Anzeige

Plastic

Student at University of Johannesburg um University of Johannesburg
19. Oct 2016
Anzeige

Más contenido relacionado

Anzeige

Plastic

  1. These types of plastics are a family of plastics which may be reheated and reshaped quite a few times. We say the they have a memory because once heated they will attempt to return to their original form, unless they have been damaged or over-stretched. These types of plastics, once heated and formed into a shape cannot be reheated and reshaped because a process called polymerisation has taken place.
  2. Thermoplastic:
  3. Thermosetting plastic:
  4. 1. Select the correct term to fit with the given definition (Thermoplastic or Thermosetting plastic) Term: Definition: These types of plastics, once heated and formed into a shape cannot be reheated and reshaped because a process called polymerisation has taken place. These types of plastics are a family of plastics which may be reheated and reshaped quite a few times. We say the they have a memory because once heated they will attempt to return to their original form, unless they have been damaged or over-stretched.
  5. ITEM: TYPE OF PLASTIC: Water bottle Plastic chair Plumbing pipes Food containers (take-away) Pot/Pan handles Electric wall socket Shopping bags 2. Determine which type of plastic will be better suited for:
  6. 3. Evaluate the given scenario and state the problem, in your own words. Usually, you take your food in a plastic bag to school. Your sandwiches get squashed in your school bag and sometimes the plastic bag tears resulting in a big mess in your school bag. Sometimes you take food to school that needs to be kept warm or cool and then the plastic bag does not work that well. It is expected of you to use plastic waste to design and build a suitable solution.
  7. A process whereby used materials are broken down to raw material status and turned into new products to be used. A process whereby previously used products are used for the same or another purpose than for which it was originally designed. (Products remain the same and are not altered in any way through scientific processes)
  8. 1. Tabulate the difference between Recycling and Reusing Recycling Reusing
  9. 2. Develop/list 3 ways in which you can reuse 2L Soda Bottles ITEM 1. 2. 3.
  10. 3. Write a brief statement, providing a solution to the identified problem (from previous lesson) identified in the given scenario.
  11. 1. Identify the plastic identification code symbols of the given plastic products Plastic Product Identification code (number) Polystyrene take-away container 2L Soda bottle Shampoo bottle Dishwashing liquid bottle Water bottle Yogurt container Tomato sauce bottle
  12. 2. Sort the given items into different recycling bins by using their plastic identification codes. Recycling Bins Plastic items
  13. Recycling Bins Plastic items
  14. 3. List 3 products that can be used for the same purpose as the product that you have to design and make (container to carry your lunch in that will keep it warm/cold). Then tabulate the advantages and disadvantages of each. Consider things like quality, affordability, availability of material, appearance and fitness for purpose E.g. Portable cooler bag ADVANTAGES DISADVANTAGES 1. Looks pretty 1. Expensive 2. Can keep food cold 2. Not environmentally friendly 3. Closes tightly (doesn’t spill) 3. Difficult to clean after use
  15. Before you start making your product it is important to first write down what needs to be done to meet the need/solve the problem. There are four aspects that should be considered: - What should be done? Elaborate on your design brief. - Specifications List the specifications to ensure that you can comply with all the requirements that your product should adhere to. E.g. Size, shape, cost, maintenance, function, safety, appearance, environmental factors, materials and reliability - Limitations Identify any implied limitations - Time plan Any project should be completed within a certain time. Establishing a timeframe is a good way of measuring your progress.
  16. 1. State in your own words what exactly it is that you intend to make. 2. You have 5 lesson periods to utilise. Complete the time plan below to give a rough indication of how you would utilise the allocated time. Technological Process Stage Number of periods used 4. Proposal 5. Initial idea generation 6. Research 7. Development 8. Planning 9. Make/Manufacture 10. Test/Evaluate
  17. 3. Make a list of the specifications of requirements of the product.
  18. 1. Develop at least 3 ideas that may be a solution to the problem that you have identified. 2. Use freehand sketches with captions to illustrate your ideas. 3. Analyse all of these ideas by listing the advantages and disadvantages of each. 4. Select one idea/a combination of ideas and justify your choice.
  19. ADVANTAGES DISADVANTAGES 1. 1. 2. 2. 3. 3.
  20. ADVANTAGES DISADVANTAGES 1. 1. 2. 2. 3. 3.
  21. ADVANTAGES DISADVANTAGES 1. 1. 2. 2. 3. 3.
  22. During the investigation stage (lesson 3) you did research on various materials; their properties, uses, etc. You should search for information that could help you to solve problems and answer any questions with regard to problematic aspects.
  23. Example questions that you may have: - For how long will my product be usable if I use this material? For instance, water bottles have an expiration date and if this is ignored, the plastic gives off gases that are very harmful to your health and it could kill you. - What method should I use to attach the different parts of my product? This answer will depend on the material you are using. - If I use glue, which glue would work the best? For instance, you cannot use Bostik glue on polystyrene – it will start to melt and completely disintegrate – rather use wood glue. - It is important to consider such aspects and to do thorough research.
  24. 1. List some problematic aspects that still needed to be resolved with regard to the chosen idea before you can develop it any further
  25. 2. Find the information that you need to resolve these problematic aspects so that you may develop your chosen idea into a workable solution.
  26. Now you should model your chosen idea to see if it works and how it can be improved. There are four aspects that should be considered: - Materials: Begin to identify suitable materials for each part of your product. Properties to consider are weight, strength, toughness, resistance to heat/corrosion, colour, conductivity, hardness, appearance, flexibility, etc. - Size and Shape: Specify accurate sizes. Ergonomics is a key factor here and should be considered. - Appearance: The overall appearance should be considered, since visual qualities are important. Different preferences and opinions will affect this factor. - Safety: It is important that safety be taken into consideration when any product is being developed. Proper safety standards should be applied.
  27. 1. Develop a working model of your chosen idea. Take the necessary safety precautions
  28. During this phase, it is time for you to make a working drawing of your final idea, complete with details and measurements. Usually you sketch: - a first-angle orthographic projection and - an isometric projection of your final chosen idea.
  29. 1. Sketch your final chosen idea in first-angle orthographic projection Front View Top View Left View
  30. 2. Sketch your final chosen idea in isometric projection
  31. 3. Compile a resource list containing all of the parts, their sizes and the materials they are made of.
  32. During this stage you are finally ready to start making your final product. Remember to keep checking whether you are still on track by referring back to the design brief and the specifications which you have identified. Safety is very important. Think before each step and never rush – if you do, it is easier to make mistakes. Record everything you do by taking pictures while you work. Should you be unsure of anything (especially concerning safety and how to use any of the tools) do not be afraid to ask for help before attempting it on your own.
  33. MOULDING PROCESS: EXPLANATION Extrusion During the manufacture of plastic rods, tubes and curtain rails plastic is pressed through an opening in long moulds. Blow moulding Plastic is blown into moulds to produce a variety of containers. The containers have a visible seam that looks as if the two looks as if the two parts were glued together, as can be seen in bottles and cans. Vacuum and pressure moulding Plastic is heated until it is soft before a sheet of plastic is sucked in over a mould. Injection moulding Warm plastic is injected under high pressure in a mould.
  34. 1. Choose one of the moulding processes and write one paragraph (not more than ½ a page) explaining the process in your own words. 2. Consider all of the work you have done during all of the previous lessons. Now, make the product which you have designed. Remember to keep checking whether you are still on track by referring back to the design brief and the specifications which you have identified.
  35. •Why did you choose to evaluate your product based on these points? •Do you think that this criteria could also be important? •Develop a list of aspect that you feel could be improved upon? •Suggest ways in which these aspects could be approached differently in the future?

Hinweis der Redaktion

  1. See p.28 of teacher guide
  2. See p.28 of teacher guide
  3. See p.29 of teacher guide
  4. See p.29 of teacher guide
Anzeige