me 6606 - project report

DESIGN OF BINS FOR FOOD WASTE MANAGEMENT SYSTEM

ME 6606 COMPUTER AIDED PRODUCT DEVELOPMENT

GREEN BIN RECYCLOMANIA

ARAVIND BASKAR A0136344J

ANIRUDH AGARWAL A0147793N

ELEFTHERIOS CHRISTOS STATHARAS A0135961B

VADRI SIVA SAI A0146540L

ME 6606 Computer Aided Product Development

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TABLE OF CONTENTS

Introduction ....................................................................................................................... 2 Background ........................................................................................................................................................ 2 Observations and customer needs ....................................................................................................................... 3 present technologies ............................................................................................................................................. 4 Customer needs: ................................................................................................................................................. 5 concept generation and selection ......................................................................................................................... 9 External Search Results ...................................................................................................................................... 9 Internal Search Results ..................................................................................................................................... 10 concept Selection Matrix: ................................................................................................................................. 12 Design concepts iteration & Final Design ........................................................................................................ 12 detailed design steps .......................................................................................................................................... 13 Stress analysis ................................................................................................................................................... 17 Product Specifications....................................................................................................................................... 21 Cost Analysis [6-18] ............................................................................................................................................. 22 Cost of Material ............................................................................................................................................... 22 Cost of equipment ............................................................................................................................................ 23 Pay of employees and rent ................................................................................................................................ 23 Business model.................................................................................................................................................. 23 Final model: ..................................................................................................................................................... 24 Summary: ......................................................................................................................................................... 25 Financials: ........................................................................................................................................................ 25 Conclusions and recommendations ................................................................................................................... 26 References ......................................................................................................................................................... 26


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INTRODUCTION

BACKGROUND

The modern life has high consumption rates which result in a negative impact on the environment. Every year

2.12 billion tons of waste is generated globally. Because of this large amount of waste, countries are trying to find a convenient and efficient waste management system to reduce the overall impact of waste. In order to achieve that, the waste management is moving towards processing and recycling wastes. The true aim of every system that aims to minimize the impact of wastes is to find a way to minimize the waste. In order to reduce the waste generated a deeper communication and community participation is needed so that the people can understand the economic and environmental impact their waste have.

Its crucial in order to have a functional waste management system, to cover all the dimensions. The most important dimension is of that of the political and administrative, since this will oversee and control all the minimization, recycling and disposal processes.

According to the United Nations, one third of the food waste produced for human consumption every year gets lots or wasted. This amounts to US$ 680 billion in industrialized countries and US$ 310 billion in developing countries. Every year, consumers in rich countries waste 222 million tons of food, which is almost as the entire net

food production of sub-Saharan Africa (230million tons).

More specifically, Singapore aims to be zero waste country. Working towards this goal, Singapore has integrated a lot of mechanisms to improve waste recycling and disposal. Pulau Semakau is an island located to the south of mainland Singapore, and there is the only remaining landfill of Singapore on the eastern side of the island. It covers of a total area of 3.5 km2 and has a capacity of 63million m3. In August 2011 it was estimated that this landfill which began operation in 1999 will last until 2045. In order for that deadline to be extended the Singaporean government has implemented various ways of minimizing and recycling the waste.

Figure 1. Pulau Semakau

Working towards that goal in 2014 it generated 7.5 million tons of waste and managed to recycle 4.5 million tons. From these numbers close to 800,000 tons of waste were food and of those only 100,000 tons were managed to be recycled. This study aims to develop and incrementally integrated system for food waste management. The system aims to be integrated in households, HDB complexes and hawker centers in steps with increasing degrees of change. The resulting system hopes to increase the amount of food waste recycled and inform the public about waste management.


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OBSERVATIONS AND CUSTOMER NEEDS

The bins that are currently being used are not used very efficiently. The trash is not separated and thus making recycling, difficult if not impossible. Also the trash care loosely packed together which leads to bins being full fast and lots of waste being around the bins. This leads to an increasing time for waste collection and a potential public health risk

.

Figure 2. Singaporean food waste statistics

Graph 1 shows data collected from the ZerowasteSG website, which shows the low amount of food waste recycled and the potential for further enchantment. In order to achieve that, the public should first be informed and educated about the environmental and economic impact their waste have and then a system should be designed in order the food waste to be efficiently and conveniently recycled.

Figure 3. Inefficient food waste management system

Types of waste classification in Singapore [1]:

% Composition of Waste Generated: The top 5 waste types make up 75% of the total waste generated in Singapore, which are either disposed of at the waste-to-energy plants and landfill, or recycled locally and exported:

Ferrous Metal (19%) Construction Debris (17%) Paper/Cardboard (16%) Plastics (12%) Food Waste (10%)

% Composition of Waste Disposed: The top 3 waste types make up 68% of the total waste disposed in Singapore:

Plastics (26%) Food Waste (23%) Paper/Cardboard (19%)

http://www.zerowastesg.com/


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% Composition of Waste Recycled: The top 3 waste types make up 74% of the total waste recycled in Singapore:

Ferrous Metal (31%) Construction Debris (28%) Paper/Cardboard (14%)

PRESENT TECHNOLOGIES

In order to find a way to implement the Reduce Reuse Recycle concept we considered three different concepts that we could potentially use.

1) Efficient Packaging mechanisms

Today, there is no efficient mechanism to collect the waste and package it in order to further process them. The wastes are disposed in bins without any form of strategy and then the trash is being collected in order to be transported into landfills. The team would aim to come up with a concept for a more efficient packaging of the waste in order for the collection to be easier and less frequent.

2) Incineration

Incineration is a way to combust organic substances contained in waste materials. This combustion will create ash, flue gas and heat which can be used to generate electric power. The team could design an easy process for each household to use its wastes in order to generate power.

3) Composting Anaerobic Digestion

The third way is to focus on organic waste and develop a bin and a process in order to make composting easier for the user. This process will help increase the recycling rate of food, while at the same time provide natural and organic fertilizer in order to grow more natural crops. Another way to use organic waste is anaerobic digestion which in the process of breaking down the organic matter to produce fertilizer, also produces natural gas which can be used to produce electricity. The team would be able to come up with a bin to facilitate the composting process for the users and also, design a way anaerobic digestion can be used to benefit the society.

For this project we focused our study in organic wastes so and the final concept was a combination of concept 1 and 3. Incineration was immediately disqualified because of its byproducts is causing an environmental impact. The idea for the use of biogas for anaerobic digestion was also ruled out after taking into consideration an expert in waste management who suggested that the installation of biogas plant in populated areas would not be feasible.

So the aims of this project is to design a system that will involve the optimization of a bin and the processing of waste and the setting up a location that the users can deposit food wastes.

The system aims to use full capacity of the bin in order to store organic waste. The system aims to process waste in order to have large surface area The system aims be help people recycle their food waste conveniently The system aims promote environmental awareness


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CUSTOMER NEEDS:

Based on the teams understandings of the general problem, the team designed a survey so that they could learn from the customers what is it that makes them not recycle their food waste and what is important for their bin to have.

Demographic

The survey was conducted using googles integrated survey system and overall of 75 people out of whom 33 were female and 42 were males. The people were chosen to live in different housings like HDB (28%) Condominiums (29.3%) landed houses (22.7%) and dormitories/ hostels (20%). The professions of the customers varied from students to engineers, researchers and IT consultants and their age group ranged from 21 to 55 years old.

Questions about current waste disposal and composting

The first set of questions was designed to understand the current practice of waste disposal. A remarkable 80% answered that they throw away their food waste together with all the other waste in their home. While most of the people (84%) have heard of composting, they didnt know that 80% of the food wastes end up in landfills.

Figure 4. Customer Survey

Next, we found out that most of the customers have not tried composting for various reasons. Most common reason for the people not trying composting is that they lack knowledge in doing (24%) it and that they dont have space in their homes (17.3). Surprisingly the fear of smell wasnt very prominent within the sample with only 10.7% answering that they are afraid that it will smell and attract insects. For people that have tried composting in their homes, when asked what was the main problem they encountered was that it resulted in a bad smell (16%) and that they couldnt find a suitable bin (13.3%). Interesting enough is the fact that some of the respondents indicated that Singapore doesnt have a proper general strategy in order to take care of their food waste. Overall despite the difficulties that composting has people seemed really interested in trying composting in their own homes (72%).


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Our next set of questions was aimed to understand the features that the current bins have. The majority of the people used bins with cover either plastic (42.7%) or metal (5.3%). As to the main problems these bins have is a mix of liquid and content spillage during to overflowing. Additionally, when the customers were asked what is the most important feature they want their bin to have they replied that, hands free use (41.3%) was very important while, high capacity (24%) and affordable price (20%) also ranked pretty high.


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Lastly, in the question If there was community wide composting project for food waste, where food waste would be collected from each household, would you want to participate?, 86.7% of the participants responded that they would be interested and all of them would be willing to separate their food waste from their normal waste in order to participate to the community wide composting project.



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CONCEPT GENERATION AND SELECTION

During this stage, the team brainstormed ideas in order to see how we can address the problems that were identified during the customer survey. At first an external search was carried in order to see what products are available in the market that might be able to help us in the solution of some of the problems. Next the team did an internal search by brainstorming ideas and trying to give solutions to the problems like:

How can be the waste stored without any inconvenience? How can the process of composting be easier? How can the involvement of the people be minimized?

In the next section the results of the external and internal search are presented and later the concept selection matrix is presented.

EXTERNAL SEARCH RESULTS

1. In-house bio gas plant [2]: The concept of producing biogas in everyones home is something that the company Home Biogas has tackled by their product. The product aims to recycle organic waste at the source, generating Biogas in the eco-friendliest and effective way. The product can be installed in the backyard of peoples homes and the customer can add food and animal waste continuously in the bin. The price of such a bio gas plant is 1500 USD and can digest 6 liters of food per day. Pros: Biogas Production using a continuous process Cons: Very large, very expensive, and user involvement is large

Figure 8. In-house Biogas Plant

2. In-house composting bin [3]: This product aims to make the composting process less complex by integrating a three bin vertical system. The bin gets aerated naturally and material can be continuously inserted from the top, and the compost can be removed from the bottom when needed. The bin aims to be more productive from traditional do-it-yourself bins using this 3 step process and by having a capacity of 466l. The cost of the bin is 200USD. Pros: Composting using a continuous process Cons: Very large, expensive, and user involvement is large


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Figure 9. In-house Composting Bin

3. Totem 60 Waste Separation & Recycling Unit [4] This bin is an all in one bin with different compartments in order to combine different kinds of waste. It features a food caddy for all the food waste, a general waste compartment and a multi-purpose drawer so the user can choose what to recycle. The price of the bin is 250 USD

Figure 8. Retail Product

INTERNAL SEARCH RESULTS

For the internal search results we considered two problems that needed to be addressed. The first problem was to choose how the storage would be stored. The second problem was to see how the waste could be processed in order to have a large surface area.

1. Storage options: a) The first option considered is a sliding metal box that could store organic waste and could also be sealed in

order to avoid smell, leakage and content spillage. The box should be made of a metal in order for it to be recyclable and to be sturdy. Because of its properties the box is going to be reusable and could be beneficial to any modular design. Also an option like this is going to be relatively cheap since its a simple design, and reusable. Pros: Sturdy, Reusable, Good for modular design, cost Cons: Bulky, inflexible.


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b) The second choice for storing the waste is a biodegradable bag. Changing the bags that lots of the customers use from plastic into a biodegradable material, can prove very convenient since the users are already using a similar product. The bags would be disposable and could be directly used for composting. Pros: Small, Convenient, Disposable Cons: needs to be designed.

Figure 9. Storage Options

2. Processing options: a) Vertical Mincer: For the processing of the waste two options were considered. First a vertical mincer that

would receive waste from the top and then the passing the waste trough the mincer would result in food waste in a much smaller size. The rotation of the mincer would be from the top using a handle. Pros: Small, easy collection Cons: Not ergonomic rotation

b) Horizontal Mincer: The second choice for processing the food waste is a vertical mincer. This mincer would receive the waste from a funnel at the side of it and then as in the case of the vertical mincer, the waste would go through the mincer and would result in food waste in a smaller size. The horizontal axis of rotation is more ergonomic but the resulting product would be large overall. Pros: Ergonomic processing Cons: Large, a flexible collector cant be attached to it.

Figure 10. Processing Options

VERTICAL HORIZONTAL


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CONCEPT SELECTION MATRIX:

The selection matrix was constructed using: space, cost, ease of use and recyclability as parameters. The products that were benchmarked were the three concepts that were found during the external search, plus three concepts that were born by combining storage and processing options that were found during the internal search. By looking at the selection matrix, we saw that that the concepts of using a horizontal mincer with a box and a vertical mincer with a bag were scoring higher than any other concepts. So our process for designing the product began having these results in mind.

DESIGN CONCEPTS ITERATION & FINAL DESIGN

Design-1

Figure 11. CAD Model of Design - 1


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Design-2

Figure 12. CAD Model of Design - 2

We have considered two designs initially. Among the two designs design-2 is selected for simulations because of its flexibility and usage of lesser design components and the steps have been detailed.

DETAILED DESIGN STEPS

Setting Dimensions Iteration 1: Conceptualization The first design was made to demonstrate a simple crushing mechanism that can be used for our purposes. Initially it was just made considering the diameter of rotation to be ergonomic for use by people. Thus the approximate length from palm to elbow of the team members was used to get the initial diameter. With that the following design was produced:

Figure 13. Design Conceptualization in CAD


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The initial design did not consider joining, assembly or manufacturability either. The top mover made of hard wood had spokes inbuilt in it and the screw flange was attached to the spokes without regard to physical constraints and assembly. Figure 14 shows the mechanism showing how the screw was mounted.

Figure 14. Mechanism Conceptualization

This design did not consider the weight of components. The screw was initially designed for crushing and not shredding and thus had very thick blades (2cm) as shown:

Figure 15. Initial Design of Screw

The screw was initially thought to be made of SS to be food grade. The screw alone had a volume of 9334.45 cc which gives it a weight of about 75 kg! Iteration 2: Functional Design Due to the impracticality of the previous design, there was severe redesign required to make the design more functional. Thus dimensioning was done starting from the volume of waste per week that had to be contained. As calculated before, about 9kg of waste is produced in a week. Thus the volume required should be enough to be able to accommodate roughly 9kg of water as the density of water is slightly less than most foods. Thus net volume needed = 9L. The shape of the bag was to be roughly cylindrical to be most space efficient while maintaining axial symmetry. Symmetry is needed since the opening between the screw and the holder from which the food comes is also axially symmetric. The height is taken roughly equal to the diameter for ease of handling and ease of calculation.


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Figure 16. Design of bag for Collecting wastes

To get a volume of 10L, where H = 2R we have: 9000 = 23 = 11.27

Also it is noted that the lower diameter of the bag should be less than the top diameter so that it easily fits in a regular cylindrical wire bin as shown in figure 1. Take a top diameter of 12cm (R) and a bottom diameter of 10cm (r) and a length of 24cm (H). The volume of the resulting frustum is given by:

=13

(3 3) = 9148.32 > 9

To avoid sharp corners in a fabric bag, a fillet of 3cm is also given at the end which further reduces the final capacity.

Figure 17. Design of Holder Block

Based on the 12cm top radius, giving extra room for the food to fall beyond the boundary of the holder block, the inner diameter of the holder block is chosen to be 20cm. To save volume it is made of 1cm thick material with screw holes to attach to the frame. In order to give a clearance of 5mm for the food to escape so that the final particles are in the size range of millimeters to centimeters, the maximum diameter of the screw is given at 19cm. The screw is given 4cm long blades at the lower end. So at the base of the blade diameter is 11cm.

Figure 18. Design of Screw & Shaft


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In order to reduce overall screw volume, the screw is hollowed out, giving a wall of 5mm, thus the inner diameter of 10cm. A wooden shaft goes through the screw which is fastened to it using 6 screws as shown. The 4 screw holes on the top of the wood block are to attach to the top mover, while the 4 holes at the bottom are to attach to the bearing at the base of the holder block. The wooden frame was first designed to have handles so it I easy to pick up. It had all the holes to screw all metal and wood parts together to assemble the bin. The full bin initially looked as follows:

Figure 19. Assembly View

Figure 7 shows how every component has holes for screws to hold various parts in place together. For connections to the frame, M10 screws are used in the holder block. For connection of wood parts to each other and to circular portions, M6 screws are used. The wood used is 1cm thick and M6 holes are made along the thickness so that screws can be attach to connect to wooden portions. Iteration 3: Aesthetic Design The previous design looked like a UFO and people are not expected to lift a 20kg bin very often. Moreover, they want the hideous mechanism and parts to be hidden to give a standard box shape. Thus the final design was born as shown below:

Figure 20. Final CAD Model


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STRESS ANALYSIS

The hardest material in food waste is usually bone. We made the design based on the ability of it to be able to crush bone.

Material Youngs Modulus, E (GPa)

Collagen (dry) 6

Bone mineral (Hydroxyapatite) 80

Cortical bone, longitudinal 11-21

Cortical bone, transverse 5-13

Longitudinal direction Transverse direction

Tensile strength (MPa) 60-70 ~50

Compressive strength (MPa) 70-280 ~50

Typical stress-strain curves for compact bone, tested in tension or compression in the wet condition, are approximately a straight line. Bone generally has a maximum total elongation of only 0.5 - 3%, and therefore is classified as a brittle rather than a ductile solid. So bending force on blade F= transverse compressive strength of bone*area of contact. Area of contact = thickness of blade*width gained from transverse compression of bone. Thickness of blade t= 3cm-1cm of fillet = 20mm. Let width gain be w which depends on the change in radius or directly on area strain as shown.

Area Strain =2

;

= 1 cos() = 2 sin2 2 ; = 2 sin() = 4 sin

2 cos

2 ;

2 2

= 2. Stress = area strain*elastic modulus = and this stress should be equal to the

compressive strength, for failure = 50 MPa, =

= 5080 103 = 0.000625. The radius of a bone would

be half of the clearance available. Initially the clearance given was = 1.5cm/2 r = 7.5mm. Thus w=0.375m. Hence the transverse force = , where t is the thickness at tip. Initially we started with a tip of 2cm end thickness. This gives F=375N. Later we made the end sharp so as to be able to shred and slice food and also to reduce contact area and hence friction. A sharp end would prevent the blade getting stuck. The new design was made much smaller so it is lighter and easier to manage. It also gave less clearance so the food is shredded to smaller bits for a more efficient division. The new minimum clearance at the end of the screw was from 20cm inner diameter of the holder block to 19cm max diameter of screw blade. Thus r=2.5mm, w = 0.125mm. While designing, for ease of manufacturing and making the blade not too slender, a base thickness of 8mm was used. The tip does not have a defined thickness but through usage and wear and tear we assume the edge thickness (t) to go up to 1mm. This gives a force F=6.25N. The maximum clearance was at the top where the diameter was 15cm. This gives clearance of 2.5cm or r=12.5mm, w = 0.0625mm for the same thickness of 1mm, we get = . or around 3.2kgf transverse force. Axial force

To push food, the edge of the blade should be able to crush a bone in the axial direction standing vertically on the base of the holder block. Compressive strength in the longitudinal direction ~70-280MPa. Take 300MPa. Length of bone getting embedded in the blade =r = 0.004mm. Assuming 10 times of that we have = 0.04 of bone embedded in the blade. Thus the force per unit length along the edge of the blade is = 0.04 = 12 /. The blade being 4cm long has a base radius of 5.5cm while the edge radius is 9.5cm.


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The change in radius increases force per unit length at the base by the same factor giving = 12 9.55.5

=

20.73 /. Moment per unit length is given by: = 4 = 829.1 . Bending stress =

where M is the moment, y is the distance from the neutral axis and I is the area moment of inertia about the

neutral axis. Taking a cross section of length dl along the blade: = and =3

12 Here b is the

blade thickness and = 2. This gives =

or = ----- (eq 1)

Here is the maximum allowable bending stress = tensile yield strength of the material. Taking = 250

we have = 6829.1250

= 4.46. The blades were already designed at 8mm base thickness which gives a

factor of safety of 1.79. For load simulation in solidworks only pressure can be applied.

So the initial edge force of = 12 / is converted to an equivalent distributed weight of w.

If the moment per unit length = where l is the length of the blade = 40mm, then for distributed weight

per unit length per unit length w, = 2

2.

Thus: = 22

= 21240

2 = 0.6 = The result of the simulation is as follows:

Figure 21. Analysis of the screw for bending due to axial force on blades

The top is fixed while the lower surface of the entire blade is given uniform pressure of 600 kPa. Note that the yield strength of Aluminium is 250MPa and the maximum stress experienced is 129.4MPa which is well below the limit still.

Torque requirement Assuming that the coefficient of friction is maximum is 1. Then the bending load on the blade edge will be equal to the tangential force on the same edge.


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This gives a tangential force of 12N/mm, applied for the corresponding width = 22

= 250.0812.5

= 2

where = 0.04 = 12.5 This gives a tangential force of = 24~2.45 applied at 9.5cm radius. This will translate to force at the top handle of =

9.511

as the handle is in a circle of diameter 21cm. This gives ~2.1 An average man can apply 15kgf of pushing/pulling with 1 hand with ease (personal experience). Taking half of that for our maximum allowable limit, we have a force of 7.5kgf. This allowable limit is still ~3.4 times the load experienced in normal operation. Thus this design is easy to work with. This gives a torque requirement of = . = . shared by 4 screws at the top at a radius of 2.75cm. Each screw takes a load of =

40.0275= 20.73 As calculated before, additional transverse load is

31.25N which can be in any direction. Maximum net force per screw = 20.73 +31.254

= 28.54 For the poorest quality steel, the yield strength ~179MPa. This gives shear strength of = 89.5. Using this shear strength limit, we get a cross sectional area required per screw of: =

2 = 28.54

89.5=

0.31892 or a radius of =

= 0.3186 0.32.The screws used are M6 (r=3mm) but apparently

much smaller ones would do too. Weight of the entire bin is nearly 20kg (~200N). This is to be held by 8 screws

in the holder block. Cross sectional area required per screw: = 2008179

= 0.142 =0.345. Screws used are M10 (r=5mm). The screw holes are fixed while the rim where the handle connects to the body, is given a torque of 3 Nm (instead of the needed 2.28 Nm) as shown. The simulation results are shown in the following figure.

Figure 22. Torque analysis of top mover

Note that the yield strength of Aluminium is 250MPa and the maximum stress experienced is 1.36MPa which is well below the limit even with a torque of 3Nm instead of the required 2.28 Nm being applied.

Spokes design The entire weight of the bin is also required to be supported by the 3 spokes that hold the screw in the top mover and the holder block. Each spoke thus carries about 66.7N force which is at 10cm from the base of the spoke. This creates a bending moment of = 66.7N 0.1m = 6.7Nm


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The width of each spoke in both the top mover and the holder block are 2cm in width. For a thickness of b we

have an area moment of inertia of = 0.023

12 and =

2 for rectangular cross section.

The bending stress at the base of each spoke is given by = 30.012

=

Thus = 300203250

= 2.83 The thickness chosen was 1cm for ease of design. For easy flow of food over the surface it has been rounded using a fillet of 1cm radius. This reduces the cross section to a semi-circle for the spoke length but increases the cross section at the base even more to 2cm thickness and ~4cm width. This is definitely safe enough for the load. Note that the entire weight of the bin coming on the spokes is a worst case scenario when it gets stuck. The analysis for the spokes done in SolidworksTM for the holder block and the top mover as shown. The bottom rim of the top mover is fixed as it will be supported by the bearing while a 20kg force is applied to the surface where the wooden shaft is connected as shown.

Figure 23. 20 kg axial load stress analysis of top mover

For the screw holder, the side screw holes are made fixed (as they connect to the wood frame) while a 20kg force is applied to the surface where the wooden shaft rests as shown.

Figure 24. Axial load stress analysis of holder block

Note that the yield strength of Aluminium is 250MPa and the maximum von Mises stress experienced is 10.05 MPa in the top mover and 7.91 MPa in the holder bock which are both well below the limit even with a load of 20 kg which is slightly above the entire weight of the bin (17.42 kgs. In this light, the ability of the wood to be able to hold the weight of the entire bin was also tested by simple gravity analysis. The entire weight of the bin


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is (17.42 kgs). The holes for the screws connecting the holder block and the wood are constrained together while the weight of the bin is supported by the wood as shown:

Figure 25. Axial load stress analysis of holder block

The tensile strength of wood is given as: 57MPa which shows that this design is safe.

PRODUCT SPECIFICATIONS

After the above analysis, the final specifications of the product are described are as follows: Capacity: 9L

Dimensions: 30L * 30W * 75H

Materials: Aluminium, Wood


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COST ANALYSIS [6-18]

This cost analysis is done to incorporate the cost of manufacturing in the cost of the bin. This includes the following costs:

1. Material used in all parts 2. Equipment for manufacturing 3. Energy/power usage 4. Salary of employee personnel

COST OF MATERIAL

Cost of screws and fasteners: ~ 1 cent/piece 30 needed per bin: 0.3$/bin. Note patterns are assumed to last 100 parts but actual life is going to be much more. Total cost =35.75$ To get the cost right, find aluminum


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COST OF EQUIPMENT

Machines needed:

1. Lathes: a. Wood: for making wood block cost 800USD = 1086 SGD b. Metal: for finishing of metal parts and some hole drilling 1000USD = 1358SGD

2. Furnace: to melt castings: 50kg capacity 1000USD=1358SGD 3. Table top drill: to make screw holes cost 1358 SGD (1000USD) 4. Welding machine: cost=75USD=102SGD

Total cost of these machines is thus: 1086+1358+1358+1358+102=4302$. If each lasts for the first 500 bins ordered/made, we have cost of 4302/500=8.6$/bin. Total cost = 35.75+0.13+8.6=44.5$

PAY OF EMPLOYEES AND RENT

Taking a salary of 10$/hour and 5 bins made/hour by 1 person we have a cost of 2$/bin of manpower cost. Since bins are not produced all the time, a place to manufacture can be rented temporarily. Assuming that 2 people can work together by sharing various machines we have 10 bins/hour. For the first 500 bins we need 500/80 days or about a week. Monthly rent for enough space in SG would be ~ 2000$. So 500 bins need only 500$ worth of rent of a week thus rent = 1$/bin. Cost of power for Melting 50kg of Al (45MJ=12.5units(kW-hour)) at 0.18$/kwhr = 2.25$. Adding additional cost for operation of other machines ~2.5$. Cost of power per bin=2.5/4 = 0.63$. This gives a total cost inclusive of everything = 47.13$. Taking the price to be 50$ for simplicity and to accommodate for costs we may not have considered.

BUSINESS MODEL

Assumptions:

1. Bin selling price 100$. 2. SP of fertilizer = 0.25$ per kg waste (0.5kg/kg waste and 0.5$/kg) 3. We give 10% of total revenue from fertilizer to the following things:

10% is 0.025$/kg. Of that, we give benefits to customer 20% discount on buying fertilizer = 0.25*0.1*0.2=0.005 (If 10% of total is bought by customers). Remaining 0.02$/kg goes half to R&D and half to sales and marketing. So 10% revenue from fertilizer goes to 2% customer benefits, 4% R&D 4% sales and marketing

4. Bags cost 2$/kg. 1kg=50 bags so 0.04$/bag [5] 5. Pressure washing cost 1$/feet sq and total surface area of screw and block to be cleaned ~3k cm^2 so it is

0.05 US$/assembly ~0.1$/assembly 6. Cost of transportation and truck rent 1.8$/km 20km a trip=36$/trip 7. 4.5 change of bags in a month. Initially, 4.5 trips/ month since collection is direct 8. Each trip worker paid 10$/hr for 20 bags=0.5$/bag 9. 1 team of 2 sells bin to 20 households/month. We push harder in later stages to make it more for some

months increasing 10 households/ month so it is 3-5 households extra per team. 10. Stage 2: Based on capacity of holding 0.5 month of waste of 1 complex (400 households) = 400*20=8 tons.

This gives volume~16m3 which gives cost of ~300$ we add 200$ cost for a place for placing bags for collection.


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11. Once we have stage 2 collectors, we use 2 trips/month. 12. Based on truck capacity: ~14.5tons [6]

40kg waste/month/household gives 0.02ton/ half month. So truck can carry 725 households waste in 1 trip. For every 700 more households, we have 1 extra trip. Final rate at 7 years = 14 trips/month.

13. We always try to keep no of stages and bins more than requirement so we have room to spare as all localities are not in the same hdb complex and bin washing needs extra parts.

14. At the end we cover only 4500 households (~12 HDB complexes). Out of total households (1613700) this is only 0.28% of the houses. Which is reasonable.

FINAL MODEL:

STAGE 1: Collecting from individual houses

Year 1 Hire a team of 2 which covers 20 households a month. Order 500 bins and a 200$ lathe for wood working and making holes in wood and cast parts. [5] Cover 240 households

Year 2 Order 500 more bins totaling 1000 Cover 500 total households

Year 3 Order 750 more bins totaling 1750 Cover 760 total households By the end of the year purchase 2 stage 2 collectors. These can hold the waste for 800 households. Those collectors also give space for putting fresh bags for users to take while they dump used bags in the collection point.

STAGE 2: Collecting from central deposit

Year 4 Hire another team of 2 which covers 20 households a month total 40/month. Total 2 teams. Cover 50 in last month to give total 1250 houses covered Order 500 bins totaling 2250 and make Make 3 new collectors totaling capacity of 2000 households.

Year 5 Hire another team total 3 teams = 60/month. Last 3 month 70/month Total 2000 houses covered Order 750 more bins totaling 3000 Make 3 new collectors totaling 3.2k households capacity

Year 6 Hire another team total 4 teams = 80/month. Last 4 month 90/month Total 3000 houses covered Order 1000 more bins totaling 4000


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Make 2 new collectors totaling 4k households capacity

Year 7 Hire another team total 5 teams = 100/month for 1st 2 months. Then 130/month 10 months Total 4500 houses covered Order 1500 more bins totaling 5.5k Make 3 new collectors totaling 5.2k households capacity

SUMMARY:

At the end we have: 4500 households covered 14 trips a month 5500 bins 5200 household worth of collector capacity

FINANCIALS:

year 1 2 3 4 5 6 7

revenue 38040 85230 144310 235250 377660 573060 859050

cost 114866.8 122227.1 143620.7 227171.5 343315.2 467260.2 616450.5

income -76826.8 -36997.1 689.3 8078.5 34344.8 105799.8 242599.5

Investment needed 113823.9 5 yr return 43112.6

6 yr return 148912.4

Year 7 return 391511.9

5 yr cash on cash return 0.378766



Revenue growth rate year 3-6 158.35% 534.52%

58.35% by rev 434.52% by income

Revenue growth rate year 1-6 1.7202514 72%

Revenue growth rate year 3-7 156.20% 433.13%

56.20% by rev 333.13% by income

Revenue growth rate year 1-7 1.6812048 68%


Page 26 of 26

CONCLUSIONS AND RECOMMENDATIONS

Designed a model to incorporate profitable system for collection, processing and recycling of organic wastes.

Optimization of the bin has been done to use lesser material, but with same capacity. This project main intention is to increase the awareness about food waste recycling & involvement of

people. We were attempted to increase the energy production capacity in a year of up to 10% of total consumption

& reduction of carbon footprint by a significant margin.

REFERENCES

1. ZeroWaste Singapore 2. http://www.homebiogas.com/ 3. http://www.earthmaker.co.nz/ 4. http://asm.matweb.com/search/SpecificMaterial.asp?bassnum=MA6061t6 5. http://www.engineershandbook.com/Tables/steelprop.htm 6. http://www.alibaba.com/product-detail/100-PP-Spun-boned-Breathable-

Anti_60407812153.html?spm=a2700.7724857.29.28.LKxrJH&s=p 7. http://www.answers.com/Q/How_much_can_the_average_American_garbage_truck_hold 8. http://www.ebay.com/sch/Lathes-/57121/i.html 9. http://www.iron-foundry.com/green-sand-iron-casting-cost.html 10. http://www.amazon.com/dp/B0019CGYLM/?tag=woodlatherepo-20 11. http://www.ebay.com/itm/WARNER-SWASEY-TURRET-LATHE-MODEL-M-842-NO-8-

/220517742035?hash=item3357e1b5d3:m:m_vZy-PN91iAwRFyVKY1jKw 12. http://www.indexmundi.com/commodities/?commodity=aluminum&currency=sgd 13. http://www.hearnehardwoods.com/hardwoods/pricelist/pricelist.html 14. http://www.alibaba.com/product-detail/Thermal-conductive-silicone-

grease_1174483835.html?spm=a2700.7724857.29.3.sp9884&s=p 15. http://www.dhgate.com/product/welded-mesh-fence-with-iron-wire-material/372705800.html#se1-2-

1b;price|2195169337 16. http://www.alibaba.com/product-detail/low-price-Induction-Melting-Electric-

Furnace_60330039664.html?spm=a2700.7724857.29.12.CNYH5r&s=p 17. http://www.alibaba.com/product-detail/table-drill-machine-wmd25v-at-

discount_60323913494.html?spm=a2700.7724857.29.87.Vp7cZZ 18. http://www.alibaba.com/product-detail/2015-welding-machine-price-list-

WS_60280239608.html?spm=a2700.7735675.30.67.lpo4dk&s=p 19. http://www.hometowndumpsterrental.com/blog/futuristic-trash-and-recycle-bin-designs 20. http://www.nea.gov.sg/energy-waste/waste-management/waste-statistics-and-overall-recycling 21. http://www.atlas.d-waste.com/ 22. http://www.biomaxtech.com/web/index.php 23. http://www.engineeringtoolbox.com/wood-density-d_40.html 24. http://www.indexmundi.com/commodities/?commodity=soft-sawn-wood&currency=sgd 25. http://www.engineeringtoolbox.com/latent-heat-melting-solids-d_96.html

http://www.homebiogas.com/http://www.earthmaker.co.nz/http://asm.matweb.com/search/SpecificMaterial.asp?bassnum=MA6061t6http://www.engineershandbook.com/Tables/steelprop.htmhttp://www.alibaba.com/product-detail/100-PP-Spun-boned-Breathable-Anti_60407812153.html?spm=a2700.7724857.29.28.LKxrJH&s=phttp://www.alibaba.com/product-detail/100-PP-Spun-boned-Breathable-Anti_60407812153.html?spm=a2700.7724857.29.28.LKxrJH&s=phttp://www.answers.com/Q/How_much_can_the_average_American_garbage_truck_holdhttp://www.ebay.com/sch/Lathes-/57121/i.htmlhttp://www.iron-foundry.com/green-sand-iron-casting-cost.htmlhttp://www.amazon.com/dp/B0019CGYLM/?tag=woodlatherepo-20http://www.ebay.com/itm/WARNER-SWASEY-TURRET-LATHE-MODEL-M-842-NO-8-/220517742035?hash=item3357e1b5d3:m:m_vZy-PN91iAwRFyVKY1jKwhttp://www.ebay.com/itm/WARNER-SWASEY-TURRET-LATHE-MODEL-M-842-NO-8-/220517742035?hash=item3357e1b5d3:m:m_vZy-PN91iAwRFyVKY1jKwhttp://www.indexmundi.com/commodities/?commodity=aluminum&currency=sgdhttp://www.hearnehardwoods.com/hardwoods/pricelist/pricelist.htmlhttp://www.alibaba.com/product-detail/Thermal-conductive-silicone-grease_1174483835.html?spm=a2700.7724857.29.3.sp9884&s=phttp://www.alibaba.com/product-detail/Thermal-conductive-silicone-grease_1174483835.html?spm=a2700.7724857.29.3.sp9884&s=phttp://www.dhgate.com/product/welded-mesh-fence-with-iron-wire-material/372705800.html#se1-2-1b;price|2195169337http://www.dhgate.com/product/welded-mesh-fence-with-iron-wire-material/372705800.html#se1-2-1b;price|2195169337http://www.alibaba.com/product-detail/low-price-Induction-Melting-Electric-Furnace_60330039664.html?spm=a2700.7724857.29.12.CNYH5r&s=phttp://www.alibaba.com/product-detail/low-price-Induction-Melting-Electric-Furnace_60330039664.html?spm=a2700.7724857.29.12.CNYH5r&s=phttp://www.alibaba.com/product-detail/table-drill-machine-wmd25v-at-discount_60323913494.html?spm=a2700.7724857.29.87.Vp7cZZhttp://www.alibaba.com/product-detail/table-drill-machine-wmd25v-at-discount_60323913494.html?spm=a2700.7724857.29.87.Vp7cZZhttp://www.alibaba.com/product-detail/2015-welding-machine-price-list-WS_60280239608.html?spm=a2700.7735675.30.67.lpo4dk&s=phttp://www.alibaba.com/product-detail/2015-welding-machine-price-list-WS_60280239608.html?spm=a2700.7735675.30.67.lpo4dk&s=phttp://www.hometowndumpsterrental.com/blog/futuristic-trash-and-recycle-bin-designshttp://www.nea.gov.sg/energy-waste/waste-management/waste-statistics-and-overall-recyclinghttp://www.atlas.d-waste.com/http://www.biomaxtech.com/web/index.phphttp://www.engineeringtoolbox.com/wood-density-d_40.htmlhttp://www.indexmundi.com/commodities/?commodity=soft-sawn-wood&currency=sgdhttp://www.engineeringtoolbox.com/latent-heat-melting-solids-d_96.html

IntroductionBackgroundObservations and customer needspresent technologiesCustomer needs:concept generation and selectionExternal Search ResultsInternal Search Resultsconcept Selection Matrix:Design concepts iteration & Final Designdetailed design stepsStress analysisProduct SpecificationsCost Analysis [6-18]Cost of MaterialCost of equipmentPay of employees and rentBusiness modelFinal model:Summary:Financials:Conclusions and recommendationsReferences

me 6606 - project report

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