butting bracket

8/11/2019 Butting Bracket

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ABSTRACT

In modern world reducing material cost is not an easy job because design

approval has to be obtained and trial run should be done with that particular

component in the engine. Instead of targeting the material cost, we addressed the

tool cost which is directly under our control. Initially, we listed out the total tools

used for machining a cylinder head and their corresponding tool costs are also

tabulated. From the tabulations operation 315 contributes 50% of tool cost. So our

team decided to concentrate on facing & centering process which is enlarging push

rod holes and drilling and tapping mounting holes. In operation 315 we focused on

solid carbide drill and U drill which consumes more cost. Actually two

regrinding were done previously in the solid carbide drill. We have planned to

increase the life time of the carbide tool by regrinding four times thereby reducing

the shank portion. Still it consumes more cost due to various reasons like cost of

regrinding is high, frequent tool change, etc. Instead of using the solid carbide drill

we have planned to use the U drill with inserts for those operations. If the inserts

are worn out it can be replaced easily and the cost of inserts is also less. By this

approach we reduced the tool cost of the cylinder head.

Keywords: Tool cost, Operation 315, Solid carbide drill, U drill, Regrinding.


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CHAPTER 1

1.1 PROFILE OF THE COMPANY

Following the independence of India, Pandit Jawaharlal Nehru, Indias firstPrime Minister, persuaded Mr Raghunandan Saran, an industrialist, to enter

automotive manufacture. The company began in 1948 as Ashok Motors, to

assemble Austin cars. The company was renamed and started manufacturing

commercial vehicles in 1955 with equity participation by British Leyland.Today

the company is the flagship of the Hinduja Group, a British-based and Indian

originated transnational conglomerate.

Early products included theLeyland Cometbus which was a passenger body

built on a truck chassis, sold in large numbers to many operators, including

Hyderabad Road Transport, Ahmedabad Municipality, Travancore State Transport,

Bombay State Transport and Delhi Road Transport Authority. By 1963, the Comet

was operated by every State Transport Undertaking in India, and over 8,000 were

in service. The Comet was soon joined in production by a version of the LeylandTiger.

Ashok Leyland had collaboration with the Japanese company Hino Motors

from whom the technology for the H-series engines was bought. Many indigenous

versions of H-series engine were developed with 4 and 6 cylinder and also

conforming to BS2 and BS3 emission norms in India. These engines proved to be

extremely popular with the customers primarily for their excellent fuel efficiency.

Most current models of Ashok Leyland come with H-series engines.

Ashok Leylands long-term plan to become a global player by benchmarking

global standards of technology and quality was soon firmed up. Access to
http://en.wikipedia.org/wiki/Pandit_Jawaharlal_Nehruhttp://en.wikipedia.org/wiki/Pandit_Jawaharlal_Nehruhttp://en.wikipedia.org/w/index.php?title=Mr_Raghunandan_Saran&action=edit&redlink=1http://en.wikipedia.org/wiki/Ashok_Motorshttp://en.wikipedia.org/wiki/Austin_Motor_Companyhttp://en.wikipedia.org/wiki/British_Leylandhttp://en.wikipedia.org/wiki/Hinduja_Grouphttp://en.wikipedia.org/wiki/United_Kingdomhttp://en.wikipedia.org/w/index.php?title=Leyland_Comet&action=edit&redlink=1http://en.wikipedia.org/wiki/Leyland_Tiger_%28front-engined%29http://en.wikipedia.org/wiki/Leyland_Tiger_%28front-engined%29http://en.wikipedia.org/wiki/Hino_Motorshttp://en.wikipedia.org/wiki/Hino_Motorshttp://en.wikipedia.org/wiki/Leyland_Tiger_%28front-engined%29http://en.wikipedia.org/wiki/Leyland_Tiger_%28front-engined%29http://en.wikipedia.org/w/index.php?title=Leyland_Comet&action=edit&redlink=1http://en.wikipedia.org/wiki/United_Kingdomhttp://en.wikipedia.org/wiki/Hinduja_Grouphttp://en.wikipedia.org/wiki/British_Leylandhttp://en.wikipedia.org/wiki/Austin_Motor_Companyhttp://en.wikipedia.org/wiki/Ashok_Motorshttp://en.wikipedia.org/w/index.php?title=Mr_Raghunandan_Saran&action=edit&redlink=1http://en.wikipedia.org/wiki/Pandit_Jawaharlal_Nehru


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international technology and a US$200 million investment programme created a

state-of-the-art manufacturing base to roll out international class products. This

resulted in Ashok Leyland launching the 'Cargo' range of trucks based on European

Ford Cargo trucks.

In association with the Australian company Eden Energy, Ashok Leyland

successfully developed a 6-cylinder, 6-liter 92 kW BS-4 engine which uses

Hythane (H-CNG,) which is a blend of natural gas and around 20% of hydrogen.

Hydrogen helps improve the efficiency of the engine but the CNG aspect makes

sure that emissions are at a controlled level. A 4-cylinder 4-litre 63 KW engine is

also being developed for H-CNG blend in a joint R&D program with MNRE

(Ministry of New and Renewable Energy) and Indian Oil Corporation.

The H-CNG concept is now in full swing, with more than 5,500 of the

technologys vehicles running around Delhi. The company is also already

discussing the wide-scale use of Hythane engines with the Indian government.

Hythane engines may be expected in the near future, but these may not be brought

to the United States as yet. Ashok Leylands partnership with Nissan is also

focusing on vehicle, powertrain, and technology development listed under three

joint ventures. With impressive investment, the joint ventures will focus on

producing trucks with diesel engines that meet Euro 3 and Euro 4 emission

standards.

An Ashok Leyland-Nissan joint venture produced light commercial vehicles(LCVs) from the former's Hosur facility near Bangalore as well as from Renault-

Nissan's car plant near Chennai.
http://en.wikipedia.org/wiki/Ford_Cargohttp://en.wikipedia.org/w/index.php?title=Eden_Energy&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Eden_Energy&action=edit&redlink=1http://en.wikipedia.org/wiki/Ford_Cargo


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1.2 Major Achievements of Ashok Leyland, listed as follows:

In 1993, became first Indian Auto Company to receive ISO 9002

certification.

Received ISO 9001 certification in 1994, QS 9000 in 1998, and ISO 14001

certification for all vehicle manufacturing units in 2002.

Became the first Indian auto company to receive the latest ISO/TS 16949

Corporate Certification (in July 2006).

First company to introduce full air brakes, power steering and rear engine

bus in India.

Ashok Leyland has a near 85% market share in the Marine Diesel engines

markets in India

It is one of the leading suppliers of defense vehicles in the world and also

the leading supplier of logistics vehicles to the Indian Army.

1.2 Manufacturing Facilities:

The company has seven manufacturing locations in India:

o Ennore,Tamil Nadu

o Hosur,Tamil nadu (Hosur - 1, Hosur - 2, CPPS)

o Alwar,Rajasthan

o Bhandara,Maharashtra

o Pantnagar,Uttarakhand
http://en.wikipedia.org/wiki/Ennorehttp://en.wikipedia.org/wiki/Hosurhttp://en.wikipedia.org/wiki/Tamil_naduhttp://en.wikipedia.org/wiki/Alwarhttp://en.wikipedia.org/wiki/Rajasthanhttp://en.wikipedia.org/wiki/Bhandarahttp://en.wikipedia.org/wiki/Maharashtrahttp://en.wikipedia.org/wiki/Pantnagarhttp://en.wikipedia.org/wiki/Uttarakhandhttp://en.wikipedia.org/wiki/Uttarakhandhttp://en.wikipedia.org/wiki/Pantnagarhttp://en.wikipedia.org/wiki/Maharashtrahttp://en.wikipedia.org/wiki/Bhandarahttp://en.wikipedia.org/wiki/Rajasthanhttp://en.wikipedia.org/wiki/Alwarhttp://en.wikipedia.org/wiki/Tamil_naduhttp://en.wikipedia.org/wiki/Hosurhttp://en.wikipedia.org/wiki/Ennore


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2. INTRODUCTION

2.1 INTRODUCTION TO CAMSHAFT:

In internal combustion engines with pistons, the camshaft is used to operate

poppet valves. It then consists of a cylindrical rod running the length of the

cylinder bank with a number of lobes protruding from it, one for each valve. The

cams force the valves open by pressing on the valve, or on some intermediate

mechanism as they rotate.

Ashok Leyland manufactures inline, 6 & 4 cylinder engines. So the Cam

Shaft consists of 12 & 8 cams through the length depending on the number of

cylinders. These cams are placed at regular intervals and at specific angles.

The model of the camshaft is shown in the figure:

Fig.1 Camshaft model of AL 6 cylinder engine.


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2.2 FUNCTIONS OF CAMSHAFT:

A camshaft is commonly used to operate poppet valves in the engine.

It is situated in the cylinder block or cylinder head and has oblong lobes called

cams which push the intake and exhaust valves. The force is applied on the valve

directly or through push rod and rocker arm assembly.

The camshaft receives its motion from the crankshaft, from which all of the

accessories also must be driven. The camshaft provides a means of actuating the

opening & controlling the period before closing, both inlet as well as exhaust

valves. It provides a drive for the ignition distributor and the fuel pump through

gear train. It also drives the oil pump with the help of a gear provided in the middle

of the camshaft.


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Fig 2 - Cam and follower arrangement

2.2.1 Cam Shaft Timing:

The relationship between the rotation of the camshaft and the rotation of the

crankshaft is of critical importance. Since the valves control the flow of the air/fuel

mixture intake and exhaust gases, they must be opened and closed at the

appropriate time during the stroke of the piston. For this reason, the camshaft is

connected to thecrankshaft either directly, via agear mechanism, or indirectly via

a belt or chain called a timing belt or timing chain. Direct drive using gears is

unusual because the frequently reversing torque caused by the slope of the cams

tends to quickly wear out gear teeth. Where gears are used, they tend to be made

from resilient fiber rather than metal, except in racing engines that have a high

maintenance routine. Fiber gears have a short life span and must be replaced

regularly, much like a cam belt.

In some designs the camshaft also drives the distributor and theoil andfuel

pumps.Some vehicles may have the power steering pump driven by the camshaft.

With some early fuel injection systems, cams on the camshaft would operate the

fuel injectors.
http://en.wikipedia.org/wiki/Crankshafthttp://en.wikipedia.org/wiki/Crankshafthttp://en.wikipedia.org/wiki/Gearhttp://en.wikipedia.org/wiki/Timing_belthttp://en.wikipedia.org/wiki/Roller_chainhttp://en.wikipedia.org/wiki/Distributorhttp://en.wikipedia.org/wiki/Lubricanthttp://en.wikipedia.org/wiki/Fuel_pumphttp://en.wikipedia.org/wiki/Fuel_pumphttp://en.wikipedia.org/wiki/Fuel_injectionhttp://en.wikipedia.org/wiki/Fuel_injectionhttp://en.wikipedia.org/wiki/Fuel_pumphttp://en.wikipedia.org/wiki/Fuel_pumphttp://en.wikipedia.org/wiki/Lubricanthttp://en.wikipedia.org/wiki/Distributorhttp://en.wikipedia.org/wiki/Roller_chainhttp://en.wikipedia.org/wiki/Timing_belthttp://en.wikipedia.org/wiki/Gearhttp://en.wikipedia.org/wiki/Crankshafthttp://en.wikipedia.org/wiki/Crankshaft


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2.2.2 Duration:

Duration is the number of crankshaft degrees of engine rotation during

which the valve is off the seat. As a generality, greater duration results in more

horsepower. The RPM at which peak horsepower occurs is typically increased as

duration increases at the expense of lower rpm efficiency (torque).[citation needed]

Duration can often be confusing because manufacturers may select any lift

point to advertise a camshaft's duration and sometimes will manipulate these

numbers. The power and idle characteristics of a camshaft rated at .006" will be

much different than one rated the same at .002".

Many performance engine builders gauge a race profile's aggressiveness by

looking at the duration at .020", .050" and .200". The .020" number determines
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how responsive the motor will be and how much low end torque the motor will

make. The .050" number is used to estimate where peak power will occur, and the

.200" number gives an estimate of the power potential.

2.3 TERMINOLOGIES OF CAM:

Terminology for angles and lift

Lobe terminology

Lift curves
http://en.wikipedia.org/wiki/Torquehttp://www.tildentechnologies.com/Cams/CamBasics.html#Angleshttp://www.tildentechnologies.com/Cams/CamBasics.html#Lobeshttp://www.tildentechnologies.com/Cams/CamBasics.html#LiftCurveshttp://www.tildentechnologies.com/Cams/CamBasics.html#LiftCurveshttp://www.tildentechnologies.com/Cams/CamBasics.html#Lobeshttp://www.tildentechnologies.com/Cams/CamBasics.html#Angleshttp://en.wikipedia.org/wiki/Torque


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2.3.1 Angle and Lift Terminology

There are several terms and abbreviations which are used when discussing

camshafts. The following abbreviations have to do with the location of the piston

in the cycle.

TC or TDCTop Center or Top Dead Center (piston at the highest point)

BC or BDCBottom Center (piston at lowest point)

BTC or BTDCBefore Top Center (piston rising)

ATC or ATDCAfter Top Center (piston lowering)

BBC or BBDCBefore Bottom Center (piston lowering)

ABC or ABDCAfter Bottom Center (piston risinng)

Some of the other terms used are illustrated in the drawing and are explained

below.


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Valve Opening and Closing Angles the angles (usually measured in crankshaft

degrees) when the valves first leave and then return to their seats. The opening and

closing angles may also refer to a specified nominal lift, e.g. at 0.050 in cam lift.

For example, a cam's timing may be stated as 25-65-65-25. These numbers are (1)

intake opening BTDC, intake closing ABDC, (3) exhaust opening BBDC and (4)

exhaust closing ATDC. For these numbers to have meaning, the lift at which the

numbers are taken must be specified.


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idle quality. A large overlap causes a rough or lopey idle. Increasing the duration

or decreasing the lobe separation cause an increase in overlap

Lobe CenterlineThe highest lift point of a cam lobe, expressed in crankshaft

degrees. For a symmetric lobe, the centerline is the average of the opening and

closing angles. A symmetric cam with timing 25-65-65-25 has intake and exhaust

centers of (65+180-25)/2 = 110 ATDC and 110 BTDC, respectively.

Lobe Separation Angle or Lobe Displacement Angle Theangle between the

centerlines of intake and exhaust lobes, expressed in camshaft degrees. For timing

25-65-65-25, the lobe separation is 110 cam degrees (220 crank degrees).

Cam Advance- The position of the midpoint between intake and exhaust lobes

relative to TDC. A cam with timing 25-65-65-25 has no advance and is said to be

"straight up". If the same cam is advanced 4 degrees, its timing becomes 29-61-

69-21. The intake and exhaust centerlines are now at 106 ATDC and 114 BTDC

respectively.

Dual Pattern Cam- if the intake and exhaust lobes have a different grind, the cam

is called a dual pattern cam or dual pattern grind. From the earliest days of cam

design, it has been common to use an exhaust lobe with 10 to 20 degrees more

duration than the intake lobe.


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Lobe Terminology

Some of the terminology, which describes a single lobe, is illustrated in the

drawing below.

Heel or Base Circle - The portion of the cam which is concentric with the bearings

and has no lift.

Ramps- Immediately adjacent to the base circle, the cam has a portion with low

velocity so there is not a major collision as slack is removed from the valve train at

the start of the lift event. Similarly, a closing ramp is used so the valve will seat

gently and not bounce off the seat.


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Flanks- The portion of the cam with large acceleration and velocity to get the

valve moving as quickly as possible

Nose or Toe- The portion of the cam with the smallest radius of curvature,

opposite the heel. This part has the greatest lift.

Asymmetric Lobe- The opening and closing side of the cam are different

Core- The rough part of the camshaft between the lobes, bearings and gears

Lift Curves

The purpose of the cam lobe is to raise the lifter and open the valve. One

can look at the lobe, but it doesn't tell you exactly how it is going to do its job. The

lift curve is a more precise way to look at the cam lift. It is a graph of the lifter (or

valve) motion as the cam rotates.

Below is an example for a cam with 251 degrees of duration at 0.050 lift.

The lift curve can be measured using adegree wheel anddial indicator or more

accurately using a computer driven cam profiling system. The opening intake

ramp and flank and the intake nose are indicated on the graph. The ramp does not

extend much beyond the valve opening, usually less than 0.015 in (0.4 mm) lift.
http://www.tildentechnologies.com/Cams/Tip_DegreeCam.htmlhttp://www.tildentechnologies.com/Cams/Tip_DegreeCam.htmlhttp://www.tildentechnologies.com/Cams/Tip_DegreeCam.htmlhttp://www.tildentechnologies.com/Cams/Tip_DegreeCam.html


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After the ramp, the large upward curvature indicates the start of the flank. The nose

portion is the large central area with negative curvature.


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2.4 MATERIAL COMPOSITION OF CAMSHAFT:

EN-8D & BS-970:

0.42% to 0.45% of Carbon,

0.35% Maximum of Silicon,

0.7% to 0.9% of Manganese,

0.06% Maximum of Sulphur & Phosphorous

2.5 CAMSHAFT POSITION:

Depending on the location of the camshaft, the cams operate the valves either

directly or through a linkage of pushrods and rocker arms.

In the past, when engines were not as reliable as today this was seen as too

much bother, but in modern gasoline engines the overhead cam system,

where the camshaft is on top of the cylinder head, is quite common.

Some engines use two camshafts each for the intake and exhaust valves;

such an arrangement is known as adoubleor dual overhead cam (DOHC).


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3. MACHING OPERATIONS OF CAM SHAFT

3.1 CAMSHAFT:

Camshaft is the important part of the engine and is mainly used for the inlet

and outlet valve operating in the engine. The Ashok Leyland engine has 6

cylinders and 4 stroke engine. The camshafts have 12 cams and 4 journals and one

gear in the middle (For oil pump drive) in a lengthy shaft.

3.2 CAMSHAFT MACHINING SEQUENCE:

The rough material from the Casting area in the foundry goes through the

following process as represented in sequence.

3.2.1 FACING AND CENTERING:

MACHINE:Endomatic (or) Facing and Centering

In this process the total length of the camshaft is maintained by milling on

both the faces and the work center is produced by drilling operation on the centre.

Further the collar position is maintained for the purpose of doing the operation in

the CNC machine as the program is developed based on the length of the camshaft.

Gauges used

Dimension of length gauge:

Go: 821.18 mm No Go: 820.928 mm


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Centre Depth Gauge

Go: 10.87 mm No Go: 10.72 mm

3.2.2 STRAIGHTENING:

Machine: Hydraulic Press

As the camshaft is so lengthy it may get bend during transportation. So

before turning operation the straightening of the component is to be carried out.

3.2.3 ROUGH TURNING:

Machine:CNC turning machine (Warner & Swashey Turning center)

In this process all the journals, stem diameter, cam width, collar width is

turned to rough size.

3.2.4 FINISH TURNING:

Machine:CNC Turning machine (Warner & Swashey turning center)

In this process all the journals, stem diameter, cam width, collar width is

turned to the required size here. The journals and gear diameter is maintained with

0.050mm tolerance.

Dimension of gauge used:

Collar width

Go: 7.82mm No Go: 7.77mm


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Camshaft

Go: 17.065mm No Go: 16.815mm

Journals

Go: 53.683mm No Go: 53.632mm

Gear

Go: 50.825mm No Go: 50.775mm

Stem (between gears)

Go: 33.25mm No Go: 32.75mm

Stem (between cams)

Go: 29.45mm No Go: 28.95mm

3.2.5 STRAIGHTENING:

Machine:Hydraulic press

Straightening is the process by which the bend in the component is

eliminated by the application of the pressure by the timed provision. The reason for

the application of the straightening is the length of the camshaft the job may get

bend due to the turning operation and hence the straightening process is carried out

and tolerance is maintained by 0.050mm.


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3.2.6 KEYWAY MILLING:

Machine:BFW VMC

Keyway is the vital requirement of a camshaft carried out after the

straightening process. Keyway is machined in the front end of the camshaft and its

due to the reason that the cam gear that can be fitted in the engine assembly

process which is driven by crank shaft gear. Another need of the keyway is that it

acts as locating reference pointfor cam milling/grinding.

In the process of cam grinding/milling the keyway which acts as the basis for

holding the chuck so the keyway is of great importance. Following shows the

specifications of a keyway.

Specifications

Key width Go: 4.813mm No Go: 4.839mm

Length Go: 14.402mm No Go: 14.529mm

Depth Go: 2.607mm No Go: 2.632mm

3.2.7 Cam Milling:

Machine: CNC milling machine (KOPP) Germany

Cam milling is the next operation carried out after the keyway milling. As

studied earlier the keyway milling has two purposes i.e. For the cam gear

positioning in the engine and also to act as a reference point for the cam milling

process.cam milling process is carried out in the camshaft due to the reason that the


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cam noses are placed by the different angles for valve operation. So the cam is

being milled with the help of CNC using the mill cutter. In this machine, there is

X and Z axis in addition to this it has C and W axis. The C axis is called as Chuck

axis. The W axis is called work piece axis. The chuck has a key on which the job is

placed by keyway. The C axis determines the position of the nose of the cam and

according to that the milling is done.

3.2.8 Gear Hobbing:

Machine: Hobbing Machine (Cooper)

Gear hobbing mechanism is discussed in depth ,in gear manufacturing

process and in the camshaft the hobbing is carried out using hobbing machine

named as cooper The camshaft that has to be hobbed is placed vertically with the

help of the carrier and the other end is holded with the help on pneumatic chuck. In

the middle of the camshaft, one spiral gear with 15 teeth and 450angle is produced.

The purpose of the gear is to drive the oil pump gear.

3.2.9 Gun Drilling:

Machine: Gun Drilling Machine (or) Deep hole drilling

It is a special purpose machine to make an 11mm hole through the entire

length of the camshaft through which the oil passes for lubrication purpose.

Oil hole diameter after drilling = 11mm


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3.2.10 Counter Boring and Tapping:

Machine: Esskay machine tools

Counter boring is the operation of enlarging the end of a hole cylindrically.

The enlarged hole forms a square shoulder with the original hole. This is necessary

in some cases to accommodate the heads of bolts, studs and pins. The tool used for

counter boring is called a coulter bore. The counter bores are made with straight or

tapered shank to fit in the drill spindle. The cutting edges may have straight or

spiral teeth. The tool is guided by a pilot which extends beyond the end of the

cutting edges. The pilot fits into the small diameter hole having running clearance

and maintains the alignment of the tool

In the assembly, the camshaft is placed and the cam gear with locking nut is

to be placed on the front end and the plug with hole has to be placed (to drain the

lubricating oil) on the rear end of the camshaft. For inserting the locking nut and

plug, thread is needed on both ends. Further as the work centre is removed during

the gun drilling operation, a new work centre has to be created for the further

process which is done between centres of the job. So, we need a tap and bore on

both ends.

For BSF thread, the tap is needed and the required drill size for the tap is

16.7mm diameter and length of 45mm.


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To determine the start of the thread and to get the required length of the thread,

step reaming is done. The step reaming is done for 19.8mm diameter and 12.7mm

length. To produce the new work center counter boring for 25.4mm diameter and

counter sink for an angle of 600is done. Finally the threading is done in the job. So

all this 4 process are done in this single stage.

3.2.11 OIL HOLE DRILLING:

Machine:Small Radial Drilling Machine

For the purpose of lubrication two holes (through hole for the entry and exit

of the oil) are put perpendicularly on the collar. In addition to this single hole is

machined on other two journals.

3.2.12 DRESSING:

To remove the burr in the inner surface of the camshaft a deburring tool is

inserted and removed in the through hole, so that if there is any bur it will get

removed. The gear is dressed using file.

3.2.13 WASHING:

As the job passed through the above mentioned process, some oil particles

may stick on the job. Before hardening, the oil particles have to be removed


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otherwise it may lead to unwanted burning. So the oil particles are removed in the

Washing Machine using heated Soda Water.

3.2.14 NUMBER PUNCHING:

Each and every camshaft has a unique serial number and it is punched on the

job for the purpose of identification.

E.g., xx x xx

The first two variables represent the model code, third variable represent the place

it is manufactured ie Ennore (E), and the last two variables represent the year code.

3.2.15 INDUCTION HARDENING:

Machine: CNC Hardening Machine (EMA)

Induction hardening is a form of heat treatment in which a metal part is

heated by induction heating and then quenched. Induction hardening is used to

selectively harden areas of a part or assembly without affecting the properties of

the part as a whole. . The temperature is raised to about 840 degree Celsius and

cooled rapidly using water.

During the operation of engine, the journals, cams and the gear (oil pump

drive) have to overcome very high stress. So it has to be strengthened. For this, the

hardening is done. Instead of hardening the whole length of the job, the required

parts alone is hardened in this process. If the whole length of the camshaft is


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hardened, then there may be chances to get broken because of the high stress. In

this process according to the required hardness the program is developed in the

CNC and further hardness testing is done.

3.2.16 TEMPERING:

After the hardening treatment is applied, job is often harder than needed and

is too brittle for most practical uses. Also, severe internal stresses are set up during

the rapid cooling from the hardening temperature. To relieve the internal stresses

and reduce brittleness, you should temper the steel after it is hardened.Tempering

consists of heating the steel to a specific temperature about 260 degrees Celsius,

holding it at that temperature for the required length of time, and then cooling it,

usually instill air.

During the hardening process, the hardening is done only on the journals, cam and

gear but not on the stem diameter. This will create temper (an uneven hardness) on

the job and may lead to breakage of the job during the operation of the engine. So

to avoid this tempering is done.

In this process, the job is heated up to a particular temperature and hot air is

blown on the whole length of the job for 3 hrs and then kept at room temperature

for 1 hr. Thus the temper is neutralized thereby unwanted stress is relieved.


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3.2.17 STRAIGHTERNING:

Machine: Hydraulic Press

In the hardening process, there may be a chance for the job to get bend. So the

straightening is done and maintained by 0.050mm tolerance.

3.2.18 GRINDING:

For the camshaft, the grinding is done in three stages. It is an important

process as it determines the accuracy of the job. The finishing is done very

accurately so that the efficiency of the engine will be increased.

The four stages are:

Camshaft Gear Diameter grinding

Steady diameter grinding

Journal diameter grinding

Cam grinding

3.2.19 CAMSHAFT GEAR DIAMETER GRINDING:

At the front end of the camshaft, a gear has to be placed. This gear

is driven by crank shaft gear during the engine operation so that the camshaft is

rotated and the valves will be operated. Thus the front end of the camshaft is

grinded in this stage. The grinding is done accurately.


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In this grinding, the thickness of the collar is also maintained. The

dimension of the collar is: Go: 7.44mm No Go: 7.42mm

3.2.20 STEADY DIAMETER GRINDING:

In the camshaft, there are four journals- one at the front end, one at the rear

end and two in the middle. As higher finishing is required on the job, the vibration

should be very less during the grinding process. As the job is placed in between

centre in the machine, the front end and the rear end of the job will be supported by

headstock and tailstock respectively. So there will be no vibration during the

grinding process.

But for grinding the middle journals, there is no proper support. So in the

journal diameter grinding, the support is given using a pin on which the stress is

given. The pin is made to contact on the stem diameter near the middle journals so

that the required support is given during the grinding. Thereby the vibration is

reduced and the required finishing can be achieved.

For placing the pin on the stem, the diameter is maintained according to the

need in this steady diameter grinding process. There is no need for the specific

dimension for the diameter of the stem. But the grinding should be done accurately

without any ovality. If there is any ovality in the stem diameter, it will be reflected

in the journal diameter.


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3.2.21 JOURNAL DIAMETER GRINDING

In this process, the four journals are grinded to the required diameter and

maintained by 0.025mm tolerance. The collar width is also maintained by

0.025mm tolerance.

3.2.22 CAM GRINDING:

Machine: CNC grinding machine (SCHOUD German made)

In this process the 12 cams are ground to the required dimension. As the cam plays

the vital role in the value operation, higher finish is required in this process.

Tolerance of 0.25mm is maintained for cam height

3.2.23 HARDNESS CHECKING:

During the operation of engine, large stress is developed in the camshaft. So

the hardness of the camshaft should be maintained up to a particular depth. Hence

the hardness of the camshaft is checked using Rockwell hardness test and the range

is about 55 RC on the cam lobe and 45 RC on other sides of the lobe.

3.2.24 CRACK DETECTION:

There is possibility of cracks and blow holes in the camshaft; hence the

cam shaft to be tested is magnetized by passing a heavy current through it or by


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making it the core of a coil through which a heavy current is passed. Cracks or

inclusions cause the magnetic flux to break the surface forming free magnetic

poles. When the finely divided magnetic particle mixed with kerosene (8:100) is

sprayed, they collect at the free poles to visibly show the presence of defects.

The presence of a surface or sub surface flaw (void or crack) in the material can be

easily viewed by looking the cam shaft in ultra violet light through this method.

3.2.25 DEMAGNETIZATION:

In this process, the component is made to pass through a current

carrying coil and thus the component is demagnetized.


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COST MANAGEMENT INITIATIVES

Cost management is the process by which companies control and plan the

costs of doing business. Individual projects should have customized cost

management plans, and companies as a whole also integrate cost management into

their overall business model.There is no single accepted definition for this term,

because it has such broad applications and possible strategies. When properly

implemented, cost management will translate into reduced costs of production for

products and services, as well as increased value being delivered to the customer.

For a company's management to be effective overall, cost management must

be an integral feature of it. It is easiest to understand this concept if it is explained

in the context of a single project. For instance, before a project is started, the

anticipated costs should be identified and measured. These expenses should then

be approved before any purchasing occurs. During the process of completing a

project, all incurred costs should be noted and kept in a record of some kind, to

help ensure that the costs are controlled and kept in line with initial expectations, to

the extent that this is possible.

Taking this approach to cost management will help a company determine

whether they accurately estimated expenses at first, and will help them more

closely predict expenses in the future. Any overspending can also be monitored in
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this way, and either eliminated in future projects or specifically approved if the

expense was necessary. Cost management cannot be used in isolation; projects

must be organized and tailored with this strategy in mind.

Starting a project with cost management in mind will help to avoid certain

pitfalls that may be present otherwise. If the objectives of the project are not

clearly defined at first, or are changed during the course of the project, cost over-

runs will be more likely. If costs are not fully researched before the project, they

may be underestimated, thereby inflating the expectation of the project's success

unrealistically. Construction projects are subject to their own particular challenges;

these can include constraints in the form of laws and regulations that must be

planned around.


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4. SELECTION OF PROJECT TITLE

After studying the entire camshaft section, we decided to do our project on

Material scrap reduction in Cam Shaft manufacturing process.

In cam shaft process, there were few areas which had scope of cost reduction they

were

Tool cost reduction

Scrap Reduction

Consumable reduction

Electricity

In these four areas, tool cost reduction was already carried out by few of the

employees and they achieved half the initial cost in tool. Scrap Reduction was the

area which still needed improvement and we chose to do it in Scrap Reduction.

Considering the present market scenario and need for WAR ON COST, we

decided to focus on scrap reduction.


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4.1 TYPES OF SCRAP IN CAMSHAFT MACHINING:

The various types of scrap in CAM SHAFT process are operational

scrapand material scrap.

4.1.1 Material Scrap:

These are the scraps that occur due to the defects in the material itself.

Following are the examples of material scrap:

a.)Cam width less

b.)Collar width less

c.)Journal width less

d.)Gear width less

e.)Total length less

f.)Cam unwashed

g.)Insufficient material in stem and journal

h.)Crack in forging.

1.1.2 Operation Scrap:

These scrap occur due to the improper machining operation. These might

occur due the worker negligence or some problem in the machine. Following are

the examples of the operational scrap:


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a.)Overall length undersize

b.) Collar width undersize

c.)Journal diameter under size

d.) Gear diameter undersize

e.)Cam gear diameter undersize

f.)Keyway oversize

g.)Cam height undersize

h.)Gear teeth overlap

i.) Run out in counter boring.

We collected the material scrap details from the company and studied it.

The plant requirement for manufacturing cam per month is 2697 Nos. We took the

data sheet for scrap for past 4 months from July to October and studied it.

The table below shows the percentage of the material and operational scrap

produced. The total number of components produces in the company for 4 months

is 10785 nos.

Scrap analysis of CamshaftJULY-OCTOBER 2011

TYPE OF

SCRAP

E0/E1 E2

TOTAL%

O/S 99 133 232 2.15

M/S 228 258 486 4.51


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Above graph describes the percentage of the material scrap and operational

scrap.

The material scrap was found to be 45000PPM (486 NOS OUT OF 10785)

during period of JUL-OCT2011 in camshaft machining process. Since material

scrap is the highest, preventing the material cost would increase the profit and

improve the production.

2.15 4.51

O/S M/S

%AGE

SCRAP

CAMSHAFT SCRAP JUL-OCT 11

TOTAL

PRODUCED5163 5622 10785


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GOAL:

To reduce the material scrap in cam shaft manufacturing process from

45000ppm to 1000ppm within a period of 3 weeks [From 3/12/2011 to

28/12/2011].

ANALYSIS

4.2 PARETO ANALYSIS:

Pareto analysisis astatistical technique indecision making that is used for

selection of a limited number of tasks that produce significant overall effect. It uses

thePareto principlethe idea that by doing 20% of work, 80% of the advantage of

doing the entire job can be generated. Or in terms of quality improvement, a large

majority of problems (80%) are produced by a few key causes (20%).

Production control can use the same principle by identifying these vital few

processes, which control the manufacture, and then building the planning around

these key processes. In quality control concentrating in particular on the most

troublesome causes follows the principle. In management control, the principle is

used by top management looking continually at certain key figures. Thus it is clear
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that the Pareto conceptthe vital few and the trivial manyis of utmost

importance to management.

The above pareto analysis is for material scrap, where the cam width less,

cam lobe unwashed, journal width less, cam crack and gear width less are the main

reasons for the material scrap.

From the pareto diagram I came to know that the cam width, journal & gear

unwashed contribute to 71.6 % of material scrap. The above said material scrap

occurred in turning process.

251

81 8057

19

0

10

20

30

40

50

60

70

80

90

100

0

50

100

150

200

250

300

350

400

450

Cam

width less

Cam lobe

unwash

Jl width

less

Cam

crack

Gear

width less

CU

M%

Q

TY

DEFECTS

PARETO ANALYSIS OF CAMSHAFT MATERIAL SCRAP

NOV-DEC 11


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The component which is scraped cannot be reworked again, hence it is a

huge loss for the company and productivity is decreased. So all the turning

machining process is to be analyzed to reduce the material scrap.

5.1 PROBLEM ANALYSIS

The reason for material scrap is found out that is because of the turning

operation in the machining process and then we started to inspect all the turning

operation in the production of the cam shaft.

The focus is now on the turning operation which causes high amount of

material scrap. We analyzed the turning operation which causes material scrap and

plotted a cause and effect diagram in the following page.


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5.2 CAUSE AND EFFECT DIAGRAM:

LEVEL 1

LEVEL 2


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5.2.1 BEND IN COMPONENT:

If the component is having bent, it will lead to unwash

in cam and journals. After checking it is found that bend in component is found

within the tolerance and also there is straightening process before turning.

5.2.2 MACHINING ALLOWANCE:

In the rough material I checked the machining

allowance for 50 NOS and found to be 2.5mm both side in journal, cam and gear.


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5.2.3 POSITIONAL VARIATION:

We found out that the positional variation in the

rough material will lead to unwashed in journal, cam and gear width in turning

process.


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5.2.4 WORK HOLDING DEVICES:

When chuck pressure and centre spring tension is

checked, it is found ok. When tail stock and steady pressure is checked it is found

to be 20bar and 14bar respectively and the working condition of the chuck is found

to be ok.

5.2.5 MALFUNCTION:

There was no malfunction problem in encoders, as the

mechatronics department found it ok, also the same is ensured through quality

check of dimension after turning.


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5.2.6 ROOT CAUSE:

It has been found that the main reason for cam, journal and gear

width unwashed in turning process is due to the positional variation of the tool

during the turning process, which is shown in the root cause diagram.

5.3 BRAINSTORMING FOR SOLUTIONS:

The rough material is bought from SHARDLOW INDIA LTD and

SAMROT FORGINGS in pre machined condition. To avoid tool breakage and

control tools consumption and cycle time, pre-machining is being done at supplier

end with a machining allowance of 2.5 mm per side in length and diameter. When

100 numbers of cam shaft rough materials is checked using the template provided

and found the cam and journal position is ok.

5.4 ANALYSIS:

Hence we concluded that positional variation occurred after facing and

centering, so we analyzed the facing and centering process. We checked the

position of the work piece and any error in material loading.


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Facing and centering machine


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PRESENT METHOD:

The butting pad locates the cam shaft over the clamping jaws in correct

position. As the front end of cam shaft hits the butting plate, it is released &seated in

position.

Now the facing operation begins.


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By using the L gauge collar centre position is checked visually and length

is also checked using the gauge and centre depth is also checked at both ends

after facing and centering. It is found that the length, centre drill depth is ok

but the collar length varies in 5 numbers out of 100 numbers(50000 ppm)


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Collar Center Position Is Checked Using L Gauge

LENGTH BEING CHECKED


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5.5 INFERENCE:

We checked cam gear diameter length in 100 numbers and found that 5

numbers have excess length of 3mm.

But in the facing and centering process cam gear dia face is the butting

surface.

Hence length variation of cam shaft gear dia will lead to positional variation.

The length variation in the cam shaft gear dia will advance the component to

the rear side in facing and centering process.

Due to this the length of rear end journal will be less.

The rear end journal is the butting surface as shown .

Length variation leading to unwashed in turning.

Hence these length variations in the front end of the component lead to

positional variation in turning.

The cam position is maintained from collar face in pre-machining operation

at supplier end.

They do the pre machining with allowance of 4 mm, & face the end portions

to maintain the overall length.

So any variation in the cam shaft length is compensated by adding or

reducing the cam gear dia.


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CAMSHAFT POSITIONAL CHECKING IN ROUGH MATERIAL

ROUGH MATERIAL CHECKED THROUGH T MPL T

FOR CAM,JOURNAL AND COLLAR.

Rough material after the removal of the pip/ uneven surface, is being loaded

in the machine and passed to the processes. Though the mistake was rectified the

scrap occurred in the process. On next step through the help of the template (as

shown in fig above) we checked the linear position of the cam, collar and the

journals.

The template checking implied the result the position is maintained from the

collar surface and cam gear diameter has not been taken into consideration.

We finalized this result; the position of butting should be changed to collar position

in order to avoid scrap and following design process is carried out.


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6. NEW BUTTING BRACKET

6.1 EVOLUTION OF DESIGN:

The design of the butting plate is divided into four major sections A, B, C.

Ais the head portion consisting the provision for mounting the bracket in the

machine.

Bis the central extension providing the required length to reach the cam collar

surface.

Csection holds the pin assembly.


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Due to the shift from cam front end surface to the collar, the displacement

required:

i. Reduce the overall height of the bracket from 160mm to 110mm.

ii. Extend the length from 70mm to 90mm.

6.2 DESIGN:

1. The butting pin needs to be raised by a distance of 25mm from its present

position.

2. To achieve this, the height of section B and C is reduced.

3. The height of the section A is maintained as same in old bracket as it should

hold the bracket in the machine, rigidly in position.

4. Section C height is brought down from 60mm to 30mm.

5. Section B is reduced by 20mm.

6. The nose length of the new bracket needs to be stretched to make the pin

reach front side of the cam collar.

7. The length of section A is extended by 5mm.

8. The section B & C are also stretched.

9. The position of the pin assembly section D is shifted left from centre axis of

the bracket by 10mm to prevent the bracket from striking against the

machine during operation.


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10.The section C is sliced by 10mm to make the pin fit inside the dimension of

the bracket.

NEW BUTTING BRACKET DRAWING


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We designed a new butting pad and we implemented that in the machining

process. After absorbing the components for 5 days, we came to know that there is

0% failure in those absorbed components. Then we checked those components

with L gauge and length is also checked with reference to collar. Then we

implemented this project to run in the centering and facing machine.

6.4 PROPOSED METHOD:

Butting pad

So, as the result of our work, where we found it to be the successful, we

further confirmed it to the Unit Planning and we standardized our new modified

budding pad in the Facing and Centering process.


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6.5 RESULT:

After the implementation of the project the material scrap due to positional

variation in turning process reduced from 3.28% to zero%.

Cam shaft material scrap reduced from 4.51% to 1.23%.

6.6 ROUGH MATERIAL COST:

Component cost (Rough Material) - Rs 1300

Material scrap before project3.28%

Material scrap after project - Nil

Component produced /Annum =18,000 NOS

Projected material scrap /Annum = 18000*3.28 = 590 NOS

Cost of saving (50/50% Production basis of models) =590*1300

Projected cost saving/Annum =Rs 7, 67,000/Annum

6.7 PROCESS COST:

Up to turning process, process cost per work piece = Rs 36.60

Components saved by the project -590 numbers (3.28% of total production)

Cost saving =590* 36.60 = Rs. 21,594/Annum

Rough Material cost + Process cost = 7, 67,000 + 21,594 = 7, 88,594/Annum.


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7. CONCLUSION

When 50 numbers of cam shafts is machined in facing and centering

process, we found that there was no unwashed cam and journal width by

implementation of new pad. Thus material scrap was reduced drastically and

productivity is increased.

butting bracket

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