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(a) (i) Name the three plastic manufacturing processes shown at A, B and C - Leaving Cert Engineering - Question 5 - 2019
Question 5
(a) (i) Name the three plastic manufacturing processes shown at A, B and C. (ii) Describe with the aid of a labelled diagram any one of the manufacturing process... show full transcript
Worked Solution & Example Answer:(a) (i) Name the three plastic manufacturing processes shown at A, B and C - Leaving Cert Engineering - Question 5 - 2019
Step 1
Step 2
(ii) Describe with the aid of a labelled diagram any one of the manufacturing processes, named by you, at 5(a)(i) above.
Answer
Injection Moulding
Injection moulding is a process used to create a variety of plastic products. The process involves several key steps:
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Heating: Thermoplastic material is heated until it reaches a molten state. This occurs in the injection nozzle where the material is softened.
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Injection: The molten plastic is forced into a mold under high pressure through a plunger. The force helps ensure that the material fills all cavities in the mold.
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Cooling: After the mold is filled, the plastic is allowed to cool and harden. This occurs inside the mold, where it adopts the shape of the cavity.
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Ejection: Once hardened, the mold is opened, and the final product is ejected. This allows for rapid production of components with high precision.
(Labelled diagram illustrating the injection moulding process)
Step 3
(i) Thermosetting plastic;
Answer
Thermosetting plastics are materials that become permanently hard when exposed to heat. During the molding process, the thermosetting plastic is set into a specific shape by applying heat, which causes a chemical reaction that hardens the material. Once cured, thermosetting plastics cannot be remolded or reshaped, making them ideal for applications requiring durability and heat resistance.
Step 4
(ii) Elastic memory;
Answer
Elastic memory is a property of certain plastics that allows them to return to their original shape after being deformed. This means that if a thermoplastic is stretched or compressed, it will revert to its initial form when the stress is removed. Certain plastics exhibit this characteristic, making them useful in applications where flexibility and durability are necessary.
Step 5
(iii) Thermoplastics.
Answer
Thermoplastics are a class of plastic materials that can be heated and softened multiple times. Unlike thermosetting plastics, thermoplastics do not undergo a chemical change upon heating. This reversibility allows them to be molded and reshaped repeatedly. Additionally, thermoplastics are suitable for recycling, making them an environmentally friendly option in many applications.
Step 6
(c) Select any two of the products shown below and name a suitable plastic material which can be used to make each of the products selected:
Answer
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Rear light cover for vehicles: A suitable plastic material for rear light covers is Perspex / Acrylic (PMMA). This material offers high transparency and weather resistance.
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Tool handles: An appropriate plastic material for tool handles is Cellulose acetate (CA) / ABS. These materials provide a good grip and durability.
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Kitchen worktops: A recommended material for kitchen worktops is Melamine-formaldehyde (MF) / Bakelite. Both are strong, heat-resistant, and easy to clean.