Summer 2021 Flashcards
What are the 2 types of plastic?
- Thermosetting
* Thermoforming
What is stock form?
the original form that it can be bought and is stored in, it is usually a standardised size
What are 3 stock forms for plastic?
- Powder
- Granules
- Sheet
What are the 7 plastic manufacturing techniques?
- Line Bending
- Injection Moulding
- Vacuum Forming
- Blow Moulding
- Extrusion moulding
- Compression Moulding
- Rotational Moulding
What is line bending?
Line bending is one of the simplest ways of forming a plastic sheet. A strip heater consists of a hot wire that heats the polymer until it becomes pliable and can be bent into shape. Jigs and formers can be used to achieve consistent desired results for multiple products. You should not overheat the polymer as it may blister or discolour
What is injection moulding?
Plastic granules are fed into a hopper. The screw in the chamber below the hopper sends the granules forward. Heated jackets around the screw melt the polymer. The screw winds back and the hydraulic ram comes forward into position. The mould is closed and sealed as the ram forces the melted plastic into the mould. The plastic is allowed to cool and the halves of the mould release. The sprew is machined off
What is vacuum forming?
The mould is placed in the former. A sheet of thermoplastic, such as HIPS is clamped over the mould. The plastic is slowly heated to become soft. The former is raised and the air is sucked out, drawing the plastic over the former to take its shape. The plastic is allowed to cool and then removed from the mould. Individual products may then be die cut from the plastic sheet.
What is blow moulding?
The mould is opened into its 2 halves. A hollow tube of polymer known as the parison is heated. The parison is lowered into the mould. Mould is clamped shut, leaving only a small hole for the air hose. Air is forced into the mould at high pressure. The plastic is forced to the mould side and cools
What is extrusion forming?
A motor turns a thread which feeds granules of plastic through a heater. The granules melt into a liquid which is forced through a die, forming a long “tube like” shape. The extrusion is then cooled and formed a solid shape in the cooling chamber. The shape of the die determined the shape of the tube
What is an example use of line bending?
a menu holder/covid screen
What is an example use of injection moulding?
a Lego brick
What is an example use of vacuum forming?
a school food tray
What is an example use of blow moulding?
a disposable plastic water bottle
What is an example use of extrusion moulding
a plastic tube
What is anthropometrics?
anthropometrics is the practise of taking measurements of the human body and provides a categorised data that can be used by designers
What is ergonomics?
ergonomics is the study of how well and comfortably people can interact with products and systems
How would designers have used anthropometrics in the design of the kitchen units?
When designing the kitchen, the designers would have measured peoples height and adjusted the height of the counters so that it is correct for the majority of people. Also, they would have adjusted the height of the cabinets so that it appeals to people between the 5th and 95th percentile
How would designers have used ergonomics in the design of the kitchen units?
When designing the kitchen, the designers would have positioned features such as the sink and stove so that people can comfortably interact with them. Also, they would have adjusted the handles on the cabinets so that they can be opened comfortably and are easily opened. Finally, they would have adjusted the location of the cabinets so that they are accessible from the correct positions and can be easily opened
What is pewter?
pewter is a metal alloy mostly made from tin. Most modern pewter is 96% tin, 4% copper and contains some antimony, although there are many variations
What is casting?
casting is a manufacturing technique in which a liquid metal is used to fill a mould. Casting involves pouring molten metal into a mould or injecting it into a die, and then allowing it to cool
Why is pewter a suitable alloy to be used in the casting process?
Pewter has a relatively low melting point of 230*C
What is the stock form of pewter?
A bar
Why is lead no longer used in pewter?
Lead is poisonous, and because pewter is often used to make cups, jewellery and doorknobs many people where poisoned and where killed by lead poisoning
Why is antimony used in pewter?
antimony is resistant to acids
