2. ACKNOWLEDGEMENT
One flower makes no garland; similarly accomplishment of a task
is never a single‐handed effort. There are so many people
attached to it directly or indirectly. And this project bears no
exception to this fact. On the completion of this project I takeexception to this fact. On the completion of this project I take
the opportunity to express my deep gratitude and sincere thanks
to my project mentor, Mr. RAHUL SHARMA, mentor whose
support and guidance had always been there since the start of
this project to the end. I am highly grateful to him for his time‐
to time feedbacks and precious suggestions He taught me howto‐time feedbacks and precious suggestions. He taught me how
to ask questions and express my ideas and how to work in
corporate world.
I cannot fully express my gratitude to Dr. D.C.Roy(HOD) for
d h d h l k l d d lproviding me the required theoretical knowledge and clearing
my concepts prerequisite for undergoing this project .I would
specially like to thank Mr. Asim Mahapatra and Mr. S Roy
Chowdhury for guiding me at various instances.
3. Contents:
d i1. Introduction
2. History
3. Maruti Fundamentals
‐5S Principle
‐3 K
‐Japanese Idea of Hansei
‐Poka‐Yoke
‐Kaizen
4.Maruti Suzuki Products and Services4.Maruti Suzuki Products and Services
5. Quality Management
‐Principles
‐Methods of Quality Improvement
6 ISO Certification6. ISO Certification
‐Certification principles
‐Certification Benefits
7.Transmission Systems
8 Pl P l8. Plant Process layout
9. Manufacturing Processes
10. List Of Parts Manufactured
11. Processes lines for manufacturing
12. Heat Treatment and Hard Machining
13. Assembly Operations
14. Quality Room
15. Terminologies commonly used for gears
4. MARUTI SUZUKI INDIA LTD.
Maruti Suzuki India Limited is a publicly listed automaker in India.It is the
largest automobile manufacturer in South Asia. Suzuki Motor Corporation
of Japan holds a majority stake in the company. It was the first company in
India to mass‐produce and sell more than a million cars. It is largely
d d f h b h b l l d hcredited for having brought in an automobile revolution to India. It is the
market leader in India and on 17 September 2007, Maruti Udyog
Limited was renamed Maruti Suzuki India Limited. The company's
headquarters are located in Delhi.
Maruti Suzuki India Limited
I d A iIndustry Automotive
Predecessor(s) Maruti Udyog Limited
Founded 1981
Headquarters New Delhi, India
Key people R. C. Bhargava(Chairman)
Kenichi Ayukawa (CEO & MD)
Products Automobiles
Revenue Rs. 43272 crore (US$7.3 billion)
(2013-14)
Net income Rs. 2469 crore (US$410 million)
(2013-14)
Employees 6,903 (2011)
Parent Suzuki
5. HISTORY
Maruti Udyog Limited was established in February 1981, though the actual
d i d l i 1983 I d i h M i 800 b dproduction commenced only in 1983. It started with Maruti 800, based on
theSuzuki Alto kei car which at the time was the only modern car available in
India. Its only competitors were Hindustan Ambassador and Premier
Padmini. Originally, 74% of the company was owned by the Indian
government, and 26% by Suzuki of Japan. As of May 2007, the government
of India sold its complete share to Indian financial institutions and no longerof India sold its complete share to Indian financial institutions and no longer
has any stake in Maruti Udyog.
Beginnings
Maruti's history begins in 1970, when a private limited company named
'Maruti technical services private limited' (MTSPL) is launched on NovemberMaruti technical services private limited (MTSPL) is launched on November
16, 1970. The stated purpose of this company was to provide technical
know‐how for the design, manufacture and assembly of "a wholly
indigenous motor car. After a series of scandals, "Maruti Limited" goes into
liquidation in 1977.
Suzuki Enters
In 1982, a license & Joint Venture Agreement (JVA) is signed between Maruti
Udyog Ltd. and Suzuki of Japan. At first, Maruti Suzuki was mainly an
importer of cars. In India's closed market, Maruti received the right to
import 40,000 fully built‐up Suzuki in the first two years, and even after that
the early goal was to use only 33% indigenous parts.This 796 cc hatchback is
based on the SS80 Suzuki Alto and is India’s first affordable car.
In 1985 the Suzuki SJ410‐based Gypsy, a 970 cc 4WD off‐road vehicle, is
launched. In 1986 the original 800 is replaced by an all‐new model of the
796 cc hatchback Suzuki Alto/Fronte. This is also when the 100,000th vehicle
is produced by the company In 1987 follows the company's first export tois produced by the company. In 1987 follows the company s first export to
the West, when a lot of 500 cars were sent to Hungary. Maruti products are
being imported worldwide.
6. 5S Principle
Seiri(Sorting):‐ Separate necessary items from unnecessary items. Dispose
off unnecessary items.
Seiton (Systematic Arrangement):‐ Arrange necessary items in proper order ( y g ) g y p p
so that they can be easily picked for use.
Seiso(Cleaning):‐Clean your workplace &equipments.
Seiketsu(Standardizing):‐ Maintain high standards of above 3S at all times &
strive to improve the current level.
Shinseki (Discipline):‐ Make a habit of observing the decided rules & train
l f ll d lpeople to follow discipline.
3 KS
Typically, any task, regardless of industry, can qualify as a 3K job:‐
Kitanai:‐refers to dirty jobs
Kiken: refers to dangerous jobsKiken:‐ refers to dangerous jobs
Kitsui:‐ refers to difficult jobs
Japanese idea of Hansei
It is a central idea in Japanese culture. It means to acknowledge your own
mistake and to pledge improvement. Product design on today's markets hasmistake and to pledge improvement. Product design on today s markets has
become increasingly complex since products contain more functions and
have to meet increasing demands such as user‐friendliness,
manufacturability and ecological considerations. With a shortened product
lifecycle, development costs are likely to increase. Since errors in the
estimations of market trends can be very expensive, companies therefore
perform benchmarking studies that compare with competitors on strategic,
process, marketing, and product levels. However, success in a certain market
segment not only requires knowledge about the competitors and the
performance of competing products, but also about the impressions which a
product leaves to the customer. The latter requirement becomes much more
important as products and companies getting mature Customers purchaseimportant as products and companies getting mature. Customers purchase
products basing on subjective terms such as brand image, reputation,
design, impression etc. A large number of manufacturers have started to
consider such subjective properties and to develop their products that
convey the company image.
7. Poka‐yoke
Poka‐yoke [poka‐yoke] is a Japanese term that means "mistake‐proofing".
A poka‐yoke is any mechanism in a lean manufacturing process that helps
an equipment operator avoid (yokeru) mistakes (poka). Its purpose is to
eliminate product defects by preventing, correcting, or drawing attention
to human errors as they occur. The concept was formalized, and the term
adopted, by Shigeo Shingo as part of the Toyota Production System. It was
originally described as baka‐yoke but as this means "fool‐proofing" (ororiginally described as baka‐yoke, but as this means fool‐proofing (or
"idiot‐proofing") the name was changed to the milder poka‐yoke.
The term poka‐yoke was applied by Shigeo Shingo in the 1960s to
industrial processes designed to prevent human errors. Shingo redesigned
a process in which factory operators, while assembling a small switch,
would often forget to insert the required spring under one of the switch g q p g
buttons. In the redesigned process, the worker would perform the task in
two steps, first preparing the two required springs and placing them in a
placeholder, then inserting the springs from the placeholder into the
switch. When a spring remained in the placeholder, the operators knew
that they had forgotten to insert it and could correct the mistake
ff l leffortlessly.
Shingo distinguished between the concepts of inevitable
human mistakes and defects in the production. Defects occur when the
mistakes are allowed to reach the customer. The aim of poka‐yoke is to
design the process so that mistakes can be detected and corrected
immediately eliminating defects at the sourceimmediately, eliminating defects at the source.
Kaizen
Japanese for "improvement" or "self‐changing for the best of all", refers to
philosophy or practices that focus upon continuous improvement of
processes in manufacturing, engineering, business management or any
process. It has been applied in healthcare, psychotherapy, life‐coaching,
government, banking, and other industries. When used in the business
sense and applied to the workplace, kaizen refers to activities that
8. continually improve all functions, and involves all employees from the CEO to
the assembly line operators. It also applies to processes, such as purchasing
d l i ti hi h i ti l b d i i t th l h iand logistics, which cross organizational boundaries into the supply chain.
The Sino‐Japanese word "kaizen" simply means "good change", with no
inherent meaning of either "continuous" or "philosophy" in Japanese
dictionaries or in everyday use. The word refers to any improvement, one‐
time or continuous, large or small, in the same sense as the English word
"improvement"improvement .
9. Maruti Suzuki Power train
Earlier known as Suzuki Power train India Limited was a joint venture of
Maruti Suzuki with Suzuki Motor Corporation, Japan at Manesar. It
manufactures world class diesel engines and transmissions for cars. This
diesel engine plant has a capacity to manufacture 300,000 diesel engines a
year. Maruti Suzuki is confident that the future demand for diesel cars in
the country will remain at about 40 per cent of total sales.
To speed up addition of diesel engine capacity and reduce costs, Maruti's
board approved the merger proposal of Suzuki Power train India Ltd (SPIL)board approved the merger proposal of Suzuki Power train India Ltd (SPIL)
with itself.
SPIL supplies about three lakh diesel engines a year to Maruti, while petrol
engines are made in‐house. Currently, Maruti has a 30 per cent stake in
SPIL, while the rest lies with Japanese parent Suzuki Motor Corporation
(SMC).(SMC).
With Maruti proposing a fresh issue of 13.17 million shares to SMC in lieu
of its majority holding in SPIL, SMC's stake in Maruti will go up from 54.2
per cent to 56.2 per cent.
Manufactures SX4 Engines & Swift diesel engines and in future all diesel
engines are planned to be manufactured here. Almost Every Gearbox
manufactured here.
The transmission plant manufactures the transmission assemblies for
many vehicles of Maruti Suzuki like Swift, Swift Dzire, Celerio,SX4,
WagonR. Despite it has 2‐W transmission and its assembly plant.
10. QUALITY MANAGEMENT
Quality management ensures that an organization, product or service is
consistent. It has four main components: quality planning, quality
control quality assurance and quality improvement Quality managementcontrol, quality assurance and quality improvement. Quality management
is focused not only on product and service quality, but also the means to
achieve it. Quality management therefore uses quality assurance and
control of processes as well as products to achieve more consistent
quality. For specific approach to quality management the term total
quality management was used from 1980s.It considers the following 5 qua ty a age e t as used o 980s. t co s de s t e o o g 5
factors:‐
11. PRINCIPLES
The International Standard for Quality management (ISO 9001:2008)The International Standard for Quality management (ISO 9001:2008)
adopts a number of management principles] that can be used by top
management to guide their organizations towards improved
performance.
Customer focus
Since the organizations depend on their customers, they should
understand current and future customer needs, should meet customer
requirements and should try to exceed the expectations of customers.
Leadership
Leaders of an organization establish unity of purpose and direction of it.
Th h ld f ti d i t f h i t lThey should go for creation and maintenance of such an internal
environment, in which people can become fully involved in achieving the
organization's quality objective
Involvement of people
People at all levels of an organization are the essence of it. TheirPeople at all levels of an organization are the essence of it. Their
complete involvement enables their abilities to be used for the benefit of
the organization.
Process approach
The desired result can be achieved when activities and related resources
are managed in an organization as a process.
System approach to management
An organization's effectiveness and efficiency in achieving its quality
objectives are contributed by identifying, understanding and managing
all interrelated processes as a system Quality Control involves checkingall interrelated processes as a system. Quality Control involves checking
transformed and transforming resources in all stages of production
process
12. Continual improvement
One of the permanent quality objectives of an organization should be the
continual improvement of its overall performance leveraging clear andcontinual improvement of its overall performance, leveraging clear and
concise PPMs (Process Performance Measures)
Factual approach to decision making
Effective decisions are always based on the data analysis and information.
Mutually beneficial supplier relationships
Since an organization and its suppliers are interdependent, therefore a
mutually beneficial relationship between them increases the ability of
both to add value.
13. METHODS OF QUALITY IMPROVEMENT
There are many methods for quality improvement. These cover product y q y p p
improvement, process improvement and people based improvement.
These include:‐
ISO 9004:2008 — Guidelines for performance improvement.
QFD — Quality function deployment, also known as the house of quality
approach.
K i J d i h f h b hKaizen — Japanese word meaning change for the better; the common
English term is continuous improvement.
Zero Defect Program — Created by NEC Corporation of Japan, based
upon statistical process control and one of the inputs for the inventors of
Six Sigma.
PDCA — Plan Do Check Act cycle for quality control purposesPDCA Plan, Do, Check, Act cycle for quality control purposes.
Kansei Engineering — an approach that focuses on capturing customer
emotional feedback about products to drive improvement.
Quality circle —A group (people oriented) approach to improvement.
TQM(Total Quality Management)‐ is a management strategy aimed at
embedding awareness of quality in all organizational processes.
Six Sigma — 6σ, Six Sigma combines established methods such as
statistical process control, design of experiments and failure mode and
effects analysis (FMEA) in an overall framework.
Quality circle — A group (people oriented) approach to improvement.
TRIZ — Meaning "Theory of Inventive Problem Solving".
14. ISO CERTIFICATION
ISO 9000 is a series of standards, developed and
published by the International Organization for Standardization (ISO),
that define, establish, and maintain a quality assurance system for
manufacturing and service industries. The standards are available
through national standards bodies ISO 9000 was first published in 1987 Itthrough national standards bodies. ISO 9000 was first published in 1987.It
was based on the BS 5750 series of standards from BSI that were
proposed to ISO in 1979The global adoption of ISO 9001 may be
attributable to a number of factors. A number of major purchasers
require their suppliers to hold ISO 9001 certification. China is the leading
and India is at 8th position in terms of number of certificates being p g
issued.ISO does not certify organizations itself. Numerous certification
bodies exist, which audit organizations and, upon success, issue ISO 9001
compliance certificates.
An ISO 9001 certificate is not a once‐and‐for‐all award, but must be
renewed at regular intervals recommended by the certification body,
usually once every three years. There are no grades of competence within
ISO 9001: either a company is certified (meaning that it is committed to
the method and model of quality management described in the standard)
or it is not.
Advantages include positive effect on investment, market share, sales
growth sales margins competitive advantage and avoidance of litigationgrowth, sales margins, competitive advantage, and avoidance of litigation.
Following are some of the advantages of this system:‐
1. Creates a more efficient, effective operation
2. Increases customer satisfaction and retention
3. Reduces audits
4. Enhances marketing
5. Improves employee motivation, awareness, and morale
6. Promotes international trade
7. Increases profit
16. Principle Of Motion Economy
The principles of motion economy form a set of rules and suggestions to
improve the manual work in manufacturing and reduce fatigue and
unnecessary movements by the worker, which can lead to the reduction in
h k l d D i i l fl i lthe work related trauma. Due to improper material flow it was also
violating the Law of Motion Economy.
This helped the organization in following ways:‐
It helped in easy material flow from the forging section to the machining
and to the heat treatment section.
It helped in better supervisor control over the lines assigned to him for
supervision.
It also helped in easier and prompts addressing of any sort of problem in
the line without suffering any production loss.
It also reduced the labour requirement for moving the material from
forging to heat treatment plant.
These factors in turn helped in more production rate and easier
hi t f d ti t tachievement of production targets.
17. Transmission System:
A machine consists of a power source and a power transmission
system, which provides controlled application of the power. Merriam‐
Webster defines transmission as an assembly of parts including the
speed‐changing gears and the propeller shaft by which the power is
transmitted from an engine to a live axle. Often transmission refers
simply to the gearbox that uses gears and
gear trains to provide speed and torque
conversions from a rotating power source
to another device.
Th b i ll 2 t f t i iThere are basically 2 types of transmission
systems, namely Automatic and Manual.
An automatic transmission (also called
automatic gearbox) is a type of motor vehicle transmission that can
automatically change gear ratios as the vehicle moves freeing the
A five speed plus reverse transmission
system
automatically change gear ratios as the vehicle moves, freeing the
driver from having to shift gears manually. Most automatic
transmissions have a defined set of gear ranges, often with a parking
pawl feature that locks the output shaft of the transmission stroke
face to keep the vehicle from rolling either forward or backward.
A manual transmission, also known as a manual gearbox, stick
shift (for vehicles with hand‐lever shifters), standard
transmission, 4/5/6 speed (depending on gears) or simply a manual, is
type of transmission used in motor vehicle applications. It uses a
driver‐operated clutch engaged and disengaged by a foot pedal
( t bil ) h d l ( t l ) f l ti t t f(automobile) or hand lever (motorcycle), for regulating torque transfer
from the engine to the transmission; and a gear selector operated by
hand (automobile) or by foot (motorcycle).
19. Forging
Raw material in the form of round billets or rod is imported from Japan.
The composition of alloy is SCr420H2V2.
These rods are fed to shearing die machinesThese rods are fed to shearing die machines.
There are 2 different types of Shearing die Machines:
For cutting input & counter shaft.
For cutting 4 types of gears.
Forging of ShaftsForging of Shafts
Shearing dies are programmed for cutting both input & counter shafts of
different sizes for various models.
Shot Blasting:
After shearing process, the shafts are shot blasted because:
The ends of the shafts were too sharp such that it is injurious to hands of
the workers.
More over the surface of the shafts were too smooth so it was difficult to
coat chemical and lubrication over it.
So after the shot blasting process the surface is rough it can easily retainSo after the shot blasting process the surface is rough it can easily retain
the chemical coat & lubricant. This is required so as to reduce the chances
of scratching of dies & also prevents tearing of shaft material. Moreover if
the surface is having burrs over its face or on its edges then the
component will not clamped over the machine.
Both input and counter shafts are cold forged in cold forging die machine.p g g g
There are various types of dies & machine is computer numerically
controlled, as per the operations the dies changes according & machined
is programmed for various types & sizes of shafts.
To maintain quality shafts are inspected, every shaft is visually checked for
the scratches over its surface, and then their dimensions are checked by
GO & NO GO gauges to control the dimension.
If some scratch is found over the shaft then dies are inspected for
scratches and if found they are lapped to remove scratches but still
keeping the dimensional accuracy.
20. Dies are used until they are cracked or their dimension is changed a lot.
Now after cold forging, the shafts are isothermally annealed to remove
internal stresses.
Isothermal Annealing:
Material is fed to the chamber were it is pre‐heated by indirect heating,
and then it goes into the furnace chamber where it is heated to
temperature of 900° Celsius.
Then it moved to low temperature zone of about 600° CelsiusThen it moved to low temperature zone of about 600 Celsius.
Then it is cooled in the furnace itself and a fan is employed to flow air
over it.The grain growth takes place in this manner.
After this shafts are dispatched for machining.
Hot Forging:Hot Forging:
Gears are produced by hot forging
There are 3 forging dies for 3 different types of gears namely Atsunyu,
Ittai&Hira.
The temperature during hot forging is 1200° Celsius because here the
flow of material in the die is moreflow of material in the die is more
Now after hot forging the gears we get are not dimensionally accurate
and many specifications are not up to the mark, so the gears are cold
worked.
Cold Working of Gears:Cold Working of Gears:
‐Specifications like internal diameter, external diameter,
flange width and total thickness are controlled.
‐Rib thickness is controlled.
‐Groove for oil hole is formed.
Now we have controlled the dimensions but to improve the surface
conditions gears are shot blasted.
Shot blasting is necessary because it removes burrs from the surface
and controls the surface roughness. This is important because if the
surface is
21. having the burr of size of 0.2 mm then the component will not be
clamped in CNC machine.
h l li i d b h h b ldNow Isothermal Annealing is done because the gears have been cold
worked.
Dog gear is directly produced by cold forging.
Die machining:
As the name suggest this shop produces various dies for all
kind of forging operations for both hot & cold forging. The time involved
in developing a die varies from 21 days to 45 days depending up on it its
complexity and size.
Steps involved in die machining are as follows:
Step 1: Firstly die blanks are cut from large billets of diameters rangingStep 1: Firstly die blanks are cut from large billets of diameters ranging
from 30 mm to 220 mm on belt saw machine & then sent to die machine
shop 1.
Step 2: After cutting, they are machined on CNC lathes various
operations like milling, turning, drilling, facing, step turning, boring,
reaming etc are performed. Here only specifications like ID, OD, chamfer, g p y p , , ,
etc are produced no intricate shapes are formed.
Step 3: Now it is sent to die machine shop 2, here intricate tooth profile is
generated on EDM machine, wire cut EDM machine
Dog teeth are created in EDM machine, it is the lengthiest process among
all.
Wire cut EDM machine is used to cut dies and punches of greater depth
or thickness.
Step 4: Now they sent to furnace to remove stress concentrations and for
heat treatment to make it hard.
Step 5: After heat treatment the dies are grinded both external as well as
internal grinding is done to control its surface roughnessinternal grinding is done to control its surface roughness.
23. List Of Parts Manufactured:
•Input Shaft: The input shaft receives power from the engine of the
car and transmits it to the counter shaft. It has gears and sleeves
fitted on it of varying sizes for different speeds.
C t Sh ft Th t h ft i di tl i t t ith th i t•Counter Shaft: The counter shaft is directly in contact with the input
shaft via gears and receives power from it and delivers it to the final
gear which carries the differential mechanism.
•ITTAI Gear: It is used as the 1st and 2nd gear on the counter shaft
and the 5th gear of the input shaft.and the 5 gear of the input shaft.
•ATSUNYU Gear: It is used as the 3rd and 4th gear of the input shaft.
•HIRA Gear: It is used as the 3rd,4th and 5th gear of the counter shaft.
•DOG Gear: It is press fitted on the ATSUNYU Gear and is used for
meshing purpose.
•Final Gear: It receives power from the counter shaft and is attached
to the differential mechanism.
•Sleeve High Speed: It is used in the shifting mechanism for 3rd and
4th gear.
•Sleeve Low Speed: It is used in the shifting mechanism for the 1st
and 2nd gear.g
•Sleeve 5th Speed: It is used in the shifting mechanism for the 5th
gear.
24. Process Lines:
Input Raw Material
Process Layout:
Input Shaft:
T i
Facing and Centering Turning OP‐1 Turning OP‐2
Turning
Roll Forming OP‐1Roll Forming OP‐2
Two Spindle Gun Drilling Milling (Fuel Hole) Spline Forming OP‐1
Turning OP‐3
Gear Hobbing OP‐1 Turning OP‐4 (Grooves) Spline Forming OP‐2
Output Final Product
Gear Hobbing OP‐2 Deburring Gear Shaving OP‐1
Gear Shaving OP‐3 Gear Shaving OP‐2
Models Manufactured:
•YR9
•YC5
•YE3
Number of Process Lines: 5
Production Rate: 42.85/hour
25. Process Layout:
Counter Shaft:
Input Raw Material
Turning OP 1Facing and Centering Turning OP‐1 Turning OP‐2
Roll Forming OP‐1Roll Forming OP‐2Turning OP‐3 (Grooves)
Two Spindle Gun Drilling Milling (Fuel Hole)
Gear Hobbing
Milling (Key Forming)
Thread FormingChamfering Gear Hobbing
Output Final Product
Thread FormingChamfering
Gear Shaving
Models Manufactured:
•YN4
•YY4
•YN2
•YL8
•YE3
•YC5
Number of Process Lines: 4
Production Rate: 42.3/hour
Facing
34. Input Shaft Hard:
Process Layout:
Input Raw Material
Distortion Correction Outer Grinding OP‐1 Outer Grinding OP‐2
Number of Process Lines: 4
Production Rate: 50/hour
Distortion Correction Outer Grinding OP 1
Checking
Outer Grinding OP 2
Outer Grinding OP‐3
Output Final Product
Counter Shaft Hard:
Process Layout:Process Layout:
Input Raw Material
Number of Process Lines: 4
Production Rate: 54/hour
Distortion Correction Outer Grinding OP‐1
Checking
Outer Grinding OP‐2
Outer Grinding OP‐3
Output Final Product
38. Heat treatment:
Heat treatment refers to the heating and cooling operations required
t lt th ti f t l ll l ti d i t i lto alter the properties of metals, alloys plastic and ceramic materials.
Changes in material’s properties result from changes made in
microstructure of the material.
During heat‐treatment of a metal piece, when it is heated to a definite
temperature followed by cooling at a suitable rate, there occur changes
in the micro‐constituents of the metal. These changes in the microin the micro constituents of the metal. These changes in the micro
constituents of the metal may be in their nature, form, size and
distribution in the metal piece. Obviously, temperature of heating and
rate of cooling are the main controlling factors of changes in micro‐
constituents.
These changes in micro‐constituents then control the changes in
physical and mechanical properties of heat treated metal specimen.
The purpose of heat treatment is to achieve any one or more
objectives cited as follows:
(i) To remove strain hardening of a cold worked metal and to improve
its ductility.
(ii) To relieve internal stresses set up during cold working casting(ii) To relieve internal stresses set up during cold‐working, casting,
welding and hot‐working treatments.
(iii) To remove gases from castings, to soften a metal to improve its
machinability, and to increase the resistance to wear, heat and
corrosion.
(iv) To improve the cutting ability, i.e., hardness of a steel tool, to (iv) To improve the cutting ability, i.e., hardness of a steel tool, to
improve grain structure after hot working a metal and to remove
effects of previously performed heat‐treatment operations.
(v) To improve magnetization property, especially of steels, for
producing permanent magnets.
(vi) To refine grain structure after hot working a metal.
(vii) To soften and toughen a high carbon steel piece.
(viii) To produce a single phase alloy in stainless steel, and to produce a
hard, wear resistant case on a tough core of a steel part.
40. Step 3: Pre‐heating
In this material is held for 42 minutes at a temperature of 920° for pre
heating the components. Although here there should be no CP (carbon
potential) but it contains some as it leaks into it.
Step 4: Carburizing 1:
Here the components are held for 84 minutes at temperature of 930° C
and the CP is 0.95.
At thi t t th b d l th f th l tti i d hAt this temperature the bond length of the lattice increases and hence
carbon atoms get into it.
CP – Carbon Potential is the percentage of carbon in atmosphere of the
chamber
Step 5: Carburizing 2:
Here the components are held for 84 minutes at temperature of 930° CHere the components are held for 84 minutes at temperature of 930 C
and the CP is 0.95.
This is done to reduce the cycle time because this process is more time
consuming. Hence there are 2 Carburizing chamber to reduce the
overall time.
Step 6: Diffusing
Here the components are held for 84 minutes at temperature of 930° C
and the CP is 0.85. Carbon is allowed to get into depths.
Step 7: Hardening 1
Here the components are held for 18 minutes 30 sec at a temperature
of 830° C and ideally there should be no carbon in atmosphere but
some leaks into itsome leaks into it.
This is also called case hardening. As the temperature reduces the
lattice length reduces which results in trapping the carbon atom at the
surface hence resulting in hardening of the surface.
Step 8: Hardening 2
Here the components are held for 17 minutes at a temperature of 830°p p
C. This is done to reduce the cycle time.
41. Step 9: Quenching
After hardening material should be immediately sent for quenching g y q g
within 40 sec otherwise whole material is discarded and sent to scrap.
Quenching is done by oil by dipping it into oil, components on the jig are
placed in the chamber then oil is filled in the chamber at very faster rate.
It is very critical process for them, because in this change of micro
structure is involved. Before quenching material is pearlite and after
quenching it is martensite.
During quenching temperature is 160°C and it takes 8 min.
Step 10: Vacuum Washing:
In this process, solvent Daphenic Cleaner is used. Since this oil is
inflammable so it is not directly heated rather it is heated in heat
exchanger by exchanging heat with thermic oilexchanger by exchanging heat with thermic oil.
Solvent is heated up to the temperature of 160° C it done to remove the
quenching oil from the components. The component are submerged in it
for 1 hr. Solvent dissolves all the quenching oil from it, now with the help
of vacuum pump all the solvent is extracted from chamber and vacuum is
maintained, to break this vacuum Nitrogen is use to provide inert , g p
atmosphere because air contains moisture so it can react to form rust.
Step 11: Tempering:
It is done at 160° C & components are kept for 2 hrs in it.
Note: Curtain flame is used when material comes out of quenching and
tempering this is done so as to inhibit the air from atmosphere containing
i i id h fmoisture to enter inside the furnace.
Step 12: Shot Blasting:
In this, steel balls of diameter 2 mm imported from Japan are used. They
are first pre‐heated & then sent to rotor which pushes the steel balls at
very high speed over the components.
43. Flow meter is used to measure the flow of propane and Endothermic
gas.
Using the Infrared CO2 Analyzing Device they measure the CO2 level in
Case Hardened Gear
Using the Infrared CO2 Analyzing Device they measure the CO2 level in
Carburizing, Diffusion and hardening zone
Hard Machining Process
The material that comes after heat treatment process is then hard
machined to meet the final specification of the product. Hard machiningmachined to meet the final specification of the product. Hard machining
for the gears involve following processes:‐
1.Taper outer grinding:‐It involves grinding of the outer face of the
component. The jigs and fixtures used are base plate,pusher,collet,guide
bar and locking nut.
Base plate:‐It is the support on which the gear rests upon.
Pusher:‐Pusher is used in order to tighten the collet so that the gear is
held and grinding process could be carried upon.
Collet:‐It is used to hold the gear from its ID since it has taper ID so as
the rod is inserted inside the collet it expands and gear gets fixed on the
collet and grinding process could be done.
44. Collet
2.Taper Inner Grinding:‐
It involves grinding of the internal ID of the component. The jigs and
fixtures used are Pin cage, Out chute, Fingers and Spacers.
Pin cage: It is used for holding the gear from its outside diameter with
Collet
Pin cage:‐It is used for holding the gear from its outside diameter with
the help of the fingers.
Dressing Interval:‐It is time after which the grinding wheel is
dressed.During the grinding process the grinding wheel gets blunt in
order that we get better finishing the wheel is dressed after a specific
interval of time which varies with the material that is grinded.g
3. Gear Checking
Gear that is hard machined is then checked for P.C.D. run out ,nicks and
dents.
P.C.D. run out:‐It is used to check whether the pitch circle diameter is
within the specification mentioned. In order to check the P.C.D. the gear
i h d i h h d h di l i h d hi his meshed with the master gear and the dial gauge is attached which
measures the run out if it is not according to the spec. mentioned it is
discarded.
Besides that the gear is also checked for nicks and dents on its profile.
Nick:‐Nick is the outward extrusion in the profile of the gear.
Dent:‐Dent on the surface of the gear is also checked and if it occurs it isDent:‐Dent on the surface of the gear is also checked and if it occurs it is
discarded.
45. Assembly Operation
Mainly there are 4 Transmission assembly lines along with hub andMainly there are 4 Transmission assembly lines along with hub and
sleeve assembly, differential assembly, AMT assembly and GNT section.
They use synchronous type of transfer system. In this the work carriers
continuously move and the operators remain at their position and fit
their parts. This builds a lot of pressure on the worker and in case of
any delay or wrong pick the whole of the assembly line is halted for
some time by the operator. To meet the demand supervisors had to be
keep strict check on the workers & continuously replenish the demands
of the components.
During assembly operation transmission is continuously checked at
various stations for its major faults.
M i l h 2 t f t i i f t d MF 60 & MF 70Mainly here 2 types of transmission are manufactured MF 60 & MF 70,
number represents the distance between the input & counter shaft.
For heavy vehicles MF 70 is used for e.g. in diesel variant of most of the
cars or in heavy cars like Ertiga, SX4, etc and for small cars like Alto 800,
Astar, etc. MF 60 is used.
Quality Room:‐
The first off piece checking is done in the quality room. The component
here is examined for its various dimensions. The instruments used are:‐
Micrometer
Digital Depth Calliper
47. Other instruments used include CNC Gear tester, OBD micrometer,
Roundness testing machine etcRoundness testing machine etc.
Some of the Gear terminologies used are:‐
Lead:‐Lead is the axial advance of a helix gear tooth during one complete
turn (360°)
Outer Ball Diameter(OBD):‐A ball of particular diameter is fixed on the
micrometer and between the tooth diameter is examined which is
referred to as OBD.
Module:‐It is the unit of size that indicates how big or small a gear is. It is
the ratio of the reference diameter of the gear divided by the number of
teeth.
Backlash:‐It is defined as the clearance between the mating gears.
S i t i S i t i i th h f i f th t th' t ItSemi‐topping:‐ Semi topping is the chamfering of the tooth's top corner. It
is done to reduce noise during teeth meshing.
Helix angle:‐The angle between the axis of a helical gear and an imaginary
line that is tangent to the gear tooth.
