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1. INTRODUCTION

1.1 TITLE:

“Study of parameter affecting variation in diameter of driven plate of clutch”

1.2 EXPLAINATION OF TITLE:

During the manufacturing of driven plate, there is some variation occurs in produced driven

plate. The cause of this variation are parameters that are subject to study. Variation comes

in dimensions of driven plate. Variations like changing in outer diameter of driven plate,

distance between two holes of driven plate, burred surface and etc. During manufacturing

process, they inspects the product after every operation to check the dimension of product,

that should come in the range of designed dimension and also met to the given clearances

or allowances. If inspected driven plate not meet the real designed dimensions, than the

product is scrap. That raw material, labour work, input time- all are failed.

1.3 OBJECTIVES:

Objective of doing this bunch of work on this problem is following,

To reduce the occurrence of variation in production.

To reduce the rejection of lot and reduction in scrap.

To increase the quality of product by producing direct finish product without any variations

in dimensions.

To reduce the cost of inspection and also reduce the wastage of labour work.

Our other objective is to increase our skills and knowledge. By taking the part in industry

to solve their problem and want to experience the environment of industry, aware to

industry work plans, ultimately our objective is to get exposure to industrial management,

their environment and at last want to get exposure of industry.

1.4 AIM:

Our ultimate goal is to reduce variation in outer diameter (OD) after blanking and piercing

operation of driven plate during manufacturing.

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2. INTRODUCTION OF INDUSTRY

SETCO AUTOMOTIVE LTD

Vadodara Godhra highway, KALOL – 388 330

They at SETCO Automotive place their customer’s need for exceptional service and

responsiveness at the top of their service agenda. Through an ever-expanding network, they

assist and provide support to their customers with a focus on total customer satisfaction.

They conduct training programs for vehicle manufacturers, their dealers and distributors,

on the mechanics of their clutch settings and maintenance. They recently initiated Service

Meets to garner critical customer feedback, assimilate best service practices and stay

updated on current market trends in the field.

Growth and change are a constant in any organization. As SETCO strive to become bigger

they would like to emphasize on excellence and tradition in the organization and build a

synergistic work ethic. Harnessing the passion of an employee is critical towards value

addition. Employee satisfaction through training and investments in better facilities is a

focus area. SETCO produces LIPE brand clutches. Products of SETCO Automotive Ltd

are following.

“14”/ 352 Single & Twin” “16”/400 Twin”

“17”/430 Single” “15”/ 380 Single And Twin”

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3. DETAILED DISCRIPTION OF PROBLEM

We worked to solve the problem of outer diameter variation in DRIVEN PLATE. This

driven plate is assembled in “14”/ 352 Single & Twin” Clutch. There is biggest problem

occurred in assembly of clutch production.

Following is the total detail of driven plate design and manufacturing process.

3.1 DESIGN:

Part No: C019-L1739l

Part Name: Automatic Clutch Ceramic 14” Driven Plate

Material: 80C6 (IS 2507)

MS02 CRCA HRC 26±2

Thickness: 2.5 mm

Process: Parts blanks to be cold flattening and stress relieved to maintain 22 HRC

minimum.

Outer Diameter of driven plate: 352 mm

Surface Treatment: Phosphating (after complete operations)

3.2 Material properties:

Properties of C80 grade cold rolled annealed steel strips Chemical composition by weight:

Chemical Content (%)

Carbon 0.75 - 0.85%

Manganese 0.60 - 0.90%

Silicon 0.0-0.35%

Sulfur 0.025%

Phosphorous 0.025%

This grade is similar to 80c6 of IS2507 of 1975 & C1080.

3.3 Physical properties:

Hardness is annealed condition 200Hv Max

Yield strength 290 N/MM2

Elongation 25% Minimum

Tensile strength 640N/mm2

Surface bright and free from any detrimental surface defect

Edges Clean slit

This material is cold rolling closed annealing (CRCA) processed.

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4. VIEW OF PART NO 1739

Figure 1: DRIVEN PLATE PART NO 1739

This driven plate manufactured by following operation in sequence:

1. ID profile & holing – During this operation internal hole and all small holes are

created first on press.

2. Blanking – In blanking operation from square shape material, designed shape shown

in figure 1 is blanked.

3. Window piercing: After blanking the rectangular window are formed in material.

4. Deburring: This operation in done on driven plate to make smooth surface of it on

deburring machine.

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6. Literature Review

6.1 Sheet Metal Forming:

Sheet metal forming, involves operation such as cutting, drawing, spinning etc on sheets.

Sheet metal forming involves predominantly tensile forces, compared to bulk forming,

which involve compressive forces. Due to tensile stress, sheets may undergo localized

deformation followed by cracking. Sheets are rolled products, which have thickness less

than 6mm. Sheet metal operations involve work pieces with large surface area to thickness

ratio. Blanks are cut from sheets. These blanks are subsequently subjected to one or more

sheet forming operations in order to get the finished component. Sheet metal forming is

widely used for producing wide range of products starting from household vessels to

aerospace parts, to automobile or aircraft bodies. Final shape is obtained by applying

tensile, shear or combination of forces and stretching or shrinking the sheet metal blanks.

Part No-1739 Automatic Clutch Ceramic 14” Driven Plate is manufacture by sheet metal

forming processes like blanking, window piercing, holing, punching, shearing etc on

mechanical press.

6.2 Shearing:

Shearing is the process of cutting off of sheets using die & punch. Applying shear stress

along the thickness of the sheet. Shearing happens by severe plastic deformation locally

followed by fracture which propagates deeper into the thickness of the blank. The clearance

between the die and punch is an important parameter which decides the shape of the

sheared edge. Large clearance leads to rounded edge. The edge has distortion and has burr.

The shearing load is also higher for large clearance for harder material and larger sheet

thickness larger clearance is required. Generally, clearance can vary between 2% to 8% of

the sheet thickness. Shear zone width depends on the speed of punch motion. Larger speed

leads to narrow shear zone, with smooth shear surface and vice versa. Shearing a blank

involves plastic deformation due to shear stress. Therefore, the force required for shearing

is theoretically equal to the shear strength of blank material. Due to friction between blank

and tool, the actual force required is always greater than the shear strength. Variation of

punch force during shearing process is shown below. The maximum force required on the

punch for shearing can be empirically given as:

F max = 0.7tL

Where, ‘t’ is blank thickness and ‘L’ is the length of the sheared edge.

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6.2.1 Shearing Zone Geometry:

Figure 2: Stages of shearing operation

6.3 Blanking:

Blanking is a kind of shearing operation, in which the punch removes a portion of

material from the stock, which is a strip of sheet metal of the necessary thickness and

width. The removed portion is called a blank and is usually further processed to be of

some use. Simply we can say that in blanking what you cut out is our interest. For

example: you cut a hole in sheet metal, if you are interested in the disc that is cut out,

then the process is called blanking. It is a constrained shearing operation that involves

elastic deflection, plastic deformation and failure of the work material. In the blanking

process, some factors such as the punch-die clearance, the tool geometry and the

mechanical properties of the materials influence the quality of the cross-section and the

dimension precision.

Figure: 3 Blanking Operation

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The punch diameter has to be smaller than the die hole. The clearance between die and

punch is based on the type of process. For blanking operation for obtaining a blank of

diameter Db the clearance is given on the punch. Diameter of punch and die are given

by:

For blanking operation,

The Die of Punch (Dp) = Db-2C

Where, Db = The Die hole Diameter,

& C is the clearance.

Figure 4: Blanking and Punching tool

In general, the clearance can be expressed as:

C=0.032×t×√𝜏

Where, t=Thickness of plate

𝜏= Ultimate tensile stress

For easy removal of scrap during blanking, a small angular clearance of 1 degree to 1.5

degree is provided in the die hole. Typical recommended clearances for the operations are

given in table below:

Materials

Radial clearance as percentage of thickness

High Precision Good finish General

Low carbon steel 1-2 4-6 9-11

Stainless steel 1-2 4-5 10-11

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Blanking process can be considered to include series of phases in which sheet metal

undergoes deformation and separation as seen in figure 5.

Contact of punch

The punch first touches the fixed sheet .at impact a compressive stress rapidly builds on

the punch and sends a shock wave through it

Elastic and plastic deformation

The punch penetrates into the sheet. First causing an elastic and then plastic deformation.

Shearing and crack formation

When the stresses increase shearing occurs followed by fracture .fracture begins from both

the punch end and die end of the sheet they usually meet and complete fracture of the

material takes place

Breakthrough

If the sheet material has a high strength or is thick. A large force is required for blanking

process. During fracture compressive forces are stored in the tool.

Stripping

The punch move down to the bottom dead Centre and ejects the part.

Figure 5 Steps in blanking operation

6.4 Mechanism of blanking die:

As far as sheet metal working is concerned, the die mechanism is very important aspect

that these tools determine the final shape of the product. Die hole made in die plates must

be exactly the same shape & dimension as the finished product. The complete die set

consists of a punch, die and some other accessories which are described in this section later.

Perfect alignment of punch and die is most important for satisfactory working of punch.

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Accessories of die set provides the require alignment and rigidity to the system and

improves accuracy of the system performance. These accessories are the finished parts,

removal of waste.

Figure 6: Blanking Die Accessories

Punch Holder:

It is also known by its other name upper shoe of die set. Punch holder is clamped to the

ram of press. It holds the punch below it.

Punch:

The design of the punch mainly depends upon the plan area to be blanked or pierced.

Design of the punch also depends upon the pressure which is required to penetrate through

the work piece. The method of mounting the punch is determined by the plan area to be

blanked or pierced. For example, a punch for small work piece may require a punch block

for mounting the punch into the die holder, whereas a punch of large work piece may be

made up of solid block of tool steel and bolted to the punch holder. A punch must withstand

the maximum blanking or piercing pressure. Small punches require a punch support to

avoid breakage. Standard punch material SKD11 expects hardness through heat treatment

is approximately 60HRC.

Die Block:

The design of die block depends upon work piece size and thickness. The type of die and

contour of work piece also play an important role while designing of the die block. The

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selection of size of the die block also depends upon the experience. Sectional components

may be screwed and doweled to a die holder with sections butting against each other. This

arrangement reduces the cutting forces.

Die Holder:

It is also called die shoe. Its work as a support for the die block and it is rigidly fastened to

the balster plate of the press.

Punch plate:

Punch plate is also known as punch retainer. This is fixed to the punch holder. Punch plate

serves as a guide way to hold the punch in right position and properly aligned. This makes

the replacement of punch quick and correct.

Backing plate:

Backing plate is used to distribute pressure uniformly over the whole area (maintains

uniform stress), it prevents the stress concentration on any portion of punch holder. This is

generally made of hardened steel inserted between the punch and punch holder.

Pilots:

Pilot is used for correct location of blank when it is fed by mechanical means. The pilot

enters into the previously pierced hole and moves the blank to the correct position to be

finally spaced by the stops. Normally pilots are fitted to the punch holders.

Guide Posts:

Accurate alignment between die opening and punch movement is very important. Guide

posts are used for correct alignment of punch and die shoe.

Strippers:

The main purpose of stripper is to remove the stock from the punch after blanking or

piercing operation. Stripper acting as a pressure pad and withstanding against the work

piece. The stock does not make contact with the stripper. Best method for guiding the strip

is the use of guide rails.

Stock stops and Automatic stops:

The device by which the strip has to be advanced correct distance after each blanking is

called stock stops. After each stroke of the press, an edge of previously blanked hole is

pushed against a dowel pin. To release the strip from the pin, enough clearance is provided

in a strip channel to allow the stock to be lifted above the pin during upward stroke of the

press. Skilled operator is required for such type of operation.

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6.5 Mechanical Press:

The sheet metal operations are mainly carried out by the help of presses and press tool.

These operations include deformation of metal work pieces to the desired size and size by

applying pressure or force. A Press is a sheet metal working tool with a stationary bed

and a powered ram can be driven towards the bed or away from bed to apply force or

required pressure for various metal forming operations. The punch is generally into the

punch holder and punch holder is attached to ram. A blaster steel plate is attached to the

bed of the press and die I mounted on the blaster steel plate. Presses are available in a

variety of capacities, power system and frame type.

Figure 7: Mechanical Press

Some parameters are expressed following as specification of a press.

1. Maximum force:

Maximum force that its ram can exert on the work piece, this is expressed in tones

and called tonnage. It varies from 5 to 4000 tons for mechanical press.

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2. Maximum stroke length:

Maximum distance travelled by the ram from its top most position to extreme

down position. it is expressed in mm. the stroke length is adjustable so difference

values that can be obtained between minimum and maximum of stroke length

3. Die space:

Total (maximum) surface area along with of bed base, ram base. These is the area

in which die can be maintained.

4. Shut height:

Total opening between the ram and base when ram is at its extreme down position.

This is the minimum height of the processed work piece.

5. Ram speed:

It is expressed as number of strokes per minute. Generally it can be 5 to 5000

strokes per minute.

6.6 Factor affecting in the blanking processes:

The effect of clearance:

Clearance C is the space (per side )between the punch and the die tool and die

producers enjoy some kind of mystique related to their work as being both an art

and science proper clearance between cutting edges enable fractures to start ideally

at cutting edge of the punch and also at the die. For optimum finish of a cut edge,

correct clearance is necessary and is function of the kind, thickness, and temper of

the material. Excessive clearance will also cause large radius at this corner as well

as a bur on opposite corner.

When clearance is not sufficient, additional layers of the material must be cut

before complete separation is accomplished. With correct clearance, the angle of

fractures will permit clean break below the burnish zone because the upper and

lower fracture will extend toward one another.

Excessive clearance will result in tapered cut edge because for any cutting

operation, the opposite side of the material that the punch enters after cutting, will

be the same size as the die opening.

Harder metals require large clearance and permit less penetration by the punch

than ductile materials; dull tool (punch and die) create the effect of too small a

clearance as well as bur on the die side of the stock. Clearance is generally

expressed as a percentage of the material thickness, but some authorities

recommend absolute values.

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C = Dm -dp/2

The effect Punch geometry:

Punch geometry affects the punch stresses and temperature as well as punch life.

Figure shows the maximum forces by using different punch shapes when blanking

a round part. The punch forces differ because the area of contact with the sheet at

given instant in the penetration length is not the same. Shear angles/chamfers on

the punches are also used for easy stack up of the slugs. The slugs, when bent,

become neatly stacked over and one another fig 8 shows the various punch shapes

The effect of tool wear:

Tool wear leads to the Formation of burrs and increases burr length. Burr length is

generally an important criterion in the industry to evaluate part quality. Burr length

in- dictates when the tool should be reground to obtain the sharp die-and-punch

radius. It has also been observed that the effect of tool wear is more pronounced at

higher blanking clearances. The effect of tool wear on part edge quality is

significant. Tool wear leads to the formation of buns and increases burr where the

effect of tool wear was simulated by assuming different punch corner radii in

simulations. It has also been observed that the effect of tool wear is more

pronounced at higher blanking clearances

The Effect of the Sheet Thickness

For a given material, the energy requirement in blanking is influenced by the sheet

thickness. It has been observed that: 1. The blanking energy decreases with

increasing clearance-to-sheet thickness ratio c/t and increases with increasing sheet

thickness. 2. The proportions of the different depth characteristics of the sheared

profile are affected by the thickness.

The Effect of Material:

The part edge quality also depends on the material being blanked. Materials with

large ductility, low yield strength, and homogeneity will have better blanked edge

quality, dimensional tolerances, and longer tool life

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6.7 Process Identification:

Different types of processes involved in the manufacturing of driven plate, which

produce variation in diameter are given in table. Its mainly occurs during mainly blanking

operation.

Process: Blanking

Defect: blank out (Outer Diameter Variation)

Harmful Effect: Quality Issue

Observation Table:

Standard size: 352 mm diameter (as per design)

Acceptable size: 348 mm to 352 mm

Table of Measurement of Outer diameter

NOTE:-Red line indicates a lot is rejected

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7. SOLUTION TO OVERCOME AFECTING FACTORS

7.1 Defect Understanding:

Following data was observed in industry with the help of design data book of driven plate

which shows the how important is to control the variation in diameter, a defect, which has

a major difficulty in assembly of clutch.

7.2Study of all factors causing variation in diameter of driven plate:

1. Man :

Identify cause Reason Countermeasure

(solution)

Operator Awareness Operator is not locating

the part in specified

location gauge.

Feeding of double parts /

sheets which can damage

the sharp edge of die and

punch.

This leads to variation in

diameter defect.

Training has to be

provided to workers to

aware them about defects

and parts.

Skill of Labour Operator should be

capable to grasp the

given training. Due to

absence of skill he will

repeat the mistake thus it

increase the chance of

accident.

Operator should be

according to process

criticality. Operator

should have proper skills.

2. Method:

Identify cause Reason Countermeasure(solution)

Part Handling Method is directly related with

Man i.e. operator resource. In

absence of proper handling or

part loading method into tool

may cause of burr. Sometimes

part trim / edge get damage due

to unsafe part handling or

movement.

Operator should be

sufficiently trained.

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3. Material:

Identify cause Reason Countermeasure

(solution)

Raw Material Grade

& Thickness

Due to die & punch

clearance is depend on

raw material thickness.

So it is important to feed

actual sheet thickness

material. If we select a

sheet having less

thickness from actual

then in this condition

clearance between die &

punch will be more and at

the time of cutting proper

shearing & breakage will

not be produce. Thus

variation in diameter will

be occurred.

As well if we will use

higher sheet thicknesses

then less clearance will

be maintained or no

clearance thus cutting

process will be

interrupted and heavy

accident will go on.

Proper control on raw

material should be taken

place by the raw material

department. Also quality

and production

supervisors insuring

about the raw material

before feeding in tool.

For proper

implementation of the

above idea this should be

converting into system.

4. Press machine alignment:

As far as diameter variation is concern press machine alignment is an important factor

which is responsible for this defect.

From figure 7 at the time when slide comes down for the intended operation then linear

dimensions between slide plate and bolster plate should be equal. This is the press

alignment. If it is not, then loaded tool perpendicularity will be hit i.e. die & punch will not

meet at 90°. Upper half will hit lower half beyond clearance provided. In this condition

uniform shearing & breaking of edge will not be happen and will cause the diameter

variation and reduces the tool as well life.

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Figure8: Press machine alignment

7.3 Solution of problem:

This following causes are factors which are affect the manufacturing of driven plate as

discussed in previous pages:

Operator awareness: operator should aware about all the defects which would be

commence. So the worker should properly trained and skilled.

Raw material: raw material should be treated properly in transportation. Die and

punch clearance is totally dependent on raw material thickness so clearance should

be given accurately to die and punch.

Part handling: handling of part is totally related with men. Absence of proper

handling or part loading method into tool or machine may cause variation in diameter

or cause defects.

Press machine alignment: This is the main an important factor which mainly cause

our area of interest “variation in diameter of driven plate during blanking operation”.

Because of misalignment in press machine between die and punch, the material

misaligned in striper of die. Because of this misalignment during blanking operation,

variation comes in driven plate’s outer diameter. So proper alignment is very much

necessary in die and punch setting, and also proper part or material loading on die

or striper.

Figure 9: Press alignment (Die & Punch assembly)

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8. CONCLUSION

In conclusion, after carried out comprehensive literature, there are few observation and

expected outcomes that can be made:

Most of studies are preferring experiment investigation as their methodology.

Furthermore, die & punch clearance and material properties are the most influential

process/design parameters that may cause variation in diameter of driven plate

during blanking operation.

Raw material should be of proper grade and thickness, so worker can adopt all

necessary operations on the material.

Material should properly loaded on striper of die, which die should properly aligned

with punch of mechanical press. Die setter should skilled and aware about all factors

that affects the dimensions of driven plate.

Skilled worker employed for manufacturing.

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9. REFERENCE

1. Manufacturing science by Amitabh Ghosh & Kumar Malik.

2. Manufacturing Technology by P.N. Rao.

3. Sheet metal operations - Cutting and related processes, NPTEL material.

4. Mechanical Press types and nomenclature, Mechanical Press Types and

Nomenclature © 1993-2005 C02.doc C02.PDF David Alkire Smith, 530

Hollywood Drive, Monroe, Michigan 48162-2943 Rev August 19, 2005.

5. Causes & Preventation of Defects (Burr) In Sheet Metal Component by Pawan

Kumar Rai, Dr. Aas Mohammad, Hasan Zakir Jafri / International Journal of

Engineering Research and Applications (IJERA) ISSN: 2248-9622

www.ijera.com Vol. 3, Issue 4, Jul-Aug 2013, pp. 511-515

6. Geometrical Defect in Precision Blanking/Punching: A Comprehensive Review on

Burr Formation by H.Y. Chan and A.B. Abdullah School of Mechanical

Engineering, University Sains Malaysia, Engineering Campus, 14300 Nibong Tebal,

Penang, Malaysia.

7. An Overview Of Factors Affecting In Blanking Processes by Amol Totre, Rahul

Nishad, Sagar Bodke, International Journal of Emerging Technology and Advanced

Engineering Website: www.ijetae.com (ISSN 2250-2459, ISO 9001:2008 Certified

Journal, Volume 3, Issue 3, March 2013).

8. Application of fine piercing process for roller chain link plate to increase breaking

load of roller chain By Patil R.A., Prof. Gaikwad B.D., and Swapnil Kulkarni.

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