Blog entry 5

Bonjour!  

😊

I'm back with a new blog entry, and I will be talking about what I have learned(or re-learned) in week 11 and 12. 

Do recall the product design process that was briefly mentioned in my first blog entry. Well these 2 weeks basically describes the 4th stage of this process, the Prototyping and Product Development stage.

For Week 11, I learned about Materials for Design, followed by a group activity that my team and I worked on for the last hour before the end of the tutorial. Unironically, Materials for Design was the name of one of my core modules in Year 1, which was about material properties etc. Sadly, the syllabus just changed and it is no longer a module for the current year 1s :(

 

Alright let's get back on track. In week 12, Dr. Noel went through Design for Materials followed by Sustainable Design and of course not forgetting the group work. More on this will be described later on in the blog!

Materials for Design (MFD)

Generally speaking, MFD is about material selection. Material knowledge and selection is a very important concept in chemical product design. The design of the chemical product involves three interrelated problems which are 

1) Selecting a material,

2) Specifying a shape, and 

3) Choosing a manufacturing process

Acquiring the right selection the first time by determining the optimal combination of one's design is extremely beneficial for any engineering-based company as it leads to lower product costs, faster time-to-market as well as a reduction in the number of in-service failures.

For the selection of materials, one would need to identify one or more materials with material properties that satisfies the functional requirements of a product. The superior materials are those that are able to optimize the performance objectives of the product. Some examples of material properties include Young's Modulus, Tensile Strength, Chemical Resistance and many more.

Overall, there are three stages for material selection, 

Basically, 

for step 1, we have to be familiarized with the product function and then identify relevant material property such that the product can be used effectively based on its purpose. For example, a pot has to be able to transmit and spread heat effectively from the heat source to the food in it, thus it requires high thermal conductivity. 

for step 2, we have to select the most relevant and important material properties. the COWS matrix will be used for this step. For this matrix, at least 4-5 material properties has to be selected, then each property will be weighed(total weightage is 100%) based on its importance to the product functionality and performance. 

The picture above is an example of a COWS matrix for a pot. The pot must be able to transfer heat from the source to the food quickly, so thermal conductivity will be given the highest percentage of 50%. The material with the highest total will most likely be selected as the material for the given product, which in this case, is aluminium with 360%

lastly, for step 3, this step will compare materials with high percentage total based on step 2 at a different standpoint. COWS matrix will still be used, but instead of the material properties, it is the economical properties. Some examples of economical properties include Cost of the material, Availability of the material, Ease of manufacturing and more! The same steps will be repeated for the COWS matrix to determine the best material.

After this part of the tutorial, we were tasked to do our own material selection based on a product given to us by Dr. Noel. For my group, we have to do material selection for a face shield. 

The key components that we were focused on were the foam at the top of the face shield to rest out forehead on as well the as the material of the shield. My group and I decided to split the work. Hong Yi and I will focus on the face shield material whereas Hannah and Isabelle will focus on the foam. 

Following the Material Selection process that we learned earlier, 

For step 1, Hong Yi and I have decided that the transparent sheet should be 

• effective and useful, the sheet must be transparent to allow the user to see the surroundings while wearing it.
• must be lightweight so that it will not be uncomfortable for the user to wear for a long period of time.
• should be flexible so that it can be bent to provide a larger surface area of protection and be aesthetically pleasing
• should be UV resistant so that it will not degrade under prolonged use under the sun

We determined that the function of it is to provide the user a layer of protection against viral particles while allowing the user to see through.

For Step 2, we have identified certain constraints(or material properties) which are:

1. Light weight (Low Density)

2. Transparent (High Light Transmittance value)

3. Flexible ( Low modulus of Elasticity)

4. UV resistant

The main objective is to maximize the UV resistance and the Transparency.

Hence, we were able to shortlist 4 suitable polymers which are Polycarbonate (PC), Polyethylene Terephthalate (PET), Polyethylene Terephthalate Glycol (PETG) and Polyvinyl Chloride (PVC). Next will be out COWS matrix.

Thus, it can be seen that Polyethylene Terephthalate Glycol (PETG) and Polyvinyl Chloride (PVC) are the 2 highest scored candidates.

Lastly for step 3, we did another COWS matrix for economical properties for the 2 highest scored candidates based on the previous COWS matrix. The two properties that we have decided on is Ease of fabrication/manufacturing and Cost of material.

Hence, we have decided that Polyethylene Terephthalate Glycol (PETG) is most suitable material for the transparent sheet!! 🎉🎉

That concludes week 11, MFD! 😌

Now for week 12, it is technically the reverse...Design for Materials! 

Design for materials is all about changing the design to suit a specific material. It can basically be described by the image below 

Pretty straightforward as compared the MFD right? 😆

Once we understood what Design for Materials is about, we were tasked to select ONE material that appeals to my group and complete an activity sheet given to us by Dr. Noel. Unfortunately, I do not have a soft copy of it, but rather a scanned copy of the hard copy :)

Based on this Design for material tutorial, my group and I learned that we are able to improve existing products by changing its design so that only one particular material can be used. This will be important in the future because this process will definitely be used in the next module in determining other materials that can be used to improve a prototype.

Last but not least, Dr. Noel also went through Sustainable Design in the same tutorial. Sustainable design is important especially in this day and age due to climate change, pollution and more. By using a sustainable design, the product will be safe for the environment as well as the biological cycles present on earth. 

Thus, we were tasked to come up with possible changes that can be made to our haircare product to make it more environmentally sustainable. The image below shows the question that we have to answer in order to complete our task. 

Thus, after an engaging discussion, my team and I have decided that instead of using 2 different materials for the handle and the barrel,. the handle and barrel will be combined into one component, which utilizes only one material which is ABS plastic that is recyclable.

Moreover, we are going to make our product such that we can split and detach the different components to promote a longer product life. The bristle body component can be separated and detached from the handle. When the bristle has been worn out, instead of purchasing the whole product again, they could just purchase a new component for the bristle and attach it to the existing, old handle. This would reduce the wastage of material. Since the bristle body is made out of rubber and ABS, it can be recycled after the body has worn out. The picture below shows a sketch of our product after modification.

This marks the end of this blog entry. Thanks for reading! Cya soon...