Desk Tidy Questions

1. Choose 2 machines that you used in the fabrication of your desk tidy. With these machines in mind, outline WPH&S considerations that must be adhered to when using these machines. Include photographs of your chosen machines (OnGuard may be an excellent resource for this question). Electic Belt & Disc Sander:
- Must have saftey glasses on
- Aprons must worn
- No items can be sanded unless they are bigger than 3cm
- Make sure no one is within half a metre when using
- Machine must be turned of when not in use
- Girls must have long hair tied back away from machine
- Must have leather closed in shoes when using

Band Saw:
- Must wear saftey glasses
- Aprons must be worn
- Items smaller than 3cm can not be used for this machine
- No one is allowed within a metre of the working area if one person is already using
- Machine must be turned off when not in use
- Anyone with long hair, it must be tied back when using machine
- Must have leather closed in shoes when using

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.
Poly:
Industrial Name = Methyl Methacrylate
Common Name = PMMA/Plexiglass
Properties =
- Shatterproof
- More transparent than glass
- Stronger than glass
Uses = Shatterproof Replacement for Glass, In a fish aquarium it is used to see through so you can see the fish, Used as barriers in ice hockey rinks.
Lexan:
Industrial Name = Polycarbonate
Common Name = Lexan
Properties =
- 250 times stronger than plate glass
- 30 times stronger than acrylic of equal thickness
- Provides lasting protection
- Unlikely to break, twisted, bent or smashed against
Uses = Provides lasting protection against vandalism and burglary, also provides protection against natural occurrences, such as high winds, snow loads, and hailstorms

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.
Vacuum Forming:
- First, a former is made from a material such as a soft wood. The edges or sides are shaped at an angle so that when the plastic is formed over it, the former can be removed easily.
- The former is placed in a vacuum former.
- A sheet of plastic (for example, compressed polystyrene) is clamped in position above the mould.
- The heater is then turned on and the plastic slowly becomes soft and pliable as it heats up. The plastic can be seen to 'warp' and 'distort' as the surface expands.
- After a few minutes the plastic is ready for ‘forming’ as it becomes very flexible.
- The heater is turned off and the mould is moved upwards by lifting the lever until it locks in position.
- The 'vacuum' is turned on and this pumps out all the air beneath the plastic sheet. Atmospheric pressure above the plastic sheet pushes it down on the mould. At this stage the shape of the mould can be clearly seen through the plastic sheet. When the plastic has cooled sufficiently the vacuum pump is switched off.
- The plastic sheet is removed from the vacuum former. The sheet has the shape of the former pressed into its surface.
- The excess plastic is trimmed so that only the plastic bowl remains
- The completed item.

4. Extension Work - Using processes acquired from your maths lessons, calculate the amount of acrylic sheet that your FINAL desk tidy represents. Show all calculations; answer needs to be in square metres.

Therefore the total area of the desk tidy is 4.3525m2