Sand casting conventional and rapid prototyping manufacturing approaches
PG thesis
1. PRODUCTIVITY IMPROVEMENT IN MANUFACTURING DIVISION
OF SHEET METAL INDUSTRY
KANNAN P
(13MM09)
Dissertation submitted in partial fulfillment of the requirements for the degree of
MASTER OF ENGINEERING
BRANCH: MECHANICAL ENGINEERING
SPECIALIZATION: LEAN MANUFACTURING
Anna University
Chennai
MAY 2015
DEPARTMENT OF MECHANICAL ENGINEERING
PSG COLLEGE OF TECHNOLOGY
(Autonomous Institution)
COIMBATORE – 641 004
2. PSG COLLEGE OF TECHNOLOGY
(Autonomous Institution)
COIMBATORE – 641 004
PRODUCTIVITY IMPROVEMENT IN MANUFACTURING DIVISION OF
SHEET METAL INDUSTRY
Bonafide record of work done by
KANNAN P
(13MM09)
Dissertation submitted in partial fulfillment of the requirements for the degree of
MASTER OF ENGINEERING
BRANCH: MECHANICAL ENGINEERING
SPECIALIZATION: LEAN MANUFACTURING
Anna University
Chennai
MAY 2015
...……………………… ... .……..……………….
Dr. Gukan Rajaram Dr. D. Rajenthirakumar
Faculty guide Program Coordinator
Certified that the candidate was examined in the viva-voce examination held on ………………...
………………………….. …………………………..
(Internal Examiner) (External Examiner)
3. Acknowledgement
i
ACKNOWLEDGEMENT
I wish to express my gratitude to Dr.R.Rudramoorthy, Principal, PSG College of
Technology for providing an opportunity and necessary facilities to carry out this project.
I wish to express my deep sense of gratitude to Dr. K. Natarajan, Professor and Head,
Department of Mechanical engineering, PSG College of Technology, for his enthusiasm and
knowledge which has helped to shape my project and enabled me to proceed in the right path.
I take it as a privilege to thank my guide, Dr. Gukan Rajaram, Associate Professor,
Department of Mechanical Engineering, PSG College of Technology, for the valuable guidance,
whose guidance stimulated my interests in knowing the various know-how’s of the project.
I would like to express grateful thanks to Mr. Vikas Vijayan (Unit Head- Madras
Radiators and Pressing Limited) and Mr. Kalairasan , (Head Planning Department -
Madras Radiators and Pressing Limited), Coimbatore, for their guidance, great
encouragement and constant support, which inspired me during the project period.
I wish to express my gratitude to all the Industrial staffs who gave me full co-operation
and essential inputs for my project work.
I also thank all my friends, classmates and family members for supporting me in all my
endeavours.
4. Abstract
ii
ABSTRACT
Sheet metal fabrication comprises a variety of product categories, and design
requirements based on constantly changing customer requirements. This in turn, is a major
limitation to introduce the automation for the production system. Compared to other
production process, sheet metal fabrication process involves large amount of material
transaction between the stations. Productivity improvement could be achieved either by
reusing the waste material or reducing the material movement and labour idle time in the
shop floor.
In sheet metal industry, the fabrication process includes a set of workstations, at
which a specific task is carried out in a restricted sequence with number of components
having different styles simultaneously. In order to focus on this kind of material intensive
structure CE-Carrier assembly product was chosen for this study. The production line was
analysed by considering the innovative use of lean manufacturing concepts such as time
study, layout analysis and scrap management.
This project was carried out at a sheet metal industry in Coimbatore. From the time
study, layout diagram and spaghetti diagram waste in the existing production process were
identified. It was found that labour idle time is more in some stations. By assigning more than
one task to that labour the idle time could be reduced. Simulation was carried out using
Arena software. Based on that, the layout was modified. After modification the distance
travelled between sections is minimized and work in progress is reduced. Scrap tracking and
management system is developed to track and retrieve the suitable sheet from inventory
which increases the utilization of wasted sheet in punching operation without increasing the
inventory and material tracking time.
5. Table of Contents
iii
TABLE OF CONTENTS
CHAPTER PAGE NO
ACKNOWLEDGEMENT i
ABSTRACT ii
LIST OF FIGURES vi
LIST OF TABLES vii
1. INTRODUCTION 1
1.1 Sheet metal products 1
1.2 Sheet metal manufacturing operations 2
1.3 Productivity 3
1.4 Measuring outputs and inputs 4
1.5 Interpretation of productivity data 5
1.6 Need for the project 5
2. LITERATURE SURVEY 6
3. PROBLEM STATEMENT 8
3.1 Problem statement 8
3.2 Objectives 8
3.3 Scope of the project 9
4. METHODOLOGY 10
4.1 Identification of problem statement 10
4.2 Data collection and analysis 10
4.3 Simulation study 12
4.4 Development of scrap tracking and management system 12
4.5 Implementation and follow-up phase 12
6. Table of Contents
iv
5. WORK STUDY AND PLANT LAYOUT 13
5.1 Work study 13
5.1.1 Basic procedure 13
5.1.2 Timing method 13
5.1.3 Number of cycles to study 14
5.2 Plant layout 15
5.2.1 Product selected 15
5.2.2 Process flow chart 16
5.2.3 Spaghetti diagram 17
5.2.4 Material movement distance in current layout 20
6 VALUE STREAM MAPPING 21
6.1 Value stream mapping 21
6.2 Terms used in VSM 21
6.3 Current state VSM 21
6.4 Identification of waste 23
6.5 Improvement activities 23
6.6 Proposed layout 23
6.7 Material movement distance in proposed layout 26
7 SIMULATION STUDY 27
7.1 Current layout simulation 27
7.2 Proposed layout simulation 29
8 DEVELOPMENT OF SCRAP MANAGEMENT APPLICATION 31
8.1 Punching operation 31
8.1.1 Existing method 32
8.1.2 Proposed method 32
8.2 Need of scrap management system 33
8.3 Functional requirement 33
7. Table of Contents
v
8.4 Software architecture 34
8.5 Database creation 34
8.6 Functional architecture 34
8.7 Creation of scrap tag 35
8.8 Testing of software system 36
8.9 System requirement 36
9 RESULTS AND DISCUSSIONS 37
9.1 Reduction in material movement distance 37
9.2 Comparison of simulation result 38
9.3 Future state value stream mapping 38
9.4 Scrap management system 40
10 CONCLUSION 41
APPENDIX 1 42
BIBILIOGRAPHY 53
8. List of Figures
vi
LIST OF FIGURES
Fig. No. Name Page No.
4.1 Block diagram of methodology 11
5.1 Catia diagram of product 16
5.2 Plant layout diagram 18
5.3 Spaghetti diagram 19
6.1 Current state value stream mapping 22
6.2 Proposed layout 24
6.3 Spaghetti diagram for proposed layout 25
7.1 Existing model 27
7.2 Existing process in powder coating section 28
7.3 Proposed model 29
7.4 Proposed process in powder coating section 29
8.1 Catia model of punched sheet 31
8.2 Existing method 32
8.3 Proposed method 33
8.4 Software architecture 34
8.5 Functional architecture 35
9.1 Comparison of layout 37
9.2 Future state value stream mapping 39
9. List of Tables
vii
LIST OF TABLES
Table No. Name Page No.
5.1 Time study 15
5.2 Flow process chart 17
5.3 Distance calculation for current layout 20
6.1 Distance calculation for proposed layout 26
7.1 Current layout simulation 28
7.2 Proposed layout simulation 30
9.1 Comparison of simulation result 38
10. Introduction Chapter 1
1
CHAPTER 1
INTRODUCTION
In today's competitive and rapidly changing environment, globalization and
liberalization have broken boundaries of trade barriers. Thus the world has shrunk and
made business free from boundaries. Consumers are free to buy any product and services
of their liking and producers are free to sell their product and services anywhere. Also the
shift of market is from sellers to buyer's choice. In this competitive situation to obtain the
market share the industry has to change the strategy from “Good quality product for
reasonable cost” to “Good quality product for lower cost” but without compromising the
quality. This demands specific tangible efforts by Indian industry in bringing down the cost,
improving quality, making optimum use of resources and timely delivery of products and
services to stay competitive. One of the best way to develop the industry for global
competition is improving the productivity.
1.1 SHEET METAL PRODUCTS
Over half of total metal production ends up in sheet metal products - auto bodies,
appliance shells, cans, etc. Consequently the processing of sheet metals is vital importance
to a range of industries. The raw material for sheet metal manufacturing processes is the
output of the rolling process. Typically, sheets metal are sold as flat, rectangular sheets of
standard size. If the sheets are thin and very long, they may be in the form of rolls.
Therefore the first step in any sheet metal process is to cut the correct shape and sized
‘blank’ from larger sheet.
Major process involved in the manufacturing of sheet metal product are
Punching process
Part removal process
Deburring process
Pressing process
Welding/fabrication process
Pre-treatment process
11. Introduction Chapter 1
2
Powder coating process
Drilling process
Paint touch up process
Inspection process
Packing process
1.2 SHEET METAL MANUFACTURING OPERATIONS
The first operation in any sheet metal production is punching operation. The
manufacturing of sheet metal product starts with the design department. Most of the sheet
metal product requires punching operation to seize the required parts from the standard
sheet. In a single rectangular sheet of standard dimension, number of parts can be
prepared. The designer creates an optimum layout using the software to avoid wastage of
sheet metal. Once it has been designed, a CNC program will be generated in the software
and a program id will be given to each programs. The operators enter the appropriate
program id to carry out the punching operation.
Once the punching operation is finished, the individual parts are removed from the
sheet metal with help of spanner and hammer, which creates burr. Separate station is
framed to carry out the deburring operation. After finishing the deburring operation the parts
have been sent to the pressing station to finish the pressing operation. According to the
customer requirement, the parts have been bend by the pressing machine. Then the
pressed parts are shifted to the fabrication unit using the material handling device.
In the fabrication unit, individual parts are welded together to create base product and
sometimes nuts will be welded to inner surface to accommodate threaded parts. The burrs
which would be developed during welding operation, is removed by deburring process. Then
the parts are pretreated in 12 different pre-treatment tank to prepare the surface for powder
coating operation. Here group of parts are taken in a bin and the bin is immersed in each
tank for 3 minutes. After finishing the pre-treatment process, the parts are allowed to dry,
then the operator cleans the surface by the cloth and later by the compressed air.
Then the parts are loaded into the overhead conveyor which enters into the primary
furnace. In the primary furnace the temperature is maintained at 60°C to make the surface
to deposit the powder which sprayed by using the special gun. Then the conveyor with the
parts enters into the secondary furnace where temperature is maintained at 120°C to create
the permanent deposition of powder on the surface to give the smooth finishing. Then the
powder coated parts are allowed to cool at room temperature. In the entire operation the
12. Introduction Chapter 1
3
conveyor velocity is maintained at 1 m/min.
Durability of coating is depended upon the thickness of the coating. So the coating
thickness is measured by using the DFT meter. 100% inspection is followed to inspect the
coating thickness. Then quality testing is conducted for one sample for each day to identify
the durability of powder coating process. After finishing the entire process the product is
delivered to the customer.
1.3 PRODUCTIVITY
The growing international competition has put a lot of pressure on the sheet metal
product manufacturers to produce quality products at a competitive price and deliver them to
the customer just-in-time. In this scenario, the industry has to focus on the improvement
activities which leads to productivity improvement. Productivity is also one of the most
frequently encountered words in management discussions and in national economic
debates. Notwithstanding its popularity, ‘Productivity’ is not fully understood by many and
used wrongly in many cases. Therefore, it is important to understand the fundamental
concepts of productivity, this chapter is aimed at explaining productivity, different
approaches to productivity measurement, calculation of productivity index and how
productivity is lost in sheet metal industry.
Productivity in simple words is a relationship between output and input. The output in
sheet metal industries are number of products are produced. The inputs are man-hours,
machine hours, number of raw sheets consumed etc. Productivity denotes the
productiveness of the factors of production, labour and capital, in creation of wealth. In
simple words productivity is concerned with the efficient utilization of resources in producing
goods. Having discussed what productivity is, it is now important to understand how to
measure productivity in sheet metal industry. There are mainly two approaches to
measurement of productivity. These are partial and total productivity measurement. Partial
productivity is the ratio of output to one class of input. For example labour productivity is a
partial measure. Similarly material productivity and machine productivity are examples of
partial productivity.
Partial productivity measures are easy to understand and use. The data needed are
easy to obtain and easy to compute. Partial productivity is also a good diagnostic tool for
pinpointing improvement areas. However, it has some disadvantage, if used alone, it can be
misleading and may lead to costly mistakes. Partial measures cannot be used to explain
overall cost increases, studies show that among industrial corporations partial productivity
13. Introduction Chapter 1
4
measures are the most commonly used at all organizational levels.
Total productivity is the ratio of total output to the sum of all input factors. Thus, a total
productivity measure reflects the joint impact of all inputs in producing the output. It is a kind
of a higher level of productivity assessment combining several or many partial productivity
measures. Total productivity measure considers all the quantifiable output and input factors.
Therefore it is a more accurate representation of the real economic picture of an enterprise.
However, total productivity measure does not tell the management of a firm which of its
products or services is causing a decline or growth. Nor does it tell them which particular
inputs-workers, material, capital, energy or other expenses-are being utilized inefficiently so
that corrective action can be taken. Moreover, data for computation are relatively difficult to
obtain unless data collection systems are designed for the purpose.
Sheet metal manufacturers prefer to use partial productivity measures like labour or material
productivity. This is mainly because of the fact that the data needed for the partial
productivity measurement is easily available and the results of productivity computation can
be used by the department or the section in-charge to evaluate its performance or to plan
improvement.
1.4 MEASURING OUTPUT AND INPUTS
As explained earlier productivity is the relationship between output and the input. The
collection of data on the output and input, therefore, becomes important. The output and the
inputs can be measured in physical units or in financial terms depending upon the
organizational needs. Manufacturers producing a standard product tend to use physical unit
method for measuring output i.e. the output is measured in terms of the number of items
produced. In case of manufactures producing products with close similarity, the output is
converted in to ‘standard equivalent product’ for physical measurement. In case of
manufacturers with great amount of product variation, the measurement of output in physical
unit terms may not be useful, as the products are not comparable. In such cases, the output
is measured in financial terms.
Labour input is generally measured in physical units like minutes, hours, days or
months. Capital inputs like, machines can also be measured in terms of time. In sheet metal
industry it is often seen that productivity is communicated in terms of number of products
produced per machine per shift or per operator per shift.
14. Introduction Chapter 1
5
1.5 INTERPRETATION OF PRODUCTIVITY DATA
In this study partial productivity data such as labour productivity and material
productivity is used to measure the improvement. Labour productivity is nothing but the
%reduction in worker idle time after introducing the improvement.
Labour productivity = (Difference in %idle of operator in current and proposed layout)
And material productivity represents the percentage reduction in raw material usage for
the production of fixed quantity after introducing the improvement activities.
Material productivity = (Reduction in raw sheet usage in current and proposed method)
1.6 NEED FOR THE PROJECT
The project was carried out in the manufacturing division of Madras Radiators &
Pressing ltd, Coimbatore. In the manufacturing division some machines are improperly
arranged which leads to increased material movement from one station to other station.
Products are produced for four major customer. In that CE-Carrier assembly product is
chosen for the study. It currently require 36 labours to complete the product. Therefore it
was decided to study the productivity for the selected product. The current layout was
analysed and the distance travelled is calculated. Suggestion was given for improving layout
and reducing the movement distance.
In the existing method there is no system to track the non-used sheets coming out of
the punching operation which leads to lack of resource utilization. Therefore it was decided
to develop and implement the scrap management system to track the suitable sheet in the
inventory and reuse it without any extra effort.
15. Literature survey Chapter 2
6
CHAPTER 2
LITERATURE SURVEY
This chapter gives the outline of the literature supporting the applicability of layout
modification in sheet metal industry and gives the major outline for the application
development by using Microsoft Visual Studio.
Productivity loss is a major problem in any automotive industry. Especially in sheet metal
industry where the repetitive human resource are used to complete the operation. This kind
of industries subjected to severe productivity loss due to poor morale of worker. In 1880
Fredrick W. Taylor [7] had developed the work study method which is one of the major step
towards the productivity improvement. He introduced the time study to measure the work
content to improve the worker morale. Today time and motion study become one of the
necessary tool for industry to be succeed in the global competition.
Main resistance towards achieving the productivity is waste present in the existing
manufacturing process. The lean manufacturing concept first introduced in the book “The
Machine that changed the world” published by Womack et al in 1990 [8]. The main focus of
lean manufacturing is to systematic identification of waste and elimination of waste by using
suitable lean tool. It also indicates the seven kind of waste in the industry such as
transportation, inventory, motion, waiting, over production, over processing and defect.
K.Hemanand [1] had made an attempt to increase the labour productivity by reducing
the idle time of operator. And he also made an attempt to reduce the material movement
distance by modifying the existing layout. He also introduce the new material handling
device to reduce the material handling time.
Gaurav Kumar [2] had identified the opportunity to improve the productivity in sheet
metal industry with the systematic procedure. They conducted the detailed study of
production process and concluded that present facilities for rim manufacturing is not being
used as per their capabilities. Reason for this lack of productivity is less motivation morale
among employees. So he developed standard timing for each and every activities.
Winston Rey S. [3] had developed the “Laboratory inventory system” for the engineering
college. They have develop the Bar code for each component in the laboratory and
16. Literature survey Chapter 2
7
information of those components is stored in the database. Then they have installed the bar
code scanner to identify the information of the particular component.
Taner Arsan [4] had developed the “Inventory Management System” to replace the
traditional paper work based inventory records. He designed the front end application which
have an interface with the SQL database for storage and retrieval of data. The developed
application had the ability to track, to keep history, to give detailed reporting for each
inventory with reduced human intervention.
Arulogun O. T. [5] had developed the “RF id based student attendance management
system” to eliminate the time waste in the manual collection of attendance. RF id technology
facilitate the automatic wireless identification using electronic passive and active tags with
suitable readers. RF id tag information along with student detail is stored in the database.
The receiver captures the signal from the tag and marked the arrival and departure time of
the particular student.
Josphineleela.R. and M.Ramakrishnan [6] had developed the “Automatic Attendance
System using Fingerprint Reconstruction technique”. Here they designed a system such that
attendance report is generated using the thumb impression of student or staff. Hence by
implementing this system they try to reduce the false data in the attendance record.
In the cited literature researcher revealed the importance of lean concepts in the sheet
metal industry to increase the productivity. They use the layout analysis to reduce the
material movement between the stations in the plant floor. And they made an attempt to
reduce labour idle time to increase the labour productivity. And the importance of inventory
management is discussed and the procedure to develop the new software application is
identified.
Detailed literature review and production process study reveals that one of the major
problem in the industry is improper arrangement of machines in the current layout which
leads to increased material movement. It also focused to reduce the worker idle time by
assigning more than one task for some labour. New system has been developed to manage
the non-used sheets coming out of the punching operation and reuse those sheets for
further operations without increasing the inventory and tracking time.
17. Problem statement Chapter 3
8
CHAPTER 3
PROBLEM STATEMENT
3.1 PROBLEM STATEMENT
The detailed study of production process and existing layout reveals that there is
improper arrangement of machines which increases the material movement and reduces
resource utilization.
In the existing method there is no system to track the scrapped sheet coming out of the
punching station which leads to increased scrap inventory in the shop floor and reduced
utilization of scrap sheets for further production.
3.2 OBJECTIVES
To achieve reduction in material movement distance for Gilbarco’s CE Carrier
assembly by 20%.
To identify new spaces for drilling station and paint touch up station instead of the
packing area.
To reduce the man movement in the powder coating section by using the suitable
material handling device to store and drop the parts that is unloaded from the
conveyor.
To Increase the utilization of resource by availing the suitable scrap sheets for
punching operation.
To develop the scrap tracking and management system to track the scrap sheets
formed in the punching station of sheet metal industry.
3.3 SCOPE OF THE PROJECT
Layout modification ensures that the distance travelled between stations is
minimized.
Reducing the number of workstation and assigning multiple work for some operator
will result in reduced idle time of operator and it also frees some workers for other
manufacturing activities.
18. Problem statement Chapter 3
9
Implementation of new material handling system helps to reduce man movement in
the powder coating section.
Development of scrap tracking and management system will helps to utilize the
scrap sheet for further production process without any time delay.
19. Methodology Chapter 4
10
CHAPTER 4
METHODOLOGY
Methodology has been developed to locate the problem area systematically and to
implement the suitable solutions to resolve those problem. Block diagram of methodology is
shown in Fig 4.1.
The project methodology is divided into five major phases such as
Identification of problem statement
Data collection and analysis
Simulation study
Development of scrap management system
Implementation and follow-up phase
4.1 IDENTIFICATION OF PROBLEM STATEMENT
Initial phase of any project work should be identification of problem statement. Clear
definition and understanding of problem statement is must to carry out the project
effectively. Initial plant visit helped to identify the some basic details such as products detail,
customer details and supplier details. Then detailed study of existing production process has
been made to identify the waste in the exiting process. By analyzing entire waste, the
problem statement has been developed by considering the SMART activity (SMART-
Specific Measurable Achievable Realistic Time bound).
4.2 DATA COLLETION AND ANALYSIS
Initial data collection leads to identification of problem statement. While data collected
in this phase will helps to locate the possible causes which creates the problem. The
problem has many issues however finding a root cause will helps to determine the
alternative solutions to overcome the problem. In this phase spaghetti diagram has been
developed to identify the production problem in the current layout. Time study, process map
and current state value stream mapping helps to locate the problem area in the shop floor.
Cause and effect diagram is used to identify the root cause of the problem. Then list of
suggestions has been developed with the help of literature survey. Then the suitable
20. Methodology Chapter 4
11
alternative solutions has been suggested for implementation. Proposed layout and future
state value stream mapping helps to identify the benefits achieved by the industry after
implementation of improvement activities.
Redesign of layout
Development of scrap management system
Implementation and follow-up phase
Simulation study
Estimation of performance
Comparison of simulation result
Identification of waste
Development of proposed layout
Product selection
Development of spaghetti diagram
Problem identification
Identification of current layout
Plant study
Collection of data and time study
Fig 4.1 Block diagram of methodology
21. Methodology Chapter 4
12
4.3 SIMULATION STUDY
Simulation is conducted by using the Arena software, to compare the characteristics of
existing and proposed layout. Existing process in the powder coating unit is imitated by
using flow chart model. Then the simulation is carried out for the production of 60 products.
Then the proposed process is built and simulated under the same conditions to compare the
results for existing and proposed layout. Then from the results % improvement in the labour
productivity have been calculated and results have been intimated to management.
4.4 DEVELOPMENT OF SCRAP TRACKING AND MANAGEMENT SYSTEM
Scrap management application has been developed by using the Microsoft visual
studio integrated development environment. Before starting of design, the software
requirement and functional requirement of application has been developed by using the flow
chart model. Then the front end has been created using windows form application. C#
program has been used to make the system to function according to the requirement.
Database file has been created using the Microsoft access database which is linked to the
front end application to provide the storage space for the information entered by the end
user.
4.5 IMPLEMENTATION AND FOLLOW-UP PHASE
After getting approval from the management, framework has been made to implement
the proposed idea in the shop floor. Scrap management application has been tested and
implemented for trial run. During trial run application shows error message for particular type
of data those bugs has been resolved and implemented for real process.
22. Work study and plant layout Chapter 5
13
CHAPTER 5
WORK STUDY AND PLANT LAYOUT
5.1 WORK STUDY
Work study provides a scientific approach to investigate all forms of work with a view to
increase productivity. Work study is defined as follows “Work study is a generic term for
those techniques, particularly method study and work measurement, which are used in the
examination of human work in all its contexts, and which lead systematically to the
investigation of all the factors which affect the efficiency and economy of the situation being
reviewed, in order to effect improvement”.
5.1.1 Basic procedure
1. Select the job or process to be studied.
2. Record from direct observation everything that happens, using the most suitable
recording techniques, so that the data will be in the most convenient form to be
analysed.
3. Examine the recorded facts critically and challenge everything that is done,
considering in turn: the purpose of the activity, the place where it is performed, the
sequence in which it is done, the person who is doing it, the means by which it is
done.
4. Develop the most economical method, taking into account all circumstances.
5. Measure the quantity of work involved in the method selected and calculate a
standard time for doing it.
5.1.2 Timing method
Start-stop: This is good method for beginners. The watch is started at the beginning
of a cycle or element and stopped at the end. This is slow and only permits the timing of part
of the workflow. On the other hand it makes it easy to judge the breakpoint and to read the
watch at leisure.
23. Work study and plant layout Chapter 5
14
Fly back: This is the method which was, until recently most common in the industry.
The watch is started at the beginning of the first element of the first cycle. The top knob is
pushed sharply at the first breakpoint and at the same time the watch reading is noted. The
hands will immediately fly back to zero and begin once again to time. The process is
repeated until a sufficient number of cycles have been timed. This is called continuous
timing and nothing should be missed by this method.
Cumulative timing: this is useful for recording of a number of cycles by a non-
practitioner. The watch runs continuously, the time shown being recorded without returning
the hand to zero. It is necessary to perform a series of subtraction operations in order to
establish the time for each cycle or element.
Differential timing: an important element may take such a short period to perform that
it is difficult to time. The solution is to include it first with the preceding element for say, ten
cycles and then with succeeding element. The true time can then be calculated by
subtraction.
5.1.3 Number of cycles to study
Number of Cycles taken for time study depends upon the accuracy required and the
time available. Number of Cycles taken for time study is calculated by using the below
formula
n=
Where
n = Sample size we wish to determine
n’ = Number of readings taken in preliminary study
∑ = Sum of values
x = Value of the readings in 1/100th
of minutes
By using the above formula, number of sample required for taking time study is
calculated. To take time study, fly back timing method is used in which stop watch has been
reset after each observation. The time study details are shown in Table 5.1.
24. Work study and plant layout Chapter 5
15
Table 5.1 Time study
S.No Operation name Cycle time(s)
1 Punching process 920
2 Part removal process 240
3 Filling process 77
4 Deburring process 142
5 Pressing process 200
6 Welding process 700
7 Pre-treatment process 3720
8 Powder coating process 2100
9 Drilling process 160
10 Paint touch up process 130
11 Inspection process 140
5.2 PLANT LAYOUT
Plant layout refers to the arrangement of physical facilities such as man, machines,
equipment, tools and furniture etc. in such a manner so as to have quickest flow of material
at the lowest cost and with the least amount of handling in processing the product, from the
receipt of raw material to the delivery of the final product.
The current layout diagram has been developed by measuring the physical dimension
of the facility by using the standard measuring tape. Then the taken measurement are
converted into the layout drawing using the AutoCAD modelling software. From the layout
diagram the physical dimension between any machines can be identified without taking any
measurement. The layout diagram for the shop floor of Madras Radiators & Pressings is
shown in Fig 5.2.
5.2.1 Product selected
CE-Carrier Assembly product was chosen for the study. This product is used as sub
component in the fuel dispensing pump assembly. Reason for the selection of this product is
it requires more number of operations compared to the other product. Catia diagram of the
carrier assembly product is shown in Figure 5.1.
25. Work study and plant layout Chapter 5
16
Figure 5.1 Catia diagram of product
This product requires some special purpose drilling which requires high precision in
dimensions which could not be done before powder coating operation. If it done before
powder coating operation there may be a chance of powder content filling inside of the hole
which reduces the accuracy of the diameter of drilled hole.
5.2.2 Process flow chart
Process flow chart for the carrier assembly product is shown in the Table 5.2. It
represents the sequence of process required to process the customer order and deliver the
finished goods to the customer. By considering the process sequence the spaghetti diagram
is developed as shown in the Fig 5.3. Process flow chart will be different for different
kind of products. However the basic process will remain constant, only the process
sequence will differ. The below flow chart is developed for carrier assembly product.
26. Work study and plant layout Chapter 5
17
Table 5.2 Flow process chart
Operation no Process flow Process description
1 Punching
2
Part removal
3 Filing
4 Deburring
5 Pressing
6 Fabrication
7 Pre-treatment
8 Powder coating
9 Drilling
10 Paint-touch up
11 Inspection of coating
thickness
12 Packing & Delivery
Operation Inspection Transport
5.2.3 Spaghetti diagram
A spaghetti diagram is a line-based representation of the continuous flow of some
entity, such as a person, a product or a piece of information as it goes through some
process. Spaghetti diagram is one of the major tool used to locate the bottleneck process in
27. Work study and plant layout Chapter 5
18
the shop floor. To develop the spaghetti diagram the product with more number of
operations has to be chosen for the analysis.
Fig 5.2 Plant layout diagram
28. Work study and plant layout Chapter 5
19
Fig 5.3 Spaghetti diagram
29. Work study and plant layout Chapter 5
20
5.2.4 Material movement distance in current layout
Material movement distance between one station to another station in the current
layout is calculated and given in the Table 5.3. By analyzing the movement distance
alternative routes has been developed between the stations for which material movement
distance is very high.
Table 5.3 Distance calculation for current layout
Distance travelled by material
S.No Station name
Distance travelled with
MHS
(ft.)
Distance travelled
without MHS
(ft.)
1 Punching process 14 8
2 Part removal process - 10
3 Filling process 11.1 -
4 Deburring process 3 7
5 Pressing process 14.4 -
6 Welding process 62.8 21.3
7 Pre-treatment process 33.6 20.9
8 Powder coating process 17.4 64
9 Drilling process 31.9 3.5
10 Paint touch up process 8 -
11 Inspection process 8 -
12 Packing process 3 -
30. Value stream mapping Chapter 6
21
CHAPTER 6
VALUE STREAM MAPPING
6.1 VALUE STREAM MAPPING
Value stream mapping is a method of creating a one page picture of all the processes
that occur in a company, from the time a customer places an order for a product, until the
customer has received that product in their facility. The goal is to depict material and
information flows across and throughout all value-Adding Processes required to produce
and ship the product to the customer. Value Stream Maps document all of the processes
used to produce and ship a product, both value-Adding and non-value adding (Waste)
processes.
6.2 TERMS USED IN VSM
Cycle time: Time taken for a part to complete a given process (or the time it takes for
an operator to go through all of his/her work elements before repeating them).
Value added time: Time associated with those activities that actually transform the part
in a way that the customer is willing to pay for.
Lead time: Lead time is the time taken for one part to move through all the processes
of a value stream from start to finish.
Takt time: Takt time is the rate at which products are to be produced or services are to
be provided to meet the customer demand.
6.3 CURRENT STATE VSM
Current state value stream mapping is developed for the CE-Carrier assembly product
by displaying the cycle time, material movement distance and inventory time. This current
state VSM is used to locate the problem area or bottleneck process in the current method.
The current state VSM diagram is shown in Fig 6.1.
32. Value stream mapping Chapter 6
23
6.4 IDENTIFICATION OF WASTE
By analyzing the spaghetti diagram and current state value stream mapping following
non-value added activities has been identified in the existing process.
There is no drilling station in powder coating section which leads to increased
material movement distance to accomplish the drilling operation.
Current arrangement of pre-treatment tanks lead to increased movement distance
from welding station to pre-treatment station.
Material handling device cross the head up conveyor each time to move the parts
from pre-treatment station to powder coating station.
Separate paint touch-up station and inspection station in packing area increases the
number of operators.
Man movement is high from head up conveyor to WIP storage in the powder coating
section.
There is no system to track the unused sheet coming out of the punching operation
which leads to increased tracking time and inventory in the shop floor.
6.5 IMPROVEMENT ACTIVITIES
Hand driller is installed in the powder coating section to reduce the requirement of
moving the material to the packaging station to accomplish the drilling operation.
Tank arrangement in the pre-treatment section has been reversed to reduce the
material movement distance from the welding station to pre-treatment section.
Operations with the lowest cycle time is combined to reduce the labour idle time and
also to reduce the number of labours.
The suitable material handling device is developed and installed in the powder
coating station to temporarily store the part unloaded from the head up conveyor, to
reduce the man movement in the powder coating section.
Scrap management application has been developed using the Microsoft Visual
studio 2012 integrated development environment, to reduce the tracking time and
inventory in the shop floor.
6.6 PROPOSED LAYOUT
Waste in the current layout is identified and suitable alternative solutions is suggested in
the proposed layout. In the proposed layout, new hand driller is installed in powder coating
section and pre-treatment operation has been reversed to reduce the movement time.
35. Value stream mapping Chapter 6
26
6.7 MATERIAL MOVEMENT DISTANCE IN PROPOSED LAYOUT
Spaghetti diagram for proposed layout is shown in Fig 6.3. After implanting the
improvement activities in the new layout again the material movement distance has been
calculated and listed in the Table 6.1.
Table 6.1 Distance calculation for proposed layout
Distance travelled by material
S.No
Station name
Distance
travelled with
MHS
(ft.)
Distance travelled
without MHS
(ft.)
1 Punching process 14 8
2 Part removal process - 10
3 Filling process 11.1 -
4 Deburring process 3 7
5 Pressing process 14.4 -
6 Welding process 62.8 21.3
7 Pre-treatment process 7.1 20.9
8 Powder coating process 21 64
9 Drilling process - -
10 Paint touch-up process - -
11 Inspection process - -
12 Packing process 31.9 -
36. Simulation study Chapter 7
27
CHAPTER 7
SIMULATION STUDY
Simulation refers to methods for studying a wide variety of models of real world
systems by numerical evaluation using software, designed to imitate the system’s operations
or characteristics, often over time. From practical viewpoint, simulation is the process of
designing and creating a computerized model of a real or proposed system for the purpose
of conducting numerical experiments to give us a better understanding of the behaviour of
that system for a given set of conditions. Although it can be used to study simple systems.
The real power of this technique is fully realized when we use it to study complex systems.
7.1 CURRENT LAYOUT SIMULATION
Current method of powder coating operation is represented by the flow chart model as
shown in Fig 7.1 & Fig 7.2. The required data such as cycle time, operator assignment are
entered for each activities.
Fig 7.1 Existing model
37. Simulation study Chapter 7
28
Fig 7.2 Existing process in powder coating section
Simulation is carried out for the production of 60 products. After completion of
simulation run idle percentage and busy percentage of each operator is tabulated from the
simulation results as shown in the Table 7.1.
Table 7.1 Current layout simulation
Current layout simulation
S.No Process Station name % Busy % Idle
1 Cleaning Powder coating labor 1 15.08 84.92
2
Part loading &
unloading
Powder coating labor 2 30.16 69.84
3 Powder spraying
Powder coating labor 3 45.24 54.76
Powder coating labor 4 45.24 54.76
4 Drilling Drilling labor 1 24.13 75.87
6 Paint touch up
Drilling labor 2 40.71 59.29
7 Inspection
Total Efficiency 33.43 66.57
38. Simulation study Chapter 7
29
7.2 PROPOSED LAYOUT SIMULATION
In the propose layout simulation current method of powder coating operation is
replaced by proposed method as shown in Fig 7.3 & Fig 7.4. The required data such as
cycle time, operator assignment are entered for each activities.
Fig 7.3 Proposed model
Fig 7.4 Proposed process in powder coating section
Simulation is carried out for the production of 60 products. After completion of
simulation run idle percentage and busy percentage of each operator is tabulated from the
simulation results as shown in the Table 7.2.
39. Simulation study Chapter 7
30
Table 7.2: Proposed layout simulation
Proposed layout simulation
S.N
o
Process Station name % Busy % Idle
1 Cleaning Powder coating labor 1 16.18 83.82
2
Part loading &
unloading
Powder coating labor 2 32.36 67.64
3 Powder spraying
Powder coating labor 3 48.54 51.46
Powder coating labor 4 48.54 51.46
4 Drilling
Powder coating labor 5
69.58
30.426 Paint touch up
7 Inspection
Total Efficiency 43.04 56.96
From the Table 7.1 and Table 7.2 percentage reduction in worker idle time and percentage
increase in worker busy time could be identified.
40. Development of scrap management application Chapter 8
31
CHAPTER 8
DEVELOPMENT OF SCRAP MANAGEMENT
APPLICATION
8.1 PUNCHING OPERATION
Punching is one of the metal forming process in which punching press forces a tool
called a punch through work piece to create a part with required features. The material
coming out from the hole is called as scrap slug. Before punching process the planning
committee has to identify the number of parts that can be seized from a single standard
sheet by using the software. Then software convert the design of punched sheet into
program which is feed into the punching machine to finish the operation. If the customer
demand is less than the number of part that can be seized from single punched sheet, it
generates the scrapped sheet. In the industry they have used flat rectangular sheet of
standard dimension. For the Carrier assembly product which is used in fuel dispensing
pump, in a single sheet they have punched the parts required to assemble 6 products. For
that particular product customer demand is 500 products.
Fig 8.1 Catia model of punched sheet
41. Development of scrap management application Chapter 8
32
So to accomplish the demand they require 83 standard sheet to complete 498
products. For the remaining 2 products if they use single standard sheet it leads to 2/3 of
sheet to become a scrap. Catia diagram of punched sheet for CE Carrier assembly product
is shown in Fig 8.1.
8.1.1 Existing method
In the current method, planning committee measures the unused sheet stored in the
inventory during their free time and find the opportunity to reuse those sheets for their
upcoming production. They instruct the punching operator to pick the sheet by entering the
dimension of the sheet. The punching operator identifies the particular sheet by taking
measurement.
Fig 8.2 Existing method
8.1.2 Proposed method
In the proposed method, planning committee have the knowledge of unused sheet
dimension while designing the punched sheet. They enter those data in the scrap
management application which stores it in the database. And they also instruct the operator
to fix the scrap tag for unused sheet.
42. Development of scrap management application Chapter 8
33
Fig 8.3: Proposed method
While reusing the non-used sheet, the planning committee instruct the punching
operator to pick the particular sheet simply by entering the sheet id. The operator pick the
required sheet by reading the scrap tag.
8.2 NEED OF SCRAP MANAGEMENT SYSTEM
To reduce the time required to track the information of particular material in the
inventory.
To locate the required material in the storage without any confusion.
To eliminate the measurement activity to identify the dimensional information of the
material.
8.3 FUNCTIONAL REQUIREMENT
Scrap management application have to accomplish the following functions
The application should allow only authorized user to use the application.
It should have the database in the back end to store the information about scrapped
sheets.
There should be an option in front end to add and update the database by entering
the required information in the front end.
43. Development of scrap management application Chapter 8
34
There should be an option in the front end window to check whether the particular
record is available in the database or not.
There should be an option in front end to check current stock status of scrapped
inventory.
8.4 SOFTWARE ARCHITECTURE
Fig 8.4 Software architecture
The software architecture of application is shown in Fig 8.4. Here scrap management
application is front end which allow user to read and write the information. Database is lies
in the back end which stores the information in appropriate place and helps to display the
information whenever it required by the user.
8.5 DATABASE CREATION
In the database, part table is used to store the information of non-used sheet. In the
part table five fields are formed, to store information about the sheet id, length, width,
thickness and quantity. Data type for all the field is set as “Short number”. Sheet id should
not be more than six digit. So field size for sheet id field is set as 6. For the remaining field
maximum field size is set as 2. After creating the database the major step is to link the
database with application. To link the database, name the database file as ivendb and store
it in Local disk (D).
8.6 FUNCTIONAL ARCHITECTURE
The flow chart of functional architecture is shown in Fig 8.5. This flow chart represent
the three major function (Add, Update and Search). While clicking particular action, initially
the application will check whether the data entered by the user is correct or not. Then it will
do the necessary function required by the end user.
End
User
Database
File
Scrap
management
application
44. Development of scrap management application Chapter 8
35
Start
Enter user name and
password
Open the menu bar
ADD Update Search
Enter sheet
id, length,
width and
thickness
Enter sheet
id, length,
width and
thickness
Enter
sheet id
Valid
sheet
id
Invalid
sheet
id
Data
missing
Real
data
Databas
e
updated
Sheet id
already
exist
Valid
user
Invalid user
Database
updated
Required
data are
missing
Sheet id
already
exist
Data
missing
Real
data
Database
updated
Required
data are
missing
Sheet id
already
exist
Fig 8.5 Functional architecture
8.7 CREATION OF SCRAP TAG
In database sheet id is set as a primary key, so it will not allow us to enter the same id
more than one time. Sheet id should be in such a way that it relate all dimensions (length,
width and thickness) of the sheet. So sheet id must be in 6 digit. The first two digit
represents the length of sheet. In this two digit we can represent the one decimal place. The
digit 3, 4 represents the width of the sheet. Here we can represent the one decimal place.
45. Development of scrap management application Chapter 8
36
The digit 5, 6 represent the thickness of the sheet. Here we can represent the one decimal
place. For example sheet id 803015 represents the sheet having length 8ft, width 3ft and
thickness of 1.5mm.
8.8 TESTING OF SOFTWARE SYSTEM
The application can be built as a distributable component by using the publish option in
the Microsoft visual studio 2012. This option is used to generate the exe file of the
application which could be installed in any computer for further use. After installing the
application ivendb database file is placed in the Local disk (D) and the application has been
tested by clicking the shortcut icon from the desktop.
8.9 SYSTEM REQUIREMENT
Following software should be installed before installing the scrap tracking and
management system
1. Microsoft access database
2. Microsoft .NET framework 4 client profile(x86 and x64)
3. SQL server compact 3.5 SP2
4. Windows installer 3.1
The above software package could be downloaded from internet. The web address to
download those software is given in the installation guide.
46. Results and discussions Chapter 9
37
CHAPTER 9
RESULTS AND DISCUSSIONS
9.1 REDUCTION IN MATERIAL MOVEMENT DISTANCE
Material movement in the current layout and proposed layout has been compared as
shown in Fig 9.1. In the proposed layout, the material movement is reduced in the pre-
treatment, drilling and paint touch-up station. So after implementation of proposed layout
material movement distance is reduced from 207ft to 165ft.
Fig 9.1 Comparison of layout
9.2 COMPARISON OF SIMULATION RESULT
Comparison of simulation result for existing and proposed process in given in Table 9.1
By comparing the % idle time and % busy time in current and proposed layout we can
identify that labour idle time is reduced by 9.6%.
47. Results and discussions Chapter 9
38
Table 9.1 Comparison of simulation result
Comparison of simulation result
Parameters
Current
Layout
Proposed
Layout
Improvement
Labor
Productivity
%Busy 33.43 43.04 Increased by 9.61
%Idle 66.57 56.96 Decreased by 9.61
9.3 FUTURE STATE VALUE STREAM MAPPING
After implementation of proposed method the future state value stream map has been
developed with new process, material movement distance and time study. The future state
value stream map is shown in Fig 9.2.
49. Results and discussions Chapter 9
40
9.4 SCRAP MANAGEMENT SYSTEM
Scrap management application is developed by using Microsoft visual studio integrated
development environment. It is developed with 4 dialog boxes and one MDI window with
database in the back end which helps to store the information entered by the end user. It
has four major operation such as Sign in, Add, Update and Search operation. Each dialog
box has its own function. Basically it is used to get the necessary information from the user.
Sign in dialog box allows only authorized user to use the application to store and retrieve the
information. Add dialog box is used to enter the information of new unused sheet and later
those information is stored in the database as a new record. Update dialog box is used to
get the necessary information to update the existing record in the database. Search dialog
box is used to display the necessary information required by the user from the database.
The C# program code for the scrap management application is given in the Appendix 1.
50. Conclusion Chapter 10
41
CHAPTER 10
CONCLUSION
Material movement distance in shop floor is reduced by 20.2%.
Productivity improvement of 9.6% is achieved by reducing the idle time of operator in
powder coating department.
New material handling device is implemented to reduce the man movement in the
powder coating department
Scrap management system is developed and implemented to reduce the effort and
time required to select the suitable material.
Scrap management application provide GUI for the user to store and retrieve the
information in the database. The dimensional information of non-used sheets are
directly obtained from the design drawing which eliminate the measuring activity.
The sheet id is formed and labelled in each scrapped material. By reading the label
operator can identify the dimensional information of any material in the inventory
without taking any measurement.
51. APPENDIX 1
42
APPENDIX 1
CODE USED FOR SCRAP MANAGEMENT APPLICATION
SIGN IN FORM
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
namespace WindowsFormsApplication1
{
public partial class formsignin : Form
{
public formsignin()
{
InitializeComponent();
}
private void txtpassword_TextChanged(object sender, EventArgs e)
{
txtpassword.PasswordChar = '*';
}
private void butlogin_Click(object sender, EventArgs e)
{
53. APPENDIX 1
44
MENU BAR
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
namespace WindowsFormsApplication1
{
public partial class Mrpmenu : Form
{
public Mrpmenu()
{
InitializeComponent();
}
private void richTextBox1_TextChanged(object sender, EventArgs e)
{
}
private void Form2_Load(object sender, EventArgs e)
{
}
private void updateToolStripMenuItem_Click(object sender, EventArgs e)
{
Formsheetinformation form3 = new Formsheetinformation();
form3.Show();
form3.MdiParent = this;
}
61. APPENDIX 1
52
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
namespace WindowsFormsApplication1
{
public partial class Stockstatus : Form
{
public Stockstatus()
{ InitializeComponent();}
string cs="Provider=Microsoft.Jet.OLEDB.4.0;Data Source = D:ivendb.mdb";
private void Form4_Load(object sender, EventArgs e)
{
this.partTableAdapter1.Fill(this.ivendbDataSet5.Part);
}
private void button2_Click(object sender, EventArgs e)
{
this.Close();
}
private void button1_Click(object sender, EventArgs e)
{
dataGridView1.Refresh();
}
private void dataGridView1_CellContentClick(object sender,
DataGridViewCellEventArgs e)
{
}
private void partBindingSource1_CurrentChanged(object sender, EventArgs e)
{
}
} }
62. Bibliography
53
BIBLIOGRAPHY
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63. This is to Certify that the paper ID: SUB154252 entitled
Scrap Management in Punching Staion of Sheet Metal Industry
Authored
By
P. Kannan
has been published in Volume 4 Issue 5, May 2015
in
International Journal of Science and Research (IJSR)
The mentioned paper is measured upto the required standard.
