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.