Blog Entry 5

 Week 11: Material For Design

For the past term, my team and I have gone through 3 stages of chemical product design which are mainly needs identification, ideation and selection. Now we are at the 4th stage which is prototyping and product development. In order to start, first we have to choose the materials for our product. In this blog, I will be showing what I have learn about material for design.

There are 3 steps in material selection process which are mainly:

1. Define material requirement for design (Which is about function, constrains and objectives of the product)
2. Select and evaluate candidate materials (COWs)
3. Choose the most economical material

For CA2, we were tasked to select material for a single use water bottle (disposable) that does minimum environmental harm

Figure 1: Bottle o water

Step 1: Define material requirement for design

Table 1: Material Requirements

Step 2: Select and evaluate candidate material (COWs)

For the bottle material, we did research on the various types of plastics and shortlisted four of them which are polyethylene terephthalate, high density polyethylene, polycarbonate and 

polypropylene. We also came up with four criteria and reasons for choosing them.

Table 2: List of Criteria

Table 3: COWs

After doing the COWs matrix, we narrowed down to two materials which are high density polyethylene and polypropylene as they are the most environmentally friendly to choose the most economical material.

Step 3: Choose the most economical material

Table 4: Most economical material

In the end, the material that was best suited for a disposable water bottle is high density polyethylene.

Week 12: Design For Materials

In week 12, we were taught design for materials which is the opposite of material for design. For material for design, you would have to choose materials for a product you are making, however for design for material, you would have to pick out a material and implement it into an existing product which is really interesting. In class, Dr Noel shared with us about a product which has undergone many changes of material.

Figure 2: Very First Hair Dryer

Changes were made to make the hair dryer more portable. However it is still unsafe as metal conducts electricity to the user electrocuting them. ☠

Figure 3: Metal Portable Hair Dryer

Finally in 1930, there was a change of material of the body of the hair dryer to plastic which made it much safer to use and much more lighter.

Figure 4: Plastic Hair Dryer

For CA2, we were tasked to select a material of our choice and how it can replace another material in an existing product and be able to enhance the functionality of an existing product.

After looking through some materials at the library, the team has decided on 3M gripping.

Figure 5: 3M Gripping

Here is what we decided to do:

Lastly for part 3 of our CA2, we have to put what we learn into use by making our chemical product more environmentally sustainable.

Reflection:

For the past 2 weeks, I have learn that choosing a material for a very tedious task at many considerations have to be taken before choosing the right material. If the wrong material is chosen such as using metal for the body of a hair dryer, the consequences can be dire. However if the right material is chosen, it can bring lots of convenience. It also showed me that other materials can replace another material on a product to enhance the functionality of a existing product.

Practical 3: Material Properties

In a previous module Material For Design (MFD), we long about stress and stain, thermal conductivity and viscosity. So in this practical, we would be using the knowledge we have gain and putting it into practical use! For my team, we were tasked to find the thermal conductivity of a material using heat transfer from steam to ice. In order to find the thermal conductivity of the material, we assumed heat gained by the ice = hot loss by the steam. Lets get started!

Materials provided:

1. Retort Stand
2. 2 small beakers
3. Steam generator 
4. Test bed
5. Block of ice and test specimen
6. Infrared thermometer
7. Magnetic stirrer

Here are some of the materials:

Step 1: Attach the test bed using the clamps such that the test bed is slightly slanted

Step 2: Boil water and add into the steam generator until 75% full

Step 3: Attach the rubber stopper into the steam generator and the tube into the bed

Step 4: Start the generator and wait until the test bed is at a constant temperature (For us is around 70℃)

Step 5: Place the test sample on the top of the test bed and secure with a magnetic stirrer

Step 6: Record time taken for the ice to melt

Step 7: House keeping!!

Data collected from the experiment:

In order to find the thermal conductivity of the specimen, we assume there heat gain by ice = heat loss by steam and all heat as transferred into the ice. By manipulating the equation, this is what we got...

The calculated thermal conductivity of the specimen was actually quite close with the actual value so it was a success!