1. 1
PROJECT REPORT
ON
LOAD BODY ANALYSIS ON TATA XENON
(PRODUCTION ENGINEERING DEPARTMENT)
IN
Tata Motors Ltd
Pune, Maharashtra
Report by-
Akash Mane
National Institute of Technology
B. Tech Mechanical Engineering
Roll number: 123205
2. 2
Acknowledgement
I would like to profusely thank Tata Motors Ltd, Pune for giving me an
opportunity to undergo training in their reputed company. I would also like to
take this opportunity to thank all those people who have contributed to the
successful completion of this training report. I would like to express my deep
sense of gratitude towards my training coordinator Mr Arthur Gonsalvez
(Division Manager, Production Engineering Department), who’s valuableadvice
and guidance was very crucial in the completion of my project. He has been a
source of inspiration and has always encouraged me to learn new things and
meet different people throughout the duration of my project.
I would also like to sincerely thank all the other staff members namely: Mr
Narayan, Mr Prashant Pawar, Mr Amol and others for their help and support
that was provided to me during the course of my internship.
I hope that I can build upon this enriching experience and knowledge
that I have gained and make a valuable contribution towards this industry in
the coming future.
3. 3
CONTENTS
ACKNOWLEDGEMENT
TATAGROUP PROFILE
TATAMOTORS
MANUFACTURING PROCESS
PRODUCTIONENGINEERING DEPARTMENT
MISSIONANDROLEOFPE
DIECONSTITUENTS
DIEMANUFACTURING PROCESS
PATTERN SHOPAND MACHINESHOP
DIEASSEMBLY AND TRYOUT
SHEET METAL FORMING
TYPES OFPRESSES
MATERIALS USED AND THEIRPROPERTIES
FORMINGLIMITDIAGRAM
TYPES OFDIES
ASSESSMENT OFA SHEET METAL PANEL
DEFECTS, CAUSES AND WAYSTO REDUCE THEM
XENON LOADBODYFRONTDOOR
MANUFACTURING PROCESS
MEASUREMENTS AND READINGS
DEFECTS AND WAYSTO REDUCE THEM
CONCLUSION
BIBLIOGRAPHY
4. 4
TATA GROUP PROFILE
Tata Motors is one of the 32 publicly listed enterprises under the Tata
Group, India’s largest business corporation. Tata Group was established in
1868 by Jamsetji Tata and is headquartered in India. It comprises over 100
operating companies, with operations in more than 100 countries across six
continents, exporting products and services to over 150 countries. The revenue
of Tata companies, taken together, was $103.27 billion (around Rs.6,24,757
crore) in 2013-14, with 67.2 percent of this coming from businesses outside
India.
The Tata group’s core purpose is to improve the quality of life of the
communities it serves globally, through long-term stakeholder value creation
based on leadership with trust. There are 31 publicly-listed Tata enterprises
and they have a combined market capitalisation of about $128.1 billion (as on
May 28, 2015), and a shareholder base of 3.9 million. Tata companies with
significant scale include Tata Steel, Tata Motors, Tata Consultancy Services,
Tata Power, Tata Chemicals, Tata Global Beverages, Tata Teleservices, Titan,
Tata Communications and Indian Hotels.
Good corporate citizenship is part of the Tata group’s DNA. Sixty six
percent of the equity of Tata Sons, the promoter holding company, is held by
philanthropic trusts, thereby returning wealth to society. As a result of this
unique ownership structure and ethos of serving the community, the Tata
name has been respected for more than 140 years and is trusted for its
adherence to strong values and business ethics.
Each Tata company or enterprise operates independently and has its
own board of directors and shareholders, to whom it is answerable. Many Tata
companies have achieved global leadership in their businesses. Employing a
diverse workforce in their operations, Tata companies have made significant
local investments in different geographies.
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TATA MOTORS
Tata Motors Limited was founded in 1945 as a manufacturer of
locomotives. It is headquartered in Mumbai, Maharashtra, India and is a
subsidiary of the Tata Group. Tata Motors collaborated with Germany’s
Daimler Benz in 1954 for 15 years to manufacture commercial vehicles. Since
then, Tata Motors has grown vastly and produces numerous vehicles through
their three main divisions – Passenger Cars, Utility Vehicles and Commercial
Vehicles
Tata Motors Limited is India’s largest automobile company, with
consolidated revenues of INR2,32,834 crores(USD 38.9 billion) in 2013-14. Itis
the leader in commercial vehicles in each segment, and among the top in
passenger vehicles with winning products in the compact, midsize car and
utility vehicle segments. The Tata Motors Group’s over 60,000 employees are
guided by the mission “to be passionate in anticipating and providing the best
vehicles and experiences that excite our customers globally.''
The company’s head office is situated in Mumbai & the works at Pune,
Jamshedpur, Luck now & Dharwad. Tata motors ltd. Plant at Pune started its
production on small scale in 1965 & has gradually blossomed into sophisticated
huge plant. Besides commercial vehicles, the company manufactures a wide
range of engineering products such as excavators, overhead cranes, largepress
tools, special purpose machines (SPM) & various CNC machines GPM’s &
various other products.
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MANUFACTURING PROCESS
The Passenger Car Business Unit at Tata Motors basically deals with the
production of the following passenger vehicles namely: Tata Indica V2, Indica
V2 Turbo, Aria, Bolt, Indigo XL, Indigo ECS etc. whereas the Commercial Vehicle
Business Unit deals with the production of LCVS, MCVs and HCVs. The
assembly line of the PVB unit generally consists of BIW (Body in White) line,
trim lines, underbody lines, and mechanical lines. Each of these lines consists
of a several numbers of stations. After the completion of the specified
operations in one line, the body of the car moves to the next line. After the
complete assembly, several tests are performed on the car.
The order of assembly is given below:
PAINTTOUCH UP
SHOWER TEST
HEAD LAMP FOCUS
WHEEL ALIGNMENT
MECHANICAL LINE1&2
UNDERBODY 1 &2
TRIM LINE 1 & 2
BIW LINE
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PRODUCTION ENGINEERING DIVISION
The Production Engineering division is the central tool room for TATA
motors, Pune and occasionally makes tooling for Jamshedpur having the
distinction of being one of the biggest and most sophisticated tool rooms in
the Indian Subcontinent; it is also very versatile and employs around 850
employees. Here, high level of precision technology is employed for
manufacturing of press tools, Jigs and Fixtures, gauges, metal patterns and the
special tooling’s required to process various parts of the automobile. This
division has also developed several hydro-pneumatically automated dies and
fixtures for the first directly to the sophisticated CNC machines so that the die
geometry can be directly download onto the machine.
ROLE AND OBJECTIVES OF PRODUCTION ENGINEERING
Catering to the increasing needs of tooling for Tata Motors and its
ancillaries for introduction of new vehicle models.
Meeting demands of tooling for production of above models.
Introduction of new technologies in design and manufacture of tooling
to meet international standards.
Introducing new products designed and manufactured in PE.
Exporting dies to various companies.
Enhancing skill and involvement of operatives through training,
teamwork, healthy environment, self-working practices, small group
activity and suggestion box scheme.
Effective servicing and maintenance of tooling supplied by PE to Auto
Division and other In-House customers.
PE has these main Departments:
Sheet Metal Tool Design
Central Jigs and Fixtures Design
Metal pattern Design.
PE Shop Floor consists of the following sections:
Machine shop (Heavy And Light Machine Shop)
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Die Assembly Section(Die Assy-01, Die Assy-02)
Die Try Out Section
Jigs And Fixtures Assembly
Pattern Shop
Sheet Metal Fixtures
Jig Boring And Gauge Room
Process Planning & Production Control
DIE CONSTITUENTS
To cut and form a sheet metal into the required shape, dies are used. The
major components of a die are
1. Upper shoe/Lower shoe: These are structures made of steel and serve
as foundations for mounting die components. The upper and lower die
shoes assembled together with guide pins create the die set.
2. Guide pins: Guide pins ,sometimes referred to as guide posts or pillars,
function together with guide bushings to align both the upper and lower
die shoes precisely
3. Heel blocks and heel plates: Heel blocks are special steel blocks that are
precision-machined, screwed, doweled, and often welded to both the
upper and lower die shoes. They contain components called wear plates
and function to adsorb any side thrust that may be generated during
the cutting and forming processes
4. Punch: Component of the die set that stamps the metal to perform the
necessary cutting or non – cutting operation.
5. Blank Holder: Holds the outer rim of the sheet metal undergoing the
drawing operation and controls the material flow into the die radius.
6. Pad: A pad is simply a pressure-loaded plate, either flat or contoured,
that holds, controls, or strips the metal during the cutting and forming
processes.
7. Retainer: Retainers hold or secure cutting or forming die components
to both the upper and lower die shoes.
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COMP. DRG / CAD DATA
SMTD
PLANNING
PROD. CONTROL THERMOCOLE PATTERN
FABRICATION
PRIMARY M/CING
FOR
200 SERIES ITEMS
CASTING
PRIMARY M/CING PRIMARY M/CING
DIE & DRAWING BOOKED IN DIE ASSEMBLY
ASSEMBLY SECTIONS
COPY MACHINING L. DIE, U. DIE & PAD
ASSEMBLY SECTIONS FOR TOOLMAKING
WORK, HEAT TREATMENT & ASSEMBLY.
TRY - OUT
ASSEMBLY SECTIONS WITH FEEDBACK
FINAL TRY OUT & Q. A.
CERTIFICATION
DESPATCH WITH SHOP DELIVERY NOTE
CRITICAL PARAMETER
CHECKING WITH INSP. FIXTURE.
PE CAE
MANUFACTURING PROCESS
10. 10
DIE DESIGNING
Designing is the first stage of die manufacturing. SMTD department works
for die design. Die designing starting in CTED after receiving the computer
drawing.
PE PROCESS PLANNING & PRODUCTION CONTROL
The PE Planning looks after: Types of component and design of the
tooling. Whether the design is simple/ complex enough, so that it can be
processed in PE given to outside party, available machines & time required for
manufacturing.
After the design, the Process Planning department goes through the
process details and then prepares the process sheet. The Process Sheet has the
routing of the all the individual items of an assembly, which are to be
manufactured. It enlists all the operations to be done on the item in proper
sequence as well as the sections where the respective operations are to done.
Then the raw materials for the items are sent in the shop floor for machining.
The Production Control keeps track of the items being machined in various
machine shops (Turning, Milling and Grinding).
PATTERN SHOP
Pattern shop is basically divided into three departments:
1. Model Shop
2. Plastic shop
3. Thermo Cole shop
The model and the plastic shop area interrelated while the Thermo
Cole shop is independent.
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Generally, two types of models come to pattern shop:
1) Those, which can be made by hand.
2) Those, which require CNC machining. Here the CAD programs are directly
transferred to the M/C.
Previously wooden models were made. Wooden patterns are no
longer used. They are now being replaced by models with only a wooden base
supporting a mixture of resin and hardener in paste form, which is moulded to
the shape of the component according to the drawing. Plastic Patterns and
models are also made in this section.
THERMOCOL PATTERN SHOP
This section of pattern shop makes thermocol patterns of the dies designed
by the Die Design dept. The drawings are carefully studied and taking into
account all tolerances the thermocol model is made. This model is then off
loaded to outside parties, which convert the thermocol model into a solid cast
iron, die by the casting process.
Metal Patterns
Metal pattern design
This design office plays a highly specialized role in the design activities of
PE. It deals with all types of mass produced castings, right from ordinary green
sand-mold ones to high pressure aluminum die casting. This department
designs metal patterns used in mass production of castings.
Metal Pattern Shop
This section manufactures and repairs all tooling in the foundry, while the
routine maintenance is done at the foundry itself major maintenance work is
done in this section.
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MACHINE SHOP
HEAVY MACHINE SHOP
HMS which is known as a heart of P.E.
This section of the shop floor deals with the machining of all large work pieces
that cannot be handled on other smaller machines. These jobs are mainly
above 1 metric ton. This section has some of the most sophisticated machinery
in Tata Engineering. HMS consists of two sections called as SCHARMANN
section & CNC section.
Scharmann Section:
It consists of six NC machines & two CNC machines. Machining operation of
casting starts from sacharmann section. The primary machining of the dies
done through scharmann section.
CNC Section:
This shop consists of fourteen CNC machines. 3D machining of dies, ciba
material (inspection fixtures) , thermo Cole, are done in CNC machine shop.
The angular machining of cam also done on CNC. PE actively uses CNCs for
production and manufacturing of dies, punches, patterns etc. These machines
are epitomized by their high accuracy.
LIGHT MACHINE SHOP
This section handles jobs weighing less than 1 ton. This section is divided
into 3 sections:
1) Milling
2) Turning
3) Grinding section
These sections deal with the manufacturing of all small parts required in all
assemblies, gauges and other miscellaneous tooling. If high precision is
necessary then the jobs are machined here and finished in the jig boring and
gauge rooms. Otherwise, for routine jobs the entire manufacturing process is
completed here.
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DIE ASSEMBLY SHOP
This occupies the largest of the P.E. shop floor and is concerned with the
building of the dies as per design. Here all the sheet metal dies are assembled.
Here machining done is complicated and is done on CNCs. The operators in this
section are highly skilled and have excellent knowledge of drawing, as the
drawings of dies are very complicated. The surface finish of the finished
component directly depends on the dies. Hence, the dies are tried out several
times and finished accordingly. The material is supplied by the stores along
with the technical parts list accompanying the drawing set. There are two
sections in this shop:
Die Assembly-01
Die Assembly-02
DIE TRYOUT
Starting with a blank which is passed through a set of dies to create a final
part, a panel trial is taken. After the die is assembled, it is dispatched to Die
Try Out section where it is loaded on a press and tried out i.e. a trial
operation is performed. This section has presses of different capacities
(650T-2000T). The sheet metal undergoes the corresponding forming
operation depending on which die is loaded in the press.
The part obtained is inspected for defects like thinning, scoring, tool marks,
hole-pulling, wrinkling, spring back etc. may be present in the part. After
inspecting the component, bedding is done. In bedding operation, the part
is painted with a red paste and is allowed to be placed between the dies.
The component is removed and the dies are inspected. Wherever there is a
patch of color on corresponding areas of both the upper and lower dies,
that area is marked as the ‘hard spot’. These hard spots are eliminated by
grinding the surface of the die with a pneumatic grinder. This process is
repeated until the clearance between the upper and lower die has proper
clearences to produce consistent quality components within the specified
limits i.e. until no more hard spots can be found.
Normally 3 components are made and inspected by the QA section. After
their approval, the die is sent back to the assembly section feedback as per
try-out is cleared. The dies are then reloaded and necessary Q loops are
conducted to ensure proper achievement of quality parameters.
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SHEET METAL FORMING
Sheet metal is one of the most important semi-finished products used in
the steel industry and sheet metal forming technology is therefore an
important engineering discipline within the area of mechanical engineering.
Sheet metals are characterized by a high ratio of surface area to thickness.
Sheet metal forming is basically conversion of a flat sheet metal into a product
of desired shape without defect like fracture or excessive localized thinning.
In automobiles the sheet metal is formed into the desired shape &
brought into the required form to get auto body pressings like bonnet,
bumpers, doors, etc. In aircraft’s sheet metal is used for making the entire
fuselage wings and body. In domestic applications sheet metal is used for
making many parts like washing machine body and covers, iron tops, timepiece
cases, fan blades and casing, cooking utensils etc.
The products made by sheet-forming processes include a large variety of
shapes and sizes, ranging fromsimple bends to double curvatures with shallow
or deep recesses. Typical examples are metal desks, appliance bodies, aircraft
panels, beverage cans, auto bodies, and kitchen utensils. In many cases while
deforming the sheet metal, the component fractures at certain point. The
causes of failure are parameters related to forming process.
TYPES OF PRESSES
Press machine tools are of two main types, hydraulic presses and
mechanical presses. Selection of a type of machine press depends on the
factors of the manufacturing process. The first consideration would be the
basic type of process the press tool will be employed to perform. For example,
a press for metal forging, a press for extrusion, a press for impact extrusion, or
a press for sheet metal working will all have different general requirements.
The next very important factor in machine press selection for a manufacturing
operation is the press capacity required. Required press capacity is likely
related to the sizeof the work stock, and type of process. Length of strokeover
which the press delivers force is another primary factor when choosing a press
machine tool, this also will be related to the basic type of process being
employed.
15. 15
Hydraulic Press: The basic working principles of the hydraulic press are
simple, and rely on differences in fluid pressure. Fluid is pumped into the
cylinder below the piston, this causes the fluid pressure under the piston to
increase. Simultaneously, fluid is pumped out of the top channel, causing the
fluid pressure above the piston to decrease. A higher pressure of the fluid
below the piston than the fluid above it causes the piston to rise. In the next
step, fluid is pumped out from below the piston, causing the pressure under
the piston to decrease. Simultaneously, fluid is pumped into the cylinder from
the top, this increases the fluid pressureabovethe piston. A higher pressure of
the fluid above the piston, than the fluid below it, moves the piston
downward.
16. 16
Mechanical Press: Primarily, the mechanical press transforms the
rotational force of a motor into a translational force vector that performs the
pressing action. Therefore, the energy in a mechanical press comes from the
motor. These types of presses are generally faster than hydraulic or screw
presses, (actually the screw press may also be classified as a mechanical press).
Unlike some presses, in a mechanical press, the application of force varies in
both speed and magnitude throughout the distance of the stroke. When
performing a manufacturing operation using a mechanical press, the correct
range of the stroke is essential.
MATERIALS USED AND THEIR PROPERTIES
Material K (GPa) n E(GPa)
Poisson
’s Ratio
Uses
EDD513 0.501 0.2415 210 0.3
Skin panels and geometries
requiring high stretch
D513 0.58 0.203 210 0.3 For all medium complexity
geometries
DD1079 0.854 0.29 210 0.3
E34 0.854 0.29 210 0.3 All members requiring high yield
strength
E38 0.76 0.183 210 0.3
BSK46 0.73 0.133 200 0.33
IFHS350 0.704 0.21 200 0.33 Suitable for skin panels and
medium complexity geometries.
IFHS400 0.72 0.2-0.24 200 0.33
DP400/600 1.08 0.14 200 0.33
High strength steels mostly suitable
for open sections like channels and
pillars
DP500/800 1.303 0.14 200 0.33
17. 17
FORMING LIMIT DIAGRAM
Formability is the ability of sheet metal to undergo shape change
without failure by necking or tearing. A forming limit diagram, also known as
a forming limit curve, is used in sheet metal forming for predicting forming
behavior of sheet metal. The diagram attempts to provide a graphical
description of material failure tests. This concept of FLD reflects the maximum
principal strains that can be sustained by sheet metals prior to the start of
localized necking.
As seen from the figure, the major strain is always positive (stretching), the
minor strain may be positive or negative.
R is the normal anisotropy of the sheet.
Sheet metal is marked with small circles, stretched over a punch and
deformation is observed in failure areas. FLD shows boundary between safe
and failure zones. In production, FLD is used to predict the safety margin of the
process and direct the designer to improve forming process and tryoutthe
dies.
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TYPES OF DIES
The metal stamping die is an ideal tool that can produce large quantities
of parts that are consistent in appearance, quality, and dimensional accuracy.
Stamping is a cold-forming operation, which means that no heat is introduced
into the die or the sheet material intentionally. However, because heat is
generated from friction during the cutting and forming process, stamped parts
often exit the dies very hot. The die's cutting and forming sections typically are
made from special types of harden able steel called tool steel. Dies also can
contain cutting and forming sections made from carbide or various other hard,
wear-resistant materials.
There are many kinds of stamping dies, all of which perform two basic
operations.
CUTTING DIES
Trim Die: Trimming dies cut away excess or unwanted irregular features
from a part, they are usually the last operation performed.
Blank die: A dual purpose cutting operation usually performed on a
larger scale, blanking is used in operations in which the slug is saved for
further press working. It also is used to cut finished piece parts free from
the sheet metal. The profiled sheet metal slug removed from the sheet by
this process is called the blank or starting piece of sheet metal that will be
cut or formed later.
Pierce die: Piercing is a metal cutting operation that produces a round
or square hole in flat sheet metal or a formed part. The cutting punch that
produces the hole is called the pierce punch, and the hole the punch enters
is called the matrix.
Part off die: Part off operation is a cutting operation, in which shearing
the sheet into two or more pieces is involved.
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NON CUTTING DIES
Draw die: Draw dies create the part shape by controlling metal flow
into a cavity and over the forming punch. Draw dies utilize a special
pressure-loaded plate or ring called a draw pad or blank holder to control
the metal's flow into the cavity. This plate prevents the metal from
wrinkling as it flows into the cavity. Increasing or decreasing the pressure
exerted under the pad also controls how much metal feeds into the die.
Form die: All forming operations deform sheet material by exposing it
to tension, compression, or both. Most part defects, such as splits and
wrinkles, occur in forming operations. Successful sheet metal forming
relies heavily on the metal's mechanical properties. The metal being
formed must have the ability to stretch and compress within given limits.
It also must be strong enough to satisfy the part's fit and function.
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Restrike die: The restrike die operation fundamentally is a solid
forming operation. The main difference is that a restrike die is used after
most of the major forming already has been performed. The restrike die
function is to finish forming features that could not be obtained in a
previous operation. Restrike dies add details such as sharp radii and small
embosses. They also help compensate for spring-back that occurred
during the initial forming. A restrike die operation often follows a drawing
or trimming operation.
Flanging die: Flanging is bending metal along a curved axis. Two basic
types of flanges are tension or stretch flanges, and compression or shrink
flanges. Tension flanges are susceptible to splitting & shrink flanges are
susceptible to wrinkling. Flanges are created using a flanging die that
wipes the metal between a punch and a lower die section. Both tension
and compression occur during the flanging process.
Bending die: Bending can be defined simply as a forming operation in
which the metal is deformed along a straight axis. Items such as tabs and
channels are created using the bending process. Among the various
bending methods are wipe bending, V bending, and rotary bending. Both
compression and tension occur during bending. Compression occurs on
the inside radius, while tension occurs on the outside radius.
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ASSESSMENT OF A SHEET METAL PANEL
Before a sheet metal panel is welded to the mating part, it has to be
checked for various criteria so that the part fits and aligns between the two
surfaces. This examination is done on a checking fixture.
Checking fixture:
Checking fixture is a scale to measure complicated parts. It is a
measuring device on which the part sits as it would in the actual vehicle so as
to simulate its behavior on the vehicle. For the manufacturing of a checking
fixture, an assemblage of Cibatool blocks of specified dimensions are CNC
machined which cuts out the required 3D shape of the fixture. The fixture is
then painted and attachment of clamps, templates and gauges is done. Clamps
& templates are used in the fixture to hold the component tightly because
there should not be any movement of the component while measuring.
Gauges are used to check the hole-size. The sheet metal part is placed on the
checking fixture and adjusted using Primary Locating Points (PLPs) pins. 3mm
rectangular pads are attached at specific locations on the checking fixture.
22. 22
The economy of production can be improved by using a fixture by
allowing smooth operation and quick transition from part to part, reducing the
requirement for skilled labor by simplifying conformity across a production
run. The shape of the fixture consists of the base plate which is located
horizontally. On the base plate we have to attach the vertical plates by welding
process.
Matching area:
Matching area is the zone where the mating area of one sheet metal
part sits matches with its corresponding neighbouring parts and has to be spot
welded. These are marked in red color on the checking fixture.
Gap and Flush:
Gap and flush measurement is commonly carried out to examine fit and
alignment between two surfaces. For example, the gap between car front floor
and firewall .If fit and finish is out of specification it not only affects the
aesthetics of the product but also the performance, efficiency and risk of
failure.
The gap between the sheet metal and checking fixture for a part is
measured with the help of a tapered measuring scale. When the scale is placed
in between the sheet metal and the checking fixture at a certain point (A, B,
C.), the number coinciding on the scale with the point marked is taken as the
reading. Flushness can be measured with the help of a Vernier Caliper.
Quality Check:
The sheet metal panel is inspected for any defects which can be
classified further as geometrical and aesthetical defects. The inspection is done
visually or in a green room.
If the quality standards are not met then the report is sent back and
further modifications are made in the die.
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DEFECTS AND WAYS TO REDUCE THEM
Wrinkling: One of the primary defects that occurs in deep drawing
operations is the wrinkling of sheet metal material, generally in the wall or
flange of the part. The flange of the blank undergoes radial drawing stress and
tangential compressive stress during the stamping process, which sometimes
results in wrinkles. Wrinkling is preventable if the deep drawing system and
stamped part are designed properly.
Several factors can cause wrinkles in deep drawn parts, including:
• Blank holder pressure
• Die cavity depth and radius
• Friction between the blank, blank holder, punch and die cavity
• Clearances between the blank, blank holder, punch and die cavity
• Blank shape and thickness
Burr: A burr is a rough edge or ridge left on an object, especially of a metal,
by action of a tool or machine. It is usually an unwanted piece of material and
is removed with a deburring tool in a process called 'deburring'. Burrs are most
commonly created after machining operations, such
as grinding, drilling, milling or turning. It may be present in the form of a fine
wire on the edge of a freshly sharpened tool or as a raised portion of a surface;
this type of burr is commonly formed when a hammer strikes a surface.
24. 24
Surface Scratches: This occurs when the die and punch do not have a
smooth surface. Insufficientlubrication is also another causeof surface
scratches. To reduce these scratches we smoothen the surfaceof the die and
punch by polishing and grinding.
Thinning: Thinning is defined as the reduction in the given specified
thickness of the sheet metal due to stretching. The maximum acceptable
thinning percentage for sheet metal at Tata Motors is 20%. Too much of a
blank holder pressureand friction may causethinning of the walls and fracture
at the flange bottom and corners.
Waviness: Waviness is defined as a curvy shapeor profile which is not
uniformor smooth. This issue can be resolved by increasing matching area and
cushion pressurein the press.
Crack: A thin line in the surfaceof something that is broken but not
separated into 2 pieces.
Orange Peel: A surfaceroughening defect encountered in forming
products frommetal stock that has a coarsegrain size. It is due to the uneven
flow or to the appearanceof the overly large grains usually the result of
annealing at too high a temperature.
Fracture: Too much of a blank holder pressureand friction may cause
thinning of the walls and a fractureat the flange, bottom and the corners of
any sheet metal.
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XENON LOAD BODY FRONT DOOR
A pickup truck is a light duty truck having an enclosed cab and an open
cargo area with low sides and tailgate. Tata Xenon is a pickup
truck manufactured by Tata Motors. The Xenon is powered by newly
developed 2.2L common rail turbo diesel 140 PS (103 kW) engine (DICOR) [i.e.
Direct injection Common Rail].
The load body front floor is attached at the inside of the rear end of the
pick-up. It forms the inner side of the back door. This part is joined with the
outer side by screws and also by spot welding and some places. When the load
body front floor is closed, it can be used to safely store the goods and prevent
it from falling out. When it is open, it facilitates the easy stocking and
withdrawal of the goods.
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MANUFACTURING PROCESS:
In the try-out section, the operation sequence to manufacture the load
body front floor consists of the following two steps:
Blank and Pierce: Blanking and piercing are shearing processes in which
a punch and die are used to modify the sheet metal raw material. In blanking
the punched out piece is used and called a blank; in piercing the punched out
piece is scrap. Theblank and pierce die is inserted in the press to performthis
operation. In the try-outsection for the manufacturing of Load body front
floor, the piece of sheet metal required is cut fromthe stock material with the
help of a laser cutting machine .The holes are made with the help of laser
cutting machine. The sheet metal then moves on to the press whereformand
flange down operation is done. Laser cutting is done during the blank
development phase. Once the laser cut profile is finalised, the blank die is cut
to the finalised laser blank profile.
Form and flange down: In the forming process, the shape which is
imprinted on the punch and die is stamped on the blank of sheet metal which
produces the required design and shape. In the flange down process, bending
of the edges of sheet metal is done to 900
along an axis. In the load body front
floor, the corners of the sheet metal on three sides are bent down.
27. 27
The material used in the manufacture of load body front floor is D-513
automobile steel.
The properties of D-513 are listed below:
Strength coefficient (K) = 0.58 GPa
Work hardening coefficient (n) = 0.203
Young’s Modulus = 210 GPA
Poisson’s Ratio = 0.3
The ‘Load body front floor’ part hence obtained from the tryout dies after the
forming operations has to be checked for various criteria such as geometrical
and aesthetic defects. The geometrical parameters such as gap, flush,
matching area are verified on a checking fixture.
28. 28
MEASUREMENTS AND READINGS
Part Details:
Part No. 289670108284
Part Name Load body front floor
ERC Modification B7
PECAE revision NR-5
Released for (E1/E2/E3) Metal machining
Material Properties:
n value 0.200
r value (0/45/90 degree)1.29/1.33/1.30
Young’s Modulus 210,000.00 MPa
Yield Strength 237 MPa
UTS 344.9 MPa
Simulation Setup:
Material D-513
Thickness 1.60 mm
Master surface Upper side of initial blank
Blank size 1448 x 492
Material yield 96.4 %
Coefficient of friction 0.140
Binder stroke UpperLower 30 mm20 mm
Pad force UpperLower 40 T 120 T
Minimum draw tonnage 450 T
29. 29
Press used:
A 500 T BB (Big Bed) press has to be used for the production of the load body
frontfloor. Since the 500 T press is not available currently, the 1100 T tryout
press is used.
Press 1100 TTryout Press
Type of Press Hydraulic
Cushion Pressure(UpperLower) 40 T 120 T
Minimum Draw Tonnage 450 T
Tonnage used 1100 T
Thin sheets are frequently required to have good ductility and high
strength. r- and n-values are often also determined via tensile tests in order to
characterizeforming properties; the n-value describes the work hardening –
increase in stress – during plastic deformation up to uniform elongation, while
the r-valuedescribes the vertical anisotropy. The n-valueis determined from
the tensile stress data and strain values; for the r-valuethe transversestrain on
the tensile specimen is measured.
n value: The strain hardening exponent (also called strain hardening index),
noted as n, is a materials constant which is used in calculations for stress–
strain behaviour in work hardening.
In the formula
σ = K ε n
σ represents the applied stress on the material,
ε is the strain,
K is the strength coefficient.
The value of the strain hardening exponent lies between 0 and 1. A value
of 0 means that a material is a perfectly plastic solid, while a value of 1
represents a 100% elastic solid. Mostmetals havean n value between 0.10 and
0.50.
30. 30
r value: The Lankford coefficient (also called Lankford value, R-value, or
plastic strain ratio) is a measureof the plastic anisotropy of a rolled sheet
metal. This scalar quantity is used extensively as an indicator of
the formability of recrystallized low-carbon steel sheets.
For sheet metals, the R values are usually determined for three different
directions of loading in-plane (00
,450
,900
to the rolling direction) and
the normalR-value is taken to be the average
Yield strength: It is the stress at which a specific amount of plastic
deformation is produced, usually taken as 0.2 per cent of the unstressed
length.
Quality requirements:
The % OK requirements are 90% for matching area, 90% for trim line
and 100% for holes. 3mm rectangular pads are attached at specific locations
on the checking fixture. The load body front floor rests on these pads. A
tolerance of ±1 mm is given for the readings taken for gap measurement. The
specified norm is 3mm. Thus if the value for gap lies in between 2 mm to 4 mm
, the reading at that check point is considered as OK. For flush measurement,
the specified norm is 0 mm and the tolerance is ±1 mm. Templates have a
specified norm of 3mm and their tolerance is ±0.5 mm. If the readings
obtained for matching area, trim line and holes, on the sheet metal are greater
than or equal to the required percentage criteria, the part is considered as OK.
31. 31
Trim Table:
S.N
O
CHK
PTS
SPECIFIED
NOM &
TOLERAN
CE
(8/6/15) (11/6/15) (12/6/15)
GAP FLUSH GA
P
FLUS
H
GAP FLUS
H
1 A 3.0 ± 1.0 3.0 2.6 2.6
2 B 3.0 ± 1.0 3.0 2.5 2.5
3 C 3.0 ± 1.0 3.2 2.5 2.6
4 D 3.0 ± 1.0 2.6 2.6 2.6
5 E 3.0 ± 1.0 2.3 2.5 2.5
6 F 3.0 ± 1.0 2.4 2.6 2.6
7 G 3.0 ± 1.0 2.4 2.7 2.7
8 H 3.0 ± 1.0 2.9 2.5 2.9
9 I 3.0 ± 1.0 3.0 2.4 3.0
10 J 3.0 ± 1.0 2.6 2.4 2.9
11 K 3.0 ± 1.0 3.2 2.4 2.9
12 L 3.0 ± 1.0 3.8 2.6 3.0
13 M 3.0 ± 1.0 4.0 2.5 2.6
14 N 3.0 ± 1.0 3.9 2.7 2.7
15 O 3.0 ± 1.0 3.8 2.8 2.5
16 P 3.0 ± 1.0 4.1 3 2.7
17 Q 3.0 ± 1.0 2.6 3 3.0
18 R 3.0 ± 1.0 2.5 2.6 2.5
19 S 3.0 ± 1.0 2.2 2.4 2.2
20 T 3.0 ± 1.0 2.4 2.7 2.4
21 U 3.0 ± 1.0 2.2 2.6 2.7
22 V 3.0 ± 1.0 2.2 2.7 2.5
23 W 0.0 ± 1.0 0.8 0 0
24 X 0.0 ± 1.0 1.0 -1.5 -1
25 Y 0.0 ± 1.0 1.4 -0.2 0
33. 33
Match Table:
S.N
O
CH
K
PTS
SPECIFIED
NOM &
TOLERANC
E
(8/6/15) (11/6/15) (12/6/15)
GAP FLUSH
GAP
FLUS
H
GAP FLUSH
1 A 0 TO 1.0 0.8 0.1 0.6
2 B 0 TO 1.0 0.8 0.5 0.2
3 C 0 TO 1.0 0.6 0.1 0.2
4 D 0 TO 1.0 0.4 0.8 0.2
5 E 0 TO 1.0 0.2 0.7 0.1
6 F 0 TO 1.0 0.4 0.6 0.2
7 G 0 TO 1.0 0.4 0.3 0.1
8 H 0 TO 1.0 0.4 0.9 0.1
9 I 0 TO 1.0 0.5 1 0.2
10 J 0 TO 1.0 0.5 0.9 0.2
11 K 0 TO 1.0 0.7 0.7 0.3
12 L 0 TO 1.0 0.7 0.8 0.3
13 M 0 TO 1.0 0.3 0.5 0.2
14 N 0 TO 1.0 0.4 1 0.1
15 O 0 TO 1.0 0.4 1 0.1
16 P 0 TO 1.0 0.5 0.9 0.2
17 Q 0 TO 1.0 0.3 0.5 0.5
18 R 0 TO 1.0 0.2 0.7 0.2
19 S 0 TO 1.0 -0.4 1 0.1
20 T 0 TO 1.0 -0.5 0.5 0
21 U 0 TO 1.0 -0.3 0.8 0
22 V 0 TO 1.0 -0.7 0.7 0
23 W 3.0 TO 4.0 3.1 3 3
34. 34
24 X 3.0 TO 4.0 3.0 3.1 3
25 Y 3.0 TO 4.0 2.7 3.1 3
26 Z 3.0 TO 4.0 3.8 3.3 3
27 A1 3.0 TO 4.0 3.9 3.3 3.1
28 B1 3.0 TO 4.0 3.9 3.1 3
29 C1 3.0 TO 4.0 3.9 3.2 3
30 D1 3.0 TO 4.0 3.4 3.0 3
31 E1 3.0 TO 4.0 3.9 3.1 3
32 F1 3.0 TO 4.0 3 3 3
33 G1 3.0 TO 4.0 3.6 3.1 3
34 H1 3.0 TO 4.0 2.9 3 3
35 I1 3.0 TO 4.0 2.9 3 3
36 J1 3.0 TO 4.0 3.5 3.4 3
37 K1 3.0 TO 4.0 2.8 3 3
38 L1 3.0 TO 4.0 3.7 3.3 3
39 M1 3.0 TO 4.0 3.4 3.2 3.1
40 N1 3.0 TO 4.0 3.4 3.4 3.2
41 O1 3.0 TO 4.0 3.2 3.5 3.3
42 P1 3.0 TO 4.0 3.6 3.6 3.3
43 Q1 3.0 TO 4.0 3.9 3.5 3.4
44 R1 3.0 TO 4.0 3.5 3.2 3.1
45 S1 3.0 TO 4.0 2.9 3.0 3
46 T1 3.0 TO 4.0 2.6 2.7 2.7
47 U1 0 TO 1.0 -0.3 0.1 0
48 V1 0 TO 1.0 -0.1 0.1 0
49 W1 0 TO 1.0 -0.3 0.1 0.1
50 X1 0 TO 1.0 0.2 0.5 0
51 Y1 0 TO 1.0 0.2 0.1 0.2
36. 36
Holes Table:
The load body frontfloor consists of 6 holes in total out of which 2 of
them arePrimary Locating Points (PLPs). PLP ‘A’ signifies that the hole is of
great importance. The diameter/size of the hole is measured with the help of a
Vernier caliper whereas the position of the hole is checked with a gauge which
has a ±1 mm tolerance. All dimensions are in mm.
Hole
No.
Cluster
Class
Specified
dia. &
tolerance
(mm)
Check 8/6/15 11/6/15 12/6/15
1 PLP ‘A’ 19.00 ± 0.2 Size 19.1/19.1 19.1/19.1 19.1/19.1
Position PLP OK PLP OK PLP OK
2 PLP ‘A’ 19.00 ± 0.2 Size 19.1/19.3 19.1/19.2 19.1/19.2
Position PLP OK PLP OK PLP OK
3 20.00 + 0.5 Size 20.2/20.3 20.1/20.4 20.3/20.9
Position OK OK NOT OK
4 12.00 + 0.5 Size 12.4/12.3 12.8/13.4 12.3/12.2
Position OK NOT OK OK
5 12.00 + 0.5 Size 12.5/12.8 13.0/12.9 12.3/12.4
Position NOT OK NOT OK OK
6 20.00 + 0.5 Size 20.4/20.7 20.5/20.1 20.7/20.1
Position NOT OK OK NOT OK
OK 6 6 6
TOTAL 6 6 6
% OK 100% 100 % 100%
37. 37
DEFECTS OBSERVED, THEIR CAUSES AND WAYS TO
REDUCE THEM
Scoring marks & shock lines: The marring or scratching of any
formed part by metal pickup on the punch or die results in scoring marks on
the flange.
`Ways to reduce scoring marks and shock lines-
Futura Nano Coating : Ideal for applications where the tools are subject
to a high thermal load, Futura Nano titanium aluminum nitride tool
coatings feature a Nano layered structure engineered to provide an
optimum balance between hardness and internal stress, which helps to
reduce the propagation of cracks and delay the onset of failure. These
tool coatings also have improved sliding properties.
The coatings offer improved performance through higher speeds and
feeds, while eliminating the use of coolants. Titanium aluminum nitride
tool coatings are ideal for application on abrasive and difficult to
machine materials such as cast iron and heat treated steel and stainless
steel.
Key specifications of Futura Nano:
Thickness: 4 µm
Micro hardness: 3300hv
Thermal stability up to 900ºC
Coefficient friction vs. steel: 0.3 - 0.35
Physical Vapor Deposition: PVD describes a variety of vacuum
deposition methods used to deposit thin films by the condensation of a
vaporized form of the desired film material onto various work piece
surfaces.
Nitriding: Nitriding is a heat treating process that diffuses nitrogen into
the surface of a metal to create a case-hardened surface. These
processes are most commonly used on low-carbon, low-alloy steels.
Scoring can also be reduced by grinding, polishing and stoning on the
inner surface of the die so that these marks are not produced on the
upcoming sheet metal.
38. 38
Galling: Galling is a form of wear caused by adhesion between sliding
surfaces. When a material galls, some of it is pulled with the contacting
surface, especially if there is a large amount of force compressing the surfaces
together.
Causes: Galling is caused by a combination of friction and adhesion
between surfaces. Galling is most commonly found in metal surfaces that are
in sliding contact with each other. It is especially common where there is
inadequate lubrication between the surfaces. However, certain metals will
generally be more prone to galling, due to the atomic structureof their crystals
Ways to reduce galling: Galling occurs in forming of stainless
steel due to lubricant film breakdown leading to scoring and bad surface
quality. By hardening the sheet metal and by providing adequate lubrication
between the surfaces, we can prevent galling.
Waviness and Thinning:
Waviness is defined as a curvy shape or profile which is not uniform or
smooth. Thinning is defined as the reduction in the given specified thickness of
the sheet metal due to stretching. The maximum acceptable thinning
percentage for sheet metal at Tata Motors is 20%.
Causes and ways to reduce:
Waviness can be reduced by increasing matching area and cushion
pressure in the press.
Too much of a blank holder pressure and friction may cause thinning of
the walls and fracture at the flange bottom and corners.
Tool marks:
These are caused if there is a rough contact between some surface of
the die and the sheet metal. This can be reduced by performing operations
such as grinding, polishing and stoning.
39. 39
Deformations around all depressions:
An even surface is not obtained on the area surrounding embosses on
the load body front floor. The surface obtained has an uneven profile and the
gap can be measured by using a filler gauge. To reduce this, the contact area
has to be increased.
Burr:
A burr is a rough edge or ridge left on an object, especially of a metal, by
action of a tool or machine. It is usually an unwanted piece of material and is
removed with a deburring tool in a process called 'deburring'. Burrs are most
commonly created after machining operations, such
as grinding, drilling, milling or turning. It may be present in the form of a fine
wire on the edge of a freshly sharpened tool or as a raised portion of a surface;
this type of burr is commonly formed when a hammer strikes a surface.
INFERENCE
Parameter Required Value Observed Value
Matching Area 90% 97%
Trim 90% 96%
Holes 100% 100%
Thinning 20% within limits
The required quality parameters i.e. matching area, trim and holes
percentage were within the required limits.
Thinning of the panel was less than 20%.
Other defects like cracking, tool-marks and wrinkles were not present in
the part.
40. 40
CONCLUSION
The primary objective of this project was for the xenon load front floor
part to meet all the quality assurance requirements. This report provides a
summary of operations taking place in the production engineering division and
in particular the automotive body die-tryout section. During my project, I
learnt about the role of production engineering division & basic processes
involved in the manufacturing of dies, die constituents, different types of sheet
metal dies & presses and processes involved in the assembly of parts in a car.
The report provides information on various types of automobile sheet
metal used, their properties and the steps of forming operations performed on
a blank of sheet metal. Regarding the assessment of sheet metal, I was able to
identify defects, understand their causes and remedies and also learn about
methods used to analyze the part with the help of checking fixture, gap and
flush measurement etc. One can also understand in brief on where the load
body front floor fits and what its uses are in Tata Xenon. Once the load body
frontfloor is sent for quality check visually, the defects on sheet metal part can
be observed. To reduce the number of defects, necessary modifications have
to be done in the die set in try-out section. Once the die set is corrected, it can
be sent over to another block for mass production of that sheet metal part.
BIBLIOGRAPHY
References:
www.tatamotors.com
www.peweb.com
Basic information about die design and manufacturing
