Blog Entry 5

Hey guys it's me again. It has been almost a month since I last updated you guys! Anyways school was out for almost a month and in the past few weeks we learnt about Material For Design (MFD), Design For Material (DFM) and Sustainable design. For those who are unsure of these terms do not worry I will be explain more later so stay tune as you wouldn't want to miss it!

Week 11

Before we started MFD, Mr Chua let us watch two videos:

• The first video about how the world and everything around us is made out of materials. We often take them for granted and do not think much about them yet they are so important as different materials serve and sustain many needs in our life. Mankind is divided into different ages and era; the Stone Age, Bronze Age (Copper+Tin), Iron Age, Light Alloy Age, Plastic Age and Nano-material Age (Current era).
• The second video was about Classification of materials: Natural Material, Metals and Alloys, Ceramics, Polymers and Composite. Each material also has its unique characteristics.

Material For Design (MFD)

Each material have different properties which serves different purposes. We learnt material for design, our goal is to select the most suitable material that not only select the most suitable material that allow product to function as per our intended design but also enhance its competitiveness through cheap and easier manufacturing. 

We were tasked to select materials for a single use (disposable) water bottle that does minimal environmental damage:

There were three parts to selecting a material 

1. Listing the material requirements

2. Select and Evaluate Candidate Materials

3. Choose the Economical Material 

1.Listing the material requirements 

The very first step to selecting appropriate material is to list down the material requirement which  includes its Function (e.g. School bag- store books, writing materials, laptop.....), Constraints (e.g. School bag- high tensile strength), Objectives (e.g. School bag- cheap and affordable)

Single use (disposable) water bottle:

- Bottle Cap 

- Bottle body 

                                                 Bottle Cap 

Function	Contain drinks
Constraints	Non-reactive to food ingredients Corrosion resistances to slightly acidic and alkaline solutions Non-permeable to liquids
Objectives	Low density (Lightweight) Cheap and affordable  Minimal environmental harm

                                           Bottle Body

Function	Serves as an opening
Constraints	Non-reactive to food ingredients Corrosion resistances to mild acid and alkalis  Non-permeable to liquids Hard
Objectives	Keep the drinks within the bottle (tight)

2. Select and Evaluate Candidate Materials

Next up, we need to select a suitable material class. Before that we need to consider the mechanical, thermal, fabrication and environmental properties.

Under mechanical properties we have:

1. Strength: Yield Strength;Ultimate tensile strength; Shear Strength 
2. Ductility 
3. Young's modulus
4. Poisson's ratio
5. Hardness
6. Creep
7. High or low temperature behaviour
8. Density
9. Anisotropy
10. Fracture Toughness
11. Gas and Liquids: Viscosity 

Under thermal properties we have:

1. Thermal conductivity 
2. Thermal expansivity 
3. Specific heat capacity

Under fabrication properties we have:

1. Ease of machining 
2. Ease of welding, casting
3. Hardening ability
4. Formability
5. Availability
6. Joining techniques

Under environmental properties we have:

1. Corrosion Properties
2. Toxic Effects
3. Polluting Effects

In our case of a single use (disposable) water bottle, these are the material attributes:

Material attributes for Bottle Body

• High Young’s Modulus (stiff, highly resistant to elastic deformation)

• Low thermal conductivity 

• Non-reactive 

• High elongation at break (high ductility, non-brittle)

• Low density (lightweight)

• Corrosion resistant

• Biodegradability

• Hydrophobic (water cannot get in easily)

Material attributes for Bottle Cap

• High Young's modulus
• Non-reactive
• Low thermal conductivity
• Low density

Hence the material class of polymers was selected based on the material attributes need.

Now that we have found the material class, we will be selecting a few materials from the class of polymers and compare it against other polymers by using a COWS Matrix table to shortlist the material to use.

Bottle Body

		Options
Criteria	Weightage (%)	Polypropylene (PP)	Polybutylene adipate terephthalate (PBAT)	Polyethylene terephthalate (PET)	Polylactic acid (PLA)
High Young’s Modulus (GPa)	20	4.129 Score: 4 25 x 4 = 10%	0.54 Score: 1 25 x 1 = 25%	3.385 Score: 3 25 x 3 = 75%	3.28 Score: 3 25 x 3 = 75%
Low thermal conductivity (W/m-K)	15	0.2 Score: 3 15 x 3 = 45%	0.2445 Score: 3 15 x 3 = 45%	0.24 Score: 3 15 x 3 = 45%	0.101 Score:2 15 x 2 = 30%
High elongation at break (%0	15	296.5 Score: 4 15 x 4 = 60%	100 Score: 2 15 x 2 = 30%	302 Score: 4 15 x 4 = 60%	57.5 Score: 1 15 x 1 = 15%
Low density (g/cc)	20	1.64  Score: 1 20 x 1 = 20%	1.41 Score: 2 20 x 2 = 40%	1.15 Score: 4 20 x 4 = 80%	1.1 Score: 4 20 x 4 = 80%
Low water absorbability (%)	25	0.5 Score: 3 25 x 3 = 75	0.300 Score: 4 25 x 4 = 100	0.425 Score: 3 25 x 3 = 75	1.03 Score: 1 25 x 1 =25
Total	100	280	235	320	210

• The Young’s Modulus is given a rating of 20%. A high Young’s Modulus is desirable as the bottle will be stiffer and more resistant to elastic deformation. This allows the bottle to retain its shape better under deformation.

• The thermal conductivity is given a rating of 15%. A low thermal conductivity would be preferred as the rate at which the bottle body conducts heat when it is subjected to a unit change in temperature per unit thickness will be lower and hence the bottle will conduct less heat energy, restricting quick heat transfer from the user’s hand to the bottle and its contents.

• The elongation at break is given a rating of 15%. A high elongation at break is ideal as the bottle will not be brittle and break easily when dropped.

• The density is given a rating of 20%. We appreciate Low density bottles as it makes carrying liquid more convenient and portable. This is one of the perks of carrying a disposable water bottle instead of a metal or permanent bottle.

• The water absorbability is given a rating of 25%. We require low water absorbability so that the material will not absorb water and get soaked in water. This means that water will not penetrate the bottle easily if water absorbability is low, to serve a reason for carrying liquid around this is the number one most important aspect of a bottle.

  
  

  Based on both the material evaluation table and cost evaluation table, the selected material for the bottle body is Polyethylene terephthalate (PET).

  Polyethylene terephthalate (PET) had the highest score, a total score of 320 for the material evaluation table.

  

  Body Cap

  		Options
  Criteria	Weightage (%)	Polyethylene terephthalate (PET)	Polypropylene (PP)	High density polyethylene (HDPE)
  High Young’s Modulus (GPa)	25	3.385 Score: 2 25 x 2 = 50	4.129 Score: 3 25 x 3 = 75	1.0325 Score: 1 25 x 1 = 25
  Low thermal conductivity (W/m-K)	10	0.24 Score: 3 10 x 3 = 30	0.301 Score: 2 10 x 2 = 20	0.384 Score: 1 10 x 1 = 10
  Non-reactive	25	Excellent  Score: 3 25 x 3 = 75	Excellent  Score: 3 25 x 3 = 75	Excellent  Score: 3 25 x 3 = 75
  Low density (g/cc)	10	1.15 Score: 2 10 x 2 = 20	1.64 Score: 1 10 x 1 = 10	0.9595 Score: 3 10 x 3 = 30
  Water absorbability (%)	30	0.425  Score: 2 30 x 2 = 60	0.5 Score: 1 30 x 1 = 30	0.035 Score :3 30 x 3 = 90
  Total (%)	100	235	210	230

  
  

  • Young’s modulus is given a rating of 25% as the bottle cap should be stiff and highly resistant to elastic deformation so that the cap will stay tight.

  
  

  • Thermal conductivity is given the lowest percentage of 10% as although a low thermal conductivity is desired so that the bottle cap does not conduct heat quickly, the bottle cap makes up a small percentage of the whole bottle and the importance of this property is not as high.

  
  

  • The reactivity is given a rating of 25% as we would not want the drink to react with the bottle cap and be contaminated with unwanted substances.

  
  

  • The density is given a rating of 10% as although a lightweight product is desired, the bottle cap makes up a small part of the whole bottle and the weight of it would not affect the overall weight of the whole bottle significantly.

  
  

  • The water absorbability is given a rating of 30% as we would like the bottle cap to be as waterproof as possible so that it can hold liquids securely without any loss.

    
    

    Based on both the material evaluation table and cost evaluation table, the selected material for the bottle cap is Polyethylene terephthalate (PET).

    Polyethylene terephthalate (PET) had the highest score, a total score of 235 for the material evaluation table.

    
    

    3. Choose the Economical Material

    Choosing our material based off of one round of COWs Matrix selection (material attribute) is not enough to determine the material we should choose. Other facts like Cost, Recyclability and Biodegradability also play a big part in determining if a material is a better choice than another one.

    
    

    Bottle Body

    		Options
    Criteria	Weightage (%)	Polypropylene (PP)	Polybutylene adipate terephthalate (PBAT)	Polyethylene terephthalate (PET)	Polylactic acid (PLA)
    Cost of material (USD per ton)	40	1208 Score: 3 40 x 3 = 120	3986 Score: 1 40 x 1 = 40	935 Score: 4 40 x 4 = 160	2898  Score: 2 40 x 2 = 80
    Recyclability	30	Hard Score: 1 30 x 1 = 30	Moderate Score: 2 30 x 2 = 60	Easy Score: 4 30 x 4 = 120	Moderate Score: 2 30 x 2 = 60
    Biogdegradabitity	30	Non-biodegradable  Score: 1 30 x 1 = 30	Biodegradable  Score: 3 30 x 3 = 90	Non-biodegradable Score: 1 30 x 1 = 30	Biodegradable Score: 3 30 x 3 = 90
    Total	100	180	190	310	230

    
    

    Based on both the material evaluation table and cost evaluation table, the selected material for the bottle body is Polyethylene terephthalate (PET).

    Polyethylene terephthalate (PET) had the highest score of 320 for the material evaluation table.

    
    

    Bottle Cap

    		Options
    Criteria	Weightage (%)	Polyethylene terephthalate (PET)	Polypropylene (PP)	High density polyethylene (HDPE)
    Cost of material (USD per ton)	40	935 Score: 3 40 x 3 = 120	1,208 Score: 1 40 x 1 = 40	1197 Score: 1 40 x 1 = 40
    Recyclability	60	Easy Score: 3 60 x 3 = 180	Hard Score: 1 60 x 1 = 60	Easy Score: 3 60 x 3 = 180
    Total	100	300	100	220

    
    

    Based on both the material evaluation table and cost evaluation table, the selected material for the bottle cap is Polyethylene terephthalate (PET).

    
    

    Polyethylene terephthalate (PET) had the highest score for both tables; a total score of 235 for the material evaluation table, and a total score of 300 for the cost evaluation table.

    
    

    Despite Polyethylene terephthalate (PET) having a moderate Young’s Modulus, density, and water absorbability, its low thermal conductivity, non-reactivity, low cost, and high recyclability compensates for it.

    
    

    Week 13

    In week 13, we learnt about Design for Material (DFM). When I first heard that we were going to learn DFM, I was confused. Didn't we just learn it last week?? After Mr Chua explained DFM, I realised that it was indeed different from MFD even thought its just swapping the order of the words. 

     

    Design for Material was about finding the changing the design of a particular object to allow a specific material to be used. I know it still sounds confusing so let me show you a classic example:

    
    This was one of the earliest design idea for a hairdryer. If you have showed this to a person in today's era, likely they wouldn't even guess that it was a hair dryer. To me, when I first saw this picture I was shocked and thought at was some sort of medieval torturing machine!!
    
    Fastforward 30 years and we have a hair dryer that looked like the ones we have in the modern day. It was like a metal brick and most people using this hair dryer got tired before their hair could even dry. Not to mention that the airflow was also relatively weak. It was unsafe too as many people got electrocuted due to poor insulation of the handle during production and manufacturing.

    
    

    
    Finally, we have plastic hairdryer which was much lighter than the metal ones. It was also relatively cheaper and safer to use. Many popular brands of hair dryer derived their product in today based off this design back in the 1930s. 

    
    

    Our next activity was to choose a material that appeal to our group and for my group we chose Tyvek. I first came across Tyvek when my friend asked me to tear his 'paper wallet'. However, when I tried to tear it, it was so impossible to tear. I wondered to myself what even is this material isn't it just a paper wallet he made, how come I couldn't tear it. Turns out this 'paper wallet' was not just any ordinary wallet, it was made out of Tyvek. 

    
    

    Name of material	Non-Woven Tyvek® Paper
    Chemical Name	Flashspun high-density polyethylene fibres (HDPE)
    General Description	Made with polyethylene fibres, Tyvek® is a 100% synthetic material made from high-density spunbond polyethylene fibres. It is a virtually indestructible synthetic paper. It is durable and cannot be ripped apart by hand. This variety has been engineered to have ‘breathable’ qualities, i.e. it lets air and moisture through.
    General Properties	Lightweight Breathable Durable Water resistant Puncture and tear resistant Superb UV protection capabilities Cheap Chemical resistant
    Opportunities	Tyvek® has qualities of paper, film and fabric that are both appealing to touch and durable, making it ideal for high-end packaging and bookbinding applications.
    Discuss among the group how this material can be used as a direct replacement to a material in an existing product without any significant changes in the design Tyvek® can be used for high quality maps.  Maps are used by hikers or explorers to navigate in the wilderness where internet connection may not be available. Hence, maps often get torn apart due to environmental factors such as strong winds, rainstorms, and dirt.  Maps are also used very often and usually kept hastily in conditions where it gets crumpled easily. Without the properties of Tyvek®, the repeated crumpling of paper will eventually lead to tearing and loss of print.
    Discuss among the group how this material can be used to enhance the functionality of an existing product through some changes in the design. Tyvek® can be used in coveralls in personal protection equipment for process technicians.  Since Tyvek® is chemical resistant, puncture and tear resistant, and water resistant as well as fire retardant (B-s1,d0), it will be able to protect process technicians from common injuries from process plant environments such as chemical spillages and sharp equipment. In addition, it is lightweight and allows process technicians to move around comfortably and freely. It is durable, thus technicians will not be required to purchase new coveralls as frequently. Even if they are required to purchase them, Tyvek® is cost effective. It is tear and puncture resistant, if the technician wearing the Tyvek® coveralls comes in contact with a sharp object or equipment, it will not tear easily and will be able to protect the technician.

    
    

    
    

    For Sustainable Design

    Sustainable design is the approach to creating products and services that have considered the  environmental, social, and economic impacts from the initial phase through to the end of life.   What change can be made to your design to make it more environmentally sustainable?  Some design Considerations/Principles are included here:  ▪ Use non-toxic, sustainably produced, or recycled materials.  ▪ Use energy efficient processes.  ▪ Make product last longer.  ▪ Design for reuse and recycling. (e.g. easy to disassemble)  ▪ Consider product life cycle.  ▪ Shift from personal ownership to shared ownership.  ▪ Buy from nearby

    Discuss and document the modification in design or substituting of certain parts of the product or any other ideas that your team has made. You may include pictures and sketches to aid in the explanation. The exterior of the device can be made with recycled plastic. Plastic is chosen as it provides an aesthetically pleasing shine. The interior of the device should be made with a chemically inert material as it is involved in the processing of food. Copper alloy can be chosen as it is antibacterial and durable. Parts made with them will not need to be replaced frequently as they will last longer. Components of the device can be easily disassembled for ease of cleaning and recycling purposes. The components can be sold separately, so that when a component is broken, consumers can just purchase the damaged piece instead of the whole device again. This concept can also reduce waste and improve environmental sustainability.