Circles and teeth

YAHHŌ mina san! How's it going? Weclome back to my page, TODAY I will be sharing with you my cranky yet fun experience that went down during my practical on spinning wheels with teeth😏.

GEARS 

So as you may have guessed gears are what I am refering to as "weird spinny wheels with teeth" This practical has been insanely enlightening and I must say it was truly entertaining to see my friends and I struggle to build a gear contraption that looks so easy. Surprisingly, there are many way we use gear in our life one such example is the bicycle gear and chain. As an avid road biker I do have experience on the usage of gears and purpose of gear shifting. So, let me show you what other things I have learnt in this blog.

1. This is the definition of gear module, pitch diameter and the relationship between gear module, pitch circular diameter and number of teeth.

Gear module: The word “module specify the size of the gear. Gear module is the ratio of the diameter of the gear divided by the the total number of teeth it has, hence gear module shows the size of each teeth on the gear.

Pitch Circular Diameter (PCD): It is the space or distance between the corresponding point of the the adjacent teeth measured on the pitch circle. In simpler term, it is the space between each teeth. 

Relationship between gear module, pitch circular diameter and the number of teeth: It can be expressed as an equation where PCD can obtained by multiplying gear module(m) and number of teeth(z).

PCD = m x z

2. Relationship between gear ratio(speed ratio) and output speed for a pair of gears.

Equation to find gear ratio: gear ratio = output/input

Gear ratio also often known as gear ratio has a unique advantage of increasing torque or speed. In this case , to increase the output speed of a pair of gears, the speed ratio should be <1 (less than 1 speed ratio).

To achieve speed ratio <1, output must be smaller than input and this causes the gear to be a speed multiplier.  Therefore speed ratio is inversely proportional to the output speed.

Relationship between gear ratio and torque for a pair of gear.

Torque is the rotational force about an axis.

To get a pair of torque multiplier, the driver/input gear should be smaller compared to the follower gear which makes the gear ratio >1. This means the gear ratio is directly proportional to torque.

3. Below is my opinion on how to improve the hand-squeezed fan.

First let me show you what we have put together on that day of practical.

 We used this fan made using 3D printed material. 

From the video you can see a small piece of tape we put on the gear to see a complete rotation. As seen in the video, we came to a conclusion that for every one rotation of the first gear, the blade spin 10 times. 

To confirm our theory, Diana calculated the number of teeth on each gear. After calculating the compound gear ratio, we got 0.1 gear ratio. So our calculation and theory match!

So after some thinking there are many ways to improve on the efficiency and effectiveness of this hand squeezed fan.

Firstly, to increase the efficiency, a different material of smoother surface and be used to decrease friction between the teeth. 

Secondly, a lubricant can be used to also decrease the friction and reduce the wear and tear of the gears.

Thirdly, the fan internal parts were lose which meant that energy is wasted. We could reduce energy wastage by having a better quality design.

Fourthly, we can also increase efficiency by reducing the amount of gears so that less energy is wasted due to friction.

Next, to increase effectiveness we want the gears to be a speed multiplier. This can be achieved by decreasing the gear ratio which is possible by increasing the driver gear size or decreasing the follower gear size.

Lastly, one very troubling thing was that it was a fixed gear fan. This means that it can either go clockwise or anti-clockwise. This makes using the fan very troublesome. Instead of making a fixed gear fan, we can change it to a free gear fan. Below is an example of free gear hand pressured fan.

Internals of a free gear fan

Proposed design

                        

4. This part shows how my team put together the gears in order to raise a water bottle.

a. Calculation of the gear ratio

Gear ratio = 40/30 * 40/12 * 20/40 

= 2.22 

b. The photo of my group’s gear layout

c. Calculation if the number of revolutions required to rotate the crank handle.

Gear ratio: 2.22

Number of rotations: 200/2πr

Winch diameter: 22mm

Number of rotation: 2.89

Number of rotation of the crank: 2.89*2.22

=6.422

d. The video of the bottle being lifted.

In the video it shows that we rotated the handle 9 times because we brought the bottle up in 250mm hence the number of rotation.

 

5. Below is my learning reflection on the gear activities. 🧠

The practical on gears was really enjoyable. It has been quite some times since I worked hands on with a group and I must say it brings back childhood memories. As a cyclist, I believe I am quite good with gears as I have been cleaning and fixing them every time when I go cycling. To see how diversely gears can be used was truly fascinating. Of course other than hands on activity I also learnt about the principles of a gear as mentioned previously in this blog. From the videos in bight space I learnt about types of gears, gear modules and many more. 

Activity 1: 

We were tasked to lift a 500ml bottle for 200mm. It seem really easy at first so three of my group members wanted to do this activity. They had one simple task which was to make the gears a torque multiplier which means that the gear ratio must be larger than 1. After some trial and error, they were able to get a gear ratio of 2.22 which needed around 7 rotation to lift the bottle. Although it only needed around 7 rotations, it was quite difficult to lift the bottle up. However we had some strong members hence we were still able to easily lift the bottle. I thought about increasing the gear ratio which will in turn increase the amount of rotation to lift the bottle. However it will take much longer to lift the bottle so I decided not to implement it. 

From this activity we actually encountered some obstacles and had to learn from it before progressing.

- We should always tighten the gears to the backboard or else it will be wobbly and hard to turn. This is due to them having no proper pivot point.

- When constructing gears we should only do it from one side not both sides. As my team was rushing for time we placed the gears at the start and end and worked our ways to the middle. However, the gears could not fit in the middle as there was no space. Therefore when working with gears we should always go from one point to another.

- We had to rotate the crank more times than the theoretical number of rotations as there was friction present between each teeth. There are ways to reduce this inefficient use of energy as mentioned above. I believe using a lubricant will definitely help with smoothening the gears in rotation.

Activity 2:

This activity was particularly interesting as it was a fan made of completely 3D printed materials. It was like building legos again but this time with gears. Diana and I had some problems when putting the parts together as they were not sanded and filed properly however we managed to slowly construct the fan. The gears were loose and so the fan could not spin properly when lifted up from a solid surface, however when  used it on a table top where it was flat, the gears could spin better. One thing that was frustrating was that it could not spin freely. This means when the user let go of the handle when the fan is spinning, the handle will still move.

Even though this activity was slightly challenging, we were able to easily answer the questions and deduce the amount of rotation the fan will have every handle cranked. Most importantly, it helped us confirm that the theory on the gear calculations where correct.

In a nutshell, it was an insightful practical that opened my eyes on the purpose of gears in our lives. I realised how widely used it is even though we do not really see it in our day to day life. This practical has also reminded me on why I should set a plan before doing anything. One reason why my group was rushing for time in the last thirty minutes was due to them not watching the four videos provided by the school. If I did not watch them I would have been as lost and confused as them during the practical. It truly felt great coming into class knowing what will be ongoing for the class instead of blindly following and copying what others are doing. 

Light magic

Laser cutting

Hello guys! Welcome to my first experience to laser cutting. I want to share my exciting adventure of using intense light rays to cut some stuff.

For those of you who are unfamiliar and have not heard about laser cutting here is an awesome picture to illustrate.

I will bring you through the basics of laser cutting in this blog and I hope you are able to use this incredible machine.

1. The 4 important hazards associated to the operation of laser cutting machine and their respective safety control measures( administrative/engineering control).

2. The material that can be cut and can't be cut using the laser cutting machine.

3. The steps include pictures on the operation of UNIVERSAL laser cutter, that consist of:

a. Starting the compressor, tunning on the laser cutter machine and fume extractor.

b. Importing a .DXF file to Coreldraw and modifying the lines/fill for cutting and engraving

c. Sending the Coreldraw drawing to laser cutter software and setting the laser cutter power, 

speed, PPI in the software.

d. Starting the job on the laser cutter machine.

e. DOs and DON'Ts when there's flame/fire on the material being cut.

1. Hazards & Control measures❗❕

The laser cutter is as amazing as it looks, concentrating harmless light rays into scarily dangerous laser beams. These concentrated light beams are able to cut through things like wood so it will definitely harm your skin. So it is important to learn about the safety rules to mitigate the chance of you engraving your flawless skin👀.

I have learnt about 4 major safety concerns

1. The high powered laser beam is extremely dangerous and can cause severe burns or even blindness if it is reflected into your eyes.👀

Engineering control: The machine is smart and it has a 'safety interlock' in its system where when the lid of the machine is lifted up the dangerous laser is immediately shut off! What an amazing safety feature for placing and collecting the materials.

Administrative control: Anyone who enters the laser cutting vicinity is required to have a competency test before handling the machine to ensure their safety. An example is to never stare into the laser but, we should still glance back and forth to ensure no ignition occurs. 

2. Possibility of laser lens cracking and breaking into sharps shards. 🔎🔍

Administrative control: Students are briefed to check the laser lens if operation of laser cutting is unsuccessful after 2 attempts.

3. Possibility of open flame.🔥🔥🔥🔥

Engineering control: There are multiple fire extinguishes🧯 for quick access in reachable and visible areas in the room. There are also pictures to show it can be used effectively.

Administrative control: Firstly, the lesson materials has made it very clear and concise on the magnitude of open flame and how we can deal with them. 

A general rule of thumb is when there is visible flame we are to immediately extinguish them ASAP usually around 1-2 seconds to avoid them from going out of control.

Secondly, if the flame is negligible and small we can just lift up the lid and blow it out.💨💨

However if the flame doesn't go out we have to remove the material and step on them to extinguish the flame. If the flame is roaring please don't hesitate to use the given fire extinguishers.

4. Accumulation of toxic gases that may cause flare up.💣

Engineering control: Turning on air assist and fume extractors is mandatory as it helps reduce accumulation of fumes, smoke and toxic gas particles.

Administrative control: Ignition can be foreseen when thick fumes evolve and a sparkle will is all that is needed to set it off. Hence removing these flammable gases and fumes will mitigate this hazard.

 

These are the very basic of laser cutting please don't forget these simple requirements!🧠

2a. Materials suitable for cutting✅

Side note!! They have to be 5mm and thinner🤏🏻

Material	Photo of material
1. Acrylic-  - Must remove the top layer paper to avoid catching on fire
2. Plywood - Structural plywood is hard to cut and toxic due to the glue used.
3. Cardboard - Higher risk of catching fire.

2b. Materials NOT suitable for cutting❌ 

Material	Photo of material
1. Rubber🦆 - Smoke from rubber is TOXIC, carbon monoxide and cyanide are released.
2. Plastic  - Fumes evolved are hazardous,  they contain dioxins, furans, mercury and more.
3. Metal🤘 - Metal is highly reflective and also a heat conductor.

3. Operating procedures of UNIVERSAL laser cutter

           a. Starting and setting up the workplace

Steps and description	Photos to support the description
Turn on the power for the laser cutting machine and air assist. (switches behind the computer)
Turn on the fume extractor. (switches right below the fume extractor)

           b. To import from fusion to Coreldraw and modifying lines/fill for cutting engraving

This the three simple options for us to choose when modifying our lines and fill

1.Select file 2. Import 3. Select the .DXF file you want 4. Press import
Now for modifying your lines and fill, you have to click on this pen icon at the bottom of the screen on your computer.
This menu will pop out and click on the colour section located in the top right hand region and select RGB.
In this case I will be demonstrating the steps for cutting out an object. For cutting we have to use red which in RGB is:  R:255 G:0 B:0
For cutting we will also need to adjust the width to hairline and the picture on the right shows you the two simple steps.

    

      c. Sending the Coreldraw drawing to the Universal material setting. ( laser cutting power, speed, PPI and Z-axis)

Steps and description	Photos to support the description
Assuming you are done setting up your design product and set the cutting and engraving line, click the file and print.
Click on the cogwheel settings⚙️
After the Universal material setting appear, click on load.
Select the present that matches your material type and thickness and select open.
Last few things to take note if you are not provided with presets. Make sure the mode is red/green and that it is in raster or vector not skip.  Power to be at around 50% so as to prevent ugly cutting and excessive heat output. Speed can vary with thickness of material, the thicker the material the slower the speed to increase the time of laser exposure in a particular spot. PPI is pulse per inch. It is a way to control how many times the laser pulses over a given distance during cuts. The higher the frequency, the smoother the cut, however it causes injections of high heat. Therefore it may sometimes melt the material. Z-axis is the measure of thickness. It aid in setting the optimal focus point for materials with different thickness. With that after adjusting them to your liking, press apply then OK and print.

          d. The Universal control panel (UCP) and the starting of laser cutting

THE UCP:

  Press the red turn on button, if its green reactivate the button till red.

Steps and description	Photos to support the description
Zoom - enlarge image on ULC to ensure proper printing. (can be done by scrolling your mouse)
Focus – very handy tool for us to locate the placement on the object to be printed by showing a physical laser dot. (Also helps to check if there is sufficient materials for printing)
Move – in the case that the object is outside the printing area you can select and move the drawing to an empty space. (using a ruler in the machine to estimate the empty location using X, Y axis)
Estimated time – determine amount of time needed to cut and engrave your work and this will be the last step before cutting!

💡One final trick if your material is unsuccessful in being cut for your first attempt.

Using this picture to depict the strength of laser beam. As the laser beam is being reflected in two tiny mirrors in the machine from the top left, the further the laser is cutting from the top left the weaker it is, so with that logic I am sure you would want to use the zones 1 & 2 to have a nice smooth cut👌.

Laser cutting machine💢💢

Remember to shut the lid of the machine else no laser will appear😆

With that you can now safely press the green play button on the machine or the computer and watch the magic happen!

If there is a flame or fire DO THIS PLEASE!

Firstly we must always keep watch of the laser cutter when in operation, hence if a small fire ignite be sure to blow it off immediately. You can do so by lifting the lid of the laser cutter and blow the fire off with your mouth. In doing so you are to ensure the fire die out in 1-2 seconds.

Secondly, if you are afraid of the fire being so near to your face, bring the material out of the machine and onto the floor and vigorously step on it to extinguish the fire.

Lastly, if the fire does not subside go to the nearby fire extinguisher and kill the fire. You should also shout for help to get others attention.

On the other hand, please DO NOT LEAVE THE WORK STATION AT ANY POINT IN TIME, unless you have a certified partner or friend who is keeping an eye of the machine for you.

Also remember to be considerate and perform house keeping after every session, dispose of all unwanted material and shut off the electricity. By doing your part we can reduce material and energy wastage!♻️

Learning reflection💭

This Monday is the first time I had my first hand experience in laser cutting. It was honestly not have complicated as I thought it would be. However it was very unexpected that my class only had 2days to complete out Standard operating procedures (SOP) due to the 🎆Deepavali🎇 holiday. 

Hearing that we had to create our own SOP made me worried sick😖, I thought: how on earth am I suppose to source the working procedures of something I have no experience in?😵‍💫 I was however proven wrong as the school has kindly provided us with not just one, but two in-dept learning packages💓. One is a video showing us how to physically operate the machine and one is a theory lesson package. However it was still challenging to just internalize a whole new machine hence I was very uncertain I could past the competency test. 

We were allowed to bring a copy of our SOP into the test, so I spent donkey's years on perfecting my copy of SOP to ensure I fitted every last piece of information inside the limited pages we could bring. 😴

On the day of the test it was a breeze😄😄. The teacher in charge was extremely nice and even guide us through once more before the test started. One thing I felt that was not right was how I prioritized work>fun. I overlooked the fun part of creating endless possibilities of design just like 3D printing. I though laser cutting was just cutting maybe some keychains and simple objects like that but, boy am I wrong. In the SP library I saw a Formula 1 car🏎️ made of cardboard and I was astonished. It was incredibly detailed🧐 and really resembled the real thing. Unfortunately I forgotten to take a picture so this is the closest thing I could find on the web.

I also remembered that the teacher asked us about the purpose of fume extractor inbuilt into the laser cutting machine and I just stood frozen not knowing the answer. I knew it was something regarding safety. Was it so that the fumes do not clog up the machine and we cannot see the printing? Or was it dangerous for us not to see what the laser is cutting? I instantly picked up the use of systematic thinking I just learnt from my Process operating skills module and picked up the reason. There are multiple reasons for this engineering control. I remembered some materials when cut produces toxic gas. The thick fumes may also catch fire! And lastly the fumes and smoke may affect the power of the laser making the laser beam harder to pass through, which heats up the smoke quite a lot increasing the temperature inside the machine. 

After this incident, I realized I still missed out some detailed part of the laser cutter hence I still need some experience to fully understand the working principles of each part of the machine.😔 On the other hand I was proud that as an engineering student I could use the principles of problem solving at the tips of my finger and put what I learn to good use.😊

Thanks to my exposures to modules like LPS POS and CPDD I have gained some extremely important skills two of which is troubleshooting and problem solving. Being quick to decision making is so important in the working industry that I am kansha shite iru (thankful) I can gain this skill this early on. 🧠💬

In addition I also had a great recap on how important safety in a workplace is. It is always a common phrase "safety is our number one priority" such that it is sometimes overlooked like how I did for the fume extractor. From now on I will do my best to read the signs of the use of different equipment and not neglect the importance of safety especially when there is nobody around me to remind me to prepare myself for the upcoming internship programme.

In a nutshell this test also known as out first ever laser cutting practical was a blast.💥 I definitely had many takeaways from it and I would like to also thank the teacher in-charge to be kind enough to walk us through step by step on the procedure once again. Being such a fun experience I believe this practical has latch itself on my brain and I will certainly not forget about it!🤔

Thanks for joining me on my insightful journey I do hope you feel as pumped as I am for the next practical!