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UNIVERSITY OF MORATUWA

Faculty of Engineering

Non-GPA Module 3992: Industrial Training

TRAINING REPORT

D Samson Industries (Pvt) Ltd, Main Plant

PO Box 46, Samson rajapaksa mawatha, Bataduwa,Galle

From 19.10.2015 to 01.04.2016

SAMPATH E.B.J. - 120571T

Department of Mechanical Engineering

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PREFACE

The report I have prepared concerns the experience and knowledge gained from my

training program at D Samson Industries (Pvt) Ltd, Main plant. During my training period. I

had to be at the company engineering sections and maintenance sections.

This report consists of three chapters.

Them chapter one to give an introduction about D Samson Industries (Pvt) Ltd. The chapter

two to explain my training experience and to explain things I learned. Annex one explain my

project works done during the training period and the chapter three is the conclusion.

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ACKNOWLEDGEMENT

First of all I would like to express my sincere gratitude to Mr.S.W.D.Wijithananda,

Manager – Maintenance Engineering for handling my training placement at D Samson

Industries (Pvt) Ltd and training supervisor who did a great part in our training period.. Then

I would like to thank to NAITA for coordinating our training process properly. Further, I

should thank all the engineers, supervisors, workers, and training students who helped me in

different ways to achieve goals in my training period. Finally, I must again thank all the

people mentioned above, as well as all other people who were connected in making my

training period in D Samson Industries (Pvt) Ltd a successful and a pleasant experience.

Mr. S.W.D. Wijithananda

Chief Engineer/Engineering Manager DSI/SCOM

Mr. N.S.Porawagamage

Production Engineer(Consultant)

Mr. M. Sandaruwan

Engineer (electrical) DSI/SCOM

Mr. Nimal Chandrasiri

Mechanical Superintendent (senior)

Mr. Lesly Amarathunga

Forman

Mr. Jagath Nishantha

Tool Room Assistant

All the Technical staff of Workshop DSI/SCOM Electrical & Mechanical departments

Every person who helped me to success fully finish this training period

E.B.J.Sampath

Department of Mechanical Enginnering

University of Moratuwa

20-04-2016

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TABLE OF CONTENT

CHAPTER ONE

1.1 Introduction to training establishment

1.1.1 History of DSI

1.1.2 Vision

1.1.3 Mission

1.1.4 The Samson group

1.1.5 About D Samson Industries (pvt) Ltd.

1.1.6 Hierarchy of DSI

1.1.7 SWOT analysis(DSI)

1.2 Samson Compounds (pvt) Ltd. (SCOM)

1.2.1 Vision

1.2.2 Mission

1.2.3 Hierarchy of SCOM

1.2.4 SWOT analysis(SCOM)

1.3 Samson compounds – EVA plant

1.3.1 About EVA plant

CHAPTER TWO

2. Training experience

2.1 Technical

2.1.1 Maintenance section

2.1.2 Mechanical section

2.1.3 Automobile section

2.1.4 Electrical section

2.1.5 Tool room

2.1.6 Cutter die section

2.2 Workshop experience

2.2.1 Lathe machine

2.2.2 Bending machine

2.2.3 Shaper machine

2.2.4 Electrical arc welding experience

2.2.5 Oxy fuel welding

2.2.6 Gas welding

2.3 Machineries used in DSI

2.3.1 Bam bury machine

2.3.2 Mill machine

2.3.3 Calendar machine

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2.3.4 Kneader machine

2.3.4.1 Rack and pinion system

2.3.4.2 Pneumatic control system

2.3.4.3 Main drive system

2.3.4.4 Rotor system

2.3.5 Injection moulding machine

2.3.6 Hydraulic press machine

2.3.7 Boiler

2.3.7.1 Boiler capacity

2.3.7.2 Steam distribution

2.3.7.3 Steam traps

2.3.7.3.1 Thermodynamic (disc type) steam trap

2.3.7.3.2 Float ball steam trap

2.3.7.4 Main parts of the boiler

2.3.7.4.1 Stop valve

2.3.7.4.2 Safety valve

2.3.7.4.3 Blow down valve

2.3.7.4.4 Head(man) hole

2.3.7.4.5 Hand(mud) hole

2.3.7.4.6 Burner unit

2.3.7.4.7 Photocell

2.3.7.4.8 Water level control and alarms

2.3.7.5 Boiler safety

2.3.7.6 Backfire safety

2.3.7.7 Boiler maintenance

2.3.8 Generator

2.3.8.1 Conditions for starting and stopping of the generator

2.3.8.2 Generator maintenance

2.3.9 Chilled water plant

2.3.9.1 About chilled water plant

2.3.9.2 Main parts and their functions

2.3.9.3 Maintenance

ANNEX 1(Projects)

1. Robot arm design for horizontal injection moulding machine.

2. Automated rotating table design for laser cutting machine.

CHAPTER THREE

3. Summary and conclusion

3.1 Summary

3.2 conclusion

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1. INTRODUCTION TO THE TRAINING ESTABLISHMENT

1.1.1 History of DSI

DSI is known as the number one footwear company in Sri Lanka. The founder of Mr. D.

Samson Rajapaksa put his immense effort to build up the DSI to such position. Beginning

from 1962 company has obtained number of achievement.

1.1.2 Vision

To be the leading contributor to socio-economic development of Sri Lanka.

1.1.3 Mission

To invest in manufacturing and services, meeting highest international standards to our global

customers in conventional & niche markets.

1.1.4 The Samson Group

• D. Samson Industries Ltd.

• D. Samson & Sons Ltd.

• Samson (exporters) Ltd.

• Samson Trading Company Ltd.

• Samson Rubber Industries (Pvt) Ltd.

• Samson Manufactures Ltd.

• Samson Rubber Products (Pvt) Ltd.

• Samson International Ltd.

• Samson Engineers Ltd.

• Samson Reclaim Rubbers Ltd.

• Samson Apparel Makers (Pvt) Ltd.

• Samson Compounds (Pvt) Ltd.

• Samson Sports wears (Pvt) Ltd.

• Samson Brush Manufactures (Pvt) Ltd.

• Vechenson (Pvt) Ltd.

• D. D. P. Packaging (Pvt) Ltd.

• Kelani Valley Canaries Ltd.

• D. S. R. Exporters (Pvt) Ltd.

Figure 1.1

CHAPTER ONE

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1.1.5 About D. Samson Industries Ltd

D. Samson Industries (pvt) limited which was my second training place, is the first Shoe

Manufacturing Plant in Sri Lanka who has been certified for ISO 9001:2000. It was

established in the year 1962 is a leading manufacturer and exporter of footwear and The

Company produces more than 60,000 pairs of footwear per day and has the workforce of

1,500 employees. As a result of high quality standards that it has been maintaining since its

inception, DSI enjoys a good reputation amongst the clientele.

1.1.6 Hierarchy of DSI

Figure 1.2 Different levels of DSI

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The abbreviations used in Figure 1.2

• G.M - General Manager

• D.G.M - Deputy General Manager

• D.P.M - Data Processing Manager

• A.E - Accounts Executive

• Q.M - Quality Manager

• P.M - Personal Manager

• E.M - Export Manager

• M.E - Mechanical Engineer

• Q.A.E - Quality Assurance Executive

• S.E - Supplies Executive

• ST.E - Stores Executive

• S.K - Store Keeper

• T.C - Technical Clerk

• M.S - Mechanical Superintendent

• ASST.E.E - Assistant Electrical Engineer

• C.S - Civil Superintendent

• A.R.C - Assistant Rubber Chemist

• P.E - Production Executive

• D.E - Distribution Executive

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1.1.7 SWOT analysis (DSI)

Strengths

• DSI is a family group.

• Over 50 years of experience as the pioneer in local footwear manufacturing market.

• Massive workforce of over 2000 employees.

• High recognition and reputation for the brand name.

• 250 showrooms network.

Weaknesses

• Home grown company, hence less exposure.

• Lagging behind in application of standard techniques for maintenance, quality control,

process planning and testing.

• Not dynamic because of the less competition in the market.

• Lacks interest in product development.

Opportunities

• Growing potential market for exporting footwear.

• Technical knowledge and expertise of the universities can be harnessed for betterment

of the company.

• The demand for a diabetes shoe since the diabetes population of Sri Lanka is nearly 4

million.

Threats

• Has not identified a strong local competitor. Therefore there is possibility of an

unexpected arise.

• Modern designs being imitated by the minor scale local footwear producers.

• Importing low priced footwear from countries like China and Thailand.

• High overheads due to increasing tariffs of the national power supply.

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1.2 SAMSON COMPOUNDS (PVT) LTD.

SCOM factory was established in 1996 for supplying high quality rubber compounds. Now

there are about 243 employees in SCOM. Major purpose of the SCOM factory is to provide

high quality rubber and EVA compounds and rubber sheets using natural, synthetic rubber,

chemicals and other materials to sister companies and Other companies. Mixing capacity of

the SCOM is 10 MT Rubber compounds and 3.5 MT of EVA daily. The company has two

separate mixing plants for Natural rubber and EVA with sophisticated equipment’s and one

of the best plants in Sri Lanka.

Today Samson compounds (Pvt.) Ltd. is mixing compounds either by customer provide

recipe or designed by qualified & well-experienced R&D team of SCOM with the help of

well-equipped laboratory, where the chemicals shall provide by customer or by the SCOM.

Samson Compounds Pvt. Ltd has been awarded ISO 9001, 2001 & 2008 because of the high

quality rubber compounds. All of DSI factories use 5S concept in their factories & it helps to

be awarded those certificates to the company.

1.2.1. Vision

To be in the forefront as a recognized custom compounder in Sri Lanka.

1.2.2. Mission

To be the manufacturer of rubber compounds and products for industrial needs while

optimizing returns to stakeholders.

Samson Compounds or SCOM is also located in Bataduwa, Galle. Main product of the

SCOM is compound rubber. SCOM has large range of production as shown below

Heat expanded rubber compound sheets

Heat expanded rubber compound V-Straps

Customized compound rubber products

Rubber compounding for clients

Injection molded PVC soles and V-Straps

Rubber gumboots

SCOM consist of following sections.

Research and Development Section.

Raw material stores

Laboratory

Mixing Section

Sheeting section

Forming section

Injection molding – V- Strap section

Injection molding – sole section

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Sheet yard

Recycling section

Work Shop

Transport section

Administrative office

IT section

Human Resources section

1.2.3. Hierarchy of SCOM

Figure 1.3 Different levels of SCOM

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1.2.4 SWOT analysis (SCOM)

Strengths

• Over 30 years of experience in rubber compounding.

• Colour compounding facility.

• Well experienced technical staff.

• Well-equipped laboratory facilities.

• Huge volume machine capacity.

• Volume purchaser and bulk discount.

Weaknesses

• Lack of marketing strength.

• High inventory holding period.

• High down time production.

• Limited number of finished products.

Opportunities

• Accessibility to export market due to free trade agreements.

• Growing trend for compounding and rubber products in Middle East regions and

European region of the world.

• Massive demand for EVA sheets in local market.

• Growing trend for PVC related products in the local market.

• Technical knowledge and expertise of the universities can be harnessed for betterment

of the company

Threats

• Has not identified a strong local competitor of footwear component manufacturing.

Therefore there is a possibility of unexpected rise.

• Higher dependency on inter companies.

• Low cost footwear components imported from countries like China and Thailand.

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1.3 SAMSON COMPOUNDS – EVA PLANT

1.3.1 About EVA plant

EVA plant is located in about 2km away from the DSI main plant. Eva plant consist of two

main sections EVA forming section and Eva sole section. Both these section’s production is

based on EVA or Ethylene-vinyl acetate. Products of the EVA plant is given below

Eva formed sheets

Sandal soles (Eva formed )

Eva sheet based customized products (kick boards, writing pads etc.)

Eva plant consist of following sections

Administrative office

Mixing section

Sheeting section

Forming section

Sheet yard

Cutting & splitting section

Cold pressing section

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2. TRAINING EXPERIENCES

2.1 TECHNICAL

2.1.1 Maintenance Section

There were two mechanical maintenance workshops, automobile and civil workshop in the

DSI premises. As well as the DSI premises can be divided two sections. Those are

• Footwear Production.

• Rubber Production.

All the mechanical maintenance works of Footwear Production are done by a one

maintenance section and other maintenance work of Rubber Production are done by other

maintenance section, all the civil maintenance works done by this civil maintenance section

and the automobile maintenance works done by this automobile maintenance section. In

addition to that there was few sub sections related to this mechanical maintenance section.

2.1.2 Mechanical Section

There were lot of machines in the DSI premises; those were serviced according to a schedule

for the continued good condition of them. As well as all of mechanical breakdowns are

repaired by this section. In addition to that emergency breakdowns of EVA plant are repaired

by this section.

2.1.3 Automobile Section

All the services of delivery vehicles and all the breakdown repairs of fork lift trucks and other

vehicles were done by this section. As well as lot of automobile services of all those vehicles

in the DSI premises were done by according to a calendar.

2.1.4 Electrical Section

All the electrical parts of the machines are serviced by this section and break down also

repaired by this section. When a machine was repaired according to the service calendar of

the maintenance section, both of electrical and mechanical services were done by both

electrical section and mechanical section together.

2.1.5 Tool Room

This is the place that all the tools were stored in the workshop. All the tools required for the

factory are supplied by this section. Normally there is a procedure to take tool from this

section. There should be entering in the “Tool Book” details about tools such as tool, section,

date & time etc. And also the tools required for the work shop (Maintain Section) are

supplied by this section.

CHAPTER TWO

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2.1.6 Cutter Die Section

The cutters which are used for cutter dies of shoes and slippers were created in the cutter die

section. All the cutters created in this section for shoes and slippers.

2.2 WORKSHOP EXPERIENCE

There are 2 workshops in DSI main plant having,

• 7 Lathe machines.

• 2 Universal drilling machines.

• A shaper machine.

• A hydraulic hacksaw machine.

• A surface grinding machine.

• An engraving machine.

• A bending machine.

Also having a vehicle maintenance section, civil maintenance section to do their maintaining

activities and they starts at 7.00 am and ends at 5.00 pm. Sometimes they have to work in

night shift as required. I had a chance to engage with the jobs carried out these machines and

had a hands on practice on that.

Figure 2.1 Different cutters in cutter die section

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2.2.1. Lathe machine

Work Experience

Making a diameter gauge for the lab Facing, straight turning, Knurling.

Repairing the cracker mill bearing sleeve Facing, Straight turning, Drilling, Boring

Making a piston head using Teflon Facing, Straight turning, Cutting off,

Drilling, Boring

Preparing a bearing bush for rubber mixing

machine from bronze

Facing, Straight turning, Drilling, Boring

Forming nipples from steel Facing, Taper turning, Thread cutting,

Making bronze cutters for mill machine &

calendaring machine

Facing, Drilling, Taper turning

Making aluminum disk for buffing machine Facing , Boring ,Straight turning

2.2.2. Bending Machine.

Bend a steel cutter blade according to a desired pattern.

2.2.3. Shaper machine.

Making a keyway to a motor shaft.

Making a die for extruder machine.

Making a hexagonal nut.

Flattened cutter blades of crusher machine.

2.2.4. Electric arc welding experience

Welded a metal rack for heating chamber to heat rubber sheets.

Joined with making a pneumatically actuated sole cutting machine frame.

Weld a frame for mold changing for injection molding machine(over head

welding)

2.2.5. Oxy fuel welding

Engaged in making a tool for lathe machine. Weld a high carbon steel cutting

tool in to a metal piece using bronze as the filler material by oxy fuel welding.

Welded nipples to the cutters.

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2.2.6. Gas cutting.

Cut a thick metal plate for making hopper guard.

cut a metal plate for making washers for hydraulic press machine.

2.3 MACHINERIES USED IN DSI

2.3.1 BAMBURY MACHINE

The largest machine in the DSI is the bambury machine. There are three machines in the DSI

premises which are used for mixed rubber compound and other chemicals (Normally those

compositions were called as batch.).

The weight of the batch is normally around 80 kg. After that closed the feeding door and

compressed the upper plate that is called as floating weight of chamber by the pneumatic

power. 135 centigrade temperature was developed and that operation was done about 5

minutes. It is control by the thermo couple. The two doors were activated by using hydraulic

power.

There were separate lines to through for pneumatic and hydraulic. After operation of a

banbury, the batch was put in to the two roll mill. There were two rolling mills for each line.

Each mixture was contained about 5 minutes in the each mill. After that those sheets were

again put in to the banbury machine with small chemicals as example sulphur and pigments.

Then same procedure was done as above about 2 minutes.

Then same way collected sheets, after the operation of the rolling mill and batch off machine.

A cooling water line is flowing through inside the both of mills and bambury block for over

cooling the mills and banbury block.

All of three Ban bury mixtures can be damaged lot of times, and those are usually worked

in 24 hours. As well as those are the heaviest machine of the DSI premises.

Figure 2.2 Bam bury machine

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Those are the reasons for that. Then those machine is maintained according to a schedule

for protect the good condition of machines. The entire breaks downs of bambury are done

by correctly, as well as the services of those machines are done by according to a special

schedule.

Pneumatic system is used to open and the feeding door as well as, it is used to hoist and take

down the floating weight to compress the inside component of the bambury block.

There are two pneumatic cylinders in the bambury for two operations which are mention

above. One cylinder creates to open and closed the feeding door. Other one is operated which

rubber particles are keeping compressed inside the chamber. Those two cylinders are worked

by separately. Firstly the rubber particles put in to chamber and give a command using a push

button, can be closed the feeding door. After closed the feeding door, other cylinder which is

set to floating weight is started to work. In addition to that, the used air is not come back to

the system. That air is released to the atmosphere.

Before using compressed air to the cylinder we want to separate the water molecule and

adding. Water trap is used to the separate both water molecule and adding.

Main Parts of the Bambury

1. Pneumatic cylinder

2. Discharge door

3. Dust blower

4. Rollers

5. Dust seals

6. Cool water

7. Bambury Block

8. Feed door

9. Mixing Chamber

Dust blower

Pneumatic cylinder

Dust seals

Cool water

Bam bury block

Rollers

Discharge door

Figure 2.3 Main parts of the bambury

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It is powered by a motor.The motor speed is around 1500 rpm, but rolling mill speed is near

to 150 rpm. Therefore the speed should be reduced. For that reason there is a heavy gear box

system. There are two spherical roller bearings to coupling rolling mill and output of the gear

box. When done some gear box service, those things should be alignment. Otherwise those

are can be damaged.

2.3.2 MILL MACHINE

Mill machines are used for crush the rubber mixture after the bambury machine. The time of

that rubber mixture is crushed from mill machine is depend on the batch. Mill machine is

fixed under the discharge door of the bambury.

A steam line is used to heat those mill rollers. But that temperature is going up some value,

that batch can’t be used. Because that reason, there was a mill cooling system. There are 2

rollers in a mill and they rotate with different speeds like having 1 : 1.035 speed ratio and

rubber batch crush due to the friction because of the speed variation.

2.3.3 CALENDAR MACHINE

Calendar machines are used to make polysheet which is a product of DSI. There a 2 roller, 3

roller ,4 roller calendar machines. It can make uniform thickness on the polysheet using

calendar machines above 3 rollers. All rollers are rotating with same speed.

Figure 2.5 Calendar machine

Figure 2.4 Mill machine

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2.3.4 KNEADER

Kneader is an internal mixture machine used in DSI premises. Kneader is similar to a

bambury machine. The primary difference between the two types of mixers is rotor, throat,

chamber, size and floating weight design. The former also discharges the batch through a

bottom door whereas the kneader tilts to discharge the batch.

Kneaders have 2 tangential non-intermeshing rotors as well as pneumatic operated floating

weights. With the conventional kneader design the temperature in a batch cannot be

sufficiently controlled to achieve 1 pass mixing. With conventional kneaders the batch

temperature after the primary kneading stage is high because of poor temperature transfer

from the mixing contact surfaces to the batch. Therefore the batch has to be either cooled

down or transferred to another kneader for the final kneading stage. This additional step is

cost prohibitive as well as time consuming.

2.3.4.1 Rack & Pinion System

A rack and pinion is a type of linear actuator that comprises a pair of gears which convert

rotational motion into linear motion. A circular gear called "the pinion" engages teeth on a

linear "gear" bar called "the rack"; rotational motion applied to the pinion causes the rack to

move, thereby translating the rotational motion of the pinion into the linear motion of the

rack. A rack and pinion system can be shown as following.

2.3.4.2 Pneumatic Control System

The PLC commands the bid-direction cylinder to drive the ram going to up and down .in case

the mixing is over load; the ram floats up automatically to protect the motor from operation at

over load.

Figure 2.6 Main parts of the kneader

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2.3.4.3 Main Drive System

It is comprised of the main motor the speed reducer and the connecting gear box to drive the

two rotor shaft rotting at different or same speed in opposite direction.

2.3.4.4 Rotor

It is of the bambury type. The rotor shaft has a bore and radial holes that lead to the wing

cavities forming the cooling /heating canal. The wings are built up by welding with carbide

alloy on the top and end faces and then ground plated hard chrome and polished. They are

rotating with different speeds.

2.3.5. INJECTION MOULDING MACHINE

There are 9 injection molding machines for making v – straps for slippers and 3 machines for

making sole for shoes. I had a chance to engage in service them and also had a lecture on

injection molding machines.

Terms used in injection molding machine

Back pressure: - The resistance of the molten plastic material to forward flow. In

molding, back pressure increases the temperature of the molten and contributes to

better mixing of colors and homogeneity of the material.

Plasting time :- Time taken for material softer , more flexible, more moldable by the

addition of plasticizer.

Residence time :- The period of time for plastic resin to dwell in the barrel of a unit of

molding machine during the molding process.

Cycle time :- In the injection molding cycle time consist of

Time for mold close and clamping.

Time for injection – filling.

Cooling time(60% of cycle time)

Figure 2.7 Vertical injection molding

machine(for sole) Figure 2.8 Horizontal injection

molding machine (for v – strap

making)

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Injection pressure: - The pressure on the face of the injection screw or ram when

injection material in to the mold.

There are two categories of pvc which are soft & rigid pvc. For v – strap making they use soft

pvc in injection molding machines.

Conditions for soft pvc

Mould temperature should be 20 – 32 0C (Constant temperature)

Process temperature should be 150 -170 0C (constant temperarure)

Mould cooling temperature 15 -16 0C (doesn’t below this temperature.

Clamping force may be 180 – 200 tones.

Locking force may be 90 tons.

2.3.6. HYDRAULIC PRESS MACHINE

There is lot of number of Hydraulic press machines in the DSI premises. Those machines are

used to produce rubber sheets. This machine is use to boil the rubber sheets by heat getting

from steam. This machine is operated by pressured hydraulic oil.

In weighing and Mixing section sulphur was added in to the batch and was not completed the

vulcanized process. But by using steam hydraulic press machine vulcanize process was

completed and Rubber sheets were embossed.

In this machine hot compression die forging method was used to make designs on the rubber

sheets. The compression process was done moving the huge main piston by means of

hydraulic power. Excepting main hydraulic piston there are two small pistons in the above

press machine.

In this fresh machine one motor is connected to two pumps. One pump is in low pressure

(20bar) and other one is in high pressure. A signal is sent to the solenoids to lift the fresh.

Then the two small hydraulic actuators go up and after some time check valve is opened.

Figure 2.9 Hydraulic press machine

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For that a pressure line is supplied by the sequence valve . At this time a vacuum is created

on the large piston and hydraulic oil is sucked from the large tube which is connected to the

tank. For that process low pressure high capacity pump is used to save the time. When the

pressure is increased until 20bar the hydraulic line of low pressure pump was returned to the

tank. After that all of the three pistons were rose slowly by using the hydraulic pressure line

of the high pressure low capacity pump. After the three pistons are dropped a signal is given

to the solenoid. First the pressure of large piston was released on check valve and slowly

down due to the high weight of the piston and fresh. The relief valve is set for 75bar for the

safety of the circuit.

2.3.7. BOILER

A boiler is a closed vessel in which water or other fluid is heated. The heated or vaporized

fluid exits the boiler for use in various processes or heating applications.

Boiler is a machine which is used to generate the steam in a closed vessel by using energy

source as fuel, electricity or Nuclear energy. The boilers are categorized in to different types

based on tubes which are used inside the boilers as fire tube boilers, water tube boilers and

tubeless boilers. By considering number of times burnt air passing through boiler before

going to the chimney stack boilers are categorized as two pass boilers, three pass boilers etc.

the boilers can be categorized in to different groups by considering boiler capacity. If the

boiler capacity is greater than 5000 kg/hr it’s categorized as first class boiler. If the boiler

capacity is in between 2000 kg/hr and 5000 kg/hr it is categorized as second class boiler. If

the boiler capacity is less than 2000 kg/hr is categorized under third class boiler.

Figure 3.0 Front View of the Boiler

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In this DSI premises used two boilers. They can be categorized like follow.

• Fire tube boiler

• Horizontally mounted

• Dry back type

• First class

• Oil fired

• Three pass & other one four pass

The main function of the boiler is supplied steam for all heating process in the DSI premises.

2.3.7.1. Boiler Capacity

Boiler capacity is the weight of steam produced in a boiler per hour. The two boilers which

used in DSI have capacity of 5000 kg/hr and 6000 kg/hr. The control pressure of the boilers is

9 bars to 10 bars. High burning occurs at 8 bars to 9 bars. Operating furnace oil temperature

and pressure are 1100C and 300 PSI.

2.3.7.2. Steam Distribution

Saturated steam is generated in boilers and distribute through circular pipe system. After

steam is supplied, some amount of steam is condensed inside the pipe system. These

condensed steam come back to the feed water tank through drain pipes. After steam is used

excess steam come back to the feed water tank through the flash water line and condensed

water when machine was used steam, come back to the feed water tank through condensed

water line. However some amount of steam goes out from the closed pipe system through

valves if valves are not work properly. Then the reduced water is supplied from well water

tank through softener tank.

Figure 3.1 Stream Distribution Line

According to figure we can get the idea how to change cross section area and distribution of

pipes. So when we distribute the steam line we have to face problem due to condensate water.

This named as water hammer. The noises and vibration can be occurred due to ware homer

case. For reduce this trouble we used various method. One of the methods is using steam

trap.

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2.3.7. 3. Steam traps

2.3.7.3.1 Thermodynamic(disc type) steam trap

The thermodynamic trap is an extremely robust steam trap with a simple mode of operation.

The trap operates by means of the dynamic effect of flash steam as it passes through the trap,

as depicted in Figure 3.2.The only moving part is the disc above the flat face inside the

control chamber or cap.

On start-up, incoming pressure raises the disc, and cool condensate plus air is immediately

discharged from the inner ring, under the disc, and out through three peripheral outlets

Hot condensate is flowing through the inlet passage into the chamber under the disc drops in

pressure and releases flash steam moving at high velocity. This high velocity creates a low

pressure area under the disc, drawing it towards its seat

At the same time, the flash steam pressure builds up inside the chamber above the disc,

forcing it down against the incoming condensate until it seats on the inner and outer rings. At

this point, the flash steam is trapped in the upper chamber, and the pressure above the disc

equals the pressure being applied to the underside of the disc from the inner ring. However,

the top of the disc is subject to a greater force than the underside, as it has a greater surface

area.

Eventually the trapped pressure in the upper chamber falls as the flash steam condenses. The

disc is raised by the now higher condensate pressure and the cycle repeats.

The rate of operation depends on steam temperature and ambient conditions. Most traps will

stay closed for between 20 and 40 seconds. If the trap opens too frequently, perhaps due to a

cold, wet, and windy location, the rate of opening can be slowed by simply fitting an

insulating cover onto the top of the trap.

Figure 3.2 operation of TD steam trap

26

2.3.7.3.2 Float ball steam trap

Before steam is supplied, the trap is cold and the X-element is contracted, keeping the air

vent valve open. During startup, air is discharged through this valve and cold condensate is

discharged through the orifice. When large amounts of condensate flows in, the float is

completely lifted up and the valve is opened fully. As the X-element is also contracted,

condensate is discharged quickly and simultaneously from the air vent valve and the orifice.

The valve opening, dependent upon the condensate flow rate, discharges condensate

continuously. When steam and condensate flow into the trap after the discharge of initial air

and cold condensate, the X-element expands to close the valve seat, preventing steam loss.

The float is lifted up and hot condensate discharges from the orifice.

When hot air flows into the trap together with steam during normal operation, the

temperature of the X-element drops momentarily, causing it to contract and open the air vent,

allowing the air to discharge.

When condensate flow diminishes, the X-element expands due to the heat of the steam,

closing the air vent valve. The float also lowers to closes the orifice. A water seal is

maintained at all times over the orifice to prevent steam loss.

Figure 3.4 Float ball steam trap

Figure 3.3 operation of float ball steam trap

27

2.3.7.4. The Main Parts of the Boiler

2.3.7.4.1. Stop Valve

This is a devise which steam is distributed to the outside from the boiler. This valve is

starting to open gradually when steam pressure become 50 PSI.

2.3.7.4.2. Safety Valve

This valve has attached to open when steam pressure is exceeding the maximum pressure

which boiler can withstand without damaged. The water removing pipe is used to remove the

water which accumulated in the safety valve to prevent from corrosion. When considered

about safety valve following things are most important.

• Diameter.

• Pressure which has set to be opens the valve.

• Steam capacity which can be emitted.

Capacity of safety valve should be at least maximum capacity which can be created

by boiler. Tension of the spring should be 10% of the ordered changing pressure.

Water removing pipe is used to remove the water which accumulated in the safety

valve. It is essential to prevent from corrosion. If the boiler is not worked during that

period whole boiler should be filed with water and moisture absorbing chemical

(CoCl2 ,CaSO4 ) exhaust pipe should be above the roof of the boiler.

Figure 3.5 Safety Valve

2.3.7.4.3. Blow Down Valve

The total dissolved solid (TDS) level of the water should be in between 2500 – 3500 ppm for

well operation of boiler. If TDS value is greater than 3500 ppm it causes to deposit particles

around the inner side of the boiler, around the outside of the fire tubes and around the water

level indicators. So it causes to reduce the efficiency of boiler and gives wrong readings.

If the TDS level reduces more than 2500ppm the metal which boiler was made cause to

dissolve in the water. After checking TDS level water removed from boiler through this

valve. The blow down period depends on the water treatment procedure.

28

2.3.7.4.4. Head (Man) Hole

This located in the steam drum of the boiler. A man can enter through this hole and can clean

the inside of the boiler.

2.3.7.4.5. Hand (Mud) Hole

Mud and wasting things which are accumulated in the bottom of the boiler can be removed

by opening this Valve.

2.3.7.4.6. Burner Unit

The burner unit is used to carry fire flow of fuel combusted. Boiler burners are the functional

component of boilers that provide the heat input by combustion of a fossil fuel, including

natural gas, with air or oxygen. They are available either as part of the boiler package from

the manufacturer, as stand-alone products for custom installations, or as replacement

products.

2.3.7.4.7. Photo cell

Function of this photo cell is to supply oil after commissioning spark. After heating the fuel

near to the boiler, ignition is given by electrodes. Photo cell detects and give signal to inject

furans oil.

2.3.7.4.8. Water Level Control and Alarms

The water level control and alarms is worked according to the readings of the boiler

electrodes. AS well as water level can be controlled by considering boiler pressure.

A conductivity probe and controller can be used in a boiler or a tank for on /off pump control

and/or alarm duties. It has one electrode for each function, which is cut to the required length

on installation. Each probe electrode acts as a simple switch, indicating a low resistance to

earth if in water, or a high resistance if out of water. For example, with a low alarm, the

controller senses a change of resistance from low to high as the water level falls below the

probe tip.

This change in resistance causes the controller to disengage a relay to operate an alarm bell,

light, or both, and normally will also cut the power to the burner.

Blower

Fuel pump

Pressure gauge

Figure 3.6 Burner unit

29

2.3.7.5. Boiler Safety

If a boiler is exploded, it can cause very large damage like a-bomb. A steam boiler could turn

out be a powerful bomb and explode, if it is not maintained, repaired by competent persons

and also it should be operated by experienced and competent persons holding steam boiler

operators certificates. Therefore following causes for a boiler explosion should be considered

seriously.

• Low water in boiler.

• Scale deposits too high.

• Crack

• Corroded or thinned out, tube plate shell, boiler tubes etc…

• Improper repairs

• Presence of oil in the boiler water.

Therefore boiler safety is most important for all of are in DSI premises and neighbours. To

increase the boiler safeties following methods are introduced.

• Safety valve.

• Back fire safety.

• Alarm safety to indicate low level of water

2.3.7.6. Back Fire Safety

This is most important device in the boiler which is used as safety in the boiler.

By starting the burner before working of Forced Draft Fan enough time, accumulated

oil can be burnt and it cannot be exhausted by chimney. In such time back fire

can be happened and various dangerous case can be happened. So this safety hole

has located to exhaust directly to the chimney.

2.3.7.7.Boiler maintenance

• General Maintenance

• Boiler has electrical and mechanical devices that make it automatic or semi-automatic

in operation, these devices require systematic and periodic maintenance.

• Should have well maintained boiler room.

Lower level

Upper level

30

• Only trained and authorized personnel should be permitted to operate, adjust, or repair

the boiler and its related equipment.

• Alertness in recognizing unusual noises, improper gauge readings, leaks, signs of

overheating.

• Do not attempt to make repairs while the boiler is under pressure.

• Shift Maintenance

• Check the boiler water level in the gauge glass and the boiler steam pressure on the

gauge.

• Operate the intermittent blow down valve to remove any accumulated solids in the

mud drum.

• The valves on the water column and gauge glass should be operated to make sure

these connections are clear.

• Monitor water chemistry to adjust the chemical feed treatment and continuous blow

down as required.

• Daily Maintenance

• check of the burner operation, including fuel pressure, atomizing air or steam

pressure, visual appearance, etc.

• Clean the observation ports during periods of low fire or shutdown.

• Test the boiler level alarms and low water cutoff.

• Monthly Maintenance

• Check the condition of the refractory for significant damage or cracking.

• Test the boiler safety valves

• Annual Maintenance

• Have the unit inspected and checked by a service representative from the

manufacturer.

• Clean both the heating and heated sides of the boiler.

• Open all bottom blow down and drain valves. Hose the inside of the boiler with clean

water under high pressure.

• Use a hand scraper to remove accumulated sludge and scale.

2.3.8 GENERATOR

I engaged with the new CATEPILLAR C32 generator installation and its sound proofing.

Also had a good knowledge of its maintenance process.

Figure 3.7 Generator

31

Engine Description

Four cycle

Direct fuel injection

Mechanical Electronic Unit Injector(MEUI)

Turbocharged

Air To Air After Cooler(ATAAC)

Engine specifications

Cylinder and arrangement – 12 cylinders vee block

Bore – 145 mm

Stroke – 162 mm

Compression ratio – 15 : 1

Displacement - 32L

Firing order 1-10-9-6-5-12-11-4-3-8-7-2

Rotation(flywheel) - Counterclockwise

2.3.8.1 Conditions for starting and stopping of the generator.

Starting

Make all preliminary engine starting checks.

Be sure that the main circuit breaker or the line circuit breaker is open.

Start the engine. Allow the engine to warm up.

Adjust to the full load engine speed.

Close the main circuit breaker.

Apply the load. Do not try to apply the full load. Apply the load in increments

in order to maintain system frequency at a constant level.

Readjust the governor for rated frequency.

Stopping

Remove the load in increments.

Open the circuit breaker.

Allow the engine to run for five minutes in order to cool.

Stop the engine.

2.3.8.2 Generator maintenance

Daily Maintenance

Run through a general inspection for any corrosion, dust, dirt or grease stains on the

components.

Ensure the coolant heater is precisely on its place every time before you switch on the

diesel generator.

Check for the oil and fuel level and add the necessary quantity as per its needs.

32

Make sure that the charge-air pipe is connected correctly to the radiator without any

loose connections.

Weekly Maintenance plan

Check the air cleaner components and clear them if any dirt in it.

Adjust the voltage levels of the float voltage on the battery charger.

Drain the water levels from the container at the bottom of fuel filter housing and fuel

tank.

Monthly Maintenance Plan

Check the sample of coolant with a hydrometer.

Check the belt for tension and inspect if it needs any replacement.

Check for the exhaust condensate drain if it has any debris or dust.

Examine the charge levels of the battery and check for any loose connections.

• Semi Annual Maintenance Plan

It is ideal to replace the oil, oil-filter and coolant filters after 6 months of usage, even

if the diesel generator is not used extensively.

The crankcase breather should be cleaned according to the instructions given in

manual.

Regardless of the debris accumulation, the air cleaner element should be cleaned.

The radiator hoses must be replaced if they are damaged or affected partly.

Fuel filter should be replaced since the dust accumulated would have damaged it

internally.

2.3.9. CHILLED WATER PLANT

2.3.9.1 About chilled water plant

Systems that employ water chillers are commonly called chilled – water systems. As its name

suggest, this system makes use of water as its secondary refrigerant. Chiller is used to

remove heat from the water which is then circulated through other components to absorb heat

from the space.

Chilled water air conditioning systems are commonly used in applications that need large

cooling capacity such as hypermarket, industrial process , commercial air conditioning such

as offices and factories. More homes are using this system to air conditioned their entire

house because of its cost – effectiveness and no hazard of having refrigerant piped all over

the house. I must thank to Assistant Engineer Mr. M.S.Gunawardane for helping me to study

about chilled water plants. They are consisting of cooling towers, condenser, compressor,

expansion valve and the evaporator.

33

Figure 3.8 Cooling towers in DSI premises

Control panel

Evaporator

Condenser

Compressor

34

2.3.9.2 Parts and their functions of chilled water system

Evaporator

The evaporator works the opposite of the condenser, here refrigerant liquid is

converted to gas , absorbing heat from the air in the compartment.

Compressor

The compressor compacts the refrigerant vapor and pumps it to the reversing valve.

Condenser

A equipment that converts a gas to a liquid to obtain either the substance or the

released heat.

Air cooled condenser – Condenser in which refrigerant flows through the

tubes and rejects heat to air that is drawn across the tubes.

Water cooled condenser – Condenser that rejects the heat of the refrigerant to

water flowing through it.

Cooling towers

Cooling tower is the heat rejection device used to transfer process waste heat to the

atmosphere.

Expansion valve

A valve through which liquid or gas under pressure is allowed to expand to a lower

pressure and greater volume.

2.3.9.3 Maintenance of the Chill water plant

Monthly

Check for the debris in the condenser coil inlets for air cooled systems.

Visually inspect for water leaks and proper tank level.

Inspect oil or water leaks

Figure 3.9 Chilled water plant DSI

35

Check electrical connections

Listen for excessive vibrations or motor noise.

Check compressor oil levels.

Check fan and pump rotation in correct direction.

Yearly

Tighten all electrical connection screws.

Check operating pressures of the refrigeration system.

Washout the condenser coils af an air cooled system.

Ensure that the pipe insulation is dry and not broken.

Check mechanical mounts and vibration and wear.

36

Annex 1

1. ROBOT ARM FOR HORIZONTAL INJECTION MOULDING MACHINE

ABSTRACT

There are two types of PVC used in the injection molding machines to produce a wide range

of products. Among those products for the manufacturing of v-straps of rubber slippers soft

PVC is used. Since the v-straps are flexible and not stiff an auto ejection system of the v-

straps after the mould opens is a difficult task. Therefore the operator has to deliberately put

his arm across the mould and first remove the set of nobs of the v-straps stuck in the mould

cavity and then pull out by his hand. Normally more than 45 v-straps are produced per hour

and therefore in a shift of 12 hours the operator has to release nobs and pull the v-straps by

hand 45×12 times. This is a very labour consuming and time consuming process. The

designed machine gives the solution to the so called problem and the report contains all the

data and specifications related to the design.

ACKNOWLEDGEMENT

We would like to express our gratitude to Mr. N. S. Porawagamage, Consultant Engineer,

who gave us an immense support and guidance throughout the project with his valuable and

constructive suggestions during the different phases of this design project.

And we would also like to thank Mrs. N. Jayawardene, the head of the IT department for

providing us the facilities to carry out our project work.

Finally we would like to pay our gratitude to all the machine operators, monitors and all other

resource persons who helped us for this project putting forward their valuable views and

suggestions.

PROBLEM DESCRIPTION

The v-strap manufacturing processing from injection moulding machines cannot use auto

ejection of the finished v-strap unlike in other products which are manufactured from

injection moulding. The main reason for the above problem is the lack of stiffness in the v-

strap product. The nobs of the v-straps gets stuck in the mould core and the operator

manually have to open the door, put his hand between the opened mould halves, remove the

nobs and pull the v-strap set out of the mould cavity. Therefore the manual v-strap removing

process is a very time consuming process and it depends on the operator. Also the operator

37

manually have to remove around 45 v-straps per hour which is a very labour consuming task

considering his 12 hour work shift and therefore more than one operator is needed for a

machine per shift.

JUSTIFICATION

The prosed robot arm can remove the v-straps from the mould and put it into a bin outside the

machine in less than a minute. Therefore it improves the rate of production of the current

process. Since the v-straps are removed by the robot arm the operator’s work is minimized

and therefore the only work assigned to the operator would be to separate right and left halves

of the v-straps. Therefore only one operator will be enough for one shift. Since the door is

opened and hand is not put between the open mould the safety of the process will also be

enhanced.

USER NEEDS

Increase the number of v-straps produced per shift.

Reduce the number of labours involved in the process.

Enhance the safety of the machine operator.

ENGINEER’S PERSPECTIVE

Can be used for auto eject mould of sizes small, medium, large and extra-large.

Capable of removing a PVC v-strap from the mould core within 8 seconds.

Production rate of 60 PVC v-straps per hour.

Vertical movement

Gripper arm 0-800 mm

Ejector arm 0-800 mm

Horizontal movement

Gripper arm 0-560 mm

Ejector arm 0-230 mm

38

DETAILED DESIGN

Figure 1: SolidWorks model

The main operations performed by the proposed robot arm can be listed as follows.

Ejector arm and gripper arm coming into positions as soon as the mould starts to

open.

Both arms getting into correct vertical positions by using the pneumatic cylinders

after the mould is fully opened.

Ejector arm releasing the nobs while the gripper arm grabs the runner of v-straps.

Both arms pulling up and the mould closing.

Gripper arm taking the v-strap set over the closed door and release it to the bin and

return to the original position.

In main components of the robot arm can be listed as,

Two stepper motors used to drive the arms horizontally along the screws.

Two pneumatic cylinders which facilitate the quick vertical movement of the arms.

Two servo motors which actuate the gripper and the ejector.

Proximity sensors, limit switches and current sensors.

39

Figure 2: Robot arm design

MAIN ASSEMBLIES

Ejector arm Ejector

Pneumatic cylinder

Guide block

Screw Ejector plates

40

Gripper arm

Figure 4: Gripper assembly

There is a limit switch in the clamping unit of the machine which give a signal when the

mould starts to open. That signal will be used by the stepper motors are will start to move the

arms horizontally by rotating the screws. When the two arms will come into correct

horizontal positions the two proximity sensors in those places will signal the motor to stop

immediately. When the mould is fully open that signal will be obtained from another limit

switch of the clamping unit and that signal will actuate the pneumatic cylinders.

After the pneumatic cylinder is fully actuated it will be detected by another two sensors

which will signal the stepper motors to start. Then the arms will move towards the mould

core so that ejector plates will touch the nobs and gripper will have the runner in between the

gripper arms. When this happens the current sensor detects they are in place and gives the

signal for the stepper motors to stop and also the signal for the two servo motors to actuate so

that the ejector plates will widen quickly removing the nobs and the gripper arms will close

grabbing the runner. Then both the arms will come up with the gripper grabbing the v-strap

set with it. After they come up the proximity sensor will detect it and the mould will close

immediately moving on to the next cycle.

Gripper

Stepper motor

Guiding rods

41

While the mould is closed the stepper motor of the gripper arm will start turning in the

reverse direction so that the gripper arm will move horizontally towards the door. Once the

gripper arm is outside the door the proximity sensor there will signal the stepper motor to

stop and the servo motor in the gripper to actuate releasing the v-strap to the bin. Then the

stepper motor will again start and the arm will move towards its original position horizontally

and once it gets there from the signal obtained from the proximity sensor the motor will stop

and it will stop at position. When the mould opens again the same procedure will continue

again.

42

2. AUTOMATED ROTATING TABLE DESIGN FOR LASER CUTTING MACHING

ABSTRACT

There is a laser cutting machine use for making designs on EVA soles. In current situation

they make 3 types of designs and they take different times on each design.

Design 1 – 6 seconds

Design 2 – 12 seconds

Design 3 – 80 seconds

ACKNOWLEDGEMENT

We would like to express our gratitude to Mr. S.W.D Wijithananda, Manager – Maintenance

Engineering and Assistant Enginner Mr. S.Gunawardane who gave us the project and

guidance for the project.

And we would also like to thank Mrs. N. Jayawardene, the head of the IT department for

providing us the facilities to carry out our project work.

Finally we would like to pay our gratitude to all the machine operators and other resource

persons who helped us for this project putting forward their valuable views and suggestions.

PROBLEM DESCRIPTION

The efficiency of the machine depends on the operator and therefore has caused less

efficiency. The operator has to move between different work stations to perform each

task. The safety of the machine is low since the operator’s hands can be exposed to laser

radiation.

JUSTIFICATION

The proposed design can eliminate the safety hazards towards the operator. It can

increase the efficiency of the machine since the efficiency of the machine will be

independent of the operator and also the operator will be able to perform his tasks easily.

43

USER NEEDS

Increase the number of slippers produced per hour.

Increase the safety of machine operator.

Enhance the quality of the working environment of the machine operator.

ENGINEER’S PERSPECTIVE

Enables a vertical clearance of the table 8 cm.

Production rate of,

100 per hour

50 per hour

25 per hour

DETAILED DESIGN

Figure 1 : Solid works model

44

The main operations performed by the proposed table can be listed as follows.

First draw the outer lines of the design in four stations.

Then place the soles. After starting the process the process will carry on

automatically. But operator have to install soles.

In main components of the robot arm can be listed as,

Two stepper motors used to rotate the table

Roller ball bearings

Timers

MAIN ASSEMBLIES

Roller ball bearing

Rack & pinion

Stepper motor

Figure 2

Figure 3

45

Figure 5 : Lifting mechanism

Figure 4

46

3. ADJUSTABLE ARM DESIGN FOR BOOT MAKING

PROBLEM DESCRIPTION

The existing arms are fixed to the table and the workers have to remove the rubber boot

last from one arm and put it into the next arm in order to continue the manufacturing

process which is a very labor consuming task. Since the existing arm is horizontally fixed

the last is also in a horizontal position once it is inserted into the arm and therefore it is

difficult for the labors to carry out certain operations on the boot. The labors have to force

the rubber boot last from their body to avoid rotation while carrying out the operations.

JUSTIFICATION

The proposed design will consist of arms which can move along a rail so that labours can

finish the operations in their work station and pass it onto the other station without removing

the boot last from the arm. It will also allow the boot last to rotate in two vertical planes

perpendicular to each other and also to lock in any position when needed.

SOLID WORKS MODEL

MAIN ASSEMBLY

Figure 1

Figure 2

47

LOCKING MECHANISM

Figure 3

48

3. SUMMARY AND CONCLUSIONS

3.1 Summary

This report is prepared for the completion 24 weeks of the industrial training period (from

19/10/2015 to 01/04/2016) maintenance workshop of D Samaon Industries (pvt) Ltd of

Bataduwa.

During the training period we were able to get a good knowledge about Manufacturing field,

maintenance filed, Automobile filed and management field as a under graduate of

Mechanical Engineer of university of Moratuwa. In addition to that I got most experience

from the workshop. We were able to remove the gear box, engines, brake systems, hydraulic

systems, etc. As well as we were able to do Bambury services, Boiler services, Lathe

operations, Steam line services, etc. Because that I had to get lot of experiences about the

above mentioned fields.

In addition to that, when we do some work with mechanics of the workshop and other labors,

we have to face so many problems, in that period I got a good experience about how to face

with those problems. As well as I got a good experience about how to manage our time to

create a good efficiency and good project. I have briefly discussed in the report, the important

information I gathered during the training of this workshop.

CHAPTER THREE

49

3.2 Conclusion

Industrial training program is a very useful opportunity of engineering under graduate to get

an experience about his/her future carrier. This is the occasion that we practically come

across what we were taught in the university.

During the training I got that theory is not always practicable. We have to change according

to the workshop situation. To solve problems only theoretical knowledge is not sufficient, but

also we need practical knowledge and experience. Also to be a great engineer we have to

good knowledge about workshop conditions as well as theoretical knowledge.

It is very important to be a trainee before we play an engineer’s role straight away. As a

trainee we are given a chance to make errors. Also everyone in the workshop guides us and

helps us. This is very useful to practice engineer’s roles.

Mechanical engineering is always directly combined with people. So it is very important to

gain communication skills because we meet various people in the workshop. In the training

period I got the chance how to communicate with people. Good communication with

mechanics helped to motivate them and get optimum performance. Communicate with

consultants affects the projects we did in the workshop.

So overall in training period I got a good knowledge in that training period. This helped me a

lot of in my training life prior to be an engineer.

D Samson Industries is the largest footwear company in our country. I’m glad to be a trainee

in D Samson Industries at Bataduwa. They consider us as engineers not trainees. But always

the officers and Engineers in the workshop guide us and helped us to do our job well.