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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
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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
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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.
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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
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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
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• 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
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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.
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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.
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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.