Evaluation Questions

a. List the materials that were used in the construction of your mechanized toy.

Ply Wood

Dowel

Wood Glue

Hot Glue

b. Describe some environmental problems which are caused by the overuse of wood products (i.e. deforestation).
The main environmental problem caused by the overuse of wood products is deforestation. Trees are destroyed, but so are the habitats of many native fauna, e.g. birds loosing their nest and eggs, meaning the species of birds could become endangered. Deforestation effects flora as well, many species of plants live off the minerals contained in the trees that are chopped down. Some other environmental problems include pollution made by the factories, the increased erosion and global warming, leading to sea levels rising.

c. Explain the difference between ‘open-loop and closed-loop’ control systems. Give an example of each.
An open-loop control system is a system that doesn’t have a feedback loop and is not self-correcting. A closed-loop control system is a system in which the output has an effect on the input in such a way as to maintain the desired output value. An irrigation sprinkler system, programmed to turn on at set times could be an example of an open-loop system. An example of a closed-loop control system is a controller for a video game.

d. Provide a brief description of 3 different types of mechanisms i.e. linkage, cams

Cam: A cam is a projection on a rotating part in machinery, designed to make sliding contact with another part while rotating and to impart reciprocal or variable motion to it.

Linkage: A mechanical linkage is a series of rigid links connected with joints to form a closed chain, or a series of closed chains. Each link has two or more joints, and the joints have various degrees of freedom to allow motion between the links.

Leaver: A machine consisting of a rigid bar pivoted on a fixed point and used to transmit force, as in raising or moving a weight at one end by pushing down on the other.

e. Provide an in depth description of the primary mechanism used in your toy.

The primary mechanism used in my mechanism is offset cams. There is only two cams in the whole design. These cams are used in a circular motion by moving the handle in a circular motion, creating the output of making the peacocks move up and down.

f. Evaluate your finished product in terms of ergonomics, aesthetics and function.

Function:

Although I haven't finished the mechanism yet, I have a idea on what the mechanism will turn out like. Honestly, I think the mechanism will do what it's aimed at to do. I'm not sure how effectively it will work though. In conclusion, I think there are some improvements I can make to help my mechanism improve its overall function, I'm just not sure how to do it.

Aesthetics:
I am quite happy with the movement the cams, they still stick sometimes but I think after a bit of wear they will be working fine. I still need to paint my peacocks and add pipe cleaners to the tail, but I’m going to use bright colours giving it a very modern look.

Ergonomics:
In terms of ergonomics, this mechanism is extremely safe as there is little chance you will become injured by getting fingers stuck or hurting yourself. It is very easy to use and I think the handle is a perfect length.

workshop lesson - term 4

I have now finished making my box for my mechanism. So far I this term I have:

• Measured and cut my MBF wood pieces which were 6mm thick, 220mm in length for the top and bottom, 120mm (plus 12mm which is 132mm for the right width) on the ban saw for my box mechanism.
• Sanded down the edges of these wood pieces on the disk sander.
• Cut my stoppers from a light, thin rod of wood.
• Drilled an 8mm hole through the sides of my box making sure everything lined up.
• Glued my wood pieces together with a hot glue gun, creating the box itself. This included re-gluing my wood stoppers in the right place so my box was evenly balanced etc. 
• Threading my dowel into these holes. 
• Cutting a circular end of wood for my handle stopper with a cut-out drill (see image below of Kelsey having a panic attack while Mr Andrews forces her to use the drill again after an incident that happened in a past lesson). 
• Drilling a hole through my circular wood piece on the side. I then glued a small piece of cut-off dowel into this hole so it could be used as a handle. 

Workshop lesson - term 4

We were finishing creating our boxes from the end of term 3 this lesson. I had a bit of trouble with the hot glue gun and gluing the stoppers in the right place. I accidentally glued my stoppers on the sides of my box instead of on the lid. This then made the box uneven in height and the sides weren't parallel. I fixed this by ripping off the stoppers of wood and fitting them in the right place. 

Assesment Questions - Q3

3. Extrusion, injection moulding, compression moulding, vacuum forming and laminating are examples of common manufacturing processes used with polymers (Plastics). Choose one process and with the use of diagrams and bullet points outline the process.

Injection Moulding

• Materials such as polystyrene, nylon, polypropylene and polythene can be used in injection moulding. These are all thermoplastics - when they are heated they can be manipulated into a mould and form different shapes 
• Lego bricks are made by injection moulding.
• Here are the steps for injection moulding.

1. Plastic powder grandules are poured or fed into a hopper which stores it until it is needed.


2. A heater heats up the tube and when it reaches a high temperature a screw thread starts turning. 


 3. A motor turns a thread which pushes the granules along the heater section which melts then into a liquid.  The liquid is forced into a mould where it cools into the shape (in this case its lego bricks)

4. The mould then opens and the brick is removed (after it has cooled down).

Assesment Questions - Q2

 

2.      The material you are using for your desk tidy is called Polymethylmethacrylate (ACRYLIC). It has specific properties and uses.  Choose 2 other common polymers and in table form give their industrial name, common name, properties and uses. 

 

INDUSTRIAL NAME	COMMON NAME	PROPERTIES	USES
Polyvinylchloride	PVC	Rigid, quite hard and tough, has good resistance to chemicals	Pipes, guttering and window frames etc.
Polyethylene	Polythene 2 types: Low Density (LDPE) High Density (HDPE)	Flexible plastic, soft, good chemical resistance and has waxy feel.	Food bags, bowls, buckets and bottles.

Assesment Questions - Q1.

1.     Choose 2 machines that you used in the fabrication of your desk tidy. With these machines in mind, outline WPH&S (workplace health & safety) considerations that must be adhered to when using these machines. Include photographs of your chosen machines

• Disk sander - Used to sand woods and plastics and to remove waste material.

WPH&S - Goggles worn at all times. Hands and fingers kept away from rotating disk. In stance standing position using only the right side of the machine (school one, not one in image).

• Buffer – Used to finish off and polish plastics such as Perspex and soft metals such as copper or aluminum.

WPH&S – Goggles worn at all times. Long hair tucked into uniform or hairnet. Sturdy footwear worn. No rings or jewelry worn. No loose fitting clothing, protective clothing worn.  

What I've done/need to do

 So far this term I have: 

- drawn many ideas for my desk tidy 

- created a 1:1 scale drawing of my chosen design 

- created a full prototype out of cardboard and masking tape 

- drawn my desk tidy net on acrylic plastic 

- started cutting out my net on the ban-saw 

What I still need to do this term: 

- finish cutting out my net 

- sand, file and buff my acrylic 

- bend the acrylic where it needs to be bent 

- glue the acrylic where it needs to be glued together 

- FINISHED!!!!! (I think)