Application of Value Stream Mapping in an Indian Automotive Industry: A Case Study
19
Application of Value Stream Mapping in an Indian
Automotive Industry: A Case Study
1
A.V. DAMALE AND K.N. NANDURKAR
2
Department of Mechanical Engineering, SRES’ College of Engineering, Kopargaon,
Distt-Ahmednagar. (M.S.), India, Pin-423603, E-mail: adi_damale@yahoo.com
2
K.K.W. Institute of Engineering, Education and Research, Nashik, M.S. (India),
E-mail: keshav1965@gmail.com
Abstract: Lean manufacturing has become important tool in the era of globalization and competition.
Everyone is trying to give the product with more values and competitive prices for which “Lean”
(Manufacturing without Waste) has proved its importance. Implementation of lean manufacturing needs
various tools and techniques, and Value Stream Mapping (VSM) is of them. A major activity in the journey
towards lean is the effective management of the flow of products and services through the series of the
activities involved in providing value to the customer, known as the value stream. This requires a detailed
understanding of all the processes involved so that non-value-added activities can be identified and
eliminated. Value stream mapping (VSM) is a technique that can aid in developing this required knowledge.
This paper covers the scientific way followed at shop floor for carrying VSM at Gabriel India Ltd. (GIL)
Nashik (India) where Lean manufacturing has been implemented successfully. It has resulted in reduction
in WIP, Smooth Production flow to meet customer demands, Stress free operations. The said organization
is one of the Leading producer Shock absorbers and Front forks for OE customers as well as AM Requirements
in Domestic and Export Market.
Keywords: Value stream mapping, present state map, future state map, workcell
1. INTRODUCTION
Table 1 Cont’d
Lean production is a systematic approach to
identify and eliminating waste through continuous
improvement, flowing the product at the pull of the
customer in pursuit of perfection. It is a whole new
way of thinking and should be considered much
more than a series of programs or techniques and
become the whole system approach in order to
create a new operating philosophy, which focuses
on eliminating all non–value adding activities from
order entry to receipt of payment. Lead time and
work-in-process reduction, quality improvement,
enhanced flexibility, reduced transactions, simplified scheduling, improved communications,
reduced costs, better on time deliveries, increased
sales and improved space utilization are all possible
through the effective planning and implementation
of lean production. The basic feature of it is to
remove all types’ wastages Table 1.
2
Transportation
Information incompatibility, communication
failure, multiple sources,security issues
3
Waiting
Information created too early or unavailable,
late delivery, suspect quality
4
Processing
Unnecessary serial effort, too many
iterations, unnecessary data conversions,
excessive verification, unclear criteria
5
Inventory
Too much information, poor configuration
management, complicated retrieval
6
Unnecessary
Movement
Required manual intervention, lack of direct
access, information pushed to wrong
sources, reformatting
7
Defective Product Lacking quality, conversion errors, and
incomplete, ambiguous, or inaccurate
information, lacking required tests/
verification
Table 1
Seven Wastes as Per TPS
1
Overproduction
Too much detail, unnecessary information,
redundant development, over-dissemination, pushing rather than pulling data
Table Cont’d
Lean production is a team based systematic
approach to identify and eliminate wasteful or non
– value adding activities within an organization. In
order to identify waste on non-value adding
activities in a manufacturing unit, it is required to
map current state so that to visualize both valueadded and non-value-added activities. A value
stream mapping is defined as all the mapping of
value-added and non-value-added actions required
International Journal of Industrial Engineering Practice • January-June 2011 • Volume 3 • Issue 1
A.V. Damale and K.N. Nandurkar
20
bringing a specific product, service or combination
of products and services to a customer, including
those in the overall supply chain as well as those in
internal operations [8].
As categorized by Womack and Jones [11], the
main tenets of lean are:
Value: Providing the customer with the right
product, for the right price, at the right time
Value Stream: The set of action that bring a
product from concept to realization, order to
delivery, or raw material to finished good
Flow: Seamless movement through valuecreating steps
Pull: Acting only to satisfy customer needs,
rather than forcing, or pushing, a product upon the
marketplace
Per fection: Continuously and relentlessly
improving the value, value stream, flow, and pull
in business operations
The objective of this paper is to use a case-based
approach to demonstrate how lean manufacturing
tools when used appropriately, can help the auto
industr y to eliminate waste, maintain better
inventory control, improve product quality, and
obtain better overall financial and operational
control.
2. A CONDENSED HISTORY OF
LEAN MANUFACTURING
To help increase company profits U.S. manufacturing companies have always searched for efficient
strategies that will help improve their output,
reduce costs and establish a competitive position
to increase their market share. Early attempts can
be traced to Eli Whitney and Henry Ford.
Japanese manufacturers re-building after the
World War 2 had a difficult time. For one, they had a
limited amount of people, a limited amount of raw
material and money. These problems, born out of
necessity led to the development of lean manufacturing practices, which they called on just in time
manufacturing.
Japanese manufacturing leaders like the Toyota
Motor Company’s Eiji Toyoda, Taiichi Ohno, and
Shingeo Shingo developed a smart disciplined and
process focused production system now known as
the Toyota Production System (TPS), or lean
production. Which incorporated The Ford production, Statistical Process Control and other
techniques into a system that minimized the
expenditure of resources that added no value to
the product?
In 1990 James Womack wrote a book called
“The Machine That Changed The World”. Womack’s
book was a straightforward account of the history
of automobile manufacturing combined with a
study of Japanese, American, and European
automotive assembly plants. The “lean manufacturing” theory was made popular in American
factories in large part by the Massachusetts
Institute of Technology study of the process from
mass production toward production as written and
described in Womack’s book. A new phrase was
coined, as to which is now commonly referred to as
“Lean Manufacturing”. To implement the lean
manufacturing various tools are used like, Just in
Time (JIT), TPM, Cellular manufacturing, TQM,
SMED, Value stream mapping etc.
3. OoVER VIEW OF VSM
A value stream is a collection of all actions (value
added as well as non-value-added) that are required
to bring a product (or a group of products that use
the same resources) through the main flows,
starting with raw material and ending with the
customer. These actions consider the flow of both
information and materials within the overall supply
chain. The ultimate goal of VSM is to identify all
types of waste (Table. 1) in the value stream and to
take steps to try and eliminate these [3].
VSM is a pencil and paper tool, which is created
using a predefined set of standardized icons (the
reader is referred to Rother and Shook [8] for
details). Table 2 gives list of symbols used in this
study with their meaning. The first step is to choose
a particular product or product family as the target
for improvement. The next step is to draw a current
state map (Fig. 2) that is essentially a snapshot
capturing how things are currently being done.
Table 2
List of Symbols Used for the Study
Symbol
Exhaustive Meaning of Symbol
It represents the Supplier when in the upper left, the usual starting point for material
flow. The customer is represented when placed in the upper right, the usual end point
for material flow.
Customer/Supplier
Table Cont’d
International Journal of Industrial Engineering Practice • January-June 2011 • Volume 3 • Issue 1
Application of Value Stream Mapping in an Indian Automotive Industry: A Case Study
21
It is process, operation, machine or department, through which material flows.
Typically, to avoid unwieldy mapping of every single processing step, it represents one
department with a continuous, internal fixed flow path.
It goes under other icons that have significant information/data required for analyzing
and obser ving the system. T ypical information in a Dat a Box under neath
MANUFACTURING PROCESS icons: · C/T (Cycle Time in seconds,· C/O (Changeover Time)
- Uptime- percentage time that the machine is available for processing·
Dedicated Process
Data Box
This symbol indicates that multiple processes are integrated in a manufacturing
workcell. Such cells usually process a limited family of similar products or a single
product. Product moves from process step to process step in small batches or single
pieces.
These icons show inventory between two processes. While mapping the current state,
the amount of inventory can be approximated by a quick count, and that amount is
noted beneath the triangle. If there is more than one inventory accumulation, use an
icon for each. This icon also represents storage for raw materials and finished goods.
This icon represents movement of raw materials from suppliers to the Receiving dock/
s of the factory. Or, the movement of finished goods from the Shipping dock/s of the
factory to the customers.
This icon represents the “pushing” of material from one process to the next process.
Push means that a process produces something regardless of the immediate needs of
the downstream process.
This is an inventory "supermarket" (kanban stockpoint). Like a supermarket, a small
inventory is available and one or more downstream customers come to the supermarket
to pick out what they need. The upstream workcenter then replenishes stocks as
required.
When continuous flow is impractical, and the upstream process must operate in batch
mode, a supermarket reduces overproduction and limits total inventory.
Supermarkets connect to downstream processes with this "Pull" icon that indicates
physical removal.
These icons are used to highlight improvement needs and plan kaizen workshops at
specific processes that are critical to achieving the Future State Map of the value stream.
This is accomplished while walking along the
actual process, and provides one with a basis for
analyzing the system and identifying its weaknesses.
The third step in VSM is to create the future state
map (Fig. 4), which is a picture of how the system
should look after the inefficiencies in it have been
removed. Creating a future state map is done by
answering a set of questions on issues related to
efficiency, and on technical implementation related
to the use of lean tools. This map then becomes
the basis for making the necessary changes to
the system.
4. PRE-INTERVENTION SITUATION
manufacturer of automotive systems and components in India. The range of products include Monotube shock absorbers, Twin tube shock absorbers,
16 dia. bore to 25 dia. bore shock absorbers, and
front forks. Starting with 3 applications since
inception, they now have 60 applications to their
credit. The major domestic and overseas customers
of the group includes, Caterpillar, Cummins,
Daimler Chrysler, Eicher Motors, Escorts, Fiat, Force
Motors, Ford, General Motors, HMT, Honda,
Hyundai, Indian Army, Ingersoll Rand, L & T John
Deere, Mitsubashi, Mahindra & Mahindra, New
Holland, Tata Motors, Toyota, Yamaha Motors,
Maruti -suzuki, Ashok Leyland and Bajaj auto Ltd
etc.
4.1 About the company
4.2 Process Description
The study was conducted at Gabriel India Ltd
Ambad (Nashik) which is one of the Leading
organization supplying Shock absorbers and Front
forks for OE customers as well as AM Requirements
in Domestic and Export Market. This organization
is a part of Anand Group which is a leading
Shock absorber final assembly process has been
considered for this study. The various operations
required in the assembly are Main cell operations,
Bush fitting, Painting, Inspection and packing
(Fig.1). The mail cell operations are not discussed
in detail due to the company’s privacy policy.
International Journal of Industrial Engineering Practice • January-June 2011 • Volume 3 • Issue 1
A.V. Damale and K.N. Nandurkar
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Table 4
Quarterly Requirements of BAL
Month
Fig. 1: Sequence of Operations
4.3 Product Selection for Study
Customers give their demands on quarterly basis.
The demand is then broken into month basis, week
basis and finally on daily basis by the planning
department. As there are more than one customer
so to select the product for this study the preference
is given to the product which contributes more in
volume over the other customers. Table 2 shows
the quarterly demand of the customers. From the
table it is clear that BAJAJ AUTO LTD’s (BAL)
demand around 60%-70% of the total demand. So
the product selected is for BAL. Also the demand
of BAL consist more one products like two-wheelers
and 3-wheelers. So the BAL’s demand is further
analyzed into product wise and the higher one in
volume is selected for the study. Table 3 Shows the
BAL’s product wise demand. So from this the
product of PLATINA is selected for this study.
Table 3
Quarterly Orders of the Customers
Month
Other’s
Total Orders
(Nos.)
BAL
(Nos.)
% of BAL
Orders
Others
(Nos.)
% of
Orders
Jan.
146500
87500
60 %
59000
40 %
Feb
167000
116000
70 %
51000
30 %
March
194000
135000
69 %
59000
31 %
April
186000
134000
72 %
52000
28 %
Total Order
(Nos.)
Platina
(Nos.)
AD Three
wheeler (Nos.)
Jan.
87500
71500
16000
Feb.
116000
95000
21000
March
135000
117000
18000
April
134000
114000
20000
5. VSM: CURRENT STATE MAP
All data for the current state map were collected
according to the approach recommended by Rother
and Shook [9]. Data collection for the material flow
started at the stores department, and worked
forward all the way to the dispatch point, gathering
snapshot data such as inventory levels before each
process, process cycle times (CTs), number of
workers, and changeover (CO) times. Figure 2 shows
the current state map that was constructed; the
small boxes in the map represent the process and
the number inside the box is the number of workers
at each process. Also, each process has a data box
below, which contains the process CT, machine
reliability (MR), the number of shifts, and the CO
time. It should be noted that this data was collected
whilst walking the shop floor and talking to the
foreman and operators at each workstation. The
processing and set-up times are all based on the
average of historical data. After collecting all the
information and material flows, they are connected
as indicated by arrows in the map, representing how
each workstation receives its schedule from
business planning.
Fig. 2: Current State Map
International Journal of Industrial Engineering Practice • January-June 2011 • Volume 3 • Issue 1
Application of Value Stream Mapping in an Indian Automotive Industry: A Case Study
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6. VSM: FUTURE STATE MAP
Fig. 3: Cycle Time of Processes
The timeline at the bottom of the current state
map (Fig. 2) has two components. The first
component is the production waiting time (in days),
which is obtained by summing the lead-time
numbers from each inventory triangle before each
process. The time for one inventory triangle is
calculated by dividing the inventory quantity into
the daily customer requirements. For example, the
lead-time for the inventory triangle ahead of bush
fitting is 0.33 days; this is calculated by dividing 900
(the total inventory ahead of the bush fitting) by
2750 (the daily average demand rate for the
product). The total observed value for the waiting
time is 1.6 days.
The second element of the timeline is the
processing (or value-added) time, which is about
70 seconds. This time is calculated by adding the
processing time for each process in the value
stream. The CT for each process is the average CT,
which was determined by using actual data from
the company. Thus the total lead time is around
38.09 hours. So the total value added time is too
less capered to lead time.
Also from the current map, it is observed that
the output of main cell is output 2750 nos. per shift
which is minimum dispatch quantity per day. Also
the change over time of the mail cell found 27
minutes which is more. The final products are only
1050 nos. are available after the packing operation.
So the remaining more than 1050nos are produced
from the offline (Fig. 5). Due to off line processing
there is no proper planning for post painting
material. Post painting done as per material
availability from stores, off line processing going
on second or third shift as no pull system due to off
line operation is available. So whole system was
under pressure due to non smooth production flow.
The inventory between main cell and bush
fitting is 900, between bush fitting and post panting
is 700. The bush fitting with oil filling and the post
painting operations are performed manually. Due
to this, cycle times of the these processes is higher
(Fig.2).
The process of defining and describing the future
state map starts while developing the current state
map, where target areas for improvement start to
show up looking at the current state map for GIL
several things stand out: (a) large inventories, (b)
the difference between the total production leadtime (around 1.6 days) and the value added time
(80 seconds), which is under 5% of the total., and
(c) each process producing to its own schedule.
Inventory and lead time may be viewed as two
related issues since the more the inventory; the
longer any item must wait for its turn and thus, the
longer the lead time. In creating the ideal future
state map we try to identify lean manufacturing
tools to drive both of these down, while looking at
the schedule across the entire value stream. We
follow a systematic procedure where we try to
answer a series of structured questions; this allows
us to come up with an ideal future state map that
will help in eliminating or at least reducing different
types (Table 1) of waste in the current manufacturing system.
Q. 1. What is the takt time?
“Takt time” refers to the rate at which customers
are buying products from the production line; i.e.,
the unit production rate that is needed to match
customer requirements. If processing time of any
of the operation is greater than your takt time, you
have a candidate for a bottleneck or constraint. This
may be causing overproduction waste or work in
process (WIP) in some areas or extra processing
time, such as overtime, to meet demand. It is
calculated by dividing the total available time per
day by the daily customer demand. The customer
requirement in the month of January is 715000 nos.
(Table 2). Assuming 26 working days per month, the
average daily requirement is thus 2750 numbers
per day. The company operates single shift in a day.
The shift time is 8.5 hours with one hour lunch and
tea break. So total time available is 450 minutes or
27000 seconds. Therefore takt time is 27000/2750
= 9.81 seconds per job.
Q. 2. Are there bottlenecks or constraints?
From the data, cycle times or processing times
of the processes, namely bush fitting, post panting,
inspection and packing are 15,26,15 and 14
seconds respectively which are greater than takt
time (Refer fig. no.). Then it indicates a candidate
for a bottleneck or constraint. This may be causing
overproduction waste or work in process (WIP) in
some areas to meet demand.
International Journal of Industrial Engineering Practice • January-June 2011 • Volume 3 • Issue 1
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A.V. Damale and K.N. Nandurkar
Q. 3. Where can inventory (or queue time) be
reduced or supermarkets used?
After looking at raw material, WIP, buffer stock,
safety stock and finished goods inventories at shop
during Current state map it is clear that the
inventories are there in main cell and bush fitting,
between bush fitting and post painting. These
inventories are of 900 and 700 respectively.
To minimize the effect of these inventories, it
makes sense to put in a supermarket replenishment system. A super market is a controlled
inventor y system—the downstream process
removes items from the shelf and the process
owners upstream replenish that amount to the
supermarket. So accordingly two supermarkets
were placed (Fig. 1). One between supplier (store)
and main work cell and the other for finished
products (in house and customer end).
Q. 4. What other improvements are required?
For improvements in the current system the
problem of material flow and to minimize the
inventory were the two main problems. For this
various options were thought like does the
reliability of equipment need to be improved? Are
the first pass yield or quality levels acceptable? Do
we need to perform training in 5S (workplace
organization)? Do we need to create a new layout
for an area? And after brainstorming among
experts, the team has came to conclusion for
making layout changes and development of a new
work cell for post painting, inspection and packing.
Where workcell is a work unit larger than an
individual machine or workstation but smaller than
the usual department. Typically, it has 3-12 people
and 5-15 workstations in a compact arrangement.
An ideal cell manufactures a narrow range of highly
similar products. Such an ideal cell is self-contained
with all necessar y equipment and resources.
Cellular layouts organize departments around a
product or a narrow range of similar products.
Materials sit in an initial queue when they enter the
department. Once processing begins, they move
directly from process to process (or sit in miniqueues). The result is ver y fast throughput.
Communication is easy since every operator is
close to the others. This improves quality and
coordination. Proximity and a common mission
enhance teamwork.
Figure 4 shows the future state map. In this map
it is clear that the total process is performed in two
workcell only. Two added supermarkets before
main workcell and the other after newly formed
workcell which were joined by the conveyor control
material handling system reduces the inventory in
the system.
Fig. 4: Future State Map
International Journal of Industrial Engineering Practice • January-June 2011 • Volume 3 • Issue 1
Application of Value Stream Mapping in an Indian Automotive Industry: A Case Study
Also bush fitting with oil filling and the post
painting operations are atomized.
7. RESULTS AND DISCUSSIONS
After the implementation of VSM the review of the
system is done which has give nice results. The
changes made in layout and atomisation of
operation of oil feeling and bush fitting operations
have resulted in the Line balancing (Fig. 5).
25
8. CONCLUSION
The applied method for value stream analysis, and
the way it was conducted, appears to have been
successful as a first step for restructuring the value
stream for the product family that were object of
study. Compression of the throughput time was a
significant gain in the case. Maybe the method
would be even more useful, not at least for
priorities, if economy were considered in the same
systematic way as time in terms of value added and
non-value added. Reduction in WIP and smooth
production flow with less stress on production
persons and satisfied customers with smooth
dispatch are the outcomes of the VSM study.
ACKNOWLEDGEMENT
The authors are thankful towards the cooperation
extended by Gabriel India Ltd, Nashik during this
study. Special thanks goes to the head of Mechanical Engineering department, Principal and the
management of SRES Engineering College
Kopargaon for the encouragement received by
them during this study which has boosted the moral
of the authors.
Fig. 5: Balanced Line
Continuous flow of material resulted in zero WIP
due to elimination of off line processing (Fig. 5).
Main cell inventory in plant has been reduced
from 2750nos to 925nos, Post panting inventory in
plaint has reduced from 2500nos to 925 nos.
(Fig. 6)
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