colombo dockyard plc industrial training report

DEPARTMENT OF MECHANICAL & MANUFACTURING ENGINEERING

FACULTY OF ENGINEERING

UNIVERSITY OF RUHUNA

INDUSTRIAL TRAINING REPORT SUBMITTED IN PARTIAL FULFILMENT OF THE

DEGREE OF BACHELOR OF SCIENCE IN ENGINEERING

04th

June 2015

COLOMBO DOCKYARD PLC

PORT OF COLOMBO, COLOMBO 15

(From 26th

January 2015 To 24th

April 2015)

WICKRAMARATHNE G.T (EG/2012/2111)

Preface

I am a Mechanical & Manufacturing engineering undergraduate at University of Ruhuna.

I trained under Colombo Dockyard Public Limited Company (CDPLC) from 26th

January 2015 to 24th

April 2015 under the first industrial training session of my degree

program. Ship repairing, ship building, offshore engineering and heavy engineering tasks

are done by Colombo Dockyard Limited.

My working experience and industrial exposure in the above company during the 12

week time period is mentioned in this report. Chapter 1 is dedicated to the

“Introduction of the Colombo Dockyard PLC”. And Chapter 2 is described for the

training experience and industrial exposure of myself at there. Chapter 3 has reserved

to discuss the “Management” where it is mentioned about the managements knowledge

that I could gain at CDPLC. Finally the chapter 4 is separated for the “Summary and

Conclusion”.

I have tried my best to present what I could learn at CDPLC with graphical explanations.

Wickramarathne G.T

Department of Mechanical and Manufacturing Engineering,

University of Ruhuna.

Edited with the trial version of Foxit Advanced PDF Editor

To remove this notice, visit:www.foxitsoftware.com/shopping

http://www.foxitsoftware.com/shopping

Acknowledgment

As an engineering student I was lucky to have this valuable and rare chance to have my

first industrial training experience at Colombo Dockyard PLC where I was able to gain

great work place experience and technical knowledge.

Most especially I’m thankful to Dr. Anura P. Rathnayaka, Department head of the

Mechanical & Manufacturing Department.

And also I take this opportunity to express my profound gratitude and deep regard Dr.

J.M.R.S Appuhami who coordinated and guided us in selecting training places and

taking all the arrangements to make it more successful. My sincere gratitude goes to

Engineering Education Center of Ruhuna Engineering Faculty for giving me this

opportunity and also to NAITA for granting us for the training.

I convey my special thanks to Mr. HelaVikum De Silva, head of the Training Center and

the staff of Training Center who arranged a better training sessions for us, for supporting

and guiding us during the training period. I would also like to thank all the staff at

CDPLC for their great support and for the knowledge and experience they shared with

us.

I thank all the Engineers at CDPLC who spent their valuable time to explain and to teach

us about different fields.

My heartiest gratitude goes to my parents, my brothers and friends who helped me a lot

to make my industrial training a success .The blessing, help and guidance given by them

time to time shall carry me a long way in the journey of life on which I am about to

embark.

Thank you.

Wickramarathne G.T.-EG/2012/2111

Faculty of Engineering,

University of Ruhuna,

Galle.




i

Contents

Page No

Chapter One Introduction to Colombo Dockyard PLC

1.1 Shipping Industry 01

1.2 Operating Business Sectors 02

1.2.1. Ship Repairs 02

1.2.2. Ship Building 04

1.2.3. Offshore Engineering 04

1.2.4 Heavy Engineering 05

1.3 More about CDPLC 05

1.4 Significant Corporate Milestones of CDPLC’ Odyssey. 07

1.5 Organizational Structure 08

1.6 Vision 10

1.7 Mission 10

1.8 Quality Policy 10

1.9 Environment Policy 10

1.10 Safety Policy 11

1.11 Situation Analysis 12

1.12 Growth Strategy 13

1.14 Greatest Achievements of the CDPLC 14




Chapter Two Technical Details

2.1 Ship Building Section 15

2.1.1 Introduction 15

2.2 Machinery Outfitting Shop 16


2.2.2 Outfitting Process 16

2.2.3 Fabrication and Installation of Pipe Lines 18

2.2.4 Pipe Line Color Codes 20

2.2.5 Pipe Line Weldings 21

2.3 Hull Construction Department 27

2.3.1 Quality Inspection of Raw Materials. 27

2.3.2 Lofting Process. 28

2.3.3 Metal Cutting Process. 28

2.3.4 Metal Forming Process. 30

2.3.5 Unit Fabrication Process. 32

2.4 Plant Shop


2.4.2 Lifting Equipment Repair Section 34

2.4.3 Power Tool Repair Section 36

2.4.4 Gas Line Repair Section 36

2.4.5 Gas Equipment Section 37




2.4.6 AC Maintenance Section 38

2.4.7 Airless Spray Machine Repair Section 39

2.5 Machine Shop

2.5.1 Types of Machines 41

2.5.2 In Machining 41

2.5.3 Lathe Machine

2.5.4 Grinding Machine 48

2.3.5 Power Sawing Machine 48

2.3.6 Milling Machine 49

2.3.7 Drilling Machine 50

2.3.8 Cutting Fluids 51

2.5.9 Balancing Machine 53

2.6 Engine Fitting Shop


2.6.2 Piston 56

2.6.3 Heat Exchanger-Coolers 58

2.6.4 Turbochargers 59

2.6.5 Valves 60

2.6.6 Pumps 62

2.7 Calibration section





2.7.2 Stern Tube Alignment Using Micro Alignment Telescope 63

2.7.3 Feeler Gauge 64

2.7.4 Bore Gauge 65

2.7.5 Bearing Load Testing 65

2.8 Automation Shop


2.8.2 Types of Sensors. 67

2.8.3 Calibration Tests 75

2.9 Electrical Workshop


2.9.2 Electrical Motors 77

2.9.3 Megger Meter and Megger Testing 80

Chapter Three Management

3.1 Introduction 81

3.1.1 Business Division 81

3.2 Financial Management

3.2.1 Financial Performance and Position 82

3.3 Human Resource Management (HR) 83




3.4 Health and Safety Management 83

3.4.1 Fire 84

3.5 Waste Management 84

Chapter Four Summary and Conclusions

4.1 Summary 85

4.2 Conclusion 86

Abbreviations 87

References 87




List of Figures

Figure 1.1: Strategic Location of Colombo Dockyard PLC 1

Figure 1.2: Colombo Dockyard’s Facility in an Aerial View. 3

Figure 1.3: Workforce Of CDPLC 6

Figure 1.4: Milestones Of CDPLC’ Odyssey 7

Figure 1.5: Organizational Structure 9

Figure 2.1: Ship Construction Process 15

Figure 2.2: Pipe Joint 18

Figure 2.3: Flanges 19

Figure 2.4: Doubler 19

Figure 2.5: Pipe Bending Machine 20

Figure 2.6: Pipe Color Codes 20

Figure 2.7: Electric Arc Welding 21

Figure 2.8: Designation Code System for Arc-Welding Electrodes. 22

Figure 2.9: Arc Welding Processes 23

Figure 2.10: Welding Processes According To Types of Joints 23

Figure 2.11: Various Fillets Welds 24

Figure 2.12: Spot and Seam Welds 25

Figure 2.13: Welding Positions of Plates 25

Figure 2.14: Welding Positions of Steel Pipes 26

Figure 2.15: Numerical Control Plasma Cutting Machine 29

Figure 2.16: Plug Machine 29

Figure 2.17: Numerical Control Gas Cutting Machine 30

Figure 2.18: Rolling Machines 31

Figure 2.19: Hydraulic Pressing Machine 31

Figure 2.20: Thermal Forming Process 32

Figure 2.21: Parts of a Chain Block 35

Figure 2.22: Power Tool - Grinder 36

Figure 2.23: Gas Torch Repairing Procedure 37

Figure 2.24: Types of AC Systems 38

Figure 2.25: Parts of Airless Spray Machine 40

Figure 2.26: Parts of A Lathe Machine 42




Figure 2.27: Lathe Operations 45

Figure 2.28: Diagram of the Job 46

Figure 2.29: Surface Grinder Machine 48

Figure 2.30: Power Sawing Machine 49

Figure 2.31: Milling Machine 50

Figure 2.32: Drilling Operations 50

Figure 2.33: Radial Drilling Machine 51

Figure 2.34: Balancing Machine 53

Figure 2.35: Piston Rod 57

Figure 2.36: Piston Rod Stuffing Box 57

Figure 2.37: Shell & Tube Type Heat Exchanger 59

Figure 2.38: Turbocharger 60

Figure 2.39: Butterfly Valve 61

Figure 2.40: Globe Valve 61

Figure 2.41: Classification of Pumps 62

Figure 2.42: Micro Alignment Telescope 64

Figure 2.43: Feeler Gauge 64

Figure 2.44: Bore Gauge 65

Figure 2.45: Relationship of External Effect And Action 67

Figure 2.46: Bi-Metallic Thermostat 69

Figure 2.47: Thermistor 71

Figure 2.48: Resistive RTD 72

Figure 2.49: Thermocouple Construction 73

Figure 2.50: Temperature Calibrator 75

Figure 2.51: Pressure Gauge 76

Figure 2.52: Bourdon Tube 77

Figure 2.53: Stator Winding of the Motor 79

Figure 3.1: Financial Performance 82




1

1.0 Introduction to Colombo Dockyard PLC

1.1 Shipping Industry

Around 90% of world trade is carried by the internationalshipping industry.Without

shipping the import and export of goods on the scalenecessary for the modern world

would not be possible. So shipyards and dockyards are very important for ship buildings

and ship repairs etc.

Due to the strategic location of Colombo at the intersection of major sea routes it plays

as a maritime hub for the region for sea travels. So dockyard is a very important to a

country like Sri Lanka. SoColombo Dockyard is gearing up for more opportunities in

both ship building and ship repair.

Figure 1.1 : Strategic Location of Colombo Dockyard PLC [ Ref. 01]




2

1.2 Operating Business Sectors

1.2.1. Ship Repairs

Due to;

1. Strategic location of Colombo at the intersection of major sea routes.

2. Quality workmanship and skilled work force. ISO 9001: 2008 accredited Quality

Management System by LRQA.

3. Safety conscious work force & top management committed to safety.

4. Faster turnaround time and minimal diversion.

5. Competitive rates and no surprises.

6. Duty free spares, fast customs clearing within 4-6 hrs.

7. Urgent spares from speedy network like daily flight connections from all major

points.

8. All major paint suppliers are present in Colombo. (Sigma, Hemple, International,

Jotun, CMP, etc.).

Therefore so many ships are coming to Colombo Dockyard PLC for repairs.

At CDPLC,

Total 200 vessels repaired annually

• 100 vessels in dry-dock and 100 vessels at alongside repair berth.

ypes – from very basic to complex scope.

• Routine repairs, collision damage repairs, conversion and retrofit repairs.

• Tankers, bulk carriers, general cargo, container and cement carriers, dredgers,

tugs, offshore support vessels and vehicle carriers.

callers: India, Middle East, Europe, Far East, Japan and Maldives.




3

Colombo Dockyard operates four graving drydocks

125,000 DWT - Caters to tankers, bulk carriers, and off shore drill rigs.

30,000 DWT - Accommodates the feeders and trampers plying regional waters.

Other two drydocks provide ideal docking facilities for offshore support vessels,

naval vessels, trawlers and work boats.

Figure 1.2 : Colombo Dockyard’s facility in an aerial view[ Ref. 02]

Types of ship repairs.

Machinery repairs

Hull repairs

Propeller repairs

Electrical repairs

Electronic and automation repairs

Cargo gear repairs

Internal tank, cargo hold blasting and coating

Drydock repairs




4

1.2.2. Ship Building

From 1974 , CDPLC engages in the construction of

o Small Tug Boats,

o Patrol Boats

o Barges

o Harbor Crafts

o Work Boats

o Passenger Ships.

This has now transformed into a major income earner for the company.

Delivered more than 230 specialized and sophisticated vessels.

The company has been successful in securing orders from both local and overseas

clients by competing with leading shipbuilders.

The company’s ability to carry out the construction of these vessels to meet the

requirements stipulated by stringent international classification societies, whilst

customizing the vessel to surpass all stated and implied requirements of the

customer, has paved the way for the company’s stupendous growth in the

shipbuilding sector.

1.2.3. Offshore Engineering

CDPLC has managed some unique retrofits and repair works. Some of noteworthy

projects completed in the offshore sector are,

Major Layup repairs on Mobile Offshore Drilling Unit (MODU) Sagar Vijay.

Retrofit repairs on Floating Dock Navy 1.

Major retrofit repairs on Ocean Research Vessel SagarKanya.

Dry Dock repairs on MV Geo Explorer.




5

1.2.4. Heavy Engineering

Dockyard General Engineering Services (Pvt) Ltd., (DGES a fully owned subsidiary of

Colombo Dockyard PLC (CDPLC)) engages in distinctive fieldsof engineering such as

General infrastructure

Petrochemical

Power and energy

Irrigation

Some of noteworthy projects completed in the Heavy Engineering sector are,

Design & construction of fuel oil tanks.

Erection of LPG storage tanks- 4 Nos. 4000m3 LPG spheres for Shell Terminal

Lanka

Design, fabrication & installation of piping systems –

Design and Construction of fuel oil storage tanks at Thilafushi Island in Republic

of Maldives

Power generator systems -40 MW diesel power plant extension project in

Sapugaskanda

Fabrication of heavy steel structure

1.3 More about CDPLC

Largest and only private sector ship repairs and shipbuilding yard in Sri Lanka

certified by ISO 9001 – 2008 by Lloyds Registrar (LR) with a Japanese

collaboration, Onomichi Dockyard Company Ltd.

CDPLC Group includes two subsidiaries

o Dockyard GeneralEngineering Services (Pvt.) Ltd -To cater the country’s

needs in infrastructure development in civil, mechanical and electrical

engineering areas while providing an excellent opportunity for discerning




6

clients to procure high quality products and services in compliance with

the appropriate and accepted standards.

o Ceylon Shipping Agency (Pte) Ltd, Singapore -Supply channel for high-

tech engineering items for purchasing and shipping to Colombo office

with minimum time period.

CDPLC is a public quoted company listed in the Colombo Stock Exchange.

It is also a licensed enterprise of the Board of Investment of Sri Lanka.

There are five core values that have helped Colombo Dockyard in its odyssey,

Flexibility

Innovation

Being customer centric

Environment friendly

People focused

Human Resources Development.

Workforce as at present-

P

Permanent Staff : 1319

S

Sub Contract : 1368

T

Trainees : 394

Figure 1.3- Workforce of CDPLC




7

1.4 Significant Corporate Milestones of CDPLC’ Odyssey.

Figure 1.4 : Milestones of CDPLC’ Odyssey

CDPLC now : Issued Share Capital Rs. 684,370,712 with a Market Capitalization of

Rs.19.5 billion Current Share Holding:

*Onomichi Dockyard - Japan 51+%

*State owned entities 30 %

*Public Shareholders 19+%

Annual Average Turnover of around US$ 130 million

2008-11-Shifted to the new Head Office building with 5 floors,Automation of Steel Cutting to Plasma Cutting, PSPC Workshop, Commissioning of Kelani River Yard with

a shot blasting and priming facility

2007-Major Yard Expansion Projects commenced with an initial investment of

Rs. 380 m and continued to invest up to Rs. 3.0 billion to date

2005-Internationalized the Shipbuilding Business

2004-Ventured into Higher End Markets - Offshore Engineering

1993-Collaboration with Onomichi Dockyard Co. Ltd., of Japan

1988-Commissioning of the New Dry Dock No. 4 with 125,000 DWT capacity

1974-Company was formed as a Limited Liability Company under the auspices of the Government of Sri Lanka with Dry Docks 1, 2 & 3




8

1.5 Organizational Structure

CDPLC has divided it’s all functions and operations in to 10 divisions. Those ten

divisions are as follows,

Production Hull and Deck

Human Resource & Administration

Quality Assurance and Safety

Finance

Projects and Engineering

Yard New Building/Marketing

Production Engine

Material Procurement

Business

Colombo Dockyard PLC has very complex company structure. The other managing

levels and interconnections within the company are shown in the following diagram

Figure 1.5: Organizational Structure




9

1.6 Vision

We pursue excellence and superior performance in all what we do to enhance the long-

term interests of all our stakeholders in a socially responsible manner.

1.7 Mission

We strive:

To be the most competitive and viable business entity in South Asia in

shipbuilding, ship Repairs, heavy engineering and allied activities.

To efficiently and effectively manage all our resources.

To achieve sustainable growth.

To enhance the interests of our stakeholders, and thereby contribute to the pursuit

of our vision.

1.8 Quality Policy

We always satisfy our customers’ requirements consistently and cost effectively, strive

to exceed their expectations and add value to the interests ofour other stakeholders in a

viable corporate environment.

1.9 Environment Policy

Our policy is to conduct our present and future operations in an environmentally

friendly manner as befitting a good corporate neighbor andcitizen, through the

implementation of an environmental management system.

To meet our commitment, we shall, meet or exceed applicable legislation and

regulations as well as industry standards and practices.

Periodically review established environmental objectives and targets in order

tocontinually improve our environmental management system performance.




10

Effectively communicate with employees, customers, neighbors and

otherstakeholders regarding our environmental management system and its

performance.

1.10 Safety Policy

Colombo Dockyard PLC recognizes its corporate responsibility to provide a safe and

healthy work environment for all personnel who have legitimate business insuch work

environment.Colombo Dockyard PLC shall:

Provide safe plant, machinery, equipment and systems of work.

Ensure compliance with relevant statutory regulatory requirements

Provide procedures, information, instructions training and supervision

toemployees, contractors, customers and visitors to ensure their safety.

1.11 Situation Analysis

Strengths:

Sri Lanka’s geographic location in the cross currents of international shipping

routes makes a great chance to show its strength to whole world.

The close proximity to the growing Indian market brings lot of businesses.

Sri Lanka’s educated and English speaking workforce is another strength with

CDPLC.

Being one and only private sector shipyard and heavy industry manufacturer, for

the whole of Sri Lanka.

The Company has a well reputed long history. Due to these reason so many

clients come back for services.

Weakness:

Comparatively higher labor costs and lower productivity due to overstaffing and

narrow job specialization.




11

Due to strained public transport systems, employees in Sri Lanka face difficulty

in commuting to and from work, which again contributes to lower productivity.

The Colombo Dockyard is facing rising competition from the emerging markets

of countries like Bangladesh, Myanmar and Vietnam.

Although company is at its saturation point, it cannot increase business volumes.

Due to logistical reasons associated with ship building and maintenance, land

expansion should ideally be within the Port premises.

Behavior of some employees is not preferable for the company’s image. Some of

them do not work properly during the shift, but tend to stay overtime due to extra

money. If the company can pay the staff for their target covering rate, employees

would be more enthusiastic. Paying a higher rate for achieving the goal before

extra hours will be a good solution.

Another weakness I could observe in CDPLC is the improper distribution of

working staff to different departments. In some section they have appointed

workers more than their requirements. On the other hand, there are some sections

where they sometimes lack the work force to fulfill their workload.

1.12 Growth Strategy

For sustained growth into the future, the Colombo Dockyard requires physical

expansion space. Therefore, company should continue to negotiate with the

relevant authorities to acquire suitable land for expansion.

To sustain growth at the Colombo Dockyard over the short term, company must

focus on productivity improvements that will reduce costs, while looking to

increase business volumes. At present the company can manufacture four ships

annually. I believe this can be increased to five ships by introducing more

efficient production systems.

DGES is the one and only heavy industry company for steel structures and fabrications.

So Sri Lanka’s national infrastructure development plans indicate many growth

opportunities for DGES. So company should pay more attention on it.

Company should ready for the new opportunities that flow with the proposed new

international maritime regulations where it states that vessels should be complied

with water treatment regulations. The Colombo Dockyard is capable to provide




12

ships with ballast water purification systems that will comply with international

maritime organization regulations. But it should be extend.

By developing technology developments company can manufacture high value,

specialized vessels where the Colombo Dockyard’s current level of technology

cannot accommodate such vessels. This is possible in the near future through a

strategic partnership, for technology transfer. While these vessels require greater

technical skills, such niche markets are less competitive and are more profitable

than standard vessels. And also employee skills must be developed for those high

technologies.

Company must pay considerable attention on the safety of works more and more,

as most of workers don’t consider about the safety of work. Otherwise this would

be end up in a tragedy. So many such instances were noted down in my training

period.

1.4 Greatest Achievements of the CDPLC

Business Today Top 20 Awards 2011.

National Business Excellence Awards 2011.

Geo Responsibility Awards 2011.

CNCI Achiever Award 2011.

Winner of the Manufacturing and Engineering Sector presented by the National

Chamber of Commerce at the National Business Excellence Awards 2011.

Bronze award at the Geo Responsibility Awards 2011 in the Total Waste

Management Category conferred by Geocycle - Holcim (Lanka) Limited.

NCE Export Awards 2010.

Placed in 6th position – Best Corporates in Sri Lanka (2010).

Top Ten category winner (Category Winner – Governance and Economic

Contributions).

Chartered Accountants Annual Report Award – 2010 (Silver award)




13

Annual Forbes Financial Magazine List – 2010 (Distinction of being only one of

two Sri Lankan Companies selected for the top 200 Asian firms with sales under

a billion U.S. Dollars.

CDPLC recently was awarded the internationally recognized ISO 9001:2000

accreditation from Lloyds Register Quality Assurance, UK for quality

management systems under the terms set out by the United Kingdom

Accreditation Service (UKAS). The ISO 9001:2000 certification has been

awarded in the disciplines of ship Repair, ship Building, engineering project

management and heavy Engineering.

Presidential Export Awards for 2007 & 2008.




1

2.0 Technical Details

2.1 Ship Building Section

When we consider about the shipbuilding it is a highly technical and complicated

process. Ship construction process can be shown in a flow chart like follows.

Figure 2.1: Ship Construction Process

To increase the efficiency and productivity there are different separate workshops for

most of stages of construction process.

Bid Proposal - First presented design by Dockyard to its client

wish.

Discussion on the specifications and

agreement-Between client and Dockyard

Performance Design-To ensure the speed

of sailing

Basic Design- Design ship which comply with specifications

Detailed Design Production Design-

Organize of the detailed designs

Material Ordering Production Plan

Cutting and Processing-Steel

fabrication

Assembly- Unit outfitting

Intiallation of rigiding articles-On-block

outfitting

Mounting Huge Blocks-On-board

outfitting.

Launching-filling water to dock

Operation at the quay -

Trial Cruise Dilivery




2

2.2 Machinery Outfitting Shop

2.2.1 Introduction

Machinery out fitting shop is one of most important workshop for new construction

vessels in CDPLC. Fabrication and installation of pipe lines in new building vessels are

the main functions of this section .Installation of engines, shaft and other mechanical

accessories are also conduct by this workshop. I have worked in the MOF for about two

week.

Workshop mainly consists of

Welding section

Pipe fabricating section

Machinery section

Hydraulic works section

2.2.2 Outfitting Process

As the process is faster, less expensive and provides better quality control, today all

competitive shipbuilders worldwide constructing the vessel in subunits or modules that

have utilities and systems integrated within which can be easily connected each other

(Pre-erection outfitting of construction blocks).

So simply we can say that “Outfitting” is the process of installing parts and various

subassemblies (e.g., piping systems, ventilation equipment, and electrical components)

on the block prior to joining the blocks together at erections. The outfitting of blocks

throughout the shipyard lends itself to forming an assembly line approach to

shipbuilding.

Outfitting at each stage of construction is planned to make the process flow smoothly

throughout the shipyard. For simplicity, outfitting can be divided into three main stages

of construction once the steel structure of the block has been assembled:




3

Unit outfitting

As the working conditions on-block or on-board is very difficult (due to environmental

conditions and etc.) to increase safety and efficiency of work unit outfitting is carried out

on the ground where it is easy to access to the machinery and workshops. At unit out

fitting stage units come in varying sizes, shapes and complexities such as workshops

fittings, parts, foundations, machinery and other outfitting materials are assembled

independent of the hull block (i.e., units are assembled separate from steel structural

blocks). We use detailed designs for this most of times.

Unit outfitting involves assembling piping spools and other components together, then

connecting the components into units. Machinery spaces are areas on the ship where

machinery is located (e.g., engine rooms, pump stations and generators) and outfitting

there is intensive.

On-block outfitting

The outfitting stage of construction where most of the outfitting material is installed onto

the blocks. Outfitting materials installed on block consist of ventilation systems, piping

systems, doors, lights, ladders, railings, electrical assemblies and so on. Many units are

also installed at the on-block stage. Throughout the on-block outfitting stage, the block

can be lifted, rotated and moved to efficiently facilitate installing outfitting materials on

the ceilings, walls and floors. All of the shops and services in the shipyard must be in

communication at the on-block stage to ensure that materials are installed at the right

time and place.

On-board outfitting.

After the blocks are lifted onto the ship which is under building position (building ways

or building dock), or berthed at pier side on-board outfitting is performed. That means

simply the on-board outfitting is the process of installing large units and blocks on board

the ship. Installation includes lifting the large blocks and units on board the new ship and

welding or bolting them into place. On-board outfitting also involves connecting the

shipboard systems together (i.e., piping system, ventilation system and electrical system).

All of the wiring systems are pulled throughout the ship at the on-board stage.




4

2.2.3 Fabrication and Installation of Pipe Lines

We can see lot of pipelines in a ship that are used to,

Convey fuel oil to the main propulsion engine and power generators

Convey lubricating oils for various rotary & reciprocating machineries like main

diesel engines,

Convey sea water for coolers to take away the heat from the engines and etc.

Pipe Lines Joint

The following three methods are the most widely used for joining in piping systems,

Butt-welded Screwed Socket-weld

Figure 2.2: Pipe Joint [ Ref.03]

A butt-weld joint is made by welding the beveled ends of pipe together and

keeping two pieces of pipe by a space, known as a root gap.

In screwed joint, pipe and its mating fittings will have threads at the end of pipe.

Pipe used for socket-weld connections will be prepared with a plain end.

Socket weld joint is used only for smaller diameter pipes.

Flanges

As an alternative to welding or threading, the flange is a ring-shaped device designed to

be used various piping system components. Flanged joints may are used in joining pipe

to fittings, valves, equipment, or any other integral component within the piping system.

Flanged connections can be easily disassembled for routine inspection, maintenance, and

replacement. By using threaded bolts, two surfaces are tightly joined together in flange

fittings. A gasket (packing) is installed between the flanges to prevent leakage.




5

When selecting a flange we must consider,

Working pressure range

Nominal diameter of the flange

Inside and outside diameter of the flange

Number of bolt holes

Most commonly used Flanges

Slip on Flange Rise face Flange Square flange

Figure 2.3: Flanges [Ref.04]

Pipe Penetration

Doubler is the most commonly used pipe line penetration method for installing pipe

through bulkhead and deck. Doubler is round shape plate made out of same material and

same thickness of the bulkhead /deck plate which is weld to the pipe.

Figure 2.4: Doubler




6

Pipe Bending

We can see three types of pipe bending machines in this workshop as,

Hand Pipe Bender Hydraulic Pipe Bender Ratcheting Pipe Bender

Figure 2.5: Pipe Bending Machine [ Ref.05]

Pipe Line Color Codes

Due to the complex network of pipelines, it is not possible to identify the pipelines and

valves easily at emergencies. So that there are specified colors for different types of

pipelines as follows,

Figure 2.6: Pipe Color Code [Ref. 06]




7

Pipe Line Welding

Various units and subassemblies are joined into in outfitting process and at this juncture,

piping, electrical and other utility systems are assembled and integrated into the units.

The units are assembled using automatic or manual welding or a combination of the two.

Several types of welding processes are employed. The most common is stick welding, in

which a consumable electrode is used to join the steel. Other welding processes use inert

gas shielded arcs and even non-consumable electrodes. In pipe fabricating and welding

section we can see welding applications.

We can divide the welding processes into two major groups as Fusion welding and

Solid-state welding. Shipyard welding processes, or more specifically fusion welding, is

performed at nearly every location in the shipyard environment. The process involves

joining metals by bringing adjoining surfaces to extremely high temperatures to be fused

together with a molten filler material. A heat source is used to heat the edges of the joint,

permitting them to fuse with molten weld fill metal (electrode, wire or rod). The required

heat is usually generated by an electric arc or a gas flame. Shipyards choose the type of

welding process based on customer specifications, production rates and a variety of

operating constraints including government regulations. Standards for military vessels

are usually more stringent than commercial vessels.

Figure 2.7: Electric Arc Welding




8

In electric arc welding (most common fusion weld type), a circuit is created between the

work-piece and an electrode or wire. When the electrode or wire is held a short distance

away from the work-piece, a high-temperature arc is created. This arc generates

sufficient heat to melt the edges of the work-piece and the tip of the electrode or wire to

produce a fusion-welding system. Material is added during this welding process. This

material can come from a consumable electrode, or from a rod of material that is fed

separately. The electrodes/rods are often coated. This coating serves a number of

functions,

- It protects the welder from contact

- It deoxidizes and provides a gas shield

We can see code system on the electrode rode that we use for welding purposes. As

engineers who order those electrode must know about those code system what they

denotes.

Figure 2.8: Designation Code Systems for Arc-Welding Electrodes.[Ref.07]




9

There are a number of electric arc welding processes suitable for use in shipbuilding. All

processes require shielding of the weld area from the atmosphere. Shielding is necessary

to control the arc easily and to reduce absorption of atmospheric gases.

Figure 2.9: Arc Welding Processes

Arc welding Processes

Consumable Electrodes- Most universal welding

process

Shielded Metal Arc Welding-Covering the metal electrodes with a chemical powder

Gas Metal Arc Welding-Covering the arc and weld pool with a (inert) gas on gas mixture

Metal Inert Gas Welding – MIG Welding (Used gases Ar, He or

mixture of them)can handle

aluminum, magnesium,

titanium, stainless steel, copper, etc.

Metal Active Gas Welding – MAG

Welding (Used gas CO2)

Metal Active Gas Mixture Welding –

MAGM Welding (Used gasses Ar, He and CO2 or O2

as mixture)

Submerged Arc Welding-Covering the arc and weld

pool with chemical powder

Non-consumable Electrodes

Gas Tungsten Arc Welding- can handle aluminum, titanium,

stainless steel, copper, etc.

Plasma Arc Welding




10

Classifications of Weld Joints According to Types of Joints

Figure 2.10 : Welding Processes According to Types of Joints [Ref. 07]

(a) Butt joint. In this joint type, the parts lie in the same plane and are joined at their

edges.

(b) Corner joint. The parts in a corner joint form a right angle and are joined at the corner

of the angle.

(c) Lap joint. This joint consists of two overlapping parts.

(d) Tee joint. In a tee joint, one part is perpendicular to the other in the approximate

shape of the letter „„T.‟‟

(e) Edge joint. The parts in an edge joint are parallel with at least one of their edges in

common, and the joint is made at the common edge(s).

Classifications of Weld Joints According to Types of Welds

Fillet weld-A fillet weld is used to fill in the edges of plates created by corner, lap, and

tee joints

Figure 2.11: Various Forms of Fillet Welds [Ref. 08]




11

Various forms of fillet welds:

a)Inside single fillet corner joint

b)Outside single fillet corner joint

c)Double fillet lap joint

d)Double fillet tee joint

-

Spot welds and seam welds, used for lap joints. Spot weld is a small fused section

between the surfaces of two sheets or plates. Multiple spot welds are typically required to

join the parts. A seam weld is similar to a spot weld except it consists of a more or less

continuously fused section between the two sheets or plates.

(a) Spot weld (b) Seam weld

Figure 2.12 : Spot and Seam Welds[Ref. 09]




12

Classifications of Weld Joints According to the Weld Positions

For plates:

Figure 2.13: Welding Positions of Plates [Ref. 10]




13

For Pipes :

Applications

1G, 2G, 3G and 4G are applicable in the fabrication and installation of tanks,

vessel, structural, shipbuilding and aeronotics

1G, 2G, 5G and 6G are applicable in the fabrication and installation of piping and

pipelines for industrial plants, oil and gas industry, chemical plants and other

industry which uses piping and pipelines.

6GR is applicable mainly in the fabrication and installation of offshore structure

and other structure that have the TKY configuration

Figure 2.14: Welding Positions of Steel Pipes [Ref. 11]




14

2.3 Hull Construction Department

2.3.1 Introduction

This shop also plays an important role in new construction section. It‟s responsible for

providing and processing steel plates mainly for new constructions. After the steel

processing is done, some parts are assembled in the shop while others are done in the

north and south piers of Dock No 01.

Hull construction is carried out in four different phases. They are,

Workshop activities

Unit fabrication and welding

Unit assembly and welding

Tank testing and rectification

I have worked in the shop for one week.

2.3.1 Quality Inspection of Raw Materials.

The quality of raw material is very important in any production. So quality of raw

material is inspected. This is a most important process in the production system. The

inspection is done by comparing the raw material with the mill test certificate that sent

by supplier to the company. And compare it with required standards. If the materials are

not according to the required standards they reject it or else accept the material. Mill test

certificate includes,

Certificate number

Spec and type

Size of the metal sheet

Production number

Weight

Tensile strength

Impact

Chemical composition




15

During material inspection the information (which includes all the information about the

plate) that are punched on plates with a stamp, are compared with mill test certificate and

details like thickness of the plate are measured by using thickness gauge.

2.3.2 Lofting Process.

Mid ship plans

Make stencils out of thin wood for rolling, line heating and bending are done in

loft today. Although so many designs processes now have been jumped into

computers basis systems.

2.3.3 Metal Cutting Process.

Cutting is the next step after marking. In the workshop we can see several type of cutting

methods. To ensure best quality and continues productivity; there are modern cutting

machineries as well as conventional cutting methods like manual cutting.

Numerical Control Plasma Cutting.

CNC plasma cutting machine is the most accurate and effective cutting machine in

CDPLC. In this process, to generate plasma it required air supply with high pressure. The

machine use in the company operates with air and Oxygen. Pressure of air is a 4 bar and

pressure of Oxygen is at 0.4 bar, if it unable to supply this much of pressure, the machine

will stop. The pressurized mixture(air and O2) is blown at high speed out of a copper

nozzle, at the same time an electrical arc is formed through that gas from the nozzle to

the work piece, turning some of that gas to plasma. The plasma is sufficiently hot to melt

the metal being cut and moves sufficiently fast to blow molten metal away from the cut.

This machine can cut plates up to 40mm in thickness. The most important advantage of

plasma cutting compared to gas cutting is that plasma cutting will not generate heat like

gas cutting. But it will generate smoke which consists with metal dust. So there is an

arrangement of the machine to filter out metal dust in smoke.

Existing plasma cutting machine in the company is used to mark required line on the

surface, which are to be consider while feather fabrication of the plate. Marking is

carried out prior to cutting using molten Zinc.




16

Figure 2.15: Numerical Control Plasma Cutting Machine

Gas Cutting.

We know that simplest oxy-fuel cutting equipment is the cutting torch. The main

difference between the cutting torch and the welding torch is that the cutting torch has an

additional tube for high pressure oxygen, along with a cutting tip or nozzle.

Similar principle is used in other cutting machine such as

Pug Machine –

The pug machine can be guided to run on an aluminium track for Straight line

cuts, circle cutting attachment for circular cuts and freehand cutting simple curves

by hand steering.

Figure 2.16: Plug Machine

Optical cutting machine

Optical plate cutting machine required a 1:1 scale paper drawing but it can be

used to cut up to 150mm thick plates.

Numerical control gas cutting machine-




17

Numerical control gas cutting machine is a modern co-ordinates gas cutting

machine with numerical controlling system. The machine used in CDPLC has a

cutting capacity of 4mm to 150mm.

Figure 2.17: Numerical Control Gas Cutting Machine

2.3.4 Metal Forming Process.

Metal sheet forming is the next step of the process. There are several type of metal

forming processes,

Cold rolling

Cold pressing

Thermal forming

Cold Rolling

Metal rolling is a kind of manufacturing method used in Dockyard P.L.C. In CDPLC

mainly used roll bending method. Roll bending produces a cylindrical shaped product

from plate or steel metal.




18

Figure 2.18: Rolling Machines

Cold Pressing

Cold pressing is carried out by using hydraulic pressing machine. Hydraulic presses are

very important machines when forming different shapes from the steel plates. It may be

extensively used in the workshop for a variety of purposes such as bending, straightening

and flanging. Most of the time a template is used to get the actual curvature.

Figure 2.19: Hydraulic Pressing Machine

Thermal Forming

Single curved plate can be simply produced by rolling but the forming of double curved

plates requires skilled labor and frequent use of heavy equipment. So line heating is very




19

useful where it low in production cost. But, the surrounding area of line heating is very

noisy. So it is compulsory to wear safety instrument while line heating.

The principle behind the thermal forming process is expansion and compression. During

heating, steel expands and during force cooling (cool by using water) it gets compressed

twice quickly than expansion. Due to this principle it is possible to make curves on metal

without using a press. Not only to make curves, thermal forming process is also to

straighten the curved metal sheets.

Figure 2.20: Thermal Forming Process

2.3.5 Unit Fabrication Process.

According to unit fabrication process there are several welding methods used in the

CDPLC. Those are,

Shielded Metal Arc Welding (SMAW)

Metal Active Gas (MAG)

Tungsten Inert Gas (TIG)




20

Shielded Metal Arc Welding (SMAW).

Flux-shielded electric arc welding processes are distinguished primarily by their manual

or semi-automatic nature and the type of consumable electrode used. The SMAW

process utilizes a consumable electrode (30.5 to 46 cm in length) with a dry flux coating,

held in a holder and fed to the work-piece by the welder. The electrode consists of the

solid metal filler rod core, made from either drawn or cast material covered with a sheath

of metal powders. SMAW is also frequently referred to as “stick welding” and “arc

welding”. The electrode metal is surrounded by flux that melts as welding progresses,

covering the deposited molten metal with slag and enveloping the immediate area in an

atmosphere of protective gas. Manual SMAW may be used for down hand (flat),

horizontal, vertical and overhead welding.

Gas Metal Arc Welding (GMAW).

Another major category of electric arc welding comprises the gas-shielded processes.

These processes generally use bare wire electrodes with an externally supplied shielding

gas which may be inert, active or a combination of the two. GMAW, also commonly

referred to as metal inert gas (MIG) welding, uses a consumable, automatically fed,

small-diameter wire electrode and gas shielding. GMAW is the answer to a long-sought

method of being able to weld continuously without the interruption of changing

electrodes. An automatic wire feeder is required. A wire spooling system provides an

electrode/wire filler rate that is at a constant speed, or the speed fluctuates with a voltage

sensor. At the point where the electrode meets the weld arc, argon or helium being used

as the shielding gas is supplied by the welding gun. It was found that for welding steel, a

combination of CO2 and/or an inert gas could be used. Often, a combination of the gases

is used to optimize cost and weld quality

Gas Tungsten Arc Welding (GTAW/TIG).

Another type of gas-shielded welding process is gas tungsten arc welding, sometimes

referred to as tungsten inert gas (TIG) welding too. The arc is generated between the

work-piece and a tungsten electrode, which is not consumed. An inert gas, usually argon

or helium, provides the shielding and provides for a clean, low-fume process. Also, the




21

GTAW process arc does not transfer the filler metal, but simply melts the material and

the wire, resulting in a cleaner weld. GTAW is most often employed in shipyards for

welding aluminum, sheet metal and small-diameter pipes and tubes, or to deposit the first

pass on a multi-pass weld in larger pipe and fittings.

2.4 Plant Shop

2.4.1 Introduction

All of the yards‟ new installations of machinery and equipment, maintenance jobs,

repairs are driven by this shop. This shop is also known as the Maintenance shop. I have

worked in the shop for one week. Plant shop has several branches as it is easy to handle

the jobs coming for the shop. They are,

1. Machinery Maintenance section

2. Lifting Equipment repair section

3. Power tool repair section

4. Gas line repair section

5. Gas equipment section

6. AC maintenance section

7. Airless spray machine repair section

2.4.2Lifting Equipment Repair Section

We use chain hoist for lifting and lowering heavy loads by giving relatively low force

that works in mechanical advantage of pulley system.

There are four types of chain hoist are used in CDPLC.

Manual chain hoist

Lever chain hoist

Electrical chain hoist




22

Pneumatic chain hoist

Maintains of chain hoist are shown in following steps,

Figure 2.21: Parts of a Chain Block [Ref. 12]

Remove the hand wheel cover

Remove the check nut and takeoff the hand wheel and the chain.

Take out the disk hub, friction disc and wheel side plate assembly

Remove two chain guides, load sheave and load chain.

Remove the gear cover.

Take off the snap ring and Remove the pinion shaft, pinions and loadgear.

Clean all the parts with kerosene and dry them properly.

Once we clean all the items we have to assemble the chain block.

File the edges of the chain guide for a smooth drive.

Apply grease on all parts and fix them properly and the snap ring

Once we done with the gearbox part close the gearbox cover and tight bolts

Now install the load sheave two chain guides and two hooks

Put the wheel side plate and install the friction hub, disk hub and ratchets.

Install the load chain




23

Fix the hand wheel and the and hand chain

Finally install the hand wheel cover back

If there is any defect in chains we must replace them. If there is wear in other parts we

must replace them too.

2.4.3 Power Tool Repair Section

In this section repair of electric equipment like grinders are done. Damaged parts are

replaced (especially motors).

Figure 2.22: Power Tool - Grinder

2.4.4 Gas Line Repair Section

In CDL, there are several types of gas lines with standard pressure as,

CO2 - 5 bar

O2 - 7.5-8.0 bar

C2H2 - 1.4-1.5 bar

Air - 8 bar

First pressure test was done.

Then flanges were painted.

After that pipes were covered by tapes.




24

There are two types of tapes as,

Denso ball tape ( black / white)

PVC type – (red/black/blue)

2.4.5 Gas Equipment Section

Repairing gas cutting torches, plug machines and etc. are done in this section. Most

important safety component in gas cutting and welding torch is flash back arrester.

Flash back arrestors are used on fuel line as well as the oxygen line. It is a device used

to shuts off gas flow in event of flash back. Flash back can travel back through the hose

to gas source if flash back arrestors are not in line. A flash back arrestor shuts off gas

flow and extinguishes the flame before it can reach gas source. Therefor it prevents

causing damages to equipment or any explosions. In most of causes the ceramic filter

inside arrester malfunction due to dust and etc. So to repair the gas torch following

procedure is used.

Figure 2.23: Gas Torch Repairing Procedure




25

2.4.6 AC Maintenance Section

Common Faults of Air Condition System

The gas can be leaked

The condenser & evaporator can be corroded

Compressor run down

Fan motor faults

Impurities can be stacked in evaporator & condenser

The impurities can be stuck in filters.

Air conditioning is the process of altering the properties of air (primarily temperature

and humidity) to more favorable conditions. More generally, air conditioning can refer

to any form of technological cooling, heating, ventilation, or disinfection that modifies

the condition of air. The air conditioners can be divided in to two main categories

according to their physical appearance. 1. Window type-All parts are as one unit those

mounted on the wall of the room 2. Split type-Split type air conditioners have two units,

which evaporator fixed in the room and condenser is outside of the room.

Main Parts of the Air condition

Window type A/C Split type A/C

Figure 2.24: Types of AC Systems [Ref.13]




26

The cold side of an air conditioner contains the evaporator and a fan that blows air over

the chilled coils and into the room. The hot side contains the compressor, condenser

and another fan to vent hot air coming off the compressed refrigerant to the outdoors.

In between the two sets of coils, there's an expansion valve. It regulates the amount of

compressed liquid refrigerant moving into the evaporator. Once in the evaporator, the

refrigerant experiences a pressure drop, expands and changes back into a gas. The

compressor is actually a large electric pump that pressurizes the refrigerant gas as part

of the process of turning it back into a liquid. There are some additional sensors, timers

and valves, but the evaporator, compressor, condenser and expansion valve are the

main components of an air conditioner. Refrigerant that are used R-22 / New R-404 A /

New R-502C / R-410 A / Auto and refrigerant gas R-134 A.

2.4.7 Airless Spray Machine Repair Section

Faults of Airless Spray Painting Machine

Filter may be blocked due to the paint solidifies inside.

Sleeve and the sleeve housing may be damaged

The system is not sealed well due to worn-out O-rings, leather rings and the

Teflon seals.

If there is damage in the displacement rod the system is not sealed well.

The ball at the valve may not seat properly due do some damages, then the

leakages can be happened.

Balls at the ball valves may have been damaged and that may cause for the

leakages.

Hull protective coatings and painting of the ships are done using airless spray

machines. In this workshop we dismantled a painting machine and understood the

working principle of this system. In this system, fluid is pumped under high pressure

through a small nozzle (spray tip). The fluid emerges as a solid stream (sheet) at a high

speed. When the solid stream hits the air, it becomes disrupted. This disruption breaks

the fluid into fragments initially, then ultimately very small droplets that form the spray




27

pattern. In this system compressed air motor is used to operate the sprayer pump, the

flow of air (Maximum pressure of 8bar) through the motor causes the motor piston and

rod to move up and down. This reciprocating motion is then transferred from the motor

connecting rod to the fluid displacement rod in the pump. Pump is a reciprocating

pump with two ball checks that control the flow of fluid through the fluid section. The

displacement rod connects the pumps internal components to the drive system. The rod

moves up and down with the action of the air motor. Fluid is loaded on the upstroke

and displaced on both the upstroke and down stroke. Displacing fluid on both the up

and down strokes ensures an even flow of fluid to the hose and gun.

Parts of Airless Spray Machine

1) Upper ball check

2) Lower ball check

3) Paint outlet

4) Displacement rod

5) Paint inlet

Figure 2.25: Parts of Airless Spray Machine [ Ref.14]

2.5 Machine Shop

2.5.1 Types of Machines

There are different types of machines in machine shop. Some of them are,

1. Lathe machines

2. Boring machines

3. Milling machines

4. Drilling machines




28

5. Balancing machines

6. Thread cutting machine

7. Grinding machine

8. Shaping machine

9. Sawing machine

I could study the operations of these machines in my one week training in machine shop.

2.5.2 Safety In Machining

2.5.3 Lathe Machine

Introduction

The lathe is one of the most important machines in any workshop. Its main objective is

to remove material from outside by rotating the work against a cutting tool. It is a

power driver, well purpose machine tool, which is used for producing cylindrical work

piece. An engine lathe is a power-driven, general-purpose machine tool used for

producing cylindrical work-pieces. As the piece of metal to be machined is rotated in

the lathe, a single-point cutting tool is advanced radically into the work piece a

specified depth and moved longitudinally along the axis of the work piece, removing

metal in the form of chips. Both inside and outside surfaces can be machined on a lathe

by using attachments and accessories. Other operations such as drilling, reaming,

boring, and taper and angle turning, screw-thread chasing, form turning, knurling,

milling, grinding, and polishing may be performed.

Wear safety equipment such as goggle when operating the machine.

Check the oil level, before use the machine.

Remove barriers near the rotating part of the machine.

Give power supply to the machine.

Fix the work piece and center work piece using dial gage/surface gauge.

Choose the correct tool and tips for the work.

Ex: Consider work piece material type, surface roughness and dimension.

Choose qualitative rotating speed.

Finish the necessary steps for final production

After finishing the work, remove power supply and clean the nearby.




29

Types of Lathe Machine.

Lathe machines can be classified into 3 main categories. They are

Parts of Lathe Machine.

We can see following main parts

Bed

Headstock

Tailstock

Carriage has five major parts. They are Saddle, Cross-slide. Compound rest.

Tools Post, Apron.

Power feed and thread cutting mechanism.

In a lathe machine the operations, which are done is defined as a job. The job is held in a

chuck or between centers and rotated about its axis at a uniform speed known as RPM

(Revolutions per minute). The cutting tool held in the tool post is fed into the work-piece

for a desired direction. Since there exists a relative motion between the work piece and

the cutting tool, therefore the material is removed in the form of chips and the desired

shape is obtained.

Figure 2.26: Lathe Machine




30

Lathe Operations.

The most common operations which can be carried out on a lathe are:

Straight Turning.

It is an operation of removing excess amount of material from the surface of the

cylindrical work piece. In this operation, the work is held either in the chuck or between

centers and the longitudinal feed is given to the tool either by hand or power.

Step Turning.

It is an operation of producing various steps of different diameters in the workplace. This

operation is carried out in the similar way as plain turning.

Taper Turning.

It is an operation of producing an external conical surface on a work piece. A small taper

may be produced with the help of a forming tool or chamfering tool, but the larger tapers

are produced by swiveling the compound rest, at the required angle or by offsetting the

tailstock or by taper turning attachment. If D is the larger diameter, “d” is the smaller

diameter and “l” is the length of taper, then,

Taper, = tan-1(D-d)/2l

Facing.

This operation is almost essential for all works. In this operation, the work piece is held

in the chuck and the facing tool is fed from the center of the work piece towards the outer

surface or from the outer surface to the center, with the help of a cross slide.

Centre Drilling.

It is an operation of locating the centre of the job before proceeding for the +drilling

operation. In this operation, the work piece is held in a chuck and the drill centre is held

in the tailstock. The drill is fed manually into the rotating work piece, by rotating the

tailstock hand wheel.




31

Drilling.

It is an operation of making a hole in a work piece with the help of a drill. In this

operation, the work piece is held in a chuck and the drill is held in the tailstock. The drill

is fed manually into the rotating work piece, by rotating the tailstock hand wheel.

Knurling.

It is an operation of providing knurled surface on the work piece. In this operation, a

knurled tool is moved longitudinally to a revolving work piece surface.

Figure 2.27: Lathe Operations [Ref.15]

Apparatus Needed.

Adjustable wrench,

Slide calipers

Cutting tool

Knurling tool

Chuck key

Facing tools

Turing tools

Taper Turing tools




32

Chamfering tools

Form or profile tools

Drilling tools

External and internal threading tools

Parting or necking tools

Worked Experience

Note: All the dimensions are in mm.

Length of every section is equal.

Drill size is 6-7.5 mm.

Metal: Mild Steel.

Figure 2.28: Diagram of the Job

Working Procedure:

The job was prepared as per the following sequence:

Facing.

Straight Turning.

Step Turning.

Centre Drilling.

Drilling.

Taper Turning.

Knurling.




33

Facing.

I. The piece of metal was supplied of 24 mm diameter.

II. The work piece was held in the chuck and the facing tool was fed from the lathe

center of the work piece towards the outer surface with the help of a cross slide.

III. The machine was operated counter clockwise and the facing was done

Straight Turning.

I. The work piece was to reduce in its diameter by 2 mm.

II. First, the entire length of 60 mm was measured with the help of the slide calipers.

III. The marking was done on the 60 mm position by the turning tools.

IV. This extra metal over the diameter was measured by the slide calipers and

adjusted to the machine.

V. Then the work piece was held in the chuck and the machine was switched on.

VI. Finally, the cross slide was operated towards the left and again towards the right

so long the entire work piece was reduced to 22 mm diameter.

Step Turning.

I. In this operation, first the 40 mm length was measured with the help of a slide

calipers, leaving the 20 mm portion intact of 22 mm diameter.

II. Then the marking was done on the 40 mm position by the turning tools.

III. The work piece was to reduce in its diameter by 2 mm in this length.

IV. The extra metal of 2 mm diameter was measured by the slide calipers and

adjusted to the machine.

V. Then the work piece was held in the chuck and the machine was switched on.

VI. Finally, the cross slide was operated towards the left and again towards the right

so long the 40 mm length of the work piece was reduced to 20 mm diameter.

Centre Drilling.

I. It is an operation of locating the centre of the job before proceeding for the drilling

II. Work piece was held in a chuck and the drill centre was held in the tailstock.

III. The drill centre was fed manually into the rotating work piece, by rotating the

tailstock hand wheel.

IV. Then the machine was switched on and centre drilling was done of near about 02

mm length.




34

Drilling.

I. The diameter of the drill was given as 6-7.5 mm.

II. A drill bit of 7 mm was selected for that purpose.

III. The length of the drill 15 mm was adjusted to the machine

2.5.3 Grinding Machine

Grinding machine used for grinding surfaces. It is a type of machining using an abrasive

wheel as the cutting tool. Each grain of abrasive on the wheel's surface cuts a small chip

from the work piece via shear deformation. Grinding is used as finishing work of

machined part that requires high surface quality. In this machine shop we grinded a

engine block.

Figure 2.29: Surface Grinder Machine

2.3.5 Power Sawing Machine

The sawing machine is a machine tool designed to cut material to a desired length or

contour. It functions by drawing a blade containing cutting teeth through the workpiece.

The sawing machine is faster and easier than hand sawing and is used principally to

produce an accurate square or mitered cut on the workpiece.

All power hacksaw machines are basically similar in design. The base of the saw usually

contains a coolant reservoir and a pump for conveying the coolant to the work. The

reservoir contains baffles which cause the chips to settle to the bottom of the tank. A




35

table which supports the vise and the metal being sawed is located on top of the base and

is usually referred to as part of the base.

Power hacksaw blades differ from hand hacksaw blades in that they are generally

heavier, made in longer sizes, and have fewer teeth per inch. Hacksaw blades are

discarded when they become dull; sharpening is not practical.

Materials commonly used in manufacturing power hacksaw blades are high-speed

tungsten steel and high-speed molybdenum steel. On some blades only the teeth are

hardened, leaving the body of the blade flexible. Other blades are hardened throughout

Figure 2.30: Power sawing machine

2.3.6 Milling Machine.

Figure 2.31: Milling Machine




36

Milling is the work of machining flat, curved, or irregular surfaces by feeding the work

piece against a rotating cutter containing a multiple cutting edges. The milling machine

consists basically of a motor driven spindle, which mounts and revolves the milling

cutter, and a reciprocating adjustable worktable, which mounts and feeds the work piece.

Milling machines are basically classified as vertical or horizontal. These machines are

also classified as knee-type and bed type.

Knee-type milling machines have a vertically adjustable worktable resting on a saddle

which is supported by a knee shaped massive casting that rides vertically on the milling

machine column and can be clamped rigidly to the column in a position where the

milling head and milling machine spindle are properly adjusted vertically for operation.

Bed type mills have a fixed table that holds more weight. Vertical milling machines have

a spindle located vertically, parallel to the column face, and mounted in a sliding head

that can be fed up and down by hand or power. Modern vertical milling machines are

designed so the entire head can also swivel to permit working on angular surfaces.

2.5.7 Drilling Machine

A drilling machine, called a drill press, is used to cut holes in metal, wood, or other

materials .Drilling machines use a drilling tool that has cutting edges at its point. This

cutting tool is held in the drill press by a chuck or Morse taper and is rotated and fed into

the work at variable speeds. Drilling machines may be used to perform other operations.

They can perform countersinking, boring, counter boring, spot facing, reaming, and

tapping.

Figure 2.32: Drilling operations[ Ref 16]

A radial drilling machine or radial arm press is a geared drill head that is mounted on an

arm assembly that can be moved around to the extent of its arm reach. The most

important components are the arm, column, and the drill head. The drill head of the

radial drilling machine can be moved, adjusted in height, and rotated. Aside from its




37

compact design, the radial drill press is capable of positioning its drill head to the work

piece through this radial arm mechanism. Drilling machines can use for countersinking,

boring, counter boring, reaming, and tapping .In operating the radial drilling machine we

should have the knowledge to set up the work, set speed and feed, and to provide coolant

to get an acceptable finished product. A figure of a radial drilling machine is shown

below

Figure 2.33: Radial Drilling Machine [ Ref.17]

2.5.8 Cutting Fluids

Practically all cutting fluids presently in use fall into one of four categories,

Straight oils

Soluble oils

Semi synthetic fluids

Synthetic fluids

Cutting Fluid Application Strategies

Flood Application of Fluid: A flood of cutting fluid is applied on the work piece

Jet Application of Fluid: A jet of cutting fluid is applied on the work piece

directed at the cutting zone

Mist Application of Fluid: Cutting fluid is atomized by a jet of air and the mist

is directed at the cutting zone




38

Cutting Fluid Effects in Machining

*The primary functions of cutting fluids in machining are:

Lubricating the cutting process primarily at low cutting speeds

Cooling the work piece primarily at high cutting speeds

Flushing chips away from the cutting zone

*Secondary functions include:

Corrosion protection of the machined surface

Enabling part handling by cooling the hot surface

*Process effects of using cutting fluids in machining include:

Longer tool life

Reduced thermal deformation of work piece

Better surface finish (in some applications)

Ease of chip

Cutting Fluid Selection Criteria

The principal criteria for selection of a cutting fluid for a given machining operation are:

Process performance

Heat transfer performance

Lubrication performance

Chip flushing

Fluid mist generation

Fluid carry-off in chips

Corrosion inhibition

Fluid stability (for emulsions)




39

Cost Performance

Environmental Performance

Health Hazard Performance

2.5.9 Balancing Machine

Figure 2.34: Balancing Machine[ Ref.18]

A balancing machine is a measuring tool used for balancing rotating machine parts such

as rotors for electric motors, fans, turbines, disc brakes, disc drives, propellers and

pumps. The machine usually consists of two rigid pedestals, with suspension and

bearings on top supporting a mounting platform. The unit under test is bolted to the

platform and is rotated either with a belt-, air-, or end-drive. As the part is rotated, the

vibration in the suspension is detected with sensors and that information is used to

determine the amount of unbalance in the part. Along with phase information, the

machine can determine how much and where to add weights to balance the part.

In a soft-bearing machine which is available in CDPLC, trial weights must be added in

correction planes for each part. This is because the location of the correction planes

along the rotational axis is unknown, and therefore it is unknown how much a given




40

amount of weight will affect the balance. By using trial a weight, a known weight at a

known angle is added, and getting the unbalance vector caused by it.

Rotor Balancing Procedure

N.B. It is important that rotor balancing be performed by an experienced rotating

machinery specialist.

The following describes the procedure for performing single or two plane balancing. The

data is used in a balancing program for calculating the required balancing weight and

position for attaching a balancing mass to the rotor. The vibration magnitude and phase

angle must be obtained using a suitable balancing machine.

Single Plane Balancing Procedure :

1. Run the machine and record the initial rotor vibration and phase angle.

2. Stop the machine and firmly attach a small Trial Weight to the rotor. Record the Trial

Weigh mass and position. (Ensure that the Trial Weight is firmly attached to the rotor. It

is a serious safety risk if the Trial Weight is not firmly attached and flies off while

running the machine).

3. Run the machine and record the new rotor vibration and phase angle.

4. Stop the machine and remove the Trial Weight.

5. Input the data obtained from the 3 steps above in a single plane balancing program to

calculate the required balancing weight and position.

6. Firmly attach a balancing weight of the required mass to the calculated position on the

rotor.

7. Run the machine and re-measure vibration. If required, perform a trim balance.




41

Two Plane Balancing Procedures:

1. Measure and record the initial rotor vibration and phase angle on both bearings.

2. Stop the machine and attach a small Trial Weight to plane 1 of the rotor. Record the

trial weighs mass and position. (Ensure that the Trial Weight is firmly attached to the

rotor. It is a serious safety risk if the Trial Weight is not firmly attached and flies off

while running the machine).

3. Run the machine and record the new rotor vibration and phase angle on both bearings.

4. Stop the machine and remove the Trial Weight from plane 1. Attach a small Trial

Weight to plane 2 of the rotor. Record the trial weighs mass and position. (Ensure that

the Trial Weight is firmly attached to the rotor. It is a serious safety risk if the Trial

Weight is not firmly attached and flies off while running the machine).

5. Run the machine and record the new rotor vibration and phase angle on both bearings.

6. Stop the machine and remove the Trial Weight from plane 2.

7. Input the data obtained from the 3 steps above in a two plane balancing program to

calculate the required balancing weights and positions.

8. Firmly attach balancing weights of the required mass to the calculated positions on

planes 1 and 2 of the rotor. (Ensure that the Balancing weights are firmly attached to the

rotor. It is a serious safety risk if a Balancing Weight is not firmly attached and flies off

while running the machine).

9. Run the machine and re-measure vibration. If required, perform a trim balance.




42

2.6 Engine Fitting Shop

2.6.1 Introduction

Engine fitting shop is a very important workshop for both mechanical and marine

engineering interns. Mainly main engine and auxiliary engine repairing, turbochargers,

heat exchangers, pumps, valves, and propeller repairing are the key operations of the

workshop. This workshop has 8 main sections. They are

• Main engine fitting section

• Valves repair section

• Steam valves section

• Coolers repair section

• Pump repair section

• Turbo charger section

• Storm valves section

• Injector room

I have worked for about one week in this shop. I took lot of experience about

turbochargers, valves, pumps, heat exchangers….etc.

2.6.2 Piston

Figure 2.35: Piston Rod [Ref.19]




43

The piston transforms the energy of the expanding gasses into mechanical energy.

Pistons are commonly made of aluminum or cast iron alloys. To prevent the combustion

gasses from bypassing the piston and to keep friction to a minimum, each piston has

several metal rings around it

These rings function as the seal between the piston and the cylinder wall and also act to

reduce friction by minimizing the contact area between the piston and the cylinder wall.

Most diesel engine pistons have several rings, usually 2 to 5, with each ring performing a

distinct function. The top ring(s) acts primarily as the pressure seal. The intermediate

ring(s) acts as a wiper ring to remove and control the amount of oil film on the cylinder

walls. The bottom ring(s) is an oiler ring and ensures that a supply of lubricating oil is

evenly deposited on the cylinder walls

In this workshop we supported to replace piston crowns to piston rods. We replaced new

piston crowns for four piston rods.

Procedure:

1. Disengaged piston crowns & skirts from piston rod

2. Cleaned scraper rings, compressor rings & cross head

3. Removed engine grease from piston crowns(new piston crowns) with kerosene oil

moisture cloth

4. Fixed skirt to the piston rod

5. Replaced piston crown to the piston rod

6. Pressure test done for piston rod for find leakages of relevant pressure.(7 bar)

Figure 2.36: Piston Rod Stuffing Box




44

2.6.3 Heat Exchanger-Coolers

A heat exchanger is a device built for efficient heat transfer from one medium to another.

Heat can flow only from the hotter to the cooler fluid. In a heat exchanger there is no

direct contact between the two fluids. The heat is transferred from the hot fluid to the

metal isolating the two fluids and then to the cooler fluid. Marine diesel engine is

designed for non-stop operation, from the time the ship departs from a port until it

reaches another port. Therefore Continuous cooling of the engine is necessary. Following

are the three types of heat exchangers most commonly used in ships.

1) Shell and tube type heat exchanger

2) Plate type heat type heat exchanger

3) Tube and fins type heat exchanger

The heat exchangers can be and be parallel-flow, cross-flow, or countercurrent. In

parallel-flow heat exchangers, both fluids involved move in the same direction, entering

and exiting the exchanger side by side. In cross-flow heat exchangers, the fluid paths run

perpendicular to one another. In countercurrent heat exchangers, the fluid paths flow in

opposite directions, with each exiting where the other enters. Countercurrent heat

exchangers tend to be more effective than other types of exchangers. Aside from

classifying heat exchangers based on fluid

In this workshop we could see those three types of heat exchangers, sent to clean and

repair. I could disengage tube and shell type heat exchanger. Sell and tube heat

exchangers are used for engine cooling water and lubricating oil cooling. Normally sea

water is the cooling medium. Most of the coolers repaired to a routine and ship engineer

should check for leakages after repairing.

The repairing procedure was follows.

1) Removed the end covers.

2) Washed oil and other contaminant using pressurized Kerosene mixed water

3) Covered the threads silicone gel.

4) Sent to ultrasonic cleaning

5) After dry, Change the gaskets and fixed the end covers.

6) Pressure test done for 5 bars.

Or




45

1) Removed heat exchanger covers.

2) Removed Zn anodes.

3) Clean the aluminum Bronze tubes and the outer surface of the heat exchanger by using

SAF acid (An acid which includes sulfamic acid, sodium borate,decahydrate, magnesium

oxide).

4) Checked the leakages in the tubes by compressing the water to a pressure of 5 bars.

Figure 2.37: Heat Exchanger

2.6.4 Turbochargers

A turbocharger consists of a compressor wheel and exhaust gas turbine wheel coupled

together by a solid shaft and that is used to boost the intake air pressure of the engine.

The exhaust gas turbine extracts energy from the exhaust gas and uses it to drive the

compressor wheel. Basically there are two types of turbochargers available.

Center mounted turbochargers

End mounted turbochargers

Procedure of turbocharger repairing

In turbocharger repairing at first the turbocharger is disassembled.

Then cleaned all the parts including impellers of turbine and compressor.




46

Then the unit of turbine impeller and compressor was balanced by using dynamic

balancing machine. It was done by machine shop.

Then the thickness of the outer housing was checked to find the ability to use the

same housing again.

Then assembled the turbocharger again

Figure 2.38: Turbocharger

2.6.5 Valves

Valve is a device that regulates the flow of a fluid by opening, closing or partially

obstructing various passageways. I could see valves use in seawater line, fresh

waterlines, airlines, oil lines and drainage lines in Colombo Dockyard PLC. I could study

different type of valves in engine fitting workshop. Those are,

1. Globe Valve

2. Gate valve

3. Ball valve

4. Butterfly valve

5. Storm Valve (Scupper valve)

6. Non-return valve




47

Butterfly Valve

A butterfly valve is a valve which can be used for isolating or regulating flow. The

closing mechanism takes the form of a disk. Operation is similar to that of a ball valve,

which allows for quick shut off.

Figure 2.39: Butterfly Valve [ Ref.20]

Globe Valve

A globe valve is a type of valve used for regulating flow in a pipeline, consisting of a

movable disk-type element and a stationary ring seat in a generally spherical body. When

the hand wheel is rotated to the clock wise the plug is moved toward the stationary ring

seat and then closes the flow and vice versa.

Figure 2.40: Globe Valve [Ref.21]




48

2.6.6 Pumps

During my training period of engine fitting shop of Colombo Dockyard PLC, I was able

to get knowledge about various pumps and classification of pumps and supported to

repair double stage centrifugal pumps, which includes two impellers, and I was able to

support to repair a gear pump.

A pump is a mechanical device using suction or pressure to raise or move liquids,

compress gases, or force air into inflatable objects such as tires. Pumps can be classified

as below.

Figure 2.41: Classification of Pumps




49

2.7 Calibration Section

2.7.1 Introduction

Calibration section is the place where all the calibration work of ship repair and ship

building is carried out. All the details are recorded in separate file for each and every

ship Calibration shop has established for all the calibration operations of machine parts,

Engine alignment, ship parts...etc. The main operations of this shop are preparing dry

dock report, Main engine report, Auxiliary engine report and alternator air gas clearance

report. On the other hand this section is responsible for the below operations

Recording of stern tube wear down

Fitting of propeller

Intermediate shaft bearing load test

Inspections of rudder

Alignment works of stern tube, compressors, pumps, rudder…etc.

Recording of generator air gap clearance

In this workshop I developed experience of handling some measuring instruments such

as venire caliper, micrometer screw gauge, feeler gauge and Swedish feeler gauge, bore

gauge, poker gauge.

2.7.2 Stern Tube Alignment Using Micro Alignment Telescope

Stern tube alignment is mainly done using two particular methods. They are piano wire

method and stern tube alignment using micro alignment telescope. The accuracy of the micro

alignment telescope method is high than the piano wire method. In the micro alignment

telescope method the telescope was mounted at the propeller end of the stern tube and a

target was mounted at the engine side. Two flanges were manufactured before the test to

mount the target and the telescope. The micro alignment telescope generates a sight line

between the target at one end of the stern tube and the telescope mounted at the other end.

Then the telescope was aligned and fixed by using the target. Then the target was change and

fixed it to the engine side end of the stern tube and then the alignment of the stern tube was

checked by using telescope




50

In the period, I could participate for a piano wire alignment test in 233 vessel of shaft

and radar.

Figure 2.42: Micro Alignment Telescope[Ref.22]

2.7.3 Feeler Gauge

A feeler gauge is a tool used to measure gap widths. Feeler gauges are mostly used in

engineering to measure the clearance between two parts. They consist of a number of

small lengths of steel of different thicknesses with measurements marked on each piece.

They are flexible enough that, even if they are all on the same hinge, several can be

stacked together to gauge intermediate values. It is common to have two sets for imperial

units (typically measured in thousandths of an inch) and metric (typically measured in

hundredths of a millimeter) measurements.

Figure 2.43: Feeler Gauge




51

2.7.4 Bore Gauge

Used to measure the wearing of piston cylinder by using the deviation from standard

size.

Figure 2.44: Bore Gauge [Ref.23]

2.7.5 Bearing Load Testing

Proper shaft alignment is a key issue on ships. It is defined as a static condition observed

at the bearings supporting the propulsion shafting. Any wrong alignment on the shaft can

result in undesirable vibrations and higher operating costs. As a result there may be

damages in stern tube bearings, propulsion system, main engine and eventually gear box.

To verify acceptability of alignment, it must be confirmed that the following minimum

set of parameters are acceptable:

Bearing reactions

Bearing vertical offset

Misalignment angles

Crankshaft‟s web deflections

Bearing load testing is performed to check the bearing reactions and it generally

measured utilizing jack up method. We did bearing load lest of intermediate bearings and

AFT plumber block bearing. The required instruments are dialed gauge, filler gauges and

hydraulic jack.

Procedure




52

1. Make sure that the turning gear being declutched from the flywheel.

2. Check the top, bottom and side clearances between bearing and shaft.

3. Make sure that the shaft is resting on the bearing fully symmetrically by ensuring

bottom touching and PORT and STBD clearance equality.

4. Mount the hydraulic jack with a pressure gauge closed to the bearing housing edge

and directly under the shaft.

5. Mount the dial gauge pointer on top of the shaft inline with the jack.

6. Increase the jack pressure gradually

7. Record the dial gauge reading (lift) and corresponding jack pressure.

8. Stop loading when the shaft lift becomes small in relation to the pressure.

9. Record the jack pressure and corresponding dial gauge reading while unloading.

10. Plot the lift versus jack pressure of loading and unloading data on a same graph.

11. Draw the mean line until it intersects with the “X” axis.

12. Consider the intersection point as the pressure which gives the actual load on the

bearing

2.8 Automation shop

2.8.1 Introduction

In the Automation shop of CDPLC so many works are done.

Repairing and maintaining electronic systems.

Calibrating electronic devices.

Etc.

In the shop we can see so many electronic devices. So many devices consist of

sensors.

2.8.2 Types of Sensors.

Sensor is the device which perceives stimuli and makes a response for it. When we

consider a human body there are five sensors as eye, ear, nose, and tongue, skin which

are response for pictures, sound, order, taste and heat. Like that there are electronic




53

devices which make responses to external changing. So they are called as sensors.

There are many types of sensors as follow,

Automotive, transportation

Chemical

Electrical current, electrical potential, magnetic, radio

Environmental, weather, moisture, humidity

Flow, fluid velocity

Position, Position, angle, displacement, distance, speed, acceleration

Optical, light, imaging, photon

Pressure

Force, density, level

Thermal, heat, temperature

Proximity, presence

Figure 2.45:Relationship of External Effect and Action

Temperature Sensors

The most commonly used type of all the sensors are those which detect Temperature or

heat. These types of temperature sensor vary from simple ON/OFF thermostatic devices

which control a domestic hot water heating system to highly sensitive semiconductor

types that can control complex process control furnace plants.

External effect

Sense Action




54

We remember from our school science classes that the movement of molecules and

atoms produces heat (kinetic energy) and the greater the movement, the more heat that is

generated. Temperature Sensors measure the amount of heat energy or even coldness that

is generated by an object or system, allowing us to “sense” or detect any physical change

to that temperature producing either an analogue or digital output.

There are many different types of Temperature Sensor available and all have different

characteristics depending upon their actual application. A Temperature Sensor consists

of two basic physical types:

• Contact Temperature Sensor Types – These types of temperature sensor are required to

be in physical contact with the object being sensed and use conduction to monitor

changes in temperature. They can be used to detect solids, liquids or gases over a wide

range of temperatures.

• Non-contact Temperature Sensor Types – These types of temperature sensor use

convection and radiation to monitor changes in temperature. They can be used to detect

liquids and gases that emit radiant energy as heat rises and cold settles to the bottom in

convection currents or detect the radiant energy being transmitted from an object in the

form of infra-red radiation (the sun).

The two basic types of contact or even non-contact temperature sensors can also be sub-

divided into the following three groups of sensors, Electro-mechanical, Resistive and

Electronic and all three types are discussed below.

The Thermostat

The Thermostat is a contact type electro-mechanical temperature sensor or switch, that

basically consists of two different metals such as nickel, copper, tungsten or aluminum

etc, that are bonded together to form a Bi-metallic strip. The different linear expansion

rate of the two dissimilar metals produces a mechanical bending movement when the

strip is subjected to heat.




55

The bi-metallic strip can be used itself as an electrical switch or as a mechanical way of

operating an electrical switch in thermostatic controls and are used extensively to control

hot water heating elements in boilers, furnaces, hot water storage tanks as well as in

radiator cooling systems.

The Bi-metallic Thermostat

Figure 2.46: Bi-Metallic Thermostat [Ref.24]

The thermostat consists of two thermally different metals stuck together back to back.

When it is cold the contacts are closed and current passes through the thermostat. When

it gets hot, one metal expands more than the other and the bonded bi-metallic strip bends

up (or down) opening the contacts preventing the current from flowing.

There are two main types of bi-metallic strips based mainly upon their movement when

subjected to temperature changes. There are the “snap-action” types that produce an

instantaneous “ON/OFF” or “OFF/ON” type action on the electrical contacts at a set

temperature point, and the slower “creep-action” types that gradually change their

position as the temperature changes.

Snap-action type thermostats are commonly used in our homes for controlling the

temperature set point of ovens, irons, immersion hot water tanks and they can also be

found on walls to control the domestic heating system.




56

Creeper types generally consist of a bi-metallic coil or spiral that slowly unwinds or

coils-up as the temperature changes. Generally, creeper type bi-metallic strips are more

sensitive to temperature changes than the standard snap ON/OFF types as the strip is

longer and thinner making them ideal for use in temperature gauges and dials etc.

Although very cheap and are available over a wide operating range, one main

disadvantage of the standard snap-action type thermostats when used as a temperature

sensor, is that they have a large hysteresis range from when the electrical contacts open

until when they close again. For example, it may be set to 20oC but may not open until

22oC or close again until 18

oC.

So the range of temperature swing can be quite high. Commercially available bi-metallic

thermostats for home use do have temperature adjustment screws that allow for a more

precise desired temperature set-point and hysteresis level to be pre-set.

The Thermistor

The Thermistor is another type of temperature sensor, whose name is a combination of

the words THERM-ally sensitive res-ISTOR. A thermistor is a special type of resistor

which changes its physical resistance when exposed to changes in temperature.

Thermistors are generally made from ceramic materials such as oxides of nickel,

manganese or cobalt coated in glass which makes them easily damaged. Their main

advantage over snap-action types is their speed of response to any changes in

temperature, accuracy and repeatability.

Figure 2.47: Thermistor [ Ref.25]




57

Most types of thermistor‟s have a Negative Temperature Coefficient of resistance or

(NTC), that is their resistance value goes DOWN with an increase in the temperature,

and of course there are some which have a Positive Temperature Coefficient, (PTC), in

that their resistance value goes UP with an increase in temperature.

Thermistors are constructed from a ceramic type semiconductor material using metal

oxide technology such as manganese, cobalt and nickel, etc. The semiconductor material

is generally formed into small pressed discs or balls which are hermetically sealed to

give a relatively fast response to any changes in temperature.

Thermistors are rated by their resistive value at room temperature (usually at 25oC), their

time constant (the time to react to the temperature change) and their power rating with

respect to the current flowing through them. Like resistors, thermistors are available with

resistance values at room temperature from 10‟s of MΩ down to just a few Ohms, but for

sensing purposes those types with values in the kilo-ohms are generally used.

Thermistors are passive resistive devices which means we need to pass a current through

it to produce a measurable voltage output. Then thermistors are generally connected in

series with a suitable biasing resistor to form a potential divider network and the choice

of resistor gives a voltage output at some pre-determined temperature point or value for

example:

Resistive Temperature Detectors (RTD).

Another type of electrical resistance temperature sensor is the Resistance Temperature

Detector or RTD. RTD‟s are precision temperature sensors made from high-purity

conducting metals such as platinum, copper or nickel wound into a coil and whose

electrical resistance changes as a function of temperature, similar to that of the

thermistor. Also available are thin-film RTD‟s. These devices have a thin film of

platinum paste is deposited onto a white ceramic substrate.




58

Resistive temperature detectors have positive temperature coefficients (PTC) but unlike

the thermistor their output is extremely linear producing very accurate measurements of

temperature.

However, they have very poor thermal sensitivity, that is a change in temperature only

produces a very small output change for example, 1Ω/oC.

The more common types of RTD‟s are made from platinum and are called Platinum

Resistance Thermometer or PRT„s with the most commonly available of them all the

Pt100 sensor, which has a standard resistance value of 100Ω at 0oC. The downside is

that Platinum is expensive and one of the main disadvantages of this type of device is its

cost.

Like the thermistor, RTD‟s are passive resistive devices and by passing a constant

current through the temperature sensor it is possible to obtain an output voltage that

increases linearly with temperature. A typical RTD has a base resistance of about 100Ω

at 0oC, increasing to about 140Ω at 100

oC with an operating temperature range of

between -200 to +600oC.

Because the RTD is a resistive device, we need to pass a current through them and

monitor the resulting voltage. However, any variation in resistance due to self heat of the

resistive wires as the current flows through it, I2R , (Ohms Law) causes an error in the

readings. To avoid this, the RTD is usually connected into a Whetstone Bridge network

which has additional connecting wires for lead-compensation and/or connection to a

constant current source.

Figure 2.48: Resistive RTD [ Ref.26]




59

The Thermocouple

The Thermocouple is by far the most commonly used type of all the temperature sensor

types. Thermocouples are popular due to its simplicity, ease of use and their speed of

response to changes in temperature, due mainly to their small size. Thermocouples also

have the widest temperature range of all the temperature sensors from below -200oC to

well over 2000oC.

Thermocouples are thermoelectric sensors that basically consist of two junctions of

dissimilar metals, such as copper and constantan that are welded or crimped together.

One junction is kept at a constant temperature called the reference (Cold) junction, while

the other the measuring (Hot) junction. When the two junctions are at different

temperatures, a voltage is developed across the junction which is used to measure the

temperature sensor as shown below.

Figure 2.49: Thermocouple Construction [Ref.27]

Coolant temperature sensor

The coolant temperature sensor is used to measure the temperature of the engine coolant

of an internal combustion engine. The readings from this sensor are then fed back to the

Engine control unit (ECU), which uses this data to adjust the fuel injection and ignition

timing. On some vehicles the sensor may also be used to switch on the electric cooling

fan. The data may also be used to provide readings for a coolant temperature gauge on

the dashboard.




60

Proximity sensor

A proximity sensor is a sensor able to detect the presence of nearby objects without any

physical contact. A proximity sensor often emits an electromagnetic field or a beam of

electromagnetic radiation (infrared, for instance), and looks for changes in the field or

return signal. The object being sensed is often referred to as the proximity sensor's target.

Different proximity sensor targets demand different sensors. For example, a capacitive or

photoelectric sensor might be suitable for a plastic target; an inductive proximity sensor

always requires a metal target.

The maximum distance that this sensor can detect is defined "nominal range". Some

sensors have adjustments of the nominal range or means to report a graduated detection

distance.

Proximity sensors can have a high reliability and long functional life because of the

absence of mechanical parts and lack of physical contact between sensor and the sensed

object.

An proximity (inductive) sensor is an electronic proximity sensor, which detects metallic

objects without touching them.

The sensor consists of an induction loop. Electric current generates a magnetic field,

which collapses generating a current that falls asymptotically toward zero from its initial

trans when the input electricity ceases. The inductance of the loop changes according to

the material inside it and since metals are much more effective inductors than other

materials the presence of metal increases the current flowing through the loop. This

change can be detected by sensing circuitry, which can signal to some other device

whenever metal is detected. .

Common applications of inductive sensors include metal detectors, traffic lights, car

washes, and a host of automated industrial processes. Because the sensor does not

require physical contact it is particularly useful for applications where access presents

challenges or where dirt is prevalent. Its sensing distance is low when compared to other

proximity sensors




61

2.8.3 Calibration Tests

To check whether the measuring instruments are perform well we have to do calibration

process. And after it certification is done.

Pressure gauges

mA Calibrator

Thermometer

Multimeter

Temperature calibrator

Pressure calibrator

Resistance box

Power supply electro- automation are used for those tests.

Figure 2.50: Temperature Calibrator [Ref.28]

Pressure gauge

Figure 2.51: Pressure Gauge Calibrator




62

Bourdon tubes measure gauge pressure, relative to ambient atmospheric pressure, as

opposed to absolute pressure; vacuum is sensed as a reverse motion. Some aneroid

barometers use Bourdon tubes closed at both ends. When the measured pressure is

rapidly pulsing, such as when the gauge is near a reciprocating pump, an orifice

restriction in the connecting pipe is frequently used to avoid unnecessary wear on the

gears and provide an average reading; when the whole gauge is subject to mechanical

vibration, the entire case including the pointer and indicator card can be filled with an oil

or glycerin. Tapping on the face of the gauge is not recommended as it will tend to

falsify actual readings initially presented by the gauge. The Bourdon tube is separate

from the face of the gauge and thus has no effect on the actual reading of pressure.

Typical high-quality modern gauges provide an accuracy of ±2% of span, and a special

high-precision gauge can be as accurate as 0.1% of full scale.

Air pressure or pneumatic gauges measure the amount of air needed to maintain the

optimum use of the object containing this gas. A common container of air is a tire. Using

an air pressure gauge ensures the correct amount of air fills the tire for optimum

performance. Too little air in a tire eventually makes it flatten while too much air makes

it wear unevenly or even explode.

Figure 2.52: Bourdon Tube [Ref.29]




63

2.9 Electrical Workshop

2.9.1 Introduction

Electrical workshop is the unit which has established for repair A/C, D/C motors &

generators, panel boards, control equipment, lighting system on board vessels,

simultaneous testing, meter calibration and rewinding motors and transformers etc.

2.9.2 Electrical Motors

Electrical motors are used to convert electrical energy to mechanical energy or in

generators mechanical energy to electrical energy thus it can be classified as

electromechanical device. Electrical motors play an important role in any electrical

system such as manufacturing plants, office, workshops etc. There are number of

different types of motors and each has different operating characteristics. They can be

divide in to two main types,

DC motors

AC motors

Although DC power supply is not very common in industrial applications, DC motors

are used in many applications, coupled with DC drives; DC motors provide very precise

control. DC motors can be used with conveyors, elevators, extruders, marine

applications, material handling, paper, plastics, rubber, steel, and textile applications,

automobile, aircraft, and portable electronics, in speed control applications. There are

many advantages as well as disadvantages in DC motors.

Given below are some advantages of DC motors.

It is easy to control their speed in a wide range

Their reduced overall dimensions permit a considerable space saving which let

the manufacturer of the machines or of plants not to be conditioned by the

exaggerated dimensions of circular motors.

Given below are some disadvantages of DC motors.

Since they need brushes to connect the rotor winding. Brush wear occurs, and it

increases dramatically in low‐pressure environment. So they cannot be used in




64

artificial hearts. If used on aircraft, the brushes would need replacement after one

hour of operation.

Sparks from the brushes may cause explosion if the environment contains

explosive materials.

RF noise from the brushes may interfere with nearby TV sets, or electronic

devices, Etc.

DC motors are also expensive relative to AC motors.

AC motors are the most common type of motors use in industry. Unlike DC motors,

AC motors runs smoothly because the current supply is alternating so that motor will

run only at the frequency of the sine wave. Ac motors re use in many industrial

applications such as induction motor driving pumps, fans, compressors, elevators and

machineries of various types etc.

Procedure for repairing of three phase induction motor

At first insulation of the motor was checked using Megger meter.

Motor was disassembled and the operations like washing were done.

The starting method of the motor was identified when disassembling the motor

It was clarified that the star delta starting method has used in the motor.

The stator winding of the motor was observed and the prevailing winding

diagram was drawn roughly

Figure 2.53: Stator Winding of the Motor




65

Then the diameters of the lead wires were checked using micrometer screw gauge

and the values are shown below.

0.559 -1 wire

0.508-1 wire

Standard wire gauge chart was used and the gauge numbers were identified and it

as, Number of wires is 1 for gauge numbers 24 and 25.

Number of slots of the stator and number of turns in a coil were calculated and

the data is shown below.

Number of slots-24

Number of coils-12

Number of turns-102

Then the stator was washed and was dried in a baking oven.

Cleaned stator was kept in the oven; it should have to bake first 2 hours in 950

Celsius temperature and another 6 or eight hours in 1250 Celsius temperature if

hot water is used. 6-8 hrs at 1400C if used electro cleaner for cleaning objects.

Anticorrosive paint (sterling VA42) was applied on the stator

Brought it into winding room and insulation papers were put in side the slots.

Wound up the coils by using winding machine and placed it considering the slot

pitch.

Labeled winding coils (A1 ,A2 / B1,B2 /C1 ,C2) and connect A1 Finishing(f) to

A2 coil finishing(f) and so on.

Finally stator was assembled and the star connection was supplied to the motor.

Finally star connection was established

2.9.3 Megger Meter and Megger Testing

Megger meter works by applying a known DC voltage (normally use 500V to test

motors) to a wire for a given period of time to test the resistance of the insulation on




66

that wire or winding. When the voltage is applied we can find the high resistance

shorts. So while the wire or winding may not have a short when you test it without

voltage with an ohm meter. The resistance may change when the voltage is applied.

Since the current takes the path of least resistance, this is when the short would

present itself. Megger have to be used properly as they apply voltage which can be

destructive to the piece of equipment being tested. If we apply too high voltage the

equipment was destroyed by exceeding the insulation rating of the wire or device. In

CDPLC if the resistance obtain by megger is higher than 1.5MΩ, the insulation was

acceptable.




1

3.0 Management

3.1 Introduction

To a successful engineer it is very important to have not only the technical knowledge

but also the management skills when we are dealing with the industry. In the industry we

have to work with several kinds of fields such as

Financial Management

Human Resource Management

Safety Management

Waste Management

Etc.

Business Division

There are four main operations of Business division. They are

Marketing - Responsibility to promote the business through out the world.

Estimating - Responsibility to estimate the repair specification of the ship comes

to the business division for the preparation of the quotation.

Ship repair manager - Responsibility to decides what to do first in the ship in

repairing process and monitors the ship and timely completed the work.

Invoice - responsible for billing purpose of the ship.




2

3.2 Financial Management

Financial Performance and Position

Figure 3.1: Financial Performance [Ref.30]




3

3.3 Human Resource Management (HR)

The Human Resources Development and Administration Division continued its efforts to

ensure that their employees able to face challenges with

Team spirit

More effective

Productive

Efficient

By adding leadership skills and motivational dynamics into the everyday workplace.

Colombo Dockyard provides high salary and remuneration benefit to the team well

above local industry standards. Other than that the following benefits are provided to all

employees.

Bonuses for all employees

Loans for housing and vehicles

Welfare Facilities-

o Subsidized meals; snacks and tea free of charge

o Budget Shop managed by the Welfare Association, to procure essentials

at discounted prices

o Laundry facilities for washing overalls

o Financial contributions for funerals and weddings

3.4 Health and Safety Management

CDPLC is a company that is highly concern “Safety First” concept as the risk at there is

very high. So safety equipment for all the employs of the yard has been provided by

CDPLC for improvement of the safety. And it is a must to be equipped with them when

they are inside the yard premises.

Safety over all

Safety helmet

Safety belt and rope

Safety boot




4

CDPLC safety rules and regulations,

It is compulsory to wear overall, safety helmet, safety belt and the safety shoes in

each and every time the workers are going to work.

Should wear appropriate safety gear when welding and fabricating processes.

Should wear ear plugs when working at high noise environments.

The workers are not allowed to do any unauthorized work.

Always wear completely covered foot wear.

Use eye goggles when necessary.

Fire There are 3 factors to initiate a fire. These 3 factors are also known as the fire triangle.

Material

Combustible fuel

Heat

There are four classes, as A, B, C and D of fire. Those are

Fuel (caused for the fire) Extinguisher

Class A Organic solids

Ex. Papers ,woods

Pressurized

Water

Class B Combustible liquid/oils

Ex. Oils, Petroleum

Foams, Water

Class C Combustible Gases

Ex. LP gas,CH4

Carbonated

Water

Class D Electrical based fire Dry Chemical

dust

3.5 Waste Management

To maintain a cleaner environment in the yard there is a standard waste disposal system

in the yard according to 5S method. The buckets that collect the waste are coloured as

the type of waste is allowed for them.

*Brown – metal *Yellow – garbage, paper, cloth, etc

*Black – oil and slug *Blue – electrical shop




1

4.0 Summary and Conclusions

4.1 Summary

I have trained about 12 weeks in Colombo Dockyard PLC and I was able to learn &

study most important things related to both mechanical and marine engineering. I was

able to see most of the things I learnt in the university as theories in the practical

environment. Colombo Dockyard PLC is a very useful place to have a hard working

training period while gathering the technical knowledge not only in one section but also

each and every section regarded to Mechanical engineering field such as

Marine

Manufacturing

Thermodynamics

Electrical

Electronic

Etc.

According to my understanding, to be a good engineer at the industry, we need three

aspects to be developed inside us.

Knowledge

Skills

Attitudes

I could improve all three aspects in a considerable amount during my training period in

CDPLC which are very important when working as an engineer in field.




2

4.2 Conclusion

First of all I would like to present my gratitude to all the personnel who have involved in

providing the opportunity for me to have a valuable industrial training period under

CDPLC. During my training period, I could acquire many practical skills as well as

knowledge. I tried my best to understand the practical applications of the theories I have

learned and practiced theories in real situation, which are very helpful to develop their

future carrier as engineers.

During my training period I had to deal with different people such as foremen,

supervisors, and laborers and etc. Because of that I was able to understand their

problems, attitudes, performance and the system they like to work and the way of

handling them. On the other hand I got the opportunity to deal with the Engineers and

got some idea about the duties and responsibilities of engineers in the industry and got

some advices from engineers about our weaknesses as undergraduates and how to

eliminate those things to become a successful engineer.

The daily diary which was given by NAITA and the evaluating programs of CDPLC

guide me lot to make my training successful. Finally I am really happy to say that, now I

have got enough confidence to face any challenges in my future carrier as a Mechanical

Engineer.

During this training as well as positive aspects we got some negative aspects. Some

laborers, who have very valuable practical knowledge, are sluggishness to teach us

practical methods as we are engineering students. In the other side we face so many

problems due to the overall that we was given is similar to all other trainees who came

from various institutes like Technical colleges. So it is better to inform that fact to the

training manager of CDPLC to solve this problem as a benefit of the future trainees.

And also as our training period is only 3 months they supply a local boot set which is

low in safe and one overall only for each. But we also must engage in same works like

others so we have to face so many healthy and safety problems too.




3

Abbreviations

CDPLC – Colombo Dockyard Peoples Liability Company

Ref. - Reference

References References

http://www.cdl.lk/

http://www.cdl.lk/wp-content/uploads/2014/04/Colombo-Dockyard-Annual-Report-

2014_Final-1.pdf

http: //www.wermac.org/

http://www.thepipefitting.com/

http://www.ebay.com/

http://dougleschan.com/

[PDF] 2012 catalog 1 - American Welding Society

Groover, Mikell P,Fundamentals of modern manufacturing: materials, processes and

systems, 4th edition.





http://constructionmanuals.tpub.com/

http://weldingengineer.com/

http://deltahoist.com/

http://www.sam-thehandyman.com/

http://www.waybuilder,net/

http://www.smithy.com/

http://plus.google.com/

http://fietest.com/

http://www.okcareertech.org/

http://en.wikipedia.org/wiki/valves

http://en.wikipedia.org/



http://dougleschan.com/

http://constructionmanuals.tpub.com/

http://weldingengineer.com/

http://deltahoist.com/

http://www.sam-thehandyman.com/

http://www.waybuilder,net/

http://www.smithy.com/

http://plus.google.com/

http://fietest.com/

http://www.okcareertech.org/

http://en.wikipedia.org/wiki/valves

http://en.wikipedia.org/


4

http://www.hofstragroup.com/

http://www.hroberts-di.com/

http://www.electronics-tutorials.ws/

http://www.e-inst.com/

http://www.marshallinstruments.com/

http://www.cdl.lk/wp-content/uploads/2015/04/Colombo-Dockyard-AnnualReport-

2014_Final-1.pdf



http://www.hofstragroup.com/

http://www.hroberts-di.com/

http://www.electronics-tutorials.ws/

http://www.e-inst.com/

http://www.marshallinstruments.com/

http://www.cdl.lk/wp-content/uploads/2015/04/Colombo-Dockyard-AnnualReport-2014_Final-1.pdf

http://www.cdl.lk/wp-content/uploads/2015/04/Colombo-Dockyard-AnnualReport-2014_Final-1.pdf
