Design Of A Bar Soap Making Machine For Local Soap Industry

FINAL YEAR PROJECT REPORT

UNIVERSITY OF NAIROBI DEPARTMENT OF MECHANICAL AND MANUFACTURING ENGINEERING

PROJECT NO. DMM.02/2016 PROJECT REPORT TITLE: DESIGN OF A BAR SOAP MAKING MACHINE FOR LOCAL SOAP INDUSTRY This project report is submitted in partial fulfillment of the requirement for the award of the degree of Bachelor of Science in Mechanical and Manufacturing Engineering.

Submitted by: JULIUS CASEY KILILIKU KILONZO STEPHEN WAMBUA KIBICHII FREDRICK BITOK Project supervisor: DAVID MUNYASI MAY 2016

F18/40222/2011 F18/41129/2011 F18/40325/2011

DECLARATION The content of this document is the original work based on our own research and to the best of our knowledge it has not been presented elsewhere for academic purposes. JULIUS CASEY KILILIKU F18/40222/2011 Signed…………………………………. Date: …………………………… KILONZO STEPHEN WAMBUA F18/41129/2011 Signed…………………………………..Date:……………………………… KIBICHII FREDRICK BITOK F18/40325/2011 Signed…………………………………… Date: …………………………. This project is submitted as part of the Examiners Board requirement for the award of the degree of Bachelor of Science in Mechanical and Manufacturing Engineering from the University of Nairobi. Project supervisor: Eng. David Munyasi Signed …………………………………. Date: ……………………………….

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DEDICATION We dedicate this project to our parents whose love and understanding always empowers us.

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ACKNOWLEGEMENT We would like first to give our sincere gratitude to the Almighty God for guiding us through this project.

We also thank our families and friends who gave us physical, financial and emotional assistance in our project.

We appreciate the University of Nairobi through the Department of Mechanical and Manufacturing Engineering for the material resources availed unto us throughout our project.

Our special thanks go to our project supervisor Eng. David Munyasi for allowing us to undertake this project and for the professional and technical advice willingly accorded to us.

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Table of Contents DECLARATION .......................................................................................................................................... ii DEDICATION ............................................................................................................................................. iii ACKNOWLEGEMENT .............................................................................................................................. iv LIST OF FIGURES ................................................................................................................................... viii LIST OF CHARTS ...................................................................................................................................... ix LIST OF ABBREVIATIONS AND SYMBOLS ......................................................................................... x ABSTRACT................................................................................................................................................ xii CHAPTER 1 ................................................................................................................................................. 1 INTRODUCTION ........................................................................................................................................ 1 1.1. SOAP ................................................................................................................................................. 1 1.2 SOAP MAKING ................................................................................................................................. 1 1.3. BAR SOAP MAKING MACHINE ................................................................................................... 1 1.4. PROBLEM STATEMENT ................................................................................................................ 2 1.5. STUDY OBJECTIVES ...................................................................................................................... 2 CHAPTER 2 ................................................................................................................................................. 3 LITERATURE REVIEW ............................................................................................................................. 3 2.1. DEFINATION ................................................................................................................................... 3 2.2. BACKGROUND ............................................................................................................................... 3 2.3. APPLICATIONS OF BAR SOAP ..................................................................................................... 3 2.4. CLASSIFICATIONS OF BAR SOAP .............................................................................................. 4 2.5. DESIGN ............................................................................................................................................. 5 2.6. RAW MATERIALS .......................................................................................................................... 5 2.7. THE FUTURE ................................................................................................................................... 5 CHAPTER 3 ................................................................................................................................................. 6 METHODOLOGY ....................................................................................................................................... 6 3.1. INTRODUCTION ............................................................................................................................. 6 3.2. A SURVEY OF BAR SOAP MAKING MACHINES CURRENTLY BEING USED IN KENYA 6 3.3. CURRENT BAR SOAP MAKING MACHINE DESIGNS .............................................................. 7 3.5. BAR SOAP MAKING MACHINE FROM ITALY .......................................................................... 8 3.5.1. Small Soap Finishing Line .......................................................................................................... 8 v

3.5.2. Small soap extruder ..................................................................................................................... 9 CHAPTER 4 ............................................................................................................................................... 12 DESIGN OF BAR SOAP MAKING MACHINE ...................................................................................... 12 4.1. SELECTION OF MATERIALS ...................................................................................................... 12 4.1.1. Pulley material .......................................................................................................................... 13 4.1.2. Toothed belt material ................................................................................................................ 13 4.1.3. Extrusion shaft .......................................................................................................................... 13 4.1.4. Materials of Hopper, Stand, Mixing tank and Extrusion shaft housing .................................... 14 4.1.5. Fastener Materials ..................................................................................................................... 15 4.2. SELECTION OF MANUFACTURING METHODS FOR PARTS ............................................... 15 4.3.1. THE POWER SYSTEM ........................................................................................................... 16 4.3.2 THE FEEDING SYSTEM ......................................................................................................... 25 4.3.3 THE EXTRUSION SYSTEM ................................................................................................... 27 4.3.4. COOLING AND HEATING SYSTEM.................................................................................... 34 4.3.5. BAR SOAP EXIT SYSTEM .................................................................................................... 35 4.4. WORKING PRINCIPLE OF THE BAR SOAP MAKING MACHINE ......................................... 38 DETERMINATION OF TECHNICAL AND ECONOMIC VIABILITY ................................................. 39 5.1.1. Performance .............................................................................................................................. 39 5.1.2. Environment .............................................................................................................................. 39 5.1.3. Maintenance .............................................................................................................................. 39 5.1.4. Aesthetics .................................................................................................................................. 40 5.1.5. Safety ........................................................................................................................................ 40 5.2. ECONOMIC VIABILITY OF THE BAR SOAP MAKING MACHINE ....................................... 40 6.1. CONCLUSION ................................................................................................................................ 41 6.2. RECOMMENDATIONS ................................................................................................................. 42 REFERENCES ........................................................................................................................................... 43 APPENDIX 1: COST EVALUATION OF THE BAR SOAP MAKING MACHINE ............................. 44 APPENDIX 2: DRAWINGS ...................................................................................................................... 46

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LIST OF TABLES Table 4.1: Mechanical properties of different grades of carbon steel ………………………..….14 Table 4.2: Mechanical properties of steel …………………………………………………….....14 Table 4.3: Measurements of the screw thread …………………………………………….…….32 Table 4.4: Inclination factor .………………..…………………………………………….…….34 Table 4.5: Properties of die materials …………………………………………………………...36

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LIST OF FIGURES Figure 3.1: Bar soap making machine from Germany ……………………………………………7 Figure 3.2: Bar soap making machine front view …………………………………………….......9 Figure 3.3: Small soap extruder …................................................................................................10 Figure 3.4: Small soap mixer …………………………………………………………………....10 Figure 4.1: Bolt and nut …………………………………………………………………….…...15 Figure 4.2: 3-phase AC motor ….……………………………………………………………….17 Figure 4.3: Timing belt………… ………………………………………………………….........18 Figure 4.4: Timing pulley system..........................................................................................…....18 Figure 4.5: Pulley and belt free body diagram....................……………………………………...19 Figure 4.6: Variable frequency working principle ………………………………………...…….21 Figure 4.7: Connection of variable speed drive to motor ….........................................................22 Figure 4.8: Small variable speed drive…………………………………………………..............23 Figure 4.9: Paddle mixer ……………………………………………...........................................24 Figure 4.10: Bearing …………………………………………………………………………….25 Figure 4.11: Hopper …………………………………………………………………………..…26 Figure 4.12: Free body diagram of a hopper .................................................................................26 Figure 4.13: Screw thread free body diagram ……….………………………………………......29 Figure 4.14: Screw thread………………………………………………………………………..32 Figure 4.15: Square tube …………………………………………………………………….......38

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LIST OF CHARTS Chart 4.1: S-N curve …………………………………………………………………………….37

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LIST OF ABBREVIATIONS AND SYMBOLS Kshs – Kenyan shillings m – Meter ̊C – Degrees centigrade % - Percent $ - Dollar ft. – Foot kg – Kilogram g – Grammes in – Inch Hg – Mercury F – Fahrenheit psi – pound per square inch kpi – kip per square inch hr – Hour cm - Centimeter mm – Millimeter rpm – Revolutions per minute lbs – Pounds kW – Kilo-watts Hp – Horsepower V – Volts Hz – Hertz cm3 – Cubic centimeter GPa – Giga Pascal MPa – Mega Pascal C – Carbon VFD – Variable frequency drive

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AC – Alternating current DC – Direct current ̊ - Degree Π – Pie Be – Beryllium Cr – Chromium W – Tungsten N – Newton Eng. – Engineer Fig. - Figure Ө – Theta USA – United States of America US – United States AD – anno Domini BC – Before Christ TM – Trade mark Co – Cooperation Inc. – Incorporation L – Length W – Width H – Height A – Area

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ABSTRACT The objective of the research was to design a bar soap making machine that is cost effective, to prepare a computer simulation model of the designed bar soap making machine and to determine the technical and economic viability of the machine.

A survey of bar soap making machines currently used in the local industry was carried out to establish how much they cost and their source. This was to give an overview on the need to have a cheaper design which is simple and cost effective. This involved collection of resources from different sources, visits to various industries to obtain important data for the project and having a guideline on the steps involved in the design. Among the sources of information looked at is the internet, reference books from the library and consultant engineers in the industry.

From the survey, it was found out that the soap making machines currently in use in the country are very few and were imported mainly from USA, China or India and they came at a cost of between Kshs.300, 000 and Kshs.500, 000. For this reason, they are only purchased by well established companies.

A design of bar soap making machine was then made using the AutoCAD design software. A technical and economic evaluation of the design was carried out in terms of performance, environmental factors, maintenance, aesthetics/ergonomics, size and weight, safety and cost. The designed bar soap making machine costs about Kshs.80, 000 to produce.

From this project, it was shown that it is economical to manufacture the new design of bar soap making machine locally since the Kshs.80, 000 is much lower than the imported machines that cost more than Kshs.300, 000

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CHAPTER 1 INTRODUCTION 1.1. SOAP Soap is a water soluble compound made by the reaction between sodium hydroxide with animal and/or vegetable fats (oils) by a process called saponification. Soap has surface active properties to wet a greasy surface and suspend the grease in the water for rinsing off. Other types of soaps called detergents are made from petroleum-based products .Consumers mainly use soap for washing, bathing and cleaning. 1.2. SOAP MAKING There are various ways of bar soap making. These include kettle process, continuous process and cold making process. The most popular bar soap making process is the continuous process. The continuous process involves: a) Splitting The first step of the continuous process splits natural fat into fatty acids and glycerin. The equipment used is a vertical stainless steel column (24m tall) with the diameter of the barrel called a hydrolyzer. Molten fat is pumped into one end of the column while at the other end water at high temperature (130°C) is introduced. This splits the fat into its two components which are pumped out continuously as more fat and water enter. The fatty acids are then distilled for purification. b) Mixing The purified fatty acids are next mixed with a precise amount of alkali, abrasives and perfume to form soap. c) Cooling and finishing The soap is poured into molds and allowed to harden into a large slab. It may also be cooled in a special freezer. The slab is cut into smaller pieces of bar size, which are then stamped and wrapped. 1.3. BAR SOAP MAKING MACHINE The soap making machine is made up of two main parts namely a) The mixer 1

b) The soap plodder that is made up of various components namely the extrusion shaft, motor, pulley system, electrical heater with a thermostat, variant connected to the motor, cooling system and stands. The machine is made of mild steel because mild steel is cheaper and has good properties such as toughness, has good tensile strength. However the machine has to be painted to prevent rusting since mild steel has weak resistance to corrosion. 1.4. PROBLEM STATEMENT Bar soap used for laundry is by far one of the most used consumer commodity in Kenya. The market for bar soap in the country is under-utilized because by now less than ten manufacturers are enjoying this vast market. Some of the most popular bar soap brands in Kenya are Menengai, Whitestar, Sunlight and Jamaa. BIDCO and Pwani life are some of the major manufacturers of soap who enjoy the monopoly. (https://cosmeticskenya.wordpress.com/2014/09/16/bar-soapbusiness-in-kenya-2/) Posted on September 16, 2014 at 6:31 pm by cosmetic Kenya limited Imported bar soap making machines come at a high price ranging from Kshs300, 000 – 500,000. This has led to the following problems: (i) Locking out potential players in the bar soap making industry. (ii) High cost of imported soaps. With the design and development of a bar soap making machine which can be manufactured locally, the above problems will be eliminated. This will be a major plus in the achievement of industrialization as stipulated in the vision 2030. 1.5. STUDY OBJECTIVES The objectives of the project are: i) To carry out a survey of bar soap making machines currently used in the local soap making industry. ii) To design a bar soap making machine that is cost effective. iii) To prepare a computer simulation model of the designed soap making machine. iv) To determine the technical and economic viability of the bar soap making machine

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CHAPTER 2 LITERATURE REVIEW

2.1. DEFINATION Soap is a water soluble compound mainly used for washing, textile spinning and is an important component for lubricants. Soaps for cleansing are obtained by treating vegetable or animal oils and fats with a strongly alkaline solution. Soaps are key components of most lubricating greases, which are usually emulsions of calcium soap or lithium soap and mineral oil. Soap can exist in three forms namely bar, powder and liquid form. 2.2. BACKGROUND The exact origins of soap are unknown though Roman sources claim it dates back to at least 600 B.C. when Phoenicians prepared it from goat's tallow and wood ash. Soap was also made by the Celts, ancient inhabitants of Britain. Soap was used widely throughout the Roman Empire, primarily as a medicine. Mention of soap as a cleanser does not appear until the second century A.D. By the eighth century, soap was common in France, Italy, and Spain but it was rarely used in the rest of Europe until as late as the 17th century. Early soap manufacturers simply boiled a solution of wood ash and animal fat. A foam substance formed at the top of the pot. When cooled, it hardened into soap. Around 1790, French soap maker Nicolas Leblanc developed a method of extracting sodium hydroxide from sodium chloride, replacing the wood ash element of soap. French chemist Eugene-Michel Chevreul put saponification into concrete chemical terms in 1823. In saponification, the animal fat, which is chemically neutral, splits into fatty acids, which react with alkali carbonates to form soap. Soap was made with industrial processes by the end of the 19th century. (http://www.madehow.com/Volume-2/Soap.html)

2.3. APPLICATIONS OF BAR SOAP Soap can not only be used for cleaning but also for other uses as stated below; 1. Drive nails easier with less risk of splitting the wood by first rubbing it on the nail shank. . 2. Remove wallpaper glue by mixing with warm water and sponging it on the walls. 3. Lubricate the metal rails of sticking desk drawers. 3

4. Clean dirty windowsills by running the wet edge of a bar along them. 2.4. CLASSIFICATIONS OF BAR SOAP Bar soap can be classified according to the difference in manufacturing and ingredients and also the type of skin they are applied on.

a) Difference in Manufacturing and Ingredients

i)

Common bar soaps - The commonly found basic bar soaps have in them the most aggressive surfactants. As such, they clean dirt and from skin very well but they themselves do not go away completely when washed. They also have a high pH levels which make them irritating to the skin.

ii)

Superfatted soap bars - When manufacturing bar soaps the process of saponification is left incomplete, it results into bar soaps that have extra fats than the ordinary bar soaps. Superfatting improves the moisturization of the soap and makes it less irritating.

iii)

Transparent soap bars - When glycerin is added to the ordinary bar soap, it becomes transparent soap. However, it is still irritating to skin when compared to the super fatted bar soaps.

(http://www.detergentsandsoaps.com/articles/bar-soap.html) (August 27 2010)

b) Bar Soap Types for Different Skin

i) Soap types for sensitive skin - People who are prone to skin allergies must use organic soaps that come in form of bar soaps too. These soaps have natural ingredients that are friendly to skin. Some of the bar soaps also have herbs suitable to their sensitive skin. ii) Soap types for dry skin - Mildest soaps are best for people with dry skin. Look for such ingredients such as aloe Vera, vitamin E, cocoa butter or olive oil in bar soaps for dry skin.

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2.5. DESIGN The design of the bar soap is determined by the shape of the die. In most cases the die is rectangular. 2.6. RAW MATERIALS Soap requires two major raw materials: fat and alkali. The alkali most commonly used today is sodium hydroxide. Animal fat in the past was obtained directly from a slaughterhouse. Modern soap makers use fat that has been processed into fatty acids. Additives are used to enhance the color, texture and scent of soap. Perfumes are added to the soap mixture to cover the odor of dirt and to leave behind a fresh-smelling scent. Abrasives to enhance the texture of soap include talc, silica and marble. 2.7. THE FUTURE The demand bar soap is dependent on the fluctuations in population, which varies with the economy. Demand for this soap is also subject to competition from foreign manufacturers, further reducing profits. In Kenya, bar soap production has not been embraced as the soap making machine is unaffordable. With the growth of the population, demand for cleanliness is increasing and this consequently leads to an increase in demand for soaps. locally manufactured soap plodders are therefore required in large numbers. Desirable features these soap plodders include: i) Smooth operation ii) Less wear and tear iii) Low maintenance cost

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CHAPTER 3 METHODOLOGY 3.1. INTRODUCTION The mission of this project was to design a cheap and affordable bar soap making machine for local use. With the completion of this project we hope that our bar soap making machine design will be used widely throughout this great nation. We also hope that by domestically manufacturing the bar soap making machine, the price of the machine will be drastically reduced and this will allow creation of job opportunities within the sector in addition to contributing towards the realization of the vision 2030. Initially, we made a factory visit to some bar soap making industries in Kenya such as BIDCO in Thika and Kapa Oil industries in Athi River where we found that the existing machines had been imported mainly from India. We also visited KIRDI (Kenya Industrial Research and Development Institute) located in South C who have a similar design. We also gathered literature from a number of resources regarding existing machine designs from other countries that manufacture them such as China, USA and India. With this knowledge, we established what made a reliable soap plodder and which features and mechanisms we would modify in order to come up with an affordable machine. We thereafter prepared drawings using AUTO CAD and solid works. The objective of this project was achieved through the subsequent completion of the goals including analysis of existing soap plodder designs and determining which one can easily be fabricated using the locally available materials.

3.2. A SURVEY OF BAR SOAP MAKING MACHINES CURRENTLY BEING USED IN KENYA Today’s technology offers many different bar soap making machine designs available for purchase by the manufacturing industry. These machines are produced overseas by a wide

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variety of companies in countries like India, China and USA. The different available machines are designed for production of different bar soap designs. 3.3. CURRENT BAR SOAP MAKING MACHINE DESIGNS The first step to evaluating bar soap making machine design was to find out what products were currently available in the industry. We started our research by visiting BIDCO industries to view the machines they had. We met the engineer in charge who gave us a history of how the company makes bar soaps using machines imported from India and China. He demonstrated the bar soap making process to us. He said they were some of the most expensive machines approximating at about US $ 8,000 and together with the shipping costs and taxes it would come to over US $ 10,000. He said that it was due to this that only a few companies could afford the machine but still with the very high cost it would only follow that the bar soaps are manufactured and sold at a high cost. This, he said, was the reason for the unfair competition from other bar soap importers as they make their products cheaper which led to them not being able to work on a full capacity as the demand was lower for locally manufactured bar soaps. We then did an online research for bar soap making machines that are currently being imported mainly from India, China, Germany, Italy and USA. Some of the designs are: 3.4. BAR SOAP MAKING MACHINE FROM GERMANY

Fig. 3.1: Bar soap making machine from Germany This machine type in figure 3.1 SSP-130™ is manufactured using Superior German Technology by Express Marine Engineering Corporation. It features:

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Physical Features 1. Size: Length 122cm, Width 61cm, Height 91cm 2. Weight: Approximately 150kg.

Technical Features 1. Inter-cooled Log Processor 2. Power Source: Single and Three Phase option 3. High pressure soap extruder of 105mHg at 00C 4. Production capacity of 50kg per hour. 5. Customized name and logo automatic roller stamping unit. It is different from the locally fabricated one because: 1. It produces super refined high quality bar soaps 2. It produces soaps with Uniform Standard Weight 3. It has a very low maintenance cost The machine has high extrusion pressure of 14MPa at 00C ensuring that the soap is super refined. The circulating coolant in the cooler system allows powerful temperature control enhancements in the plodder barrel for better soap processing. The machine is sold and serviced throughout East and West Africa by Cosmetics & Detergents Kenya Ltd. It costs between Kshs 190,000 to 300,000. 3.5. BAR SOAP MAKING MACHINE FROM ITALY 3.5.1. Small Soap Finishing Line They have a complete small soap finishing line as well as single small soap machines for small companies and artisans which are affordable. These lines and machines are studied to work with soap noodles. The standard small soap finishing line in figure 3.2 is composed by an automatic

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mixer able to mix up to 15 kg of soap noodles with perfume and colors per batch, a simplex plodder to refine and extrude the soap and a manual soap press. Manual soap mixer can be used for a small capacity while the automatic mixer, about 30kg in weight is used when there is the necessity to amalgamate additional components that are required for more mixing time. The soap noodles, perfume and colors are mixed inside the soap mixer for a variable time of 8-15 minutes, depending on the coloring intensity. After the mixing, the soap base is ready to be refined and is extruded by means of the soap extruder. The extruded soap is cut into required sizes. The cut bar soaps are ready to be stamped using manual soap press. Its total cost is about Kshs. 200,000.

Fig. 3.2: Bar soap making machine front view 3.5.2. Small soap extruder The soap making machine shown in figure 3.3 is also from Italy and is designed for a double function. The first one is to mix the soap noodles, perfume and the color while the second one is to extrude. The soap extruder gets a cooling system which allows it to work continuously without a decrease in capacity. Standard model has a capacity of up to 100 kg/hr. at maximum output and a diameter of 60 mm.

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It has 2 options which are; a) Adjustable screw speed (Electrical panel with frequency inverter to adjust the speed of the screw from 10 to 35 rpm) b) Special big cone. This special cone which has a maximum output of diameter 90mm was studied to produce big soap bars.

Fig. 3.3: Small soap extruder 3.5.3. Small Soap Mixer

Fig. 3.4: Small soap mixer 10

The small soap mixer in figure 3.4 is designed to amalgamate soap noodles with colors and perfume. The batch time can vary from 8 to 15 minutes depending on the color intensity of your soap. The blades are designed with the same shape used in industrial soap manufacture. There are 3 models: one manual 5kg batch soap mixer and two electric soap mixers for 15kg and 30kg batches Small soap mixers technical data Manual Soap mixer Capacity: 5 kg/batch Tank manufactured in stainless steel Soap Mixers 15kg & 30kg 15kg model: Capacity: 15 kg/batch 15kg model: Installed Power: 0.75 kW 30kg model: Capacity: 30 kg/batch 30kg model: Installed Power: 1.1 kW Tank manufactured in stainless steel Industrial Gearbox with motor Electrical panel with push buttons Safety cover on the hopper with micro switch Discharge by means of reverse tank Electrical supply: 200/230/400V, 50/60 Hz The cost of this mixer is Kshs 300,000

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CHAPTER 4 DESIGN OF BAR SOAP MAKING MACHINE 4.1. SELECTION OF MATERIALS When selecting the materials from which the different components of the bar soap making machine is to be made, we first defined the requirements that are associated with its performance when in service and with its manipulation into the shape of the product. The machine will work at a speed of approximately 60rpm having been stepped down from the motor speed of 1400rpm. The overall weight of the machine is optimum. This requires that the stands be able to hold that weight for a long period. Secondly, we obtained a balance between these requirements and the properties and other characteristics of the materials that are available with regard to the economic considerations as per the project objectives. The extrusion shaft, for example, could be made from carbon fiber material but this is not used in this design due to the availability and cost of those materials. Manufacturing methods contribute to the cost of the machine so while designing, we considered parts that are easily and cheaply machined. The main material chosen for the bar soap making machine is mild steel also known as plaincarbon steel. It is the most common type of steel because its price is relatively small while it provides material properties that are acceptable for many applications. Mild steel is used for the housing and frame structures. It has the following properties:i)

In mild steel composition, other than mild maximum limit of 0.02 carbons in the manufacture of carbon steel, the proportions of copper and silicon are fixed while the proportions of cobalt and chromium are not.

ii)

A high amount of carbon makes steel different from other types of steel. Carbon makes mild steel stronger and stiffer.

iii)

Carbon atoms get affixed in the interstitial sites of the iron lattice and make it stronger.

iv)

Density is 7850kg/m3

v)

Young's modulus is 207 GPa

These factors make steel be suitable as the main material of the bar soap making machine. 12

4.1.1. Pulley material For the pulleys, the most preferred material is cast iron. This is chosen due to the following properties, i)

Tensile strength – this is about 483Mpa.

ii)

High resistance to deformation.

4.1.2. Toothed belt material It is also known as timing belt. It is basically a flat belt with evenly spaced teeth in its inner circumference. The teeth provide the advantage that a gear or chain drive possesses – positive transmission of rotation and power. The timing belt consists of: i) Steel wire or the tension member – This is usually a wire that takes up the load and provides the reinforcement to the belt. The various materials that are used for the tension member are steel wire and glass fibers. ii) Base material (neoprene) – A good coat of neoprene is provided to the tension member in order to prevent any damage to it by oil and moisture. It also acts as a wear resistor. iii) Nylon coating – A film of nylon fabric coating is provided on the external layers of the

belt which provides a low co-efficient of friction for the surfaces that wear out quickly. 4.1.3. Extrusion shaft The extrusion shaft is the main connection from the pulley to the die hence it should have the following properties for it to work well; i) High strength ii) Good machinability iii) Low notch sensitivity factor iv) High wear resistant properties For ordinary shafts, the material used is carbon steel of grades 40C 8 (selected), 45C 8, 50C 4 and 50C 12. The mechanical properties of these grades of carbon steel are given in the table 4.1 below: 13

British standard

Ultimate tensile

Yield Strength,

designation

strength, MPa

MPa

40C 8

560-760

320

45C 8

610-700

350

50C 4

640-760

370

Table 4.1: Mechanical properties of different grades of carbon steel 4.1.4. Materials of Hopper, Stand, Mixing tank and Extrusion shaft housing All the above parts are made from mild steel of ultimate tensile strength of 44MPa and other properties are tabulated in table 4.2 Mechanical Properties

Metric

Hardness, Brinell( Kg/mm2)

126

Hardness, Knoop (Converted from Brinell hardness) (kg/mm2)

145

Hardness, Rockwell B (Converted from Brinell hardness) (kg/mm2)

71

Hardness, Vickers (Converted from Brinell hardness) (kg/mm2)

131

Tensile Strength, Ultimate

440 MPa

Tensile Strength, Yield

370 MPa

Elongation at Break

15.0 %

Reduction of Area

40.0 %

Modulus of Elasticity (Typical for steel)

205 GPa

Bulk Modulus (Typical for steel)

140 GPa

Poisson’s Ratio (Typical For Steel)

0.290

Machinability (Based on AISI 1212 steel. as 100% machinability)

70 %

Shear Modulus (Typical for steel)

80.0 GPa

Table 4.2: Mechanical properties of steel 14

4.1.5. Fastener Materials Bolts and nuts in figure 4.1 for the bar soap making machine are made from carbon steel. Carbon steel is the cheapest and most common bolt material. Most hardware stores sell carbon steel bolts which are usually zinc plated to resist corrosion. The typical ultimate strength of this bolt material is 379Mpa.

Fig. 4.1: Bolt and nut

4.2. SELECTION OF MANUFACTURING METHODS FOR PARTS During the selection, we considered the size, shape of the components, required strength and the material from which it is to be made. In addition to this, we looked at the economics of quantity and cost, time allowed to manufacture the product and the locally and easily available manufacturing tools and machines. Putting all the above into consideration led us into selecting the best manufacturing method for each component. The frames and mountings of the machine made from L-channels and square pipes and blocks are simply machined. In this case, a power saw can be used to cut the parts into the required sizes and shapes. This method is cheap and fast especially given the number of parts that are supposed to be cut.

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The extrusion shaft will be difficult to machine, time consuming and also a lot of wastage of material from the parent material. Hence, the most preferred method of manufacturing will be welding of shaft screw threads. The extrusion shaft will be protected by a housing made of flat plate mild steel which is rolled and welded together. The hopper is also welded to the housing to provide the feeding mechanism to the extrusion shaft. The housing is also bolted and fastened to the extruder which also has its own housing. The die block could also be manufactured by casting. Various small components are held together by welding since most of them cannot be made as a single component. This would make the cost of fabrication by this method lower than that of casting. The motor and the variable speed drive are bought. 4.3. DESCRIPTION OF PARTS OF DESIGNED BAR SOAP MAKING MACHINE The design of the bar soap making machine has five major systems: i) The power system ii) Feeding system iii) Extrusion system iv) Cooling and Heating system v) Soap exit systems 4.3.1. THE POWER SYSTEM This provides the driving force for all the components of the machine. This system is composed of the motor, pulley system and the variable speed drive. 4.3.1.1. Motor The machine uses an AC motor with the following specifications: i)

2 Hp

ii)

240 V 16

iii)

50 Hz

iv)

1400 rpm

Motors as shown in figure 4.2 can mostly be found in large supermarkets, electrical shops and large hardware in the country.

Fig. 4.2: 3-phase AC Motor 4.3.1.2. Pulley system This is composed of the belt drive and two pulleys. The rotary motion of the motor is transferred to the extrusion shaft through the timing belt and two pulleys of the same diameter as shown in figure 4.3 and 4.4, one at the motor shaft and the other at the extrusion shaft .The timing belt is suited for the soap making machine for the following three main reasons: i) Eliminates Slippage Positive grip of belt teeth with "timing pulley" grooves eliminates slippage and speed variation. There's neither initial stretch nor elongation to require belt take up because of high modulus tension member. ii) Less Bearing Load Since the positive drive belt does not rely on friction; there is no need for high initial tension. Thus, overhung bearing loads are reduced to minimum.

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iii) Less Space Small timing pulleys, short centers, narrow belts and high capacity can be combined to reduce space requirements. Center distance can be permanently established.

Fig. 4.3: Timing belt

Fig. 4.4: Timing pulley system 18

The calculations on the timing belt and pulley are shown below  Total length of timing belt �

−

Where

ℎ =

�

+

+

+

−

=0

Fig. 4.5: Pulley and belt drive free body diagram D1 – diameter of the driver pulley = 20cm D2 – diameter of the driven pulley =20cm L – Total length of the belt. C - Distance between the center of pulley 1 and 2 = 35cm �

ℎ = =

�

�

+

+

= 132.83 cm.

+

+

×

19

The thickness of the belt is 30mm as seen in the drawing of the pulley in the appendix. The number of teeth as from the technical manual rubber timing drive table is 96. (www.ageraab.se/uploads/categories81.pdf). The number of teeth on each pulley is given by

Diameter of pulley =

in

8 �

Where n = number of teeth, p = pitch = 0.03m Diameter of pulley = 0.2m =

sin−

.

.

= 21 teeth. 4.3.1.3 Variable frequency drive

A variable frequency drive is a type of adjustable speed drive used in electro-mechanical drive systems to control AC motor speed and torque by varying motor input frequency and voltage. While there are a number of variations in variable frequency drive design; they all offer the same basic functionality which is to convert the incoming electrical supply of fixed frequency and voltage into a variable frequency and variable voltage that is output to the motor with a corresponding change in the motor speed and torque. The motor speed can be varied from zero rpm through to typically 100-120% of its full rated speed whilst up to 150% rated torque can be achieved at reduced speed.

20

Fig. 4.6: Variable frequency working principle The basic design consists of four elements as seen in figure 4.4 and explained below:



Rectifier: the working principle of rectifier is changing the incoming alternating current supply to direct current.



Intermediate circuit: the rectified DC supply is then conditioned in the intermediate circuit, normally by a combination of inductors and capacitors. It is used to smoothen the pulsation included in the DC.



Inverter: the inverter converts the rectified and conditioned DC back into an AC supply of variable frequency and voltage. This is normally achieved by generating a high frequency pulse width modulated signal of variable frequency and effective voltage.



Control unit: the control unit controls the whole operation of the variable frequency drive; it monitors and controls the rectifier, the intermediate circuit and the inverter to deliver the correct output in response to an external control signal.

This variable frequency drive is typically 92-98% efficient with 2-8% losses being due to additional heat dissipation caused by the high-frequency electrical switching and the additional power required by the electronic components.

21

Equally motors connected to variable frequency drives experience some additional losses due to heating caused by the high frequency electrical switching. Electrically, a variable frequency drive is installed in series between the mains electrical supply and the motor as in figure 4.7.

Fig 4.7 Connection of variable frequency drive to motor The motor in use is a three phase synchronous with specification (2 Hp, 4 poles ). The required frequency is set on the variable frequency drive vie a knob, it can be calculated using the formulae;

�=

Where N = speed required in rpm,

f = frequency in Hertz

P = number of poles

To find the frequency,

�

=

=

=

where p = 4 poles

×

�� 22

Fig. 4.8: Small variable speed drive The following are process control benefits are provided by the variable frequency drive: 

Smoother operation



Acceleration control



Different operating speed for each process



Allow slow operation for setup purposes



Adjust the rate of production

4.3.1.4. The Mixer There are a number of mixers available: handheld and machine type mixer. We will consider the hand held paddle mixer as shown in figure 4.9 here as it is the economical, takes a small space and is easy to control and clean up. Although a stand mixer can be used, it is more expensive and hard to clean up. Hand-held mixers generally consist of a metal shaft with paddles on one end that attaches to a heavy-duty drill. Some manufacturers make shafts specifically for their driver while others offer shafts that can be attached to a drill of the operator's choosing. Shafts are usually made of highstrength steel and paddles are available in different shapes and sizes.

23

In mixing of the ingredients a paddle mixer is used whereby it is placed in a tank which houses the mixing process. The prime object of this mixing operation is to coat each chip or noodle with a small amount of the additives. Dispersal of the additives is effected by the noodles tumbling and rubbing against each other so one with a high concentration of additives transfers it to one with a lesser concentration. Over mixing will result in the breakup of the noodles and the addition of too much liquid will cause clogging and inhibit the free movement of the noodles.

Fig. 4.9: Paddle mixer 4.3.1.5 Bearing The bearing is located between the hopper and the belt drive to maintain separation between the two components. This serves to reduce frictional resistance due to relative motion between contact surfaces. The standard dimensions of the diameters of the bearing in figure 4.12 used are: the outer diameter is 20cm and the inner diameter is 8.05cm. The housing of the bearing is fixed to the extrusion shaft housing through welding.

24

Fig. 4.10: Bearing It should be lubricated in order to reduce friction and wear between the sliding parts. The lubrication process forms part of the regular maintenance measures and oil or light grease is used for this purpose. 4.3.2 THE FEEDING SYSTEM 4.3.2.1 Hopper A hopper is a large pyramidal shaped container used in industrial processes to hold particulate matter as shown in figure 4.13. Hoppers are usually installed in groups to allow for a greater quantity collection. Most hoppers are made of steel. However, in this design we are using a hopper for the collections of soap noodles from the mixing tank. The hopper receives soap noodle from the mixing tank and it is positioned at 33 centimeters from the belt drive. The hopper is made of mild steel and has a total volume of 8860.3692 cm3.

25

Fig. 4.11: Hopper

Fig. 4.12: Free body diagram of a hopper �=

Tan � =

�

;

� =

=

�

an �

26

=

X

=

an

°

= 12.988 cm b = 36 – (12.988 × 2) = 10.024cm a = 30 – (12.988 × 2) = 4.024cm

Volume of the hopper, V =

�

(� + � + √� × � )

A1 = L × W

= 1080 cm2

A2 =

×

= 40.3366cm2 Thus;

V=

(

+

.

= 8860.3692cm3

+ √

×

.

)

4.3.3 THE EXTRUSION SYSTEM The soap extruder is designed for a double function. The first one is to homogenize the mixture of soap noodles, perfume and color coming while the second one is to extrude the ready to cut soap. It is a definite advantage to have a variable speed facility for the extruding operation both to influence the finished appearance of the extruded soap and to control the rate of production. Extruding plodders can be provided with refining heads which can be inter-changed with the extruding head so that only a single plodder is required for the two operations. An extrusion process for the production of a solid soap product comprises feeding a soap composition into an extruder having a housing with an inlet and an outlet and a screw thread 27

traversing the extruder, wherein at least a portion of the housing from the inlet to the outlet of the housing is tapered to form a portion of the housing with a reduced cross-sectional area and the screw thread extends at least partly into the tapered portion of the extruder where the screw thread ends and extruding the soap composition through the extruder. As the soap noodles move through the extrusion shaft, a torque is generated due to the forces incurred. This torque is calculated as:

T=� Where:

� �

�

power=1492watts (1 horse power=746 watts) T = torque (N. m) ɷ=angular speed (rad/s)

=

×

× �

= 237.4 Nm (http://www.pumpsandsystems.com/topics/motors/relationship-torque-and-shaft-size.)

28

The extrusion shaft is made up of a mild steel solid shaft with spiral screw all over its length and a cone on its rear end. The geometry of a double-flighted screw and its nomenclature are presented in the figure below.

ϴ(r)

H

Db

Dc

B

b �

L Fig. 4.13: Screw thread free body diagram

Several of the screw geometric parameters are easily obtained by observation and measurement including the number of flight starts, inside barrel diameter, channel depth, lead length, flight width and flight clearance. The number of flight starts, n, for the geometry in Fig. 4.15 is two. The inner diameter of the barrel is represented by Db, and the local distance from the screw root to the barrel is H. The diameter of the screw core is represented by Dc. The mechanical clearance between the land of the screw flight and the barrel is λ. The mechanical clearance is typically very small compared to depth of the channel. The lead length, L, is the axial distance of one full turn of one of the screw flight starts. This is constant in each section of the screw. The flight width at the tip of the screw and perpendicular to the flight edge is e.

29

The remaining geometrical parameters are easily derived from the measured parameters presented above. Several of the screw parameters are functions of the screw radius. They include the perpendicular distance from flight to flight, W(r), the width of the flights in the axial direction, b(r) and the helix angle, θ(r), the angle produced by the flight and a plane normal to the screw axis. At the barrel wall these parameters are subscripted with a b. The helix angle at the barrel wall is θb and is calculated using Eq. 1.1. The helix angle at the barrel wall for a square-pitched screw is 17.7°.

tan ϴb = Eq.1.1

�

thus ϴb = arctan =

��

=

�

��

�

= 20° The relationship between the width of the channel perpendicular to the flight at the barrel (housing) interface, Wb, and the axial distance between the flight edges at the barrel interface, Bb, is as follows:

Wb = Bb cos ϴb = e = bb cos ϴb

�

−

�b =

�

� −e

The geometric parameters are a function of the radial position (r) of the screw. It includes the helix angle and the channel widths. The length of an arc for one full turn at the barrel surface is πDb. At the screw surface the length of the arc for one turn is π (Db – 2H). The lead length, however, remains the same. This leads to a larger helix angle at the screw root than at the barrel surface.

30

The helix angle and the channel widths at the screw core or root are designated with a subscript c, and they are calculated as follows:

tan � =

�

� �− �

� = tan−

Thus

= �

�

��

��

;

= 32.38 °

Thus the screw has a narrower normal distance between flights at the screw root because the helix angle is larger while the lead remains the same.

Wc = Bc cos � =

e = bc cos �

�

�

−

cos � =

�

�

cos � −

= 6.7485 - 0.9397 = 5.8088cm

The average channel width is used for many of the calculations. This average channel width is represented as simply W here and is calculated using Eq. 1.1.

W=

=

+ .

= .

+ .

cm

The 3-dimensional view of the soild shaft screw conveyor is shown below in figure 4.16.

31

Fig. 4.14: Screw thread

Parameter

Values

Barrel diameter, Db

14cm

Core diameter, Dc

8cm

Lead length, L

16cm

Meter channel depth, H

3cm

Flight width, e

0.9397cm

Flight start, n

2

Helix angle at the barrel, �b

20°

Helix angle at the screw core, �c

32.5°

Channel width at the barrel, Wb

6.5778cm

Channel width at the core, Wc

5.8088cm

Average channel width, W Channel aspect ratio, H/W

6.1933cm 0.4844

Table 4.3: Measurements of the screw thread

32

The capacity of a screw conveyor depends on the screw diameter, screw pitch, speed of the screw and the loading efficiency of the cross sectional area of the screw. The capacity of a screw conveyor with a continuous screw: Q=V*ρ Q = 60 * (π/4) * D2 * S * N * ψ * ρ * C Where, Q = capacity of a screw conveyor V = Volumetric capacity in m3/hr. ρ = Bulk density of the material, kg/m3 D = Nominal diameter of Screw in m S = Screw pitch in m N = rpm of screw Ψ = Loading efficiency of the screw C = Factor to take into account the inclination of the conveyor Parameters Screw Pitch: The screw pitch taken is equal to the diameter of the screw, D. Rpm of Screw: The usual range of rpm of screw is 10 to 165. It depends on the diameter of screw and the type of material. Loading efficiency: The value of loading efficiency should be taken large for materials which are free flowing and nonabrasive while for materials which are not free flowing and or abrasive in nature the value should be taken low. Ψ = 0.12 to 0.15 for abrasive material = 0.25 to 0.3 for mildly abrasive material = 0.4 to 0.45 for nonabrasive free flowing materials. 33

Inclination Factor: The inclination factor C is determined by the angle of screw conveyor with the horizontal and is given in the table below.

Angle of the screw with the horizontal Value of factor C

0°

5°

10°

15°

20°

1

0.9

0.8

0.7

0.65

Table 4.4: Inclination factor Therefore the value of; D = 0.14 m S = 0.08m N = 60 rpm Ψ = 0.12 ρ = 880 kg/m3 C = 0.65 � =

�

× ×

= 304 kg/hr.

.

× .

×

× .

×

× .

Therefore the machine design has an output of 304 kg/hr.

4.3.4. COOLING AND HEATING SYSTEM 4.3.4.1. Cooling system The cooling system is basically water around the mid-section of the extrusion shaft. A water bath is fitted around the extrusion shaft but without it coming into contact with the shaft or the soap. Water is contained in a cylinder with inlet and outlet pipes where cold water from a tank (reservoir) placed at a higher level enters and warm water leaves through the exist pipe fixed at the bottom of the container. Heat generated by the operation of the shaft (extrusion) is conducted to the cold water since the material making the housing of the extrusion shaft is mild steel which has good thermal 34

conductivity properties and then transferred out. For normal operation, the screw ought to operate at an optimum temperature of 38−

̊C .Therefore the circulating water during operation

maintains this range of temperature. If the temperature goes beyond optimum, then the shaft will be hindered by thermal fatigue. Most failures of extrusion shaft results from this. High temperatures also activate corrosion in the extrusion shaft housing. 4.3.4.2. Heating system Heating system is fixed around the tip of the extrusion shaft cone. An immersion electric heater is fitted inside the barrel (water jacket) where water is heated to make the soap smooth and compact before it is extruded. The immersion heater is automated by a thermostat which controls the temperature to optimum. The electrical heater has an electrical device that converts electrical current to heat. The heating element inside the heater is an electrical resistor. The set point temp is usually

℃−

The thermostat operates by switching the immersion heater off/on when temp falls below

℃.

optimum. 4.3.5. BAR SOAP EXIT SYSTEM This system is composed of a rectangular die block. This makes the soap to be rectangular taking the shape of the die. The die block is firmly fitted at one end immediately after the edge of the extrusion shaft. Surrounding it is a bath of warm water which warms and softens the exiting bar soap. 4.3.5.1. Properties of the die block material The die material must have certain properties in order to withstand the stresses during operation. These properties include thermal expansion and modulus of elasticity, mechanical properties, resistance to thermal fatigue and chemical stress of die. 4.3.5.2. Thermal expansion and modulus of elasticity At smaller thermal expansion and modulus of elasticity, the stress at a certain thermal impact is smaller. It depends on modulus of elasticity of elementary metal that is only a little changed by alloying.

35

Material

Addition

Modulus Coefficient of of

thermal

elasticity expansion

Hardness 2

Resistance

conductivity kg/mm

against

W/mK

melting

(MPa)

(×10-6)m/mK

-

105000

16.5

0.383

60

excellent

0.5 Be

110000

11.5

0.0836

400

Excellent

0.4 C

220000

11.7

0.0627

8

Excellent

0.3 C

215000

10.5

0.0418

350

excellent

210000

13

0.0188

400

excellent

Copper Beryllium

Thermal

Heat treated soft steel

Low alloy treated steel

High alloy treated steel

0.3 C, Cr, W

Table 4.5: Properties of materials (https://en.wikipedia.org/wiki/Die_casting) The selected material is low alloy heat treated steel due to its desirable properties. It is also easy to cast in the workshop and affordable. 4.3.5.3. Die life Die life is a major concern for the bar soap making industry. Die cracking and wear are the major setbacks. Improving die life by avoiding premature die failure due to cracking is one of the dominating challenges that die and forging engineers face. Die life can be significantly improved by pre-shape produced in the blocker stage. This is achieved by removing excess material. When the soap is passing through the die, high tensile stresses are experienced by the die material. The life span of the steel made die can be described by cyclic loading (S-N) curves. These curves are obtained by plotting the magnitude of the cyclic stress(S) against logarithmic scale of cycles to failure (N). The soap plodder operates under low stresses hence the material can withstand an infinite number of loads that is, the stresses will always be below the endurance (fatigue) limit at about one million load cycles.

36

Chart 4.1: S-N curve

4.3.5.4. Die dimensions The die dimensions will determine the dimensions of the bar soap, i.e. breath (B) and height (H). The standard size of most bar soaps is B=6cm and H=3cm. The die should have similar dimensions but with smaller tolerance (allowance). For tolerance of +0.05cm, B=6.05cm and H=3.05cm. The tolerance allows the soap to have exact dimensions as per the given standards. The length of the bar depends on the wish of the customer. Most of the bar soaps in the market are approximately 0.5mand weigh between 800-1000g. 4.3.6 MACHINE FIXTURE SYSTEM This comprises of the mountings and stands made of mild steel to hold the machine in position. It should also be able to hold against the vibrations that occur during the process of extrusion. Figure 4.16 shows stands that are made of square tubes to minimize the weight.

37

Fig. 4.15: Square tube 4.4. WORKING PRINCIPLE OF THE BAR SOAP MAKING MACHINE The bar soap making machine uses a motor which when started rotates the extrusion shaft connected to it through a toothed timing belt and a pulley drive. This motor is connected electrically to a variable speed drive which steps down its speed from 1400 rpm to the required speed of 60 rpm. The extrusion shaft has bearing at its rear end to ensure that it is always in line and minimize friction. The extrusion shaft has spiral screws with lead length of 16cm. The soap noodles are made in a separate tank by mixing the various ingredients and chemicals using a mixer. The noodles at a high temperature therefore you have to give them time to cool and dry .Once the noodles are ready you pour them into the hopper directly above the extrusion shaft at the rear end (near the pulley system). As the extrusion shaft rotates, it pushes the soap noodles towards the die block. The soap noodles get into the space between the spiral screws where they are compressed as they rotate to make them compact before reaching the exit system. Apart from the opening for the hopper, the rest of the extrusion shaft is enclosed in a mild steel housing. This housing has a heater that has a thermostat placed just before the die block to heat the water jacket. After being compressed up to the right compactness, the soap exits the bar soap making machine through the die block. The bock has width of 6.05cm and height of 3.05cm in order to produce a bar soap of the standard measurement of 6cm by 3cm. A table is placed in line below the die block. The bar soap slides on this table where it is cut into the required length. The standard length is usually 50cm. The size of the bar soap produced can be altered by changing the dimensions of the die block. 38

CHAPTER 5

DETERMINATION OF TECHNICAL AND ECONOMIC VIABILITY 5.1. TECHNICAL VIABILITY OF BAR SOAP MAKING MACHINE In the analysis of the bar soap making machine in terms of technical viability, we took into account factors such as performance, environmental factors, maintenance, aesthetics/ergonomics, size and weight and safety. These are outlined below: 5.1.1. Performance In Kenya, electrical power is supplied at a rating of 240V, 50Hz. The bar soap making machine will use a motor of 2Hp and 1400rpm. From this and a variant for speed reduction, the machine will operate at a rate of 60 revolutions per minute to produce 304kg of soap per hour. The bar soap making machine is designed to run continually for 12 hours. The bearing is well lubricated to reduce friction. With adequate lubrication, there is minimal friction on the components leading to minimum heat generation. The bar soap making machine is designed to produce a rectangular shaped soap whose standard length is 50cm. 5.1.2. Environment The bar soap making machine can operate indoors and outdoors under normal working conditions. A motor insulation and protection is required to ensure that there is no sparking or arcing during operation due to the vibrations that are experienced during the operation of the bar soap making machine. 5.1.3. Maintenance Frequent lubrication of the bar soap making machine should be carried out. In addition to this general observation should be made to ensure that all the joints, bolts and nuts are well secured. For the above bar soap making machine innovation, maintenance takes a short time since it is smaller and most parts can be easily accessed.

39

5.1.4. Aesthetics The bar soap making machine is painted in blue to give it a fine finish. The color can also change according to customer specification. 5.1.5. Safety A guard is installed around the pulley system to prevent any injury that may arise. All metal edges are also blunted out to prevent cuts and bruises. 5.2. ECONOMIC VIABILITY OF THE BAR SOAP MAKING MACHINE With the objective of designing a bar soap making machine suitable for the soap industry in Kenya, it is of paramount importance to get a machine which can be fabricated locally. From the available materials and manufacturing methods, we chose cheap but appropriate combinations in order to get the most economically viable design. Considerations put in place in the design and choice of materials for the various parts of the bar soap making machine included the type, direction and operating speed, machinability and castability of the part material, cost of material and fabrication, material property and aesthetics. With the above total cost of manufacture of the bar soap making machine, it would be affordable for the soap industry as opposed to the imported machines. It would in turn lead to a reduction of bar soap retail prices which would improve the competition from imported bar soaps. Mass production of this machine would further lead in the lowering of the cost of production due to the benefit of economies of scale.

40

CHAPTER 6 CONCLUSION AND RECOMMENDATIONS 6.1. CONCLUSION The current design of the bar soap making machine has overall dimensions of 1350mm length, 500mm width and the total height 920mm. Focus is laid on the reduction of the bulk and overall price of the machine without compromising on the quality of the bar soap produced. To achieve this, the working mechanism of the bar soap making machine is designed so that the total number of moving parts is reduced to a necessary few. All motion of the bar soap plodder is conveyed from the motor to the extrusion shaft through a pulley system. This modification aided by sufficient lubrication of the machine has also rendered the machine to be adequately water cooled. Careful selection of materials observed while considering their availability without compromising on the durability of the bar soap making machine once it is fabricated. On the subsequent implementation of the above design, the cottage industry will tend to develop having introduced a business opportunity. This is a blue ocean venture that will enable not only the creation of jobs but will also, in line with vision 2030, boost the Kenyan economy. This would also come by way of reducing the cost of bar soap. This project is also aimed at cutting down the prices of bar soap making machines which are imported. By introducing this cheap and economical bar soap making machine into the Kenyan market, there would be competition with the imported machines and this would eventually lead to the reduction of bar soap prices. As is evident from the cost analysis of the bar soap making machine, it is much cheaper than the existing bar soap making machines and can be manufactured locally from the available materials. Operation of the machine is possible under normal conditions as experienced in workshops. Ingress of dust should be avoided by maintaining a clean working environment. This gives longer service life for the motor and eventual reduction in the cost of production. This bar soap making machine is found out to be economically viable as analyzed above. Its implementation 41

has the potential of promoting the manufacturing industry in Kenya along with the creation of employment opportunities for the Kenyan people. 6.2. RECOMMENDATIONS The bar soap making machine innovation can produce bar soap of between 6cm by 3cm and 8cm by 4cm. There is, however, a need for bar soap of other different sizes so there should be an innovation to this effect.

42

REFERENCES 1. Khurmi, R. S. (2004). A Textbook of Machine Design (14th Edition) Eurasia Publishing House (PVT) LTD. 2. Micheal Ashby, Hugh Sherdiff and David Ceba (2007) Material Engineering Science Processing and design. 3. George E. Dieter, (1988) .Mechanical Metallurgy SI Metric Edition. McGraw-Hill Book Company 4. William D. Callister, Jr and David G.Rethwisch, (2010) Materials Science and Engineering an Introduction – 8th edition. John Wiley & Sons. Inc 5. Cavitch, Susan M. The Natural Soap Book (1995): Making Herbal and Vegetable-Based Soaps. Storey Communications. 6. Maine, Sandy. (1995) the Soap Book: Simple Herbal Recipes. Interweave Press 7. http://www.madehow.com/Volume-2/Soap.html#ixzz3xmlMbeb7 8. https://cosmeticskenya.wordpress.com/2014/09/16/bar-soap-business-in-kenya-2/ 9. http://www.madehow.com/Volume-2/Soap.html 10. http://www.detergentsandsoaps.com/articles/bar-soap.html 11. www.ageraab.se/uploads/categories81.pdf 12. http://www.pumpsandsystems.com/topics/motors/relationship-torque-and-shaft-size 13. www.hanserpublications.com/.../9781569904480_SAMPLE%20C..

43

APPENDICES

APPENDIX 1: COST EVALUATION OF THE BAR SOAP MAKING MACHINE

No.

ITEM

MATERIAL

QUANTITY

COST PER

TOTAL COST

(Kshs) (Kshs)

Kg 1.

Motor

2.

Pulley

3.

Pulley Guard

4.

Variable Speed

Unit

1

10,000

10,000

Cast Iron

2

500

1,000

Mild steel

1

500

500

1

6,000

6,000

1

10,000

10,000

drive 5.

Mixer

6.

Bearings

Aluminum

1

100

100

7.

Hopper

Mild Steel

1

700

700

8.

Extrusion shaft

Mild Steel

1

12,900

12,900

9.

Extrusion Shaft

Mild steel

1

1,000

1,000

Mild steel

20

400

8,000

housing 10.

Frame Mounting

11.

Mixing tank

Mild Steel

1

7,000

7,000

12.

Die Block

Cast Iron

1

7,500

7,500

13.

Bolts and Nuts

Alloy Steel

15

70

1,050

14.

Timing Belt

Rubber

1

1,200

1,200

15.

Immersion

1

3,500

3,500

Heater 44

16.

Fatty Acid

5kg

1,000

5,000

5,000

17.

Perfume

50grams

500

500

500

18.

Distilled water

15liters

250

3,750

3,750

19.

Oil soluble

5liters

80

400

400

20.

Sodium silicate

10kgs

200

2,000

2,000

21.

Kaolin Powder

6kgs

1,000

6,000

6,000

22.

Sodium

10kgs

500

5,000

5,000

hydroxide 23

Paints

5litres

200

1,000

1,000

24.

Brush

2

100

200

200

25.

Labor

16,000

16,000

26.

Miscellaneous

5,000

5,000

TOTAL

115,300

45

APPENDIX 2: DRAWINGS BLOCK DIAGRAM OF THE HOUSING AND HOPPER

46

THE HOPPER

47

BLOCK DIAGRAM OF BAR SOAP MAKING MACHINE SIDE VIEW

48

FRONT VIEW

49

TOP VIEW

50

HOUSING AND PLODDER

51

DIFFERENT VIEWS OF THE HOUSING AND HOPPER

52

SCREW CONVEYOR AND ITS DIMENSIONS

53

DIFFERENT VIEWS OF THE TIMING PULLEY

54

TIMING PULLEY BLOCK DIAGRAM

55

BEARING

56

SOAP PLODDER FROM KIRDI

57

SOAP PLODDER FROM Kenya Industrial Research & Development Institute (KIRDI)

58