mtp report

7/23/2019 Mtp Report

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Application of Six Sigma and reduce rejection rate at

TVS Sundram Fasteners Limited

A thesis entitled to be submitted in fulfillment of the partial requirements

For the degree of

Master of Technology

In

Industrial System Engineering

By

M!"ATI #M$A%

&''MF(IM'')

Under the guidance of

Prof. PL Narashimhan

*epartment of Industrial System Engineering

Indian Institute of Technology+ $haragpur

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,E%TIFI,ATE

This is to certify that the thesis entitled Application of Six Sigma and reduce rejection rate at

TVS Sundram Fasteners Limited submitted by MPATI !M"A#$ #oll No.%%MF&IM%%$ to

Indian Institute of Technology$ "haragpur$ for the a'ard of the Master of Technology$ is a

record of bonafide research 'or( carried out by him under my super)ision and guidance. The

thesis$ in my opinion$ is 'orthy of consideration for the a'ard of the degree of Master of

Technology in *ngineering in accordance 'ith the rules and regulations of the Institute.

"rof- PL Narashimhan

+epartment of Industrial ,ystem *ngineering

Indian Institute of Technology

"haragpur$ -%&/

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A,$.#/LE*0ME.T

I am deeply grateful to my super)isor$"rof- "L .arashimhanIndustrial ,ystem *ngineering$

'hose insights and encouragements ha)e contributed so much to this 'or(. Not only he

pro)ided me the direction for my 'or($ he also had faith in me and ga)e me enough freedom

to pursue my o'n ideas. The )aluable help and assistance pro)ided during course of the

pro0ect.

I am grateful to the +epartment of$ Industrial ,ystem *ngineering IIT "haragpur$ for the

required facilities and T1, ,undram Fasteners Limited pro)ided to carry out the e2perimental

'or( for the pro0ect. Last but not least$ I 'ish to put record on my deep appreciation to all those

'ell 'ishers 'ho helped me acti)ely or passi)ely for the pro0ect 'or(.

+ate3 %45%/5/%6

IIT "haragpur

MPATI !M"A#

%%MF&IM%%+epartment of Mechanical *ngineering$

IIT "haragpur

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,E%TIFI,ATE #F E1AMI.ATI#.

This is to certify that 'e ha)e e2amined the thesis entitled Application of Six Sigma and

reduce rejection rate at TVS Sundram Fasteners Limited submitted by MPATI !M"A#$

#oll no.%%MF&IM%%$ an Undergraduate student of the department of Mechanical *ngineering.

7e hereby accord our appro)al of it as a$ study carried out and presented in a manner required

for its acceptance in partial fulfillment for the Undergraduate +egree for 'hich it has been

submitted. This appro)al does not necessarily endorse or accept e)ery statement made$ opinion

e2pressed or conclusion dra'n as recorded in this thesis

Examiners Super2isor

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ABST%A,T

The purpose of this research is to re)ie' and e2plore the basic concepts of the si2 sigma

8+MAI9:$ limitation and approach for implementation of using si2 sigma methodologies in

manufacturing industry. T1, ,undram Fasteners Limited is one of the manufacturing industry

in India 'hich targeted to achie)e the reduction in defect rate. ,i2 sigma is a process that

reduces the re0ections or 'aste by focusing on the quality issues that are essential to the

customer.

Impro)ising the process capability of the machine by manual calculation and applying the

FM*A for the most re0ected operation. Process flo' charts and pareto charts 'ere created to

easily detect the defects; data 'as collected and analy


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Contents

1)

Introduction ................................................................................................................ 7

: Literature ,ur)ey...................................................................................................... 8

&: !b0ecti)e................................................................................................................. 9

4) Theory and Methodology .................................................................................... 10

6: Problem ,tatement...................................................................................................%

=: 9urrent ,enario....................................................................................................... 1&

-: ,cope.................................................................................................................... 14

>: Analysis.................................................................................................................%4

9) QC story..............................................................................................................%?

%/: 9onclusion............................................................................................................ &%

%%: Future ,cope......................................................................................................... 31

%: #eferances............................................................................................................ &

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') I.T%#*3,TI#.

The ,i2 ,igma Methodology is a customer focused continuous impro)ement strategy

that minimi


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() #B4E,TIVE

The ob0ecti)es of this study are3

a: To be familiar 'ith manufacturing process and its problems in manufacturing industry.

b: To understand the calculation of the process capability and impro)ing the process

capability if required.

c: To understand and apply si2 sigma methodology in impro)ing quality of product and

sol)ing problems of manufacturing industry.

d: To implement +MAI9 methodology as si2 sigma method to impro)e yield on the

grinding process by reducing the defect rate from %..

"%#BLEM STATEME.T3

T1, ,undram Fasteners Limited is a manufacturing company 'hich manufactures

sproc(ets to ford 'ith re0ection rate of / but company facing problem of %.

re0ection rate.

7e focus on the high re0ection percentage in the pareto chart.

"rocess %ejected -.o "ercentage 5

9 damage face = %4

4? dia scratch mar( & %%.&

Brinding dia under / ?

-&./%6 dimn under %6 =.6

The ma0or defects are coming from grinding process; 'e focused on that process and ma(e the

FM*A

6) T7E#%! A.* MET7#*#L#0!

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9ollected the re0ection data during manufacturing the process and ma(e an pareto chart

to easily identify the problem.

,tudying capability of current measuring system and quantified it using (appa analysis.

Analy


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8) "ro9lem statement

a: T1, ,undram Fasteners Limited is a manufacturing company 'hich manufactures

sproc(ets to ford 'ith re0ection rate of / but company facing problem of %.

re0ection rate.

%eason for %ejection %ejected -.o "ercentage 5

9 damage face = %4

4? dia scratch mar( & %%.&

Brinding dia under / ?

-&./%6 dimn under %6 =.6

The abo)e listed table sho's the data of reason for re0ection and no of re0ections in one month

production.

They are getting these types of scratches and dent mar(s after grinding operation. This as ma0orissue they are facing.

b) #educing the production time and to achie)e the ta(t time in the sproc(et production

line. The ta(t time for their product is - sec but they are not achie)ing their target. Cy

implementing the steps of ,M*+8 ,ingle minute *2change of +ie:

:) ,urrent Scenario

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They are using Micromatic grinding machine to grind they products. In grinding machine 4

stages of machining ta(es place.

a: Air time

b: 9oarse feed

c: Fine feedd: ,par( out time

7ith these feeds they are used to machine their desire diameter of their product.

Parameters they are using3

Brinding 'heel type3 A=/$ 4// 8ADgrit type Aluminum o2ide$ =/D grit simm

b: 9oarse feed3 /.6mm

c: Fine feed3 /.%>mmd: ,par( out feed3 /./4mm

They ha)e to maintain an surface roughness )alue #aE /.&D/.=

The ta(t time for their component is - sec but they are achie)ing to &6 sec they can reduce to

-sec by purchasing an e2tra machine$ but they are not effort for that due to less difference.

;) Scope for Impro2ement

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9ollecting the past t'o month re0ection data of this grinding process and ma(ing a pareto

analysis. Among those >/ contributing re0ection process are consider and 'or( on that to

minimi


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9alculating the process capability of the

Bearing *ia &6=-=;6=-==

4?.?>4 4?.?>4

4?.?>6 4?.?>4

4?.?>6 4?.?>6

4?.?>4 4?.?>=

4?.?>= 4?.?>=

4?.?>- 4?.?>-

4?.?>= 4?.?>6

4?.?>4 4?.?>=

4?.?>4 4?.?>6

4?.?>6 4?.?>=

4?.?>6 4?.?>>

4?.?>- 4?.?>-

4?.?>6 4?.?>=

4?.?>6 4?.?>6

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The Process capability analysis is done by using minitab soft'are. Benerally 9p( )alue should

be H%.&& but in this machine performing the 9p( )alue is /.->. 7e can say that machine is not

capable of machining the product 'ith gi)en specific limit.

,o to impro)e the process capability of the machine the follo'ing steps to be maintain

Machine le)elling

9ollect chuc( run out

Machine #epeatability

Turret Inde2ing

Call scre' bac(lash to be chec(ed

All these chec(ing daily before starting the machine 'e can impro)e the process capability.

After doing the technique the process capability )alue is increase and achie)e the desirable

)alue 'hich is %.&&.

Bearing *ia &6=-=;6=-=&

4?.?>/ 4?.?>%

4?.?> 4?.?>4

4?.?>4 4?.?>&

4?.?>% 4?.?>4

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4?.?>4 4?.?>&

4?.?>& 4?.?>

4?.?>% 4?.?>&

4?.?> 4?.?>

4?.?>% 4?.?>&

4?.?> 4?.?>%

4?.?>& 4?.?>

4?.?> 4?.?>&

4?.?>% 4?.?>

4?.?>4 4?.?>&

From these result 'e can conclude that daily implementation of the maintenance to the machine

'hich 'e can achie)e desirable tolerances.

In this part 'e can made an pareto chart for the reason for re0ections and considering the top

most influencing re0ections and ma(ing an cause an effect diagrams. Then 'e can easily

notify the causes for re0ection from 4M 8MAN$ MA9JIN*$ MAT*#IAL$ M*TJ!+,:.

The belo' gi)en data is number of re0ections and reasons for re0ections in grinding process

in sproc(et production line.

The gi)en re0ection data is3

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Sl

no REASION FOR REJECTION QTY

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1 C Face Damage 26

2 49 Diameter scratch mark/Dent 23

3 Grinding diameter undersize 20

4 73.015 dimn oersize 15

5 !ooth dent /".3 Face dent 14

" #.1 Diameter go not ans$er 13

7 %ha&ing tooth runout 13

# 'C' Face Center dri(( ho(e damage 13

9 ) Face Damage 10

10 Grinding cham*er dent 10

11 +aser mark not ok 8

12 Grinding!a&er/,a(it- 8

13 4.20 !hickness undersize 6

14 #0.5 Diameter undersize 6

15 oing tooth &osition ot ok 6

1" %ha&&ing tooth ecess deurring 6

17 73.015 dimn undersize 6

1# 4.20 !hickness oersize 5

19 Grinding diameter undersize due to re$ork 5

20 Face Damage5

21 Damage nsert )rockenCC61 4

22 Dri(( cham*ering oersize /uneen 4

23 !eeth radius oersize 4

24 53.05 Distence undersize 4

25 73.015 Diameter runout 4

From the abo)e re0ection data 'e ha)e ma(e apareto chart to clear understand the study

on re0ection parts

Pareto analysis3 concentrate on problems that ha)e ma0or impact on re0ection parts by

sho'ing bar graphs along 'ith cur)e sho's relati)e frequency.

Pareto chart for abo)e data is

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9onsidering the top 4 re0ections and made an pareto analysis for those re0ections

=) ?, ST#%!

%: "%#BLEM I*E.TIFI,ATI#.3 set themes and target for impro)ements

: !bser)e carefully the phenomenon related to the theme for % 'ee(

&: At first pic( up the probable causes then identify the root causes by analy


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6: Implementing the action plan K e)aluate the result.

=: #e)ie' the problem sol)ing procedure applied.

-: Jori: Identify the remaining problems and ma(e a plan for the future.

Made a root cause analysis or I,JI"A7A diagram for grinding process3

/heel Speed If 'heel speed is increased friction bet'een the 'or( piece and 'heel is more so

there is a difference in surface roughness. More the 'heel speed more the #a )alue.

Spar@ out TimeCefore the 'heel is ta(e out from the grinding process its (eep still air near to

the 'or( piece for a 'hile 'hich grinds the small particles due to )ariation in the grit si


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If more feed surface roughness is more and dressing time 'ill be decrease.

/or@ speed If more the 'or( speed it causes improper grinding of the 'or( piece. 7e cant

achie)e our tolerance limit of the bearing diameter.

/heel grade The composition in the 'heel grade matters for the hardness of the 'or( piece

and 'or( speed of operation. Benerally in any manufacturing company they 'ill use AD=/ type

aluminum o2ide because many components to be grind are under ->J#9.

*ressing This process is done because of 'earing of the grit sharpness after continuous

grinding operation. +ressing ma(es the grit sharp and produce smooth surface. Improper

dressing causes the )ariation in surface roughness and probably cause of scratches.

Tail Stoc@ pressure The 'or( piece is loaded bet'een the chuc(s from front side and bac(

side. Front side is tail stoc( end and bac( side is spindle side. ,pindle consists of & 0a' chuc( to

clamp the 'or( piece and other end tail stoc( applied some pressure to ma(e the 'or( piece

linear.

More the pressure causes the o)ality in the 'or( piece. Less pressure causes irregular grinding

Alignment of tail stoc@ and head stoc@ The alignment of tail stoc( determines 'hat shape

should be done from grinding operation. To grind the slant 'or( pieces the head and tail stoc(s

should not be straight. If misalignment in head and tail stoc( leads to dimensional errors in the

'or( piece and possible of scratches and dents on the 'or( piece.

7ardness Variation Jardness is the ma0or issues in many manufacturing companies. +uring

,@F of the ra' material causes hardness )ariation in the 'or( piece. More the hardness 'e

cant achie)e the required diameter of grinding operation. Lo'er the hardness causes the

)ariation in the surface roughness.

7e 'ill analy


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Ma(ing a fish bone diagram for this defect to clear understanding and easily rectify the problem

"ro9a9le ,ause ' Tail stoc@ clamping

If the tail stoc( clamping is improper then there is a chance of burr inside the tail stoc( clamp

then for ne2t 0ob fit in that 'e can obser)e the cDface damage

*2pt.

No9ondition Produced @ty. #e0ected @ty.

% Curr at tail stoc( side %6

No burr at tail stoc( side %6 /

"ro9a9le ,ause Setting error

23

FIG: C-Face DamageFIG: Normal C-Face


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Tail stoc( should be e2actly fit to the 'or( piece. +ue to rotation of 0ob if any misalignment

causes hit to the tail stoc( 'hich leads to re0ected part. It root cause impact is more in re0ection

rate.

"ro9a9le cause ( 7ardness Lo C7igh

9onclusion3 Jardness )alues are 'ithin the specification ie.->J#9$ Jardness lo'5Jigh is not

a root cause.

) 6= *iameter Scratch mar@C *ent

"ro9a9le ,ause ' Alignment of Tail stoc@ and head stoc@

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Ma(ing slight change in alignment of tail stoc( and head stoc( then result are obser)ed as

*2pt.


% 7ithout misalignment &/ /

7ith misalignment &/ %

This is a probable cause for scratch and dents

"ro9a9le ,ause *ressing

+ressing is mainly done to sharpen the grits. +ue to improper grits siJ#9$ Jardness lo'5Jigh is not

a root cause.

() 0rinding diameter under siDe

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"ro9a9le ,ause ' /rong Loading

*2pt.


% Parts clamped 'ith 'rong loading &/ /

Parts are clamped 'ith proper

butting &/ /

9onclusion3 7rong loading is identified is not a root cause.

"ro9a9le ,ause Setting Error

26

/rong Loading ,orrect Loading


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*2pt. No 9onditionProduced

@ty.#e0ected @ty.

%,et 1alueD

4?.?->54?.?>>6/ Part got re0ected at -thpart for part print 4?.?-4

,et 1alueD

4?.?-6 54?.?>66/

Part got re0ected at =thpart for stage

specification 4?.?-4

9onclusion3 If 'e set )alue in ma2imum )alue the part 'ill not reach specification '.r.t to part

print ,etting *rror is a root cause.

"ro9a9le ,ause ( Morposs gauge

Morposs Bauge is used to grind the product for the specific )alue according to the gi)en offset

)alue. This gauge gi)es the continuous reading of diameter during grinding operation. The offset

)alue should be reset after e)ery grinding operation. If its not reset then sho' +iameter

undersi


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"ro9a9le ,ause ' /rong Loading

*2pt.


% Parts clamped 'ith 'rong loading &/ /

Parts are clamped 'ith properbutting

&/ /

9onclusion3 7rong loading is identified is not a root cause.

"ro9a9le ,ause and 1 axis repeata9ility lo

28

/rong Loading ,orrect Loading


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,l.No Test item Tolerances Test #esult

%

#epeated

accurcy

O a2is direction /.//& /.//6 /.//6

Q a2is direction /.//& /./% /.//6

9onclusion3 Test result is 'ithin the specification so #epeatability is not a root cause

"ro9a9le ,ause ( Butting face out high

,l.No Test item Tolerances Test result

%

,pindle flange face out /./%6 /./ /.//4

,pindle centre runout /./%6 /./ /.//4

9onclusion3 Test result is 'ithin the specification so face out is not a root cause.

"ro9a9le ,ause 6 Setting Error

*2pt. No 9onditionProduced

@ty.

#e0ected @ty.

%,et 1alueD

-&.//5-&./%66/ Part got re0ected at ndpart for part print -&./%=

,et 1alueD

-&.//4 5-&./%&6/

Part got re0ected at 6thpart for stage

specification -&./%4

9onclusion3 If 'e set )alue in ma2imum )alue the part 'ill go out of specification '.r.t to part

print ,etting *rror is a root cause.

"ro9a9le cause 8 7ardness Lo C7igh

9onclusion3 Jardness )alues are 'ithin the specification ie.->J#9$ Jardness lo'5Jigh is not

a root cause.

"ro9a9le cause : /rong tool path

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*2pt. No 9ondition Produced @ty.#e0ected @ty.#e0ection

% T'o different tool path 6 % /

,ingle tool path 6 / /

9onclusion3 7rong tool path is a root cause.

%oot ,ause G ' /rong Loading

%oot ,ause G /rong tool path

From these abo)e discussion 'e can easily identify the problem and rectify them and implement

the proposed methods in the production line. 7e can achie)e less re0ection rate compared to

pre)ious scenario.

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Proper maintenance of the PM9 8Process Monitoring 9hart: chart (no's the )ariation in the

dimension of the manufactured product after starting of ne' shift. This is done to (no' the

)ariation of the machine from the pre)ious shift to current shift performance and also (no's the

"%#,ESS FL#/ ,7A%T

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,#.,L3SI#.S

9alculated the )alue of 9p( using minitab soft'are before and after implementing the

maintenance steps. Identified the measures to increase process capability

Identified the root causes of the grinding operations by using I,JI"A7A +iagram 'ith

proper reasons.

Cuilt a fishbone diagram for 4 ma0or defects and @9 story for each defect.

F3%T3%E S,#"E

*stimated the 'or(er beha)ior using (appa analysis

#educe processing time using 1,M K ,M*+

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%eferences

Pande$ P.$ Neuman$ #.$ and 9a)anagg$ #. 8///:$ The ,i2 ,igma 'ay3 ho' B*$

Motorola$ and other top companies are honing their performanceR McBra'DJill$ Ne'

or(

Canuelas$ #. and Antony$ S. 8//:$ 9ritical success factors for the successful

implementation of si2 sigma pro0ects in organisations$ The T@M Maga


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