DF assignment 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).

BAND SAW

SAFETY GEAR

-Goggles 

-Appropriate clothing

HAZARDS

-Long sleeved shirts can get caught in the work or in the band saw blade.

-Keep hair tied up so it doesn't get caught in the band saw blade.

-A blade can break and the possibility exists that a piece could come loose.

-Keep attention on what you are cutting

-Turn off the band saw once you are finished using it.

-Keep fingers away from blade

BELT AND DISC SANDER

SAFETY GEAR

-Googles

-Appropriate clothing

-Mask (optional)

HAZARDS

-If wearing long sleeves, roll them up so they don't get caught in the machine.

-Tie hair so it doesn't get caught in the machine.

-Dust or a bit of the project could fling into your eye, so always wear goggles.

-Turn the machine off once you have done.

-Don't talk or look at anything while using the machine because you can slip and hurt your self.

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.

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   Industrial Name	Common Name	Properties And Uses
   Polyester	thermoplastic or thermoset polycondensate.	It has excellent dimensional stability, high dielectric strength, and good toughness. It has moderate chemical resistance, low resistance to strong acids and bases, is notch sensitive, and is not recommended for outdoor use or in hot water.
   Polyamide	PA or Nylon	It has high lubricity and moderate strength. It is tough, inexpensive, and has poor dimensional stability due to water absorption (hygroscopic nature)

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

Injection moulding is a manufacturing process for producing parts from both thermoplastic andthermosetting plastic materials. Material is fed into a heated barrel, mixed, and forced into a mold cavity where it cools and hardens to the configuration of the cavity. After a product is designed, usually by an industrial designer or an engineer, molds are made by a moldmaker (or toolmaker) from metal, usually either steel or aluminum, and precision-machined to form the features of the desired part. Injection molding is widely used for manufacturing a variety of parts, from the smallest component to entire body panels of cars.

STAGES OF INJECTION MOULDING

Stage 1
Granulated or powdered thermoplastic plastic is fed from a hopper into the Injection Moulding machine.

Stage 2

The Injection Moulding machine consists of a hollow steel barrel, containing a rotating screw (Archemidial Screw). The screw carries the plastic along the barrel to the mould.

Heaters surround the barrel melt the plastic as it travels along the barrel.

Stage 3
The screw is forced back as the melted plastic collects at the end of the barrel.
Once enough plastic has collected a hydraulic ram pushes the screw forward injecting the plastic through a sprue into a mould cavity.
The mould is warmed before injecting and the plastic is injected quickly to prevent it from hardening before the mould is full.


Stage 4
Pressure is maintained for a short time (dwell time) to prevent the material creeping back during setting (hardening). This prevents shrinkage and hollows, therefore giving a better quality product.
The moulding is left to cool before removing (ejected) from the mould. The moulding takes on the shape of the mould cavity.
The image below shows an an Injection Moulding machine.

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.