c h ea p d y n am os, c on sumer au dio equ ip me n t, ser vo m ot ors, a nd p r in ters.

Th e m o d u le s y s t e m

Cou n tr ies w hi ch h a ve a dop te d t h e metr ic system ge n era ll y use t h e m od u le system. As a resu lt, t h e termm od u le is usua ll y u nd erst ood t o mea n t h e pi tc h di ameter

in m illimeters divid ed b y t h e n um ber of teet h . W h en t h em od u le is base d u pon in ch measureme n ts, it is kno wn as t h e E nglish mod u le t o a void con fus ion wit h t h e metr icm od u le. M od u le is a di rect di me n s ion , w h ereas diametra l pi tc h is a n inv erse dime n s ion (lik e "t h rea ds per in ch ").

Th us, if t h e pi tc h diameter of a gear is 40 mm a nd t h e


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n um ber of teet h 20 , t h e m od u le is 2 , w hi ch mea n s t h att h ere are 2 mm of pi tc h di ameter f or eac h t oo t h .

Man u a c tur e

.

Gear are m ost c omm onl y p rod uce d via hobbin g, but t h eyare a ls o s h a ped , b roac h ed , cast , a nd in t h e case of pl ast ic gears, inj ect ion m old ed . F or meta l gears t h e teet h are usua ll y h eat treate d t o ma ke t h em h ar d a nd m orewear res ista n t whil e lea vin g t h e c ore s oft a nd t oug h . F orlarge gears t h at are p ron e t o war p a que n ch p ress isuse d .


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GLEASON NO.610 HYPOID CUTTER

MACHINE DESCRIPTION

GENERAL DESCRIPTION -TheNo.610 Universal HypoidGear Machine sets new standards in precision highspeed roughing and finishing of medium and large non-generated hypoid and spiral bevel gears.The No.610Machine offers many production and advantages wherequantities are insufficient to justify separate roughingand finishing machines.Desinged primarily for use inthe truck,tractor and off the road equipment field,theNo.610 accomodate gear members upto 20 in diameterand a minimum ratio of 2-1/4-1.maximum whole depthis 1.000.

When the work head is in the horizontal level-load position,the work can be rapidly and convenientlyloaded.This feature provides the added benefit of

safety.The work spindle is widely separated from thecutter,when the gears are mounted or removed.

An overhead tieprovides a fixed relationshipbetween cutter and work.When the work head is raisedinto the cutting position,the tie is hydraulicallyclamped.Hydraulic pressure on the clamp is maintainedthrough the cutting cycle.

A new hydraulic mechanism rigidly clamps thework spindle to the housing,providing increased rigidityduring cutting and loading to improved surface finishand tooth spacing.The clamp is automatically releasedeach time the work is indexed.In additionto the


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over h ea d t ie a nd t h e w or k s pindl e c lam p ,r igidi ty isassure d as t h e cutt in g f orces are di recte d vert ica ll ydo wn war ds aga in st t h e mac hin e bed .W h en t h e w ork h ea d is ra ise d in t o cutt in g po s it ion ,t h e r otat in g cuttercon tacts t h e w or k ,s o t h at t h e bl a des pass do wn t h et oo t h s lot locate d at t h e lowest poin t on t h e r oug h ed gear. Thi s des ign ut ilizes t h e we igh t of t h e mac hin e in ob ta inin g ma ximum r igidi ty.

F igur e 2 GL EAS ON 610 H YP O ID CUTT E R M ACHI NE


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CUTTING METHODS -

1.FORMATE -No generating motion isemployed.Roughed out gears are finished accuratelyand quickly by the single cycle cutter,which rotatesuniformly completing one tooth with eachrevolution.Indexing takes place in the large gap of thecutterand the machine stops automatically at thecompletion of the last tooth.

Roughing is accomplished by a simple depthfeed motion of the cutter into the work .indexing takesplace when the cutter withdraws from the toothslot.One tooth slot is roughed with ech revolution of thefeed cam.The number of turns of the cutter depends onthe depth of the tooth slot.

2.CYCLEX -For low production quantities,the CYCLEXmethod may be used to rapidly produce

FORMATE,hypoid and spiral bevel gears in oneoperation from the solid.

In this form of CYCLEX cutter,the roughing andsemi-finishing blades are of gradually increasing heightand the two finishing blades are located so that theirtop and cutting edges are slightly below those of theother blades.

During the cutting cycle.the cutter makes anumber of revolution for roughing operation,as thecutter is fed into the work by means of cam.Since thefinishing blades are set lower than the preceding blades


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they do not engage the work during this position of thecutting cycle.

As the semi-finishing blades are passing

through the tooth slot at full roughing depth,the cutterspeed is reduced.The cutter is then quicklyadvanced,and the two finishing blades complete thetooth profile shape. The cutter is then rapidlywithdrawn so that the roughing blades do not contactthe work. Further withdrawal of the cutter providesclearance necessary for indexing.

3.HELIX FORM -As each blade of a HELIX FORM cutterpasses through a tooth space,the cutter is advancedaxially then quickly withdrawn, before the followingcutter blade enters the tooth space. The combinedmotion makes the path of the cutter tip tangent to theroot plane of the gear being cut.

The cutter computes one tooth with each revolution.

Indexing takes place when the large gap in the cutter isbeside the blank.

The HELIX FORM method of cutting producesgear tooth surfaces which are close to the truemathematical conjugacy with the mating pinion. It alsominimises development.


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F igur e 3 CUTT ING ON GL EAS ON NO. 610

F igur e 4 GL EAS ON 610


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F igur e 5 CROWN M ANUF ACTUR E D ON GL EAS ON NO. 610

Figure 6CROWN WHEEL


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CUTTING CYCLE AUTOMATIC MODE ROUGHING ANDCYCLEX -A blank is mounted on the work spindle andchucked manually. The cycle starts and the dual controlbuttons are activated, the work head raises to the cuttingposition, is hydraulically clamped for rigidity and the feedand coolant motor starts.

The cutting cycle is controlled by the feed camwhich feeds the cutter into the work. Indexing andChamfering is done during a dwell in the feed cam whilethe cutter is in the rear position. In the case of CYCLEXcutting set-in takes place at full depth as the twofinishing blades pass through the cut. After all theteeth have been cut, the machine automatically stops,the work head unclamps and lowers to the loadingpositon.

HELIX FORM AND SINGLE CYCLE FINISHING -A

roughed gear is mounted on the work spindle andchucked manually. The cycle starts and dual controlbuttons are activated, the work head raises to thecutting position, is hydraulically clamped for rigidityand the feed and coolant motors start. The cuttercompletes one tooth with each revolution and indexingtake place in the large gap of the cutter. After all thetooth have been cut, the machine automatically stops ,

the work head unclamps and lowers to the loadingposition.


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CONTROLS-

1.TEMPERATURE CONTROL LIGHT -The heaters inthe hydraulic unit warm the oil when the hydraulic unitis running because the hydrostatic bearings for thecutter spindle require warm oil. The heaters are set atthe factory for 150 degrees fahrenheit and thethermostat 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 hascome 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 theother will brighten significantly.

3.FILTER LIGHT -If filter becomes clogged , this lightwill come on. The machine will be inoperative until thisfilter is cleaned. The machine does not stop in the

middle of a cycle , but completes it and will not start thenext.

4.AUTOMATIC PRODUCTION COUNTER -This counteris set by the operator to the number of pieces to be cutbefore the cutter is to be sharpened.

5.SHARPEN CUTTER LIGHT -This light comes on whenthe machine has cut the amount of blanks preselectedon the production counter, signifying that the cuttershould be sharpened.

6.MAIN LINE SWITCH -This switch connects anddisconnects the machine with the input power supply.


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7.CUTTER DISCONNECT SWITCH -Before changing acutter, rotate this handle to the lock position, thenengage and secure the latch.

8.HYDRAULIC START BUTTON -After the main lineswitch is closed, depress this button to start thehydraulic, hydrostatic bearing and lubricating pumpmotors.

9.OVERSIZE BORE LIGHT -When this light is ON, itindicates the bore of the blank chucked on the arbor istoo large and the arbor drawrod has travelled too far.

This would make it unsafe to cut the part because therewould not be proper workholding pressure . The lightmust be OUT to run the machine.

10.HYDRAULIC STOP MACHINE -Depress this buttonto stop all machine functions. In an emergency, it ismore effective to depress this button than the cyclebutton.

11.GAGE CUTTER LIGHT -When ON , this lightindicates that the cutter is at the full depth. This lightmust be ON when gaging the cutter for length.

12.LOAD POSITION LIGHT - This light is ON ,when thefeed cam stop zone is adjacent to the cam follower. Tobegin an automatic cycle, this light must be ON.

13.RESET BUTTON -It is necessary to depress thisbutton prior to changing from a manual cycle to anautomatic cycle(not vice versa).

14.AUTOMATIC LIGHT -When ON , this light indicatesthat an automatic machine cycle can be started bydepressing the cycle start and the dual control button.


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15.WORK SPINDLE LIGHT -This light comes ON whenthe work spindle revolves 360 degrees. A cam on thework spindle under the index plate contacts the 360degrees switch. This indicates the work spindle hasmade one revolution and all the teeth are cut. If theindex switch is OFF and the 360 degrees switch iscontacted , the machine can be run during setup andnot index off this position.

16.CYCLE START BUTTON -This button along with thedual control button is used to jog the machine from themain control panel when a manual mode is selectedand remote jog switch is set to RUN. This button is alsoused to start an automatic cycle along with the dualcontrol button when an automatic mode has beenselected.

17.CYCLE STOP BUTTON -The machine can be stoppedat any time during an automatic cycle with this button.

18.INDEX SWITCH -When ON , the machine can be runin an automatic cycle.

19.BRAKE SELECTOR SWITCH -When OFF, the feedcam and cutter spindle can be rotated by hand. Themachine can only run with this switch in the ONposition.

20.CUTTING METHOD SELECTOR SWITCH(CYCLEX

MACHINE)- Change this switch setting when setting upto cut a new job, different type of cutter than previouslyused. Set to:

a)Finish -for Single Cycle and HELIX FORM cutters, themain motor will run at slow speed.


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b)Rough -for TRIPLEX cutters, the main motor will runat high speed.

c)Cycle -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 -Thisswitch is used in setting up the outside chamfering tooland 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 -Thisswitch is used in setting up the inside chamfering tooland may only be used when in manual cycle mode.When the machine is to be operated in the automaticcycle mode, set this switch to OUT.

23.REMOTE JOG BUTTON -This button is used to

enable the feed cam to be easily put on center must beset to JOG for this button to be operative, and willmake operator station inoperative when set on JOG as asafety feature.

24.CUTTER ROTATION SWITCH -This switch allowsthe use of both left hand and right hand cutters .

25.MAIN MOTOR SPEED SWITCH -Set this switch tohigh speed when roughing and to low speed whenfinishing.

26.MANUAL CUTTER ROTATION -The cutter spindlemay be rotated manually by rotating the upper speedpulley shaft when the brake is off . DO THIS ONLY


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WHEN THERE IS OIL PRESSURE TO THEHYDROSTATIC SPINDLE. The probable would beeither the cutter spindle or its housing would bedamaged.

27.DECHUCK CHUCK SELECTOR SWITCH- By turningthis switch counter clockwise , the work holdingequipment is dechucked. By turning this switchclockwise , the work holding equipment is chucked.

28.DUAL CONTROL BUTTON- This button is used inconjunction with the cycle start buttonto begin either a

manual or auto cycle. Both buttons must be depressedat the same time.


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CUTT E R INFORM AT ION

F igur e 5 CUTT E R U SE D ON GL EAS ON NO. 610

TR IP L E SI NGL E CYCL E CYCL E and HE L I FORM cutters fr om 5t o 18 may be use d on t hi s mac hin e. Amar kin g screw , on t h e face of cutter h ea d ,id en t if iest h e bla de setu p b y g ivin g t h e poin t w id t h a nd poin tdiameter of t h e setu p . Th e bla d es are h e ld in pl ace in t h e s lots b y bol ts. Th e last bla de of eac h set is mar ked wit h t h e f ollo win g in f ormat ion : t h e poin t w id t h , setser ia l n um ber, or der in g n um ber a nd t h e bla desp ressure a n gles.


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F igur e 6 CUTT ING PROC ESS OF CROWN

F igur e 7 WORK ING OF GL EAS ON NO. 610


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SPECIFICATIONS

GLEASON NO.610 HYPOID GEAR MACHINE

A)CAPACITY:- ENGLISH METRIC

1.OUTSIDECONE DISTANCE

a)maximum 10 254mm

b)minimum 2 .75 70mm

2.MAXIMUM GEARPITCH DIAMETER 20 508mm

3.CUTTER DIAMETERS 9 TO 18

4.WHOLE DEPTH 1.000 24 .4mm

5.ROOT ANGLE 60 to 8 0 degrees

6.FACE WIDTH 3 76mm

7.EXTREME RATIO(MINIMUM) 2 - 1/ 4 to 1

8.NUMBER OF TEETH 20 to 75

B)WORK SPINDLE:-

1.DIAMETER OF TAPERHOLE AT LARGE END 3 - 27/ 64

2.TAPERPER FOOT 1/ 2"

3.DEPTH OF TAPER 5/ 8

C)SPEEDS AND FEEDS:-

1.CUTTER SPEED(feed p er minut e)FOR ROUGHING 8 - 200 24m- 61m

2.FEEDS(second s per tooth) FOR ROUGHING 3- 35

3.CUTTER SPEED(feed p er minut e)FOR FINISHING 30 - 100 24m- 61m

4.FEEDS(second s per tooth) FOR FINISHING 3- 9


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D)ELECTRICAL EQUIPMENT:- 60Hz 50Hz

1.MAIN MOTOR 2 SPEED(10HP/ 5HP) 1800/ 900 RPM 1500/ 750 RPM

2.HYDRAULIC MOTOR 7 - 1/ 2HP1800 RPM 1500 RPM

3.COOLANT MOTOR 2HP 36 00 RPM 3000 RPM

4.CHIP CONVEYOR 1/ 4HP 1800 RPM 1500 RPM

5.HYDROSTATIC SPINDLE 1 - 1/ 2HP 1800 RPM 1500 RPM

E)MISCELLANEOUS:-

1.FLOOR SPACE 11 8 *86 - 1/ 2 3000c m*2200c m

2.HEIGHT 70 1780mm

3.WEIGHT

a)n et 16,5 00lbs 7,483kg

b) gro ss 17,5 00lbs 7,937kg


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TYPES OF CROWN W HEE L AND PI NIONMANUF ACTUR E D AT T ATA MOTOR S AND T HEI R PE R

DAY OUT PUT

TYPE OUT P UT

45 /7 240 41 /7 255 48 /7 210

35 / 9 27 0 41 / 6 240

Gra ph s ho win g per day out put

0

50

100

150

200

250

300

45/

41 /

48 /

35/ 41 /

shi t C

shi t B

shi t


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J OB SPE C IF ICAT ION: -20 Mn CR-5

CON S T ITU E NT S PE RC E NT AGE

Car bon 0 .17-0 .22 Sili con 0 .15-0 .35

Ma n ga n ese 1 .0-1 .4 Ch rom ium 1 .0-1 .3

Ir on Rest

percentage

Carbon

Si icon

anganese

Chromium

ron


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IMPROVING THE PRODUCTIVITY

Metal cutting is the outwardly simple process of removing metal on a work piece in order to get a desiredshape by using a tool, either by rotating the workpiece(as in a lathe) or by rotating the tool (as in a drillingmachine). But behind this simple process lie numerousparameters that play their roles, from a small to a bigway, in deciding many things in the act of metal cutting,including the speed of doing the job, the quality andaccuracy of the finish, the life of the tool, the cost of

production, and so on.Some parameters involved in the metal cutting processare in fact closely related with some other parameters inthe metal cutting process; playing with one will have aninfluencing effect on another. Thus, even after several

years of experience, process planning engineers may finddifficulty in confidently declaring themselves as expertsin metal cutting!

.

1) Material machinability:

The machinability of a material decides how easy ordifficult it is to cut it. The materials hardness is onefactor that has a strong influence on the machinabilty.

Though a general statement like a soft material is easierto cut than a harder material is true to a large extent, itis not as simple as that. The ductility of a material alsoplays a huge role.

2) Cutting Tool Material:

In metal cutting, High Speed steel and Carbide are twomajor tool materials widely used. Ceramic tools and CBN


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(Cubic Boron Nitride) are the other tool materials usedfor machining very tough and hard materials. A toolshardness, strength, wear resistance, and thermalstability 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 toolpasses through the work material and removes metal. Itis normally expressed in meters per minute (or feet perinch 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 isalways an ideal cutting speed available, and the toolmanufacturers generally give the guidelines for it.

Spindle speed: Spindle speed is expressed in RPM(revolutions per minute). It is derived based on thecutting speed and the work diameter cut (in case of turning/ boring) or tool diameter (in case of drilling/

milling etc). If V is the cutting speed and D is thediameter of cutting, then Spindle speed N = V /( P i 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 traversedover the workpiece to remove the material. In case of rotating tools with multiple cutting teeth (like a millingcutter), the feed rate is first reckoned in terms of feedper tooth, expressed in millimeter (mm/tooth). At thenext stage, it is feed per revolution (mm/rev).


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In case of lathe operations, it is feed per revolution thatstates how much a tool advances in one revolution of workpiece. In case of milling, feed per revolution isnothing but feed per tooth multiplied by the number of

teeth in the cutter. To actually calculate the time taken for cutting a job, it isfeed per minute (in mm/min) that is useful. Feed perminute is nothing but feed per revolution multiplied byRPM of the spindle.

6) Tool geometry:

For the tool to effectively dig into the component toremove material most efficiently without rubbing, thecutting 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 atool geometry is a vast subject in itself.

7) Coolant:

To take away the heat produced in cutting and also toact as a lubricant in cutting to reduce tool wear, coolantsare used in metal cutting. Coolants can range fromcutting oils, water soluble oils, oil-water spray, and soon.

8) Machine/ Spindle Power:

In the metal cutting machine, adequate power should beavailable to provide the drives to the spindles and also toprovide feed movement to the tool to remove the material.

The power required for cutting is based on the Metalremoval rate the rate of metal removed in a given time,generally expressed in cubic centimeters per minute,which depends on work material, tool material, thecutting speed, depth of cut, and feed rate.


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9) Rigidity of machine:

The rigidity of the machine is based on the design andconstruction of the machine, the age and extent of usageof the machine, the types of bearings used, the type of construction of slide ways, and the type of drive providedto 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 metalcutting machine at the best possible time within thedesired levels of accuracy, tolerances, and surface finish,

some or all the above parameters play their roles. Asalready mentioned in the beginning, each of theparameters can create a positive or negative impact onother parameters, and adjustments and compromises areto be made to arrive at the best metal cutting solution fora given job.

10)Process Cycle

The time required to produce a given quantity of partsincludes the initial setup time and the cycle time for eachpart. The setup time is composed of the time to setup themilling machine, plan the tool movements (whetherperformed manually or by machine), and install thefixture device into the milling machine. The cycle timecan be divided into the following four times:

1. L o ad /Un l o ad time - The time required to load theworkpiece into the milling machine and secure it to thefixture, as well as the time to unload the finished part.

The load time can depend on the size, weight, andcomplexity of the workpiece, as well as the type of fixture.


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2. C u t time - The time required for the cutter to make allthe necessary cuts in the workpiece for each operation.

The cut time for any given operation is calculated bydividing the total cut length for that operation by the

feed rate, which is the speed of the cutter relative tothe workpiece.3. I dle time - Also referred to as non-productive time, this

is the time required for any tasks that occur duringthe process cycle that do not engage the workpiece andtherefore remove material. This idle time includes thetool approaching and retracting from the workpiece,tool movements between features, adjusting machinesettings, and changing tools.

4. T oo l r eplaceme n t time - The time required to replace atool that has exceeded its lifetime and thereforebecome to worn to cut effectively. This time is typicallynot performed in every cycle, but rather only after thelifetime of the tool has been reached. In determiningthe cycle time, the tool replacement time is adjustedfor the production of a single part by multiplying bythe frequency of a tool replacement, which is the cuttime divided by the tool lifetime.


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My Role

As a summer trainee, I was placed in the TRANSMISSIONDEPARTMENT & was given the task of studying,observing and analyzing the work being done in the

TRANSMISSION FACTORY and to explore thepossibilities of improving the productivity of GLEASONNO.610 HYPOID CUTTER MACHINE which was beingused in CROWN manufacturing process.

Thus,for increasing the productivity of the

process being carried out at the TRANSMISSIONFACTORY , I have sorted out following points:-

1. Change in the CROWN WHEEL material.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:

y Loading and unloading time of crown wheely Cycle timey Idle timey Cutting Tool replacement timey Change in the machine setting

Now we will have a look at each of the points as givenabove on the productivity of the machine.


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1 . Ch ange in t h e CROWN W HEE L m a t e ri al - Th eCROWN w h ee l mater ia l use d at t h e prese n t is 20 Mn CR-5 . But t h ere are ot h er op t ion s a va ila ble f or t h e

CROWN w h ee l mater ia l t h at ca n be use d suc h as16 Mn Cr 5 a nd 42 CrM o4v ca n use d . Th e a dva n tagesof t h ese mater ia ls over 20 Mn Cr 5 h a ve bee n s ho wn gra phi ca ll y as be low:


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2. Change in the CUTTING TOOL material- HSS is thecutting 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 50Rc and cutting speed of 30-310m/min etc.could beused which will be more advantageous andproductive as a cutting tool material.HSS can also beused profitably by coating it with various materialslike applying a copper coating or a TiN(TitaniumNitrate) coating on the cutting tool.

The cutting speed and tool life of an cutting tool canbe related by the TAYLORs equation as below:

Where V=cutting speed in m/min

T=tool life in min.C=cutting speed for a tool life of 1min.n=Taylors exponent

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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Com paras ion of t h ese mater ia ls in t h e pr ocess of cutt in g ca n be viewe d pi ct or ia ll y as be low:


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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 iselectrical energy to mechanical energy to supplyrotational motion to the cutting tool which is asshown:

Belt

Fig.Pulley system used in GLEASON No.610

Driver

pu lley

Driven

pu lley

Idler

pu lley


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4 . Ch ange in t h e c utti ng de p t h - Thi s is a no t h ermet hod t o m p rove t h e prod uct ivity a nd eff ic ien cy of t h e mac hin e. Prese n t l y t h e mac hin e w orks on t h ep r in cipl e of ind exin g a nd re nd ers a s in gle cut eac h

t ime. If we c ou ld decrease t h e cutt in g dep t h t h a n it ispo ss ibl e t h at it w ou ld less stra in on t h e cutter a nd a ls o in crease t h e cutter life w hi ch is p rese n t l ych a n ge d after ma n ufactur in g ar ou nd 350-400 pieces.


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F ig. vect or ia l re p rese n tat ion of f orces


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5 . Ch ange in t h e f eed r a t e - Thi s op t ion is a ls o no ta va ila ble w it h t hi s mac hin e due t o its r igidi ty.

6 . Ch ange in t h e c utti ng too l ge o m e try- Cutt in g t ime

ca n be s igni f ica n t l y re duce d b y c h a n gin g t h ege ometry of t h e cutt in g t ool. Th e var ious s h a pes a nd stu dies re late d t o t h ese s h a pes h a ve bee n s ho wn di agrammat ica ll y as be low:

F ig.s h a pe of a cutter


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7.Cutting with and without use of coolant- Presentlycoolant is used in large scale in the process of cutting.

This cause wide loss in the form of economic losses asthe coolant oil that is recovered afterwards is very less in

comparasion to the quantity that is being used. Tominimize these losses techniques like dry cutting and of ice cooled cutters are used.

39178405 summer training report at tata motors

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