Computer Aided Design (CAD)

 

Week 1: Recalling of creating keychain using Fusion360 (CAD entry):

During the first week of tutorial in CPDD, we went through the module briefing for individual documentation as well as the module timeline. We investigated the skills that we would be learning this semester, as well as a brief recap on how strong teams are formed through the stages of forming during class. We then recapped on the use of CAD using Fusion360 as the software for making digital sketches.

Using Fusion360, we were tasked to recall our creating of the keychain during ICPD in last semester. While watching the video, I have made a step by step process on the recreation of the keychain.

First, I created a sketch and drew a rectangle using the dimensions that I am comfortable with.

In this screenshot, I filleted the sides with radius of 5mm to remove the corners of the rectangle.

I put an offset of 2mm to create a border for the keychain and drew a circle of radius 7mm for the hole for the keychain. This hole was made at the centred to the sides of the keychain width.

By using the create text function, I wrote out my name on the keychain and further adjusted the dimensions of the keychain to fit my name in.

I first extruded the outer side by 3mm as well as my name in this screenshot, to give my keychain a “pop-up” effect from its original 2D sketch.

Then, I proceed to put in an extrusion of 1.5mm for the base to make the 3D model of the keychain feasible.

The keychain is finally complete!

An embedded file of the Fusion360 shows the finalised keychain that has been modelled below.

Reflection

In this refresher activity, I have recapped on my skills in recreating a sketch, and subsequently a 3D design of a simple keychain. The use of a CAD program like Fusion360 allows engineers like us to create and design more intricate products with the use of 3D printing functionality; reducing waste during the process of production due to the 3D 'additive' manufacturing process.

This is important in ensuring sustainability of the manufacturing process, as well as the cutting of production costs due to cutting and milling of the keychain from a larger piece of material. Time is also saved in the process, and the creation of a digital design allows for greater visualisation of the product; enabling better understanding and view of product feasibility during manufacturing process. This task is interesting as CAD is something new that I have to learn, and it can be extremely helpful in this module where I have to practice a much more hands-on process in creating my own chemical product using the CAD software.

I used to think that CAD software was only used for design and art students due to the nature of work that they do, however now I have understood why the skillset of mastering designing software is important for students in Engineering to learn and develop. Following up, I should further improve and refine my skills in using Fusion360 and explore what else I can do with the software. There are even tutorials online that I can look into and discover more.

Week 2: Parametric design

This week, we have learnt on the use and operation of CO2 Laser Cutters.

How does it work?

A high voltage is passed through a CO2 tube at the side of the machine and a high intensity infrared light (laser) is produced when the CO2 gas is excited in the tube. Laser produced at the other end of the tube is reflected by 2 mirrors into the head of the carriage; where it is then reflected into the focus lens in the head of the carriage. The laser will be focused onto the material under the head of the carriage and it will cut the material.

Suitable materials that we can cut for laser cutters from 40-120W will be wood (up to 6mm), acrylic (up to 5mm), cardboard and paper.

Some important hazards to take note of when operating the laser cutter:
1. Do not stare into the beam while cutting
2. Do not use materials that contains chlorine (in case of production of chlorine gas)
3. Do not cut or engrave metal materials
Lastly, never to leave machine unattended while cutting/engraving.

We have also learnt about the differing resolutions used in laser cutting:

Vector is a scalable resolution while raster is not scalable because it is made of pixel resolution.
The drawing file for the laser cutter to work on has to be in vector. Raster or Vector can be used in engraving, however raster files will be a lot slower than vector files.

After the lesson plan on the introduction of the new equipment in the FabLab, the laser cutter, we are now individually tasked to use Fusion360 to create a handphone stand for ourselves. It has to be a laser cut product, hence I am required to be more careful with my design.

Parametric design:

Parametric designs are functions that are added into the sketch, to help us change the dimensions of the entire sketch itself. It saves us time from changing just singular values in the entire sketch. This is helpful in more complex designs where sketches have too many dimensions to be changed in case the final design has to be lengthened or shortened.

Parametric designs can be added in from Modify tab, under the Change Parameters table. Type in the function name, as well as the value for the corresponding function. Thereafter, Inspect the dimension of the sketch you want to change, and assign it to its corresponding function. The dimension of that sketch will 'snap' to the value of the function that you assign it to. How handy!

Handphone stand design

First I draw a sketch of my design for my handphone stand. It consists of two different bodies. Using 2-point rectangle from the sketch function, I created the first body with these dimensions. The first body looks as such with two slots of 5x2mm in it.

The second body is also created with multiple 2-point rectangles. It looks like this with two tabs of 5x2mm to slot into the first body. These two tabs will be slotted into the first body after extrusion.

Using parametric modelling under Modify > Change Parameters table, I put the adjustable values into the parametric model to make it easier for me to scale and change the values of the dimensions of the bodies. This can help me change the dimensions of the handphone stand easier without changing every dimension correspondingly.

Extruding the model by 3mm thickness, the model is now a 3D sketch that looks like this. All that is left to do is to put in the two shapes together.

Now to put the shapes together!
Slotting in both shapes, the phone stand is now complete!

This is the embedded design from Fusion360 for my handphone stand. It looks slightly simple and basic, however it works!

Reflections:

I think the use of parametric functions is very good in aiding with changing in sketch dimensions. It is an important skill to have and it has made my creation of the handphone stand a lot easier; even though this is an easy design that I have came out with. I realised that you have to be specific in naming your parameters in ensuring that you understand the parameters properly; because I have had a few issues where my parameters were not specified well (i.e. 'length1' and 'length2').

This caused my design to look weird because of the confusion between which parameter i should allocate for that dimension of my handphone stand.