1. Preamble
1.1 Introduction To The Project
All business organization’s prime motive is to satisfy the customer requirement
and attain a distinguished position in the world market. During the last few years, the
automobile market has been witnessing an increased competition and rising demand for the
sophisticated seating systems due to globalisation. Due to this ever changing demand and
competition among the companies in these industries, there is tremendous pressure built to
look for newer designs, cost reduction techniques, improving the product quality and process
the products on Just In Time (JIT) manufacturing system, in order to be competitive.
Therefore, it is vital to improve the availability, utilization and quality of the product and meet
the demand of the customer on time without fail.
To manage all the tough situations and be a leader in the market, organisations
should concentrate on the following
Productivity
Quality
Cost
Delivery
Morale &
Waste elimination
The main objectives behind this is to achieve the business growth, customer
delight becomes the prime focus for which the above said 6 parameters need to be improved
to world class levels to make the company to move to great heights in the competitive market
1.2 Problem on hand
In the growing business scenario, where recession has affected some of the major OE’s,
the need for cost cut & cost saving becomes a prime responsibility of any organization
Realization of the actual business against the required growth plays a major role for the
development of any organization. Harita seating being a prime company in the manufacturing
of seats supplies more than 8000 seats to TVS motor per day for their two wheelers.
Thus it gave me a hint for project to be undertaken in the following area where VA/VE
in the two wheeler seat assembly will definitely give a cost saving there by benefiting the
organization.
1
1.3 Importance of the problem
TVS Motor (TVSM) confirmed their production ramping up plan during
the third quarter of 2011- 12. TVSM has demanded for the cost reduction of the products due
to the increase in the quantity of production also.
1.3.1 Need for study
We are supplying two wheeler seats to our prestigious customer TVS
motor company located in Hosur & Mysore with 100% business share for the year 2000
onwards .The supplies are made on just in time (JIT) basis every hour .The business with them
has been consistently growing since then from 2,700 seats per day in the year 2002-03 to 6,400
upto 2009-10. The projected volume for 2011-12 is 8,400 seats per day .So from the projected
volume we got a hint that DOE in this area will definitely give a cost optimization there by
benefiting the organization. `
Table 1.3.1: Model wise Seat requirement by TVSM / Day
2
fig 1.3.1.a Year wise Seat requirement by TVSM / Day
Fig 1.3.1 .b : Two Wheeler Demand Graph
3
Model wise Seat requirement per day
2000 1500
900700 600 600 500 500 400 400 300
0
400
800
1200
1600
2000
StarSport
XLHD StarDlx
XLN U68 N45 Max100
XL -HD
N90 N17 U41
Model wise
Qty
1.4 PRIMARY OBJCTIVE
The main objective of this project is to find the optimal method of two-wheeler seat
assembly using Design of Experiment (DOE).
1.5 SECONDARY OBJECTIVES
To identify the existing methodology of material composition.
Introducing Design of Experiment (DOE), in order to obtain the best method.
To make a comparative study of existing and proposed methodology.
Conclusion
1.6 SCOPE OF THE PROJECT
The scope of the project is to find the optimal method of two-wheeler
seat assembly using Design of Experiment (DOE).
The objective of this project is to retain the basic functionality of Cushion
manufacturing and reduction of the manufacturing cost.
1.7 EXPECTED DELIVERABLES
a. This project yield gains in terms of cost, quality, delivery, time etc.
b. Increase in the contribution of products
c. Reduced in- house as well as customer end line rejections.
d. This project can result in substantial benefits to the customer.
e. Similar study can be extended to the other products in the organization where
there is a real need of the cost optimization.
4
2.0 DETAILS OF THE ORGANISATION:
Harita Seating Systems Limited (HSSL) (Formerly known as Harita
Grammer Limited) is an automotive ancillary unit situated at Belagondapalli village near
industrial town of Hosur, (A Suburb of Bangalore) Tamilnadu.
2.1 Company Profile
Shri T S Srinivasan, youngest son of Shri T V Sundaram Iyengar, the
founder of TVS group of companies, conceived the Harita Group,
which is promoted by his family. He foresaw enormous potential in
the beautiful and green, yet underdeveloped area closes to Hosur town.
Harita is the Sanskrit word for verdant prosperity and he envisioned creating prosperity here
through establishing an auto component industrial network.
Shri Venu Srinivasan, elder son of Shri T S Srinivasan, as a tribute to
his father’s vision, developed Harita into an industrial suburb. The
collaboration between Harita Group and GAG was finalised in 1986,
to incorporate Harita Grammer Limited (HGL) to provide customised
seating solutions, taking into account the difficult Indian road conditions. Commercial
production was started in 1988 and the company soon went public. Since then, the company
introduces a range of new products every year to meet demanding customer’s requirement.
Grammer AG’s (GAG) success story can be traced back to 100 years
(1880), when Mr Willibald Grammer opened a saddlery in Amberg,
Germany. Mr George Grammer, his grandson, expanded the saddlery
to an industrial manufacturing plant. Starting in 1954 with cushions
for tractor seats, by 1964 GAG entered the era of modern seating systems, supplying
suspended seats for agricultural tractors, construction machines, and material handling
equipment. Today, GAG is one of the leading suppliers of seating systems world over. GAG
group comprises 40 facilities in 19 countries around the globe, with group turnover exceeding
1.3 billion-DM.
5
Harita Seating Systems Limited (HSSL) is a complete solution provider for seats
and seating systems for both automotive and non-automotive applications. HSSL
manufactures, driver seats for commercial vehicles, buses, tractors, off-road vehicles, cars,
multi-utility vehicles, two wheeler and three wheeler segments; passenger seats for buses,
cars, multi-utility vehicles and three wheeler segments; and seating systems to the railway and
auditorium segment. The company also offers products for automotive industry through
polyurethane composites Established in 1986; HSSL commenced its commercial production
in 1988. Today HSSL has established itself as the leader in development & manufacture of
innovative seats & seating systems for the commercial vehicles, buses, tractors & off-road
vehicle industry. HSSL recorded turnover of Rs 194 Cr in 2007-08.
During the year 2008-09, the company acquired Polyflex Group of companies. Through this
acquisition, the company has paved the way for entry as a Tier-2 polyurethane foam supplier
to reputed customers like Hanil Lear in Chennai, Tata Johnson Controls and Lear in Pune and
Chennai, and Toyota Boshoku in Bangalore. The foam pads supply will go into the cars of
Hyundai, Tata Motors, Ford, Mahindra Renault and Toyota Kirloskar
6
.
2.2 Organisation profile
2 .2.1 Products and Customers
Fig 2.2.1a products and customers
7
Table 2.2.1 : List of products and major customers
2.2.1 Manufacturing Process
The main processes in the organisation are
1. Polyurethane foaming
2. Powder coating of metal parts
3. Welding
4. Assembly of the seats and seating systems
8
2.2.2 Manufacturing Facilities
Fig 2.2.2: Manufacturing facilities
HSSL has its registered office at Chennai. Infrastructure functions viz.,
Marketing, Personnel, Quality, Finance and R&D operate at the manufacturing location.
HSSL started with tractor and two-wheeler seats to begin with. Over the years, the new
product development has covered the entire range of automotive seating Systems. With clear
focus on customer service to the western market, HSSL, in 1996, set up its second factory at
Ranjangaon, 60 kilometers from Pune.
.
9
Chennai- Registered office
Unit II Ranjangaon
Land: 53,074 sq.mBuilding 3,582 sq.m
Unit I- Hosur
Land : 88,652 sq.mBuilding 7,175 sq.m
Unit III Jamshedpur- Assembly unit
Unit IV Nalagarh
Land: 12000 sq. mBuilding: 2500 sq. m
Manufacturing facilities at Hosur and Ranjangaon includes
1. Modernized Polyurethane Cushion manufacturing unit.
2. Automated Pre-treatment and Powder coating plant
3. MIG welding shop
4. Mould manufacturing shop
5. Plastic Vacuum forming
6. Assembly cells
2.2 .3 Organizational Structure
Fig 2.2.3. : Organisation structure
2.3 Sales Trend of Organization
10
President
Research &
Development
Manufacturing
QualityPurchase Marketing FinancePersonnel
& TQCBusiness Planning
The Sales trend is shown in the below chart
Fig 2.3 : Sales trend of organisation
The company has planned to exceed Rs 250 Crores sales in the next financial year
2009-2010. The company has added products, technology and closely nurtured culture of Total
Quality Management (TQM) pillared by Policy deployment, Kaizen, TEI, Training and
Standardization. The management focus this year on cost reduction under the circumstances of
stiff competition and price war in the market through alternate material, alternate processes,
and waste elimination and productivity improvement projects and also through stringent cost
control measures.
11
2.4 Milestones
Fig 2.4: Milestones
12
Contin
uous
impr
ovem
ent
Manufacturing systemsACMA – Productivity
award
Quality management systemsQS 9000
Management systems
EFQM – CII EXIM
Environmental managementISO 14001
Quality managementACMA Quality
award
Quality management systems
ISO/TS 16949
Manufacturing systemsACMA manufacturing
excellence
Energy managementEnergy conservation
award
Occupational Health and Safety
OHSAS 18000
Energy managementEnergy conservation
award
Water managementExcellent water efficient
unit
ACMA – Automotive Component Manufacturers Association of IndiaCII – Confederation of Indian Industries
Energy managementEnergy conservation
award
Water Management
1 99 9
2 00 0
2 00 1
2 00 1
2 00 3
2 00 3
2 00 4
2 00 5
2 00 7
2 00 6
1 99 6
2 00 9
2 00 7
2.4.1 Commitment to quality
HSSL is committed to provide safety, comfort and aesthetics by supplying
Quality products at right time, in right quantity and at agreed price. With Total Employee
Involvement (TEI) and through consistent innovative actions, these objectives are sure to be
rewarding realities. Total Employee Involvement is achieved through Suggestion Scheme,
Quality Control Circle, and Supervisory Improvement Team, Cross Functional Teams and
TQM activities.
HSSL Believes in:
- High productivity level through cellular manufacturing and Kaizen
- Quality ownership with the operators
- Close interaction with experts for latest technology assimilation
- High level of plant and machinery utilization through practice of TPM concepts
- Priority to environment, health and safety through practice of 5S, and atmosphere of
greenery
We also believe that the TQM practices have helped us to tide over all adverse situations and
continue to guide us towards achieving excellence in business.
2.4.2 Awards and Recognition
The company has obtained TS 16949 certification in September 2003 and
achieved Commendation for significant achievement in business excellence (EFQM Model)
from CII-Exim Bank in November 2000.
Company won ACMA Quality Award for the year 2001The company has also
obtained ISO 14001 Certification during October 2003 towards environmental performance.
13
3.0 Identified problem
3.1 Introduction
In the present period of recession prevailing in all parts of the world, the company
has to manage all the tough situations and be a leader in the market by concentrating on the
following
Productivity
Quality
Cost
Delivery
Morale &
Waste elimination
Also, Indian Economic Reforming policies demand companies to improve their Quality,
Productivity, Cost, and Delivery requirements continually. Continuous Improvement should be
present in the every aspect of the business, without which the companies cannot survive in the
present competitive market.
Particularly after globalization and liberalization, Indian companies are facing stiff competition
and threat from companies of other Countries.
To achieve the business growth, customer delight becomes the prime focus for which the
above said 6 parameters need to be improved to world class levels.
HSSL is the major source to TVSM and the share of business is 100 %. The supplies are made
on Just –In-Time (JIT) basis every hour.
The customer requirement has been consistently growing every year.
Overall Two wheeler segments in India are growing year to year and recorded a growth of
minimum of 20 % consistently. But the contribution values of the two wheeler seats are very
low. This was the main reason to concentrate in this project.
Based on the projected volumes for the year 2009-10 to the tune of 250 Cr, our company has
formulated the following objectives and guidelines.
Policy Objectives for 2011-12
Achieve sales from Rs 191 to 255 Cr
Achieve profit from 6.2 Cr to 9.0 Cr
Improve quality of the products and achieve 50 PPM rejection levels at customer end.
14
Guidelines for 2011-12
Improve productivity through constant/ continuous re-engineering the manufacturing
processes
Design of Experiment (DOE) for materials cost reduction
Apply value engineering (VE) technique for low contribution products
Explore alternate materials for cost reduction
Implement low cost automation (LCA) projects
New technologies for product and process.
JIT supplies to customers
Flexible Production
Bench marking
Lean manufacturing
3 M elimination
Standardisation
Implement waste elimination projects through TEI
Based on the guideline no. 1 & 2, this project is taken up for implementation.
3.2 Description of the problem
3.2.1Automobile sales trend in segment wise
In the below graph the sales trend in each segment for the last quarter of financial year 2011 is
shown. In that Two Wheeler Seat Production is topping the list with 65.4
15
% of the quantity.
Fig 3.2.1a: Sales details - Segment wise
HSSL has started supplies of two wheeler seats to TVS Motor Company (TVSM),
Fig 3.2.1 b: Demand v/s Capacity
Hosur and Mysore in a big way since March 2000. The business with TVSM has
16
119800
27980
10813 8777404
15421
65.4
80.786.6
91.4 91.6100.0
0
20000
40000
60000
80000
100000
120000
140000
TW LCV Tractor BPS Car Others
Segments
Qu
anti
ty
0
20
40
60
80
100
120
% C
um
been consistently growing since then from 2,700 seats per day in the year 2000 – 01 o 5,000 up
to 2007-08. The projected volume for 2011-12 is 8000 seats per day.
At present, with the increasing trend of the production volume, the contribution of the two
wheeler seats are low due to the increasing prices of the raw materials. Various proposals have
been made to reduce the cost of the seats by using value engineering techniques and usage of
alternate materials in line with our policy objectives and strategies.
3.2.2 Two wheeler sales trend in model wise
The chart below shows the product wise sales trend of the two wheeler seats.
This chart clearly shows the product wise volume of the two wheeler seats / month.
TW Sales details
16243
14664
9634
49924400
38163097
19921200 960 482 56 24
19010
43.8
23.6
100.0100.099.999.398.196.694.190.3
85.680.1
73.9
62.0
0
5000
10000
15000
20000
Model
Qu
an
tity
0.0
20.0
40.0
60.0
80.0
100.0
120.0
% C
um
Fig 3.2.2.a: Two wheeler sales details – Model wise
The objective of this project is to develop the optimal method in the material composition of
Two wheeler seat assembly using design of experiments which reduce the material cost by 1 -
3 % and improve the contribution value from 20% to 22%.
17
3.3 IMPORTANCE OF THE PROJECT
Fig 3.3. a: Contribution of Running products
Our customer TVS Motor confirmed their production ramping up plan during the First
quarter of 2011 – 12. TVSM has demanded for the cost reduction of the products
Due to the increase in the quantity of production also. We have drawn a bar chart showing the
existing and planned contribution of 4 running products as per the policy matrix.
From the above graph it is clear that we have to bring down the material cost / manufacturing
cost of the products like Star Sport, Star city and XL - HD
3.3.1 Reason for selecting Star Sport model :
18
A comparative study has been done based on the weight of the cushions running
in the Two Wheeler Foaming Line. Based on the study, we have prepared a chart with the
weight of the components have found that Star Sport model was contributing around 25 %
of the total chemical consumption. Taking this for improvement will contribute in high cost
benefits.
Fig.3.3.1.a –Chemical Consumption – Product wise
We have studied the foam production process of the Star Sport cushions and in order to
reduce the cost of the end product, we have arrived at reducing the weight of the cushions.
This can be done by adopting DOE process in cushion manufacturing using different
chemical composition and bring down the weight by 10 % without affecting the property and
hardness of the cushions.
In order to eliminate the above, we have worked out using DOE techniques to
optimal method in foaming process by changing different chemical consumption. From the
above chart, we have taken Star Sport Seats which tops with the high ratio of 25 %.
From the above table it is very much relevant that Star Sport model consumes more
chemical monthly, hence we concluded that DOE in the said model will give some cost
benefit. This triggered us to go for an idea simulation
3.3.2 Idea Simulator – Star Sport Cushion
19
To optimize the weight of the PU Foam, the company has adopted a technique called
Idea Simulator.
Table 3.1. Idea Simulator for Star Sport foam
20
Based on the discussion held by various department heads for idea simulators it gave us a
positive approach to look for alternate ideas. In the case of Star Sport model, we are optimise
the weight of the PU Foam triggered a good potential for cost benefit as well as customer
complaint elimination.
Taking into account of idea simulation the Star Sport foam hinted a good potential of
material removal without disturbing the basic functionalities benefiting the organization cost
wise.
4. REVIEW OF LITERATURE
4.1 Design of Experiments
In order to benefit the organization by DOE where the problem is dealt with the
following techniques to eliminate the seat rejection; the techniques will definitely show a
positive trend in PPM as well as rejections. Overall the objective of the organization is taken
care in all aspects in terms of delivery, quality and cost.
DOE is a structured, organized method for determine the relationship between factors
(X) affecting a process and the output of that process (Y) while using minimum number of
experimental runs.
Types of DOE
1. Factorial Experiment Design
a. Full Factorial
b. Half/one fourth / one eighth Factorial Design
c. Screening Design
2. Taguchi Approach
3. Central Composite Design
During the improvement of products and processes, there are different “knowledge levels”
starting from a scarce knowledge to a deep knowledge.
Relevant literature review
21
Reference: 1
http://www.moresteam.com/toolbox/index.cfm
Introduction
Experimental design can be used at the point of greatest leverage to reduce
design costs by speeding up the design process, reducing late engineering
design changes, and reducing product material and labor complexity.
Designed Experiments are also powerful tools to achieve manufacturing cost
savings by minimizing process variation and reducing rework, scrap, and the
need for inspection.
This Toolbox module includes a general overview of Experimental Design,
instructions and templates for conducting simple experiments, and links and
other resources to assist you in conducting more complex experiments. A
glossary of terms is also available at any time through the Help function, and
we recommend that you read through it to familiarize yourself with any
unfamiliar terms.
Preparation
If you do not have a general knowledge of statistics, review the Histogram, A
class main link heft"http://www.moresteam.com/toolbox/t404.cfm "Statistical
process Control, and Regression and Correlation Analysis modules of the
Toolbox prior to working with this module.
Although you can use the MoreSteam.com DOE spreadsheet templates to
analyze several experimental designs using Excel or lotus, you will need
statistical analysis software to go beyond these basic experiment design
templates. Several free packages can be downloaded through the
MoreSteam.com Statistical software module of the Toolbox. In addition,
the book DOE Simplified, by Anderson and Whitcomb, homes with a sample
of excellent DOE software that will work for 180 days after installation.
Purpose
Designed experiments have many potential uses in improving processes and products, including:
22
Comparing alternatives. In the case of our cake-baking example, we might want to
compare the results from two different types of flour. If it turned out that the flour
from different vendors was not significant, we could select the lowest-cost vendor. If
flour were significant, then we could select the best flour. The experiment(s) should
allow us to make an informed decision that evaluates both quality and cost.
Identifying the Significant Inputs (Factors) Affecting an Output (Response) -
separating the vital few from the trivial many. We might ask a question: "What are the
significant factors beyond flour, eggs, sugar and baking?"
Achieving an Optimal process Output (Response). "What are the necessary factors,
and that are the levels of those factors, to achieve the exact taste and consistency of
Mom's chocolate cake?
Reducing variability. "Can the recipe be changed so it is more likely to always come
out the same?"
Minimizing, maximizing, or Targeting an Output (Response). "How can the cake be
made as moist as possible without disintegrating?"
Improving process or product "Robustness" - fitness for use under varying conditions.
"Can the factors and their levels (recipe) be modified so the cake will come out nearly
the same no matter what type of oven is used?"
Experiment Design Guidelines
The Design of an experiment addresses the questions outlined above by stipulating the
following:
The factors to be tested.
23
The levels of those factors.
The structure and layout of experimental runs, or conditions.
The flow chart below Figure illustrates the experiment design process:
Factor:
Anything that contributes causally to a response; "a number of parameters
determining the outcome”. Also called independent variables.
Response:
The output of a process. Also called dependent variables.
Level:
Optimal no. of data points in which experiments should be conducted to
correctly conclude the result; a position on a scale of intensity or amount or quality.
24
Reference : II
http://www.ee.iitb.ac.in/~apte/CV_PRA_TAGUCHI_INTRO.htm
TAGUCHI Method:
Dr. Taguchi of Nippon Telephones and Telegraph Company, Japan has developed a method
based on “ORTHOGONAL ARRAY” experiments which gives much educed “variance” for
the experiment with “optimum settings” of control parameters. Thus the marriage of Design
of Experiments with optimization of control parameters to obtain BEST results is achieved in
the Taguchi Method. Orthogonal Arrays" (OA) provide a set of well balanced (minimum)
experiments and Taguchi's Signal-to-Noise ratios (S/N), which are log functions of desired
output, serve as objective functions for optimization, help in data analysis and prediction of
optimum results.
Taguchi Method treats optimization problems in two categories,
1.STATIC PROBLEMS:
Generally, a process to be optimized has several control factors which directly decide the
target or desired value of the output. The optimization then involves determining the best
control factor levels of that the output is at the target value. Such a problem is called as a
"STATIC PROBLEM".
This is best explained using a P-Diagram which is shown below ("P" stands for Process or
Product). Noise is shown to be present in the process should have no effect on the output!
This is the primary aim of the taguchi experiments - to minimize variations in output even
though noise is present in the process. The process is then said to have become ROBUST.
25
2. DYNAMIC PROBLEMS
If the product to be optimized has a signal input that directly decides the output, the
optimization involves determining the best control factor levels so that the "input signal /
output" ratio is closest to the desired relationship. Such a problem is called as a "DYNAMIC
PROBLEM".
This is best explained by a P-Diagram which is shown below. Again, the primary aim of the
Taguchi experiments - to minimize variations in output even though noise is present in the
process- is achieved by getting improved linearity in the input/output relationship.
26
STEPS IN TAGUCHI METHODOLOGY :
STEP-1: IDENTIFY THE MAIN FUNCTION, SIDE EFFECTS, AND FAILURE MODE
STEP-2: IDENTIFY THE NOISE FACTORS, TESTING CONDITIONS, AND QUALITY CHARACTERISTICS
STEP-3: IDENTIFY THE OBJECTIVE FUNCTION TO BE OPTIMIZED
STEP-4: IDENTIFY THE CONTROL FACTORS AND THEIR LEVELS
STEP-5: SELECT THE ORTHOGONAL ARRAY MATRIX EXPERIMENT
STEP-6: CONDUCT THE MATRIX EXPERIMENT
STEP-7: ANALYZE THE DATA, PREDICT THE OPTIMUM LEVELS AND PERFORMANCE
STEP-8: PERFORM THE VERIFICATION EXPERIMENT AND PLAN THE FUTURE ACTION
4.2 DOE process map :
27
Define the Objective
Choose Measures of performance
(Output Variables)
Identify Possible Factors
(Control Variables)
Design Programme of Experiments
Collect Data
Analyze and Interpret Results
Verify Results
Return to 3 as necessary
BrainstormingCause and Effect
Diagram
Full Factorial
Fractional Factorial
ScreeningTaguchi
GraphsRegressi
onANOVA
ReplicationRandomization
Repetition
88
77
66
55
22
33
44
Table 4. 1: – Design of Experiments Approach
4.3 METHODLOGY
In this project, the following methodologies are adopted to find the optimal
method of two –wheeler seat assembly (Foam cushion area) using Design of Experiment.
Study of the current process
Usage of Design of Experiment Techniques
Adaptation of DOE concept
Literature survey on DOE process in change process
Prepare questionnaire to understand the issues involved in the change process.
Implementation and Standardization
Trail running with the change process to measure the outcomes
Collection of data by experiments
Analyze the data collected thro quality tools
Conclusion
28
Approaches No of variables DOE
Screening
(Scarce know-how of the process and many variables)
> 7
Fractional Factorial Low Resolution (III)
Characterization
(Reduced number of variables and their interactions)
4 - 7
Full Factorial or Fraction Factorial with High Resolution (IV or V)
2 - 4
Optimization
(Deep investigation for few variables and their interactions)
Full Factorial
Leve
l of K
now
ledge
Leve
l of K
now
ledge
5.0 DATA COLLECTION AND ANALYSIS
5.1 TYPE OF DATA NEEDED
In order to achieve cost reduction by DOE in the two wheeler seat to improve the contribution,
we have collected the following data.
Customer complaints pertaining to Star Sport
In-house rejection trend of Star Sport
Current process parameters of Star sport cushion manufacturing.
Quality standards for cushion manufacturing.
5.1.1 Customer complaints
A detailed history of the past year trend has been taken on the seat rejection
by customer due to High Hardness. On an average there were rejections around 130
Nos/annum. For the year 2009-10 the average rejections per month was12 nos.
The below data are collected based on the customer complaint from April
2009 to March 2010.
Table .5.1.1: Customer Complaints – High hardness
Apr
'09
May
'09
Jun
'09
Jul
'09
Aug
'09
Sep
'09
Oct
'09
Nov
'09
Dec
'09
Jan
'10
Feb
'10
Mar
'10
12 22 15 9 16 18 20 25 18 10 11 13
29
Fig 5.1.1.a: Customer complaint due to Seat High Hardness–Year wise
Fig 5.1.1.b.: Customer complaint due to Seat High Hardness– Month wise
Fish Bone Diagram for High hardness
30
Past years trend
200
160
125
0
50
100
150
200
250
07 - 08 08 - 09 09-10
Year
Qu
an
tity
Monthwise trend 2009-10
12
22
15
9
1618
20
25
18
10 11
13
0
5
10
15
20
25
30
Apr '09 May'09
jun '09 Jul '09 Aug'09
Sep'09
Oct '09 Nov'09
Dec'09
Jan'10
Feb'10
Mar'10
Month
Qu
an
tity
There are many various reasons for High Hardness in foaming process. Brain
storming session conducted with employees and the reasons are correlated each other
using Fish Bone Diagram.
Fig 5.1.1.c: Cause and effect diagram
Criticality of the problem (High Hardness)
The problem of Seat High Hardness is having an average trend of 180 nos
getting rejected annually. There are certain affects to the Quality rating, Delivery commitment
causing line stoppers at the customer’s end. An increased trend of PPM is always alarming to
the company’s growth perspective.
The rejection value of seats getting rejected :
Cost of each seat : 380
No. of seats rejected /year: 180
Total rejection value : Rs.68400
Intangible cost : Rs.5000
Total cost : Rs.73400.
31
Machine setting
improper Input Chemical variation
Operator negligence
Untrained operator
Importance not known
Input Chemical problem
Improper Chemical Mixing Ratio No proper
traceability No proper pouring method
MAN MACHINE
METHODMATERIAL
High Hardness
Effect: 100%
Hence to eliminate seats getting rejected it is always necessary to go for a
DOE project, thus giving a potential for benefiting the organization
5.1.2.In-house rejections
Cushions are checked for its properties like hardness, profile, shape and
other surface defects. The parameter hardness predominantly contributes towards the seat’s
comfort level.
Testing of hardness is done as per IS 7888 for 4 wheeler cushions and JIS
6401 for Two wheeler cushions. Hardness testing will be carried out regularly to ensure
conformance to the specification.
If the manufactured cushions are not meet the quality standards it is
booked as In house rejection and moved to scrap area.
The below In house rejection data which is taken from SAP from April 2009 to March
2010.
Table 5.1.2: In house Rejections – High hardness
Apr
'09
May
'09
Jun
'09
Jul
'09
Aug
'09
Sep
'09
Oct
'09
Nov
'09
Dec
'09
Jan
'10
Feb
'10
Mar
'10
8 12 6 9 15 11 16 9 13 10 8 13
32
Past years trend
220
180
155
0
50
100
150
200
250
07 - 08 08 - 09 09-10
Year
Qu
anti
ty
Fig 5.1.2.a.: In House Rejections–Year wise
Fig 5.1.2.b: In house rejections due to Seat High Hardness– Month wise
5 .2. SOURCE OF DATA
Various sources for the types of data identified above are
a. Process flow diagrams can be collected from the Cushion Production on the basis of the
Process layout.
b. Operation standard formats can be received from the Plant Engineering
c. Customer complaint and in-house rejection details from our QAD.
d. Chemical consumption and production volume details from our SAP system
33
Monthwise trend 2009-10
8
12
6
9
15
11
16
9
13
108
13
0
5
10
15
20
Apr'09
May'09
jun'09
Jul'09
Aug'09
Sep'09
Oct'09
Nov'09
Dec'09
Jan'10
Feb'10
Mar'10
Month
Qu
an
tity
e. Test report from Quality Testing Department
5.3 DETAILS OF DATA COLLECTED
Following are the collection of data for
1. Customer complaints
2. In House rejections
3. Production Quantity
This Production quantity data has been collected from our Foaming Production
department from April 2009 to March 2010.
Table 5.3.1 : Star Sport Cushion Production quantity
Apr
'09
May
'09
Jun
'09
Jul
'09
Aug
'09
Sep
'09
Oct
'09
Nov
'09
Dec
'09
Jan
'10
Feb
'10
Mar
'10
12571 9695 15574 16138 15368 20524 19724 16226 9451 8620 12226 16600
In addition the following data also collected for supporting the analysis.
Process flow diagrams of the Hennecke PU Foaming Machine.
Operation standards for the Star sport Foaming Machine.
6. PU Foaming Process
The term "POLYURETHANE" is used to describe any polymer that has been chain extended
by reaction with di or poly-isocyanate. In other words "POLYURETHANES" are polymers
formed by the polyaddition of polyfunctional isocyanates with compounds containing at least
two hydroxyl groups.
The term polyurethane is derived from the "URETHANE" group that is predominantly
formed in the reaction. A urethane group is formed by the chemical reaction between an
34
alcohol and an isocyanate. The isocyanate group (-NCO) can react with any compound
containing 'active' hydrogen atoms. (Active hydrogen atoms are those which react with a
Grignard's reagent, generally methyl magnesium iodide to give methane.)
The typical reaction that depicts the formation of polyurethane’s (PU) is given below:
Polyol + water and/or Polyisocyanates or POLY
Blowing agent + catalyst(s) Diisocyanates URETHANE
FOAM
The two wheeler cushion production unit consists of the following machines and equipment
1. High pressure reaction moulding machine – 1 No
2. Linear carousel carrying 14 mould stations
3. 14 individual moulds each with 2 cavity
4. Injection head fitted on a rotary arm
1. High pressure reaction moulding machine:
This high-pressure reaction moulding machine is of “Hennecke” make from imported
from Germany. The machine consists of storage tanks to hold Polyol and Isocyanate in a
maintained temperature of 21 – 25 degrees centigrade, the control unit, computer controlled
programmable unit, metering units to control the quantity of both the chemicals
35
Fig 6.1 High pressure reaction moulding machine
2. Linear carousel
The linear carousel is nothing but a closed loop telescopic conveyor chain
fitted with a caterpillar drive and used to move the mould carrying fixtures. The movement &
the speed of the conveyor are controlled through a control panel and an automated lubricator
unit ensures the smooth movement of the conveyor. There are 14 moulds carrying stations or
otherwise called as Mould Fixtures (MF), individually operated through hydraulic power
pack. The mould carrying stations are locked with the towveyor chain conveyor through
towing pins. The power supply is given the MFs through an overhead 4-line bus bar.
36
High pressure reaction moulding machine
Fig 6.2: Linear carrousel with mould fixtures
3.Moulds
Moulds are used to produce PU cushions. The moulds are CNC machined to obtain
the contour of the cushion and made up of Aluminium. Different varieties of mould cavities
are used for various products. We have about 20 varieties of two wheeler moulds.
Fig 6.3: Aluminium mould cavity
There are 14 moulds with each with twin cavity are mounted in the mould carrying
stations. Each mould consists of top and bottom cavity. The top cavity is mounted in the top
frame of the MF by means of T bolts and the bottom cavity is fixed to the base frame of the
MF by means of conical locators. Hot water connection is given to the moulds to maintain the
mould temperature always between 55 – 60 degrees centigrade.
4.Injection head and the rotary arm.
The injection head is the important part of the machine where is both Polyol
and Isocyanate are mixed thoroughly inside the chamber at a high pressure of 160 – 180 bar
and the laminar flow is created inside for homogenous mixing through the injection nozzle.
Then the homogenous mixture is injected into the mould. The rotary arm consists of a pillar
37
support, rotary base, pivoted arm with a counter weight and the moving arm where the mixing
head is mounted. The movement of the mixing head is achieved by means of a robot.
Each type of cushion requires certain type of machine setting depend on the size, hardness,
weight and other requirements. These settings are stored in the PLC of the machine .
RFID will activate the signal to the foaming machine thro the sensors, The machine has the
input details and gives the signal to the control panel of the Robot , Each individual moulds
having individual program stored in the control panel of the machine. The Robot gets the
input details from the Control panel of the machine and pouring of the chemical in the mould
cavity.
Cushions are checked for its properties like hardness, profile, shape and other surface defects.
The parameter hardness predominantly contributes towards the seat’s comfort level.
Testing of hardness is done as per IS 7888 for 4 wheeler cushions and JIS 6401 for 2 wheeler
cushions. Hardness testing will be carried out regularly to ensure conformance to the
specification.
6.1 Conclusion
Following points are taken care during the data collection.
1. Data collected is done from normal sales taking place in the organization ensuring the
desired range of sales trend is covered.
2. In house rejection trend is formulated from the actual data entered in the in house
software for daily monitoring.
3. Much care has been taken to ensure unbiased data collection during the entire study in
order to achieve reliability.
The collected data has been formatted and are further used for analysis.
7.0 ANALYSIS OF DATA
7.1 CHOICE OF TECHNIQUES
DOE technique is used in this project as where applicable. The tools are selected suitable to
the analysis and study requirements.
Following techniques are used during the course of this project
38
Brainstorming is done to collect ideas.
Cause and effect diagram is used for causal analysis.
Trend charts has been used to formulate Production trend.
DOE techniques used for cost reduction and standardization.
7.1.1 DESIGN OF EXPERIEMENT IN STAR SPORT CUSHIONS
We have taken the present process parameters, specification and observations of the
Star Sport cushions
In order to optimize cost in the Star sport Cushion, we have identified the the index of
potential to achieve maximum benefits. The following sub parts are recommended.
1. Reduction in weight of the base chemical in Star Sport Cushion by DOE
We have taken the present process parameters, specification and observations of the Star Sport
cushions.
7.1.1 Selection of Factors for DOE
As a first step of DOE, we have analysed on the process parameters with respect to the local
control factors and the factors that can be taken for DOE.
Table 7.1.1– Selection of Factors for DOE – Star Sport Cushion
39
Inj time : 3.55 Seconds
Polyol qty/ Sec : 128 gms
ISO Qty / Sec : 78 gms
Cushion weight : 705 gms
Hardness : 11 - 15 Kgf
Hysterisis : 26 - 28 %
Supplier : Dow Chemicals
ISO : NE 134
Polyol : NF 755
7.1 Present Process Parameters of Star sport cushion
We have arrived at the different levels of experimental combinations by
varying the injection time and the ISO quantity. The combinations are shown in the below
table.
Factors
1. Injection Time2. ISO Qty
40
Process Parameters
1. Injection Time
2. ISO Qty
3. Injection Pressure ISO/Polyol
4. Mould temperature
5. Release agent application
6. Mould
7. Component Temperature
Factors for DOE
-
-
-
-
-
Local control
-
-
-
Levels
3.5, 3.45, 3.35, 3.25, 3.15 secs78, 80, 82, 84, 86 Gms
We have used the ANOVA table to find the significance between the different setting and the
cushion hardness.
We have compared the average response of the following parameters
1. Weight
2. Hardness and
3. Hysterisis
The ability of Flexible Polyurethane Foam (FPF) to maintain original
characteristics after flexing. Indentation Force Deflection (IFD) is generally measured as
the force in pounds required to compress a 50 sq inch circular indenter tool into four inch
thick sample. Common IFD values are general at 25 and 65% of the initial height.
41
Table 7.1.1.a – Experimental Combination of
injection time & ISO quantity
7.1.3 Experimental Combination - Full Factorial
3.15 x 78 3.25 x 78 3.35 x 78 3.45 x 78 3.55 x 78
3.15 x 80 3.25 x 80 3.35 x 80 3.45 x 80 3.55 x 80
3.15 x 82 3.25 x 82 3.35 x 82 3.45 x 82 3.55 x 82
3.15 x 84 3.25 x 84 3.35 x 84 3.45 x 84 3.55 x 84
3.15 x 86 3.25 x 86 3.35 x 86 3.45 x 86 3.55 x 86
Cushion hardness is checked using the Hardness Test as per the Quality Standard
of Japanese Industrial Standards (JIS 6401). As per the Specifications the hardness should
be 11 – 15 kgf.
Table 7.1.1.b – ANOVA Table
42
ANOVASource of Variation SS df MS F F crit
Injection time 94.444 4 23.611 122.974
3.006917ISO Qty
80.244 4 20.061 104.484
3.006917Error 3.072 16 0.192
Total 177.76 24
Both Injection time & ISO Qty are significant for Hardness. (F value > F critical)
ISO Qty78 80 82 84 86
3.15 8.8 9.2 10.8 12.4 14.8
3.25 10.2 10.8 11.2 12.7 15.2
3.35 11.4 12.1 12.7 14.8 16.2
3.45 14.8 15.7 16.2 17.9 18.5
3.55 12.5 13.7 14.2 15.8 17.9
Inje
ctio
n
Tim
e in
se
cs
Figure 7.1a – Average Response of Weight – Star Sport Cushion
Figure 7.1b – Average Response of Hardness – Star Sport Cushion
43
Average Response on Weight
705
641
661
669 670
708
600
620
640
660
680
700
720
3.15 x 84 3.25 x 84 3.35 x 80 3.35 x 82 3.55 x 78 3.55 x 80
Trial Combination
Wei
ght i
n gm
sExisting
LCL
UCL
Average Response on Hardness
13.713.1
12.712.5 12.4
12.1
8
11
14
17
3.45x 86
3.45x 84
3.55x 86
3.35x 86
3.45x 82
3.55x 84
3.45x 80
3.25x 86
3.15x 86
3.35x 84
3.45x 78
3.55x 82
3.55x 80
3.35x 82
3.25x 84
3.55x 78
3.15x 84
3.35x 80
3.35x 78
3.25x 82
3.15x 82
3.25x 80
3.25x 78
3.15x 80
3.15x 78
Trial combination
Har
dn
ess
Figure 7.1.3c– Average Response of Hysterisis
Figure 7.1.c – Average Response of Hysterisis – Star Sport Cushion
7 .1.5. Trial Result
After the following trials, we found that the Hardness, hysterisis property
which is the main parameters was satisfied at the weight of 670 Gms. So, we have set the ISO
quantity at 82 Gms / sec and Injection timing at 3.35 and done the process capability and
found the hardness was within specification.
By the application of DOE process we found the optimum method of
Injection time 3.35 sec with the chemical combination of ISO quantity of 82 Gms/sec
By implementation of the project, we were able to reduce the weight of the
Cushion by 5 %
44
Average response on Hysterisis
30.4
28.527.127.2
29.8
24
27
30
3.15 x 84 3.25 x 84 3.35 x 80 3.35 x 82 3.55 x 78 3.55 x 80
Trial Combination
Hys
teri
sis
in %
Existing process
parameter
Parameters identified
during experiments
7.1.6 Testing and Proving
Figure 7.0h – Methods of Testing
Figure 7.1.4– Testing and Proving
45
7.1.7 Test Report
46
Table 7.1.7 – Test Report – Star Sport Cushion
7.2. Standardisation
List of activities carried out towards standardisation of this Project.
Drawing modification through Engineering Change Note ( ECN )
Bill of Material ( BOM ) modification
Intimation to production and updation of the Operation standards
Norms updated in the system
Process parameters updated
Updation of the control plan
Training imparted to all individuals.
Approval from customer
8.Results and Benefits
During 2009-10 the contribution of the two wheeler seat on the overall cost was
around 16 – 20 %. Projected volumes for the year 2012-13, are 9,600 seats per day, we
have planned to improve the contribution of the Two Wheeler Seats and also improve the
profitability of our company as per the policy plan.
47
To meet the above demand, following activities were implemented.
1. Design of Experiments in Star Sport Seat.
Figure 8.0– Plan Vs Actual
After standardizing the above activities in the regular production, we could achieve the
following benefits
A. Achieved cost saving of Rs 5.12 Lakhs per annum (Break up details given below)
Cost Savings through DOE in Star Sport Seat -Rs. 5.12.00 Lakhs
8.1 Improvements planned in the year 2011 – 12
This improvement has been planned to be horizontally deployed to all similar products. The
target for implementation is during MAY ’11.
48
5 % Reduction in weight
Star Sport Cushion Weight
705
670675
600
650
700
750
Actual Plan Achieved
Wei
gh
t in
gm
s
9 Conclusions
9.1 SUMMARY OF FINDINGS
This project work has given very good information on the usage of the major tools
like Design of Experiment, ANOVA, Idea simulators etc., It has also provided me knowledge
on the PU Foaming Process.
9.2 GAINS OF THE PROJECT
This project yielded gains in terms cost, quality, delivery, time, etc., which we
have discussed in detail in section 8. Apart from the above, this project also provided an
opportunity to understand the PU Foaming Process and also implementation of projects in
practical at field and overcoming the difficulties and consequences faced. Benefit and
improvement gained out of this project has also motivated to improve my skills in problem
solving techniques.
9.3 LIMITATIONS OF STUDY
These techniques used can be horizontally deployed to other products. We could
not go about in taking trial of the four cavity mould, due to a short time span, the increased
investment and the chemical properties.
9.4 SCOPE OF FURTHER WORK
Similar study can be extended to the other products in the organization where
there is a real need of the cost optimization
49
10. CONCLUSION
This project has given me immense confidence to handle similar projects in the other
areas.
It has enhanced my knowledge on usage of Design of Experiment.
This project has benefited the organization in terms of cost reduction to the tune of Rs. 5.12
lakhs / annum.
“Insect eye view” to any problem or an activity always improves the performance and
utilization.
Tools followed like ANOVA, idea simulators has helped to detect early failures of the system
and also provided opportunity to focus on accident prevention. This also helped in team
building by involving many people in the organization to use those tools.
50
11. REFERENCES
1. Design of Experiments – Taguchi
2. Design and Analysis of Experiments – Douglas C. Montgomery, Third Edition
3. G. Woods, 1990, “The ICI Polyurethanes book, 2nd Edition: ICI Polyurethanes,
Everberg, Belgium jointly published with John Wiley & Sons.
4. Value Engineering for Cost Reduction and Product Improvement – M.S. Vittal;
Systems Consultancy Service, Bangalore.
5. Getting more at Less Cost-The Value Engineering Way-G. Jagannathan ;
6. Tata Mc Graw Hill Publishing Co. Ltd. New Delhi.
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ACKNOWLEDGEMENT
I sincerely thank Mr.P.SHANMUGAVEL, Manager-Manufacturing- Harita Seating
Systems Limited for giving me an opportunity to do a project in this organization and
valuable advice and continuous guidance in completing the project.
I express my immense gratitude to Mr.M.K.KANNAN, General Manager–
Manufacturing, for permitting me with free hand to complete the project. I wish to convey
my heartfelt appreciation to those countless friends who gave me moral support and
encouragement.
I also wish to thank all my colleagues in my department for their valuable inputs during the
project.
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