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Describe the process shown in the diagram using the following guidelines: (i) Name and describe the principle of operation; (ii) Identify the function of any three of the parts A, B, C and D; (iii) Identify one component produced by this process - Leaving Cert Engineering - Question 6 - 2008
Question 6
Describe the process shown in the diagram using the following guidelines: (i) Name and describe the principle of operation; (ii) Identify the function of any three ... show full transcript
Worked Solution & Example Answer:Describe the process shown in the diagram using the following guidelines: (i) Name and describe the principle of operation; (ii) Identify the function of any three of the parts A, B, C and D; (iii) Identify one component produced by this process - Leaving Cert Engineering - Question 6 - 2008
Step 1
Name and describe the principle of operation;
Answer
The process is known as Extrusion. In this process, thermoplastic powder or granules are fed into a heated compartment. A rotating screw, part B, moves the thermoplastic along this compartment, exerting pressure to force the softened plastic through a die (part C), where it takes on a specific shape. Once the plastic exits the die, it enters the cooling chamber (part D) to solidify and is cut to the required length.
Step 2
Identify the function of any three of the parts A, B, C and D;
Answer
A – The screw feeds the plastic from the hopper through the heating compartment towards the die.
B – The hopper, which holds a supply of plastic granules or powder, ensures a constant feed into the system.
C – The die determines the shape of the extruded plastic as it exits the machine.
Step 3
Step 4
Distinguish between thermoplastics and thermosetting plastics making reference to each of the following: Chemical bonding;
Answer
Thermoplastics: In thermoplastics, the bonding is covalent with weak van der Waals forces, allowing for flexibility.
Thermosetting plastics: These have primary bonds formed by strong rigid cross-links, which makes them more durable.
Step 5
Distinguish between thermoplastics and thermosetting plastics making reference to each of the following: Polymerisation process;
Answer
Thermoplastics: They undergo addition polymerisation which allows them to be re-moulded when heated.
Thermosetting plastics: They undergo condensation polymerisation, forming rigid structures that cannot be remoulded once set.
Step 6
Distinguish between thermoplastics and thermosetting plastics making reference to each of the following: Properties.
Answer
Thermoplastics: They generally have a low melting point, are easily moulded, and can be recycled.
Thermosetting plastics: They possess a high melting point, excellent thermal insulation, and rigidity, resisting deformation under heat.
Step 7
Step 8
Step 9
Explain any three of the following in relation to polymers: Cross linking;
Answer
Cross linking involves forming a 3D network through strong covalent bonds between adjacent polymer chains. This process enhances the mechanical properties of thermosetting plastics by increasing rigidity and heat resistance.