A Scientific Approach to Reduce 4m Wastage

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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

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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.

A Scientific Approach to Reduce 4m Wastage

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