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A SCIENTIFIC APPROACH TO REDUCE 4M WASTAGE
A project report submitted by
S.M.K.G.R.D.Bandara
(S/07/226)
In partial fulfillment of the requirement
for the award of the degree of
B.Sc. (Applied Sciences)
Of the
FACULTY OF SCIENCE
UNIVERSITY OF PERADENIYA
SRI LANKA
2012
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DECLARATION
I do hereby declare that the work reported in this report was exclusively carried out by me
under supervision of Mrs. Dilani Dilrukshi.
It describes the results of my own work conducted at Loadstar (pvt) Ltd.
Name of candidate: S.K.G.R.D. Bandara.
Signature of the candidate:
Certified by:
1. Supervisor (External)Name: Mrs. Dilani Dilrukshi.
Signature:
2. Supervisor (Internal)Name: Prof. W.B. Daundasekara.
Signature:
3. Coordinator:Name: Prof. Namal Priyantha.
Signature:..
ii
Date:
Date:
Date:
Date:
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A scientific approach to reduce 4M wastage at Loadstar (pvt) ltd.
S.K.G.R.D.Bandara
Faculty of Science
University of Peradeniya
Sri Lanka.
ABSTRACT
There are factors which determine the profit of an industry. In modern industrial
world they are called as 4M factors. They are man, machine, materials and money.
Higher the wastage of the 4M factors lower the profit of the production. Thus, there
should be methods to reduce those wastages through technological improvements andguidance of labourers to increase the profit of an industry. In this project, more
attention is paid to reduce the wastage due to technological failures. Specially the tire
rolling method described here was demonstrated and further checked for the
sustainability in the factory and will be implemented to boost up the production
process.
Key words: curing, volcanizing, deviser, rolling, compound bank
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ACKNOWLEDGEMENT
I would like to acknowledge and extend my heartfelt gratitude to the following
persons who have supported me for completing this project successfully.
I thank Prof. Namal Priyantha, the coordinator of applied science program and my
Internal Supervisor, Prof. W.B. Daundasekara, Senior Lecture Department of
Mathematics and also to the staff of the applied science program for the guidance given
to me throughout the program.
I convey my sincere gratitude to my external supervisor, Mrs. Dilani Dilrukshi , the
quality assurance manager of Loadstar (pvt) ltd, for accepting me as a trainee and also to Mr.Rupasinghe, engineering manager of the plant, for encouraging me during my training
period towards a successful invention.
Also, I would like to thank all my applied science batch mates and all my friends at
faculty of engineering university of peradeniya and all Company members who
helped me throughout my project work.
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TABLE OF CONTENT
List of Figures... ..................................................................................................................... ..v i
CHAPTER 01: Introduction
1.1 Introduction to Loadstar (pvt) ltd .... ...11.2 Introduction to solid tire production process ........ 11.3 Introduction to 4M ..... ..................... . 61.4 Introduction to the objective of the project........ 8
CHAPTER 02: SOLUTIONS FOR THE IMPROPER WATER COOLING SYSTEM
MAINTENANCE.
2.1 Introduction........... 92.2 Current methods of controlling water quality............ 102.3 Solutions for the current drawbacks ......... 12
CHAPTER 03: POOR TIRE ROLLING METHODS AND SOLUTIONS TO BOOST UP
THE PRODUCTION PROCESS
3.1 Introduction to current tire rolling method ... ......... .. 163.2 Effects of unnecessary rolling processes .. 173.3 Factors for the drawbacks of current rolling process ........ 173.4 Suggested automated method of rolling ... ........ ...18
3.4.1.
The concept of measuring weight using a parameter
... ........ .193.4.2. Method of measuring radius ... 203.4.3. Construction of the sensor... . 22
3.4.3.1. 38 kHz infrared transmitter..... 22
3.4.3.2. 38 kHz infrared receiver..... 23
3.4.3.3. Switching circuit ... ... 24
CHAPTER 04: EFFECTS OF IMPROPER USE OF PPE AND SOLUTIONS
4.1 What is a PPE?.... 264.2 Hazards faced by labourer and how to overcome....26
CHAPTER 06: References..... . 28
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LIST OF FIGURES
Figure 1.1 : Rubber rolling machine
Figure 1.2 : Rubber sheet is being rolled and well mixed in-between two rollers
Figure 1.3 : Rubber rolling process done by a labourer
Figure 1.4 : The flow diagram of the production process
Figure 1.5 : Chart showing how waste generating sources contribute to wastage
Figure 2.1 : The figure of the function of the water cooling system.
Figure 2.2 : The induced draft counter flow cooling tower used in the system
Figure 2.3 : Centrifugal sand filter
Figure 2.4 : Diagram showing the process of air filtration
Figure 3.1 : The process of rolling
Figure 3.2 : Block diagram showing the action of the automated system
Figure 3.3 : Dimensions of the tire
Figure 3.4 : During the rolling process (the required radius not achieved)
Figure 3.5 : The point which the rolling process is over
Figure 3.6 : The 38 kHz generator
Figure 3.7 : The infrared receiver module
Figure 3.8 : The block diagram showing the internal functioning of the receiver
Figure 3.9 : Diagram of the switching circuit in its simplest form
Figure 3.10: Suggested arrangement of the infrared sensor
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CHAPTER 01
INTRODUCTION
1.1 Introduction to Loadstar (pvt) ltd
Loadstar is a joint venture between the Jinasena Group and the Solideal group of
Belgium. Loadstar manufactures solid and pneumatic tires, wheels and tracks under
the Solideal brand and has been awarded the Most Outstanding Exporter of Sri Lanka
award by the National Chamber of Exporters of Sri Lanka (NCE) in 2007 and won
the National Cleaner Production award in 2008, 2009 (NCC) Silver. Loadstar
employs over 5,000 people across six plants.
Loadstar is an ISO 9000 certified company since 1996, and is one of the first tirecompanies in Sri Lanka to be certified. Loadstar is committed to its customer by
consistently delivering high quality products at competitive prices. Presently the
company consumes a significant percentage of the natural rubber production of Sri
Lanka. Loadstar has continued to grow rapidly over the last 25 years and is
continuing its journey with implementation of lean system and processes.
1.2 Introduction to solid tire production process
1.2.1 Materials
Natural rubber, or polyisoprene is the basic elastomer used in tire making.
Styrene-butadiene co-polymer (SBR) is a synthetic rubber which is often
substituted in part for natural rubber based on the comparative raw materials
cost.
Polybutadiene is used in combination with other rubbers because of its low
heat-buildup properties.
Halo butyl rubber is used for the tubeless inner liner compounds, because of
its low air permeability. The halogen atoms provide a bond with the carcass
compounds which are mainly natural rubber. Bromobutyl is superior tochlorobutyl, but is more expensive.Carbon Black, forms a high percentage of the rubber compound. This givesreinforcement and abrasion resistance.
Silica, used together with carbon black in high performance tires, as a low
heat buildup reinforcement.Sulphurcrosslinks the rubber molecules in the vulcanizationprocess
Vulcanizing Accelerators are complex organic compounds that speed up thevulcanization.
Activators assist the vulcanization. The main one is zinc oxide.
Antioxidants and antiozonantsprevent sidewall cracking due to the action of
sunlight and ozone.Textile fabric reinforces the carcass of the tire
1
http://en.wikipedia.org/wiki/Rubberhttp://en.wikipedia.org/wiki/Styrene-butadienehttp://en.wikipedia.org/wiki/Polybutadienehttp://en.wikipedia.org/wiki/Halogenhttp://en.wikipedia.org/wiki/Carbon_Blackhttp://en.wikipedia.org/wiki/Silicahttp://en.wikipedia.org/wiki/Sulphurhttp://en.wikipedia.org/wiki/Vulcanizationhttp://en.wikipedia.org/wiki/Vulcanizing_Acceleratorshttp://en.wikipedia.org/wiki/Activatorshttp://en.wikipedia.org/wiki/Zinc_oxidehttp://en.wikipedia.org/wiki/Antioxidanthttp://en.wikipedia.org/wiki/Antiozonanthttp://en.wikipedia.org/wiki/Textilehttp://en.wikipedia.org/wiki/Textilehttp://en.wikipedia.org/wiki/Antiozonanthttp://en.wikipedia.org/wiki/Antioxidanthttp://en.wikipedia.org/wiki/Zinc_oxidehttp://en.wikipedia.org/wiki/Activatorshttp://en.wikipedia.org/wiki/Vulcanizing_Acceleratorshttp://en.wikipedia.org/wiki/Vulcanizationhttp://en.wikipedia.org/wiki/Sulphurhttp://en.wikipedia.org/wiki/Silicahttp://en.wikipedia.org/wiki/Carbon_Blackhttp://en.wikipedia.org/wiki/Halogenhttp://en.wikipedia.org/wiki/Polybutadienehttp://en.wikipedia.org/wiki/Styrene-butadienehttp://en.wikipedia.org/wiki/Rubber -
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1.2.2. Manufacturing process
Tire plants are traditionally divided into five departments that perform special
operations. These departments act independently within the factory. Large tire
makers may set up independent factories on a single site, or cluster the factories locally
across a region.
Compounding
Ingredients of rubber compounds
1. SB Rubber 100 kg.2. Carbon 220 150 kg.3. Zinc oxide 20.5 kg.4. Static acid 13.5 kg.5. Accelerator 11.2 kg.6. Oil 33.5 kg.
Compounding is the operation of bringing together all the ingredients required to mix a
batch of rubber compound. Each component has a different mix of ingredients
according to the properties required for that component.
Mixing
Mixing is the process of applying mechanical work to the ingredients in order to blend
them into a homogeneous substance. Internal mixers are often equipped with two
counter-rotating rotors in a large housing that shear the rubber charge along with theadditives. The mixing is done in three or four stages to incorporate the ingredients
in the desired order. The shearing action generates considerable heat, so both rotors and
housing are water-cooled to maintain a temperature low enough to assure that
vulcanization does not begin.
Milling
Mill consists of twin counter-rotating rolls, one serrated, that provides additionalmechanical working to the rubber and produces a thick rubber sheet. The sheet is pulled
off the rollers in the form of a strip. Then this strip sheet is being rolled over a steel band
until the required weight is achieved.
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Figure 1.1. Rubber rolling machine
Figure 1.2. Rubber sheet is being rolled and well mixed in-between two rollers
Figure 1.3. Rubber rolling process done by a labourer
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Volcanizing (curing) process
After the rolling process is done, the tire is being sent to the mould to curing process. For
the sustainability of the tire the volcanizing or curing process is done in specific
temperature range.
Final inspection
After the curing process is over, the tire is being inspected for defects and tires which are
confirmed to the standard are sent to the market.
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Figure 1.4. The flow diagram of the production process
1. MIXING MILL
1st STAGE COMPOUND MIXING,WARMING AND PALLETIZING
(50-
2nd stage compound
2. ROLLING MILL2nd stage compound
warming (60-
Warmed 2nd stage
compound
3. ROLLING MILL2nd stage compound rolling
(105-
4. PRESS MOULD
Curing
(145-
Tire ready for the market
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1.3 Introduction to 4M
4M are the major factors which determine the total production of an industry and the
total profit of an industry.
1. Man2. Machine3. Materials4. Money
Following are waste generating sources which contribute to above factors that lead to
increase of waste and reduce profit.
1. Poor tire rolling methods.2. Improper cooling tower maintenance.3. Top management has a lack of comprehension about the current situation of
production process.
4. Lack of communication between top management and team members.5. Improper use of ppe.
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Figure 1.5. Chart showing how waste generating sources contribute to wastage
Poor tire Improper Improper Improper
rolling cooling use of PPE lightningmethods tower systems
maintenance
MAN MACHINE MATERIAL MONEY
Top management has a lack Lack of communicationof comprehension about the between the top
current situation of management and team
production process members (labourers)
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1.4 Introduction to the objective of the project.
The objective of the project was to understand the current situation of the ongoing
production process and understanding waste generating sources associated with it.
After that a qualitative analysis was carried out to gain a better knowledge about the
problems associated and the best method which can be implemented is being
suggested depending on the sustainability and the profitability of the suggested
system.
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CHAPTER 02
SOLUTIONS FOR THE IMPROPER WATER COOLING SYSTEM
MAINTENANCE.
2.1 Introduction
Water Cooling towers and heat exchangers are used in the cooling process of
machines in many industries and in the air conditioning of buildings etc. They are
designed and made in several types and numerous sizes, water and atmospheric air
being the common media of heat exchange in all of them. It is essential to maintain
the water quality, which is highly affected by the atmospheric air, for the efficient
operation of the cooling towers, heat exchangers, and other downstream equipment.
The tire production process is highly dependent on the temperature since the
processes are incorporated with heating. The heating should be done on necessity to
make the tire last longer under higher usage in field. If the temperature is not
controlled between the necessary range defects will occur. Most of the time the
temperature generated in the production process is kept between the given range by a
water cooling system. If the water cooling line is not working properly, the
temperatures will raise above the range or below the range the effects badly onproduction process making defects in tires and other bad effects on production
process.
Figure 2.1. The figure of the function of the water cooling system.
COOLLNG TOWER
SOLENOID VALVE
WARMING AND ROLLING MILL
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Figure 2.2. The induced draft counter flow cooling tower used in the system
2.2 Current methods of controlling water quality
Blow down
Blow down is a method used for controlling TDS concentration where a portion of the
circulating water flow is wasted and replenished with clean make-up water. Watercontinuously evaporates from cooling towers in a pure vapor state; it leaves behind its
burden of total dissolved solids (TDS) to concentrate in the circulating mass of water.Without regular blow down, the TDS level in the circulating water increases
tremendously, jeopardizing not only the cooling tower, but also the heat exchanger andall other water circuit related components as well.
Chemical treatment
Chemical treatment of water, in addition to blow down and filtration, is required to
prevent scale formation, corrosion, or biological growth. For the proper chemicaltreatment, the services of a reliable company supplying such chemicals should beobtained.
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Scale prevention
The major scale forming dissolved contaminant in cooling water is calcium
carbonate, which is formed by the decomposition of calcium bicarbonate. The
amount of calcium bicarbonate held in solution depends upon the temperature and the
free carbon dioxide content of the water. Increasing the temperature or reducing the freecarbon dioxide at the point of equilibrium, will result in the deposition ofscale. Advice
of a treatment company is required to select the chemical compounds to keep
scale-forming solids in solution.
Control of suspended impurities
Various contaminants brought into the system from the air or from incoming water
source are best removed by continuous filtration. Oils and fats are removed from the
circulating water by means of a skimmer. In case of abnormally dusty areas where
sedimentation tanks are used as part of the filtration system, the oils and other
particulates whose tendency is to float could be skimmed off by means of anoverflow weir.
Drawbacks of current cooling water maintenance system
It can be observed that sometimes the temperature controlling system is not capable of
keeping the temperature between the range due to below mentioned factors.
1. The temperature of cooled water is above the ambient temperature which in turn
reduces the heat absorption capacity of cooling water.
2. The TDS of cooling water was very high which causes precipitation of thermalinsulating layers in heat exchangers preventing the heat exchange.
3. As a result of precipitation of dust particles in solenoid valves, blocked solenoid
valves cause the cooling water flow out of control.
4. Precipitation of dust particles on fill of the cooling tower reduces the surface area of
the fill which reduces the efficiency of the cooling tower.
The main factor to above mentioned failures are higher TDS value of the cooling water.Average values of TDS of cooling water using a TDS meter (not calibrated) was
measured and recorded as below.
Cooling water 650 PPM
Bathing water 140 PPM
Drinking water 20 PPM
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2.3 Solutions for the current drawbacks
Comparing with each value of TDS, it can be observed that that TDS of cooling
water is very high. To reduce the TDS value many alternative methods can be
applied.
1. Since the area of the factory was limited CENTIFUGAL FORCEFILTERATION is the best method of reducing TDS.
2. Industries which have higher air dust levels should filtrate air which fed intocooling tower since dust particles directly mix-up in cooling water in the
cooling process and increase the TDS level, thus air filters should be used.
2.3.1 Centrifugal force filtrationWhy filtrate water?
Filtration is an essential requirement to remove contaminants like rust, sand, silt,
sediments, and other suspended impurities. If not filtered out, these particulates tend
to settle out in the cooling tower basin and other parts of the system where they can
become a breeding ground for bacteria, requiring frequent cleaning and flushing.
Such contaminations, apart from degrading system heat transfer efficiency, by their
very presence, drastically increase the cost of chemicals for water treatment.
Benefits of filtration
Clean filtered water offers many benefits:
Savings in energy use due to better heat transfer.
Savings in cost of water treatment chemicals, the cleaner the water, the lower
the dosage of chemicals required to control scale and algae etc.
Chemical treatment programs give more predictable results with filtered
water.
Savings in maintenance labor and cleaning costs.Less equipment downtime as filtration is the major part of preventative
maintenance of cooling systems.
Filtration protects and improves life of plate, frame, shell and tube heat
exchangers; pump seals, spray nozzles, valves & seats, piping and other
downstream equipment.
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Necessity of a centrifugal force filtration system design
Filtering system can comprise of one or more methods depending on the area and
location of the cooling tower site. Since the space already allocated for the water
cooling system is limited the suggested method is a centrifugal force filtration due to its
high efficiency and the effect of reduction of tds of cooling water uniquely reduce cost of
other currently used water purification systems.
Many process water systems
require pretreatment of the water taken from surface or ground water sources. Post-
filtration process water often is used in combination with other water-treatment
technologies such as softeners, demineralizers or membranes in a continuous flow
mode, feeding process equipment. For many of these applications centrifugal sandfiltration is a valuable technology. A centrifugal filtration system uses a combination
of in-situ fine-sand centrifugal separation combined with down flow sand filtration,
which ensures greater filtration efficiency than traditional down flow sand filters.
Sand filters often are deployed in cooling towers and other process cooling
applications, mainly because they tend to be more economical than other filtering
systems such as membranous solutions or systems using reverse osmosis. However,
conventional sand filters have drawbacks. As static systems, they absorb solids and
gradually become impregnated by them, requiring a sand filter media change on a
roughly biannual basis. The filtering medium typically is a fairly dense grain to
ensure that the sand will not clog the system. The dense-grain sand filters are
sometimes less effective at trapping extremely small-size particles.
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Figure 2.2. Centrifugal sand filter
Water in with higher
TDS
Water out with a lower
Benefits of centrifugal sand filters
Centrifugal sand filters force suspended solids to accumulate near the inside
walls of the tank and remove them with an automatic backwash cycle (figure
1). This design makes it possible to use a much finer grain of sand to remove small
particles (down to 0.45 m) with filtration up to 20 gal/min/ft2 without the risk of
clogging the system.
Conventional sand filters absorb solids and gradually become impregnated by
them, requiring a filter sand media change on a roughly biannual basis.
A centrifugal filtration system uses a combination of in-situ fine sand
centrifugal separation combined with down flow sand filtration, which
ensures greater filtration efficiency. For many process cooling applications,
clean water is crucial.
Centrifugal sand filters can achieve fine filtration at a high rate, using less
water for backwashing compared to other sand filter designs.
They also allow for a reduction in the amount of water-treatment chemicals
used.
With centrifugal sand filtration technology, companies can ensure clean, clear
cooling water, along with an efficient, high-quality, low-maintenance
process.
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2.3.2 Filtrating air fed into cooling towerHow air quality affects water quality
Water quality is affected by the air quality at any particular site. The air quality atmost areas are dusty and that cause of serious adverse effects upon both a cooling
towers longevity of service and its ability to function efficiently. This is because
cooling towers are extremely effective air washers; the quality of water being
circulated in a cooling tower quickly reflects the quality of the air with which it is in
intimate contact. Cooling towers pick up a lot of dust and other airborne particles from
air, which then gets washed out by the circulating water and carried as sediments
into the downstream processes.
This constant washing of the incoming atmospheric air as well as the base
characteristics of the water supply are the parameters that establish the ultimate
quality of the continuously recirculated water. The quality of circulating water is
further complicated by the fact that the process of evaporation causes incoming
contaminant levels to concentrate tremendously.
As the airborne contaminants and total dissolved solids become concentrated in the
cooling water circulating system, it leads to build up of sediments, clogging or
deposition, and eventually the system loses its efficiency and capacity to cool
effectively. Pipelines, internal passages of heat exchangers and other equipment maybe
difficult, time consuming or even impossible to clean properly. This can be directly
controlled by introducing air filters to the cooling tower.
Figure 2.3. Diagram showing the process of air filtration
Ambient air Air filter Filtered air out Cooling
in tower
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CHAPTER 03
POOR TIRE ROLLING METHODS AND SOLUTIONS TO BOOST UP THE
PRODUCTION PROCESS
3.1 Introduction to current tire rolling method
Tire rolling is the process which the compound sheets are rolled over a steel band to
obtain the required weight of compound material and shape of the tire.
Figure 3.1. The process of rolling
Tire rolling is the last process which is done before the curing process and it is a
temperature dependent process. Tire rolling should be done in between the given
range of temperature and before exceeding a maximum time interval. Tire rolling is doneusing two methods assuming that the thickness of the compound sheet rolled over is
kept constant.
1. Using timer
For each specific tire size, there are pre calculated times for rolling to be finished
since each specific tire size has its own weight. The drawback of this method is due
to the variation of the thickness of the compound sheet. Its hard to determine the
right time to achieve the right weight. Thus, after the rolling process more time is
taken to adjust the weight accurately. Since the rolling is done in higher temperatures
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and more time is taken to adjust the weight and then a portion of compound is precured.
2. Using an automated system incorporated with number of turns rolled over
In this rolling method a sensor is calculating the number of rotations rolled .Since each
tire size there are specific number of turns the automated system automatically stops the
process when the specific number of turns are rolled over. In this method even though
the system is automated it is a draw back since the thickness of the sheet deviates over the
range and as a result the achieved weight is deviated from the expected value causing
defects.
3.2 Effects of unnecessary rolling processes
Exceeding the temperature
If the rolling process exceeds the minimum tolerance range during the soft rolling the
compound is cured which is called pre-curing causes defects like short mould.
Exceeding the time limit
Modern compounds are developed for lesser curing times. Thus, if the rolling
process is done in-between the controlled range and if the rolling time is larger aportion of the rolled compound will be pre-cured.
3.3 Factors for the drawbacks of current rolling process
In each method, for accurate results or at least to keep the weight of the tire to have the
weigh between the minimum tolerances range the thickness of the compound sheet
rolled should be between the minimum tolerance range. As an example in T10 tire soft
rolling, the compound sheet thickness should be between 2.3 mm- 2.8 mm. But the realsituation is different since the thickness of the compound sheet is deviated over the
range due to below mentioned factors.
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1. The size of the compound bank on the rollers
Bigger the size of the compound bank bigger the thickness of the sheet.it is necessary to
keep a constant compound bank on the rollers but it is not practical with this
number of labours.
2. Dye swell
Its a property associated with the elasticity of the compound. The thickness of the
sheet is determined by the gap between the two rollers. That gap is adjusted using the
nip device of the rolling machine. Even though the gap is constant due to dye swell
the tire size is always over the range. Since rubber has elastic properties, between the
two rollers the sheet is compressed and when it releases from the rollers it achieves
the actual size again. The actual size is always larger than the gap between the
rollers.
3.5 Suggested automated method of rolling
This automated system is capable of controlling following sub-processes under the
rolling process.
1. Measuring the weight accurately and stopping the rolling process when theright weight of the compound is added to the tire.2. Sending a signal to pneumatically manipulated mechanical arm (deviser) toshift up the rolling tire from the rollers to stop the addition of compound.
3. Sending a signal to cutters to cut off the compound sheet.Figure 3.2. Block diagram showing the action of the automated system
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The main objective of this system is to determine the point which the necessary
weight of compound is added to the tire. This point can be taken as the point where
the whole rolling process stops. To control this whole process a specific parameter
was chosen which can be measured accurately to determine the weight accurately
instead of using the timer or calculating number of turns rotated during the rolling
process. Since its not practical to maintain the thickness of the compound sheet
between the tolerance range, a system to measure the weight accurately should be
introduced rather than currently available methods. The suggested system is in
cooperated with measurement of volume of the compound sheet rolled over.
3.5.1. The concept of measuring weight using a parameterFigure 3.4. Dimensions of the tire
The weight depends on the volume. Volume is proportional to density. The density of
compound used is kept in-between the accepted range with minimum tolerance. Thus the
volume is taken as the parameters which vary with the variation of the tire size. But also
the tire volume is also depends on the thickness and width of the specific tire. Width
is also kept constant and the only changing parameter is the thickness of the compound
sheet rolled on the steel band. The radius of the tire can be measured instead of the
thickness.
Weight volume density
When density is kept constant
Weight volume
Volume thickness width
When width is kept constant
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Volume thickness
Radius is measured instead of thickness as a direct measurement, thus
Volume radius
As the final parameter of weight radius of the tire is taken.
Weight volume thickness radius
As the final result, the radius of the tire is taken as the parameter which changes with the
weight of each tire type.
3.5.2 Method of measuring radius
The reflection of an infrared beam is used in this method to determine whether the
required value of the radius is achieved by the tire during the rolling process. Below
sketches show the process how the radius is measured.
Figure 3.5. During the rolling process (the required radius not achieved)
Deviser (pneumatically manipulated mechanical arm)
Infrared sensor
Infrared beam (not reflected)
Tire rolling in progress (the radius is not
achieved)
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Figure 3.6. The point which the rolling process is over
Tire archives the required radius and thus the
infrared beam is reflected. The sensor detectsthat the tire archived the required radius.
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3.5.3. Construction of the sensor
The sensor which is the key part of the automated system consists of a 38 kHz
transmitter, 38 kHz receiver and a switching circuit.
3.5.3.1. 38 kHz infrared transmitter
Here a 38 kHz infrared beam is generated using a oscillator circuit .This unique
frequency of 38 kHz is used here due to following reasons.
Infrared beams are narrow and further be focused by using lenses to get a
sharp beam. This sharp beam is capable of giving precise measurements in
measuring distances.
Most of the milling machines where the sensor is used are heated to a
temperature up to 120 degrees of Celsius. In this much temperature infraredradiation is emitted from milling machines. But the temperature is not enough
to emit infrared beams at 38 kHz and the infrared beam emitted by thetransmitter is uniquely identified by the receiver.
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Figure 3.7. The 38 kHz generator
3.5.3.2. 38 kHz infrared receiver
The infrared receiver is capable of receiving the infrared beam emitted by the
transmitter. Here a specific receiver called tsop 1738 is used, since it has below
specifications.
The circuit of the TSOP1738 is designed in that way that unexpected output
pulses due to noise or disturbance signals are avoided. A band pass filter, an
integrator stage and an automatic gain control are used to suppress suchdisturbances.
Photo detector and preamplifier in one package.
Low power consumption
High immunity against ambient light.
The output is active high when the receiver doesnt receive a infrared beam
and when it receives an infrared beam the output of the receiver is active law.
This variation is used via a transistor to regulate a switching circuit.
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Figure 3.8. The infrared receiver module
Figure 3.9 The block diagram showing the internal functioning of the receiver
3.5.3.3 Switching circuitThe switching circuit switches the relay on and off depending on the output of the
infrared sensor. The transistor switch off the relay when the output is high ( infrared
beam is not received by the receiver since it is not reflected by the tire ) and switches on
the relay when the output is law (when the tire reflects the infrared beam, the receiver
receives the infrared beam and the output goes law ) through a transistor switching
circuit.
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Figure 3.10. Diagram of the switching circuit in its simplest form
Figure 3.11. Suggested arrangement of the infrared sensor
Infrared led
Infrared receiver module &
switching circuit
Infrared led
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CHAPTER 04
EFFECTS OF IMPROPER USE OF PPE AND SOLUTIONS
4.1. What is a PPE?
PPE means personal protection equipment, which protects the labourers from
accidents, hazardous chemicals or anything makes adverse health effects on them.
When a person is a part of an industrial process, it is necessary to use PPE on his
own goodness and protection. PPEs used in the industrial production process are;
Goggles
Mask
Safety gloves
Safety bootsEar guards
4.2. Hazards faced by labourers and how to overcome
1. Exposure to xyleneIn the factory xylene is used as an adhesive ingredient to bond the steel band
and the rubber compound. Xylenes (mixtures of ortho-, meta-, and para-
isomers) are also used as industrial solvents, synthetic intermediates, and
solvents in commercial products such as paints, coatings, adhesive removers,
and paint thinners; they are also a component of gasoline. Xylenes are
released to the atmosphere primarily as fugitive emissions from industrial
sources (e.g., petroleum refineries, chemical plants), in automobile exhaust,
and through volatilization from their use as solvents. Xylenes, because of
their lipophilic properties, are rapidly absorbed by all routes of exposure,
rapidly distributed throughout the body, and, if not metabolized, quickly
eliminated in exhaled air. In humans, absorption has been estimated as >50%
through the lungs following inhalation exposure and
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CHAPTER 6
REFERENCES
R. Rajan et al. (1997). The Eclipse of the U.S. Tire Industry, pp. 345-386. Tata
McGraw-Hill India.
Colunson, J.M. and Rechardson, j.F. (1999). Chemical Engineering, vol 1, 3th
edition. pp. 105-107. Butterworth Heinemann.
Perry, p. (1998) Chemical Engineers Handbook. pp. 12-17. Oxford University Press. New
York.
Callister, W. (1995). Fundamentals of Materials Science and Engineering.John Wiley &
Sons, Hoboken.
Frates, W. (1984). Tire Technology, Midwest Research Institute, Kansas City, MO.
Horowitz, P., Hill, W. (1994). The Art Of Electronics pp. 61-183. Cambridge
University Press. Australia.