Plastic Components Manufacturing | Interview question and Answers

Plastic Components Manufacturing | Interview , viva , oral question and Answers

1. Classify the types of plastics.

1. Thermoplastics
2. Thermosetting plastics.

2. Classify thermoplastics.

1. Amorphous – Methacrylate, polyvinyl chloride, cellulose, fluorinated polymer
2. Crystalline – polyethylene, polyamide, polypropylene

3. List the application of blow moulding.

It is used to produce hollow components like containers, drink bottles etc.

4. What are the characteristics of thermosetting plastics?

1. It cannot soften once it moulded even at high temperature.
2. These plastics have cross linked molecules
3. These links are broken at high temperature but important properties are destroyed.

5. Give some example for thermosetting plastics.

Phenol formaldehyde, urea formaldehyde, phenolic, polyester, epoxide.

6. Distinguish between thermo and thermosetting plastics.

1. They can be repeadly softened 1. Once hardened and set, they do by heat an hardened by cooling. not soften with the application of heat.
2. They are comparatively softer 2. They are more stronger and and less strong harder than thermoplastics
3. They are produced by the 3. They are produced by the Polymerization condensation Polymerization
4. They are usually supplied as 4. They are usually supplied in granular material polymerized form.

7. What are the types of injection mouldings?

1. Straight plunger type
2. Single stage reciprocating screw type
3. Two stage plunger or screw plasticizer type.

8. What is extrusion?

It is the term applied to the Process OF shaping plastics through die orifice. It is a continuous process.

9. List the parts used in the transfer moulding.

1. Plunger
2. Sprue.
3. Knockout pins
4. Cooling systems
5. Transfer chamber.

10. What is the use of torpedo and hopper?

Hopper – It is used to feed the granular form of material in to the heated cylinder.
Torpedo – It helps in spreading the moulding material uniform around the wall of the heated cylinder.

11. What is the use of rotational moulding?

It is used to produce the hollow component like toys. Normally it is used for polyvinyl chloride, polyethylene.

12. What is calendaring?

It is used to produce sheets and films from plastics materials such as polyvinyl chloride, polyethylene.

13. What is Parison?

The blow moulding process starts with the production of a tube made of thermoplastics material. This is called parison.

14. List the types of joining of plastics.

1. Mechanical fastening
2. Solvent bonding
3. Hot plate welding
4. Induction welding.

15. Define – solvent welding.

It is used to join the plastics by the help of solvent. The solvent is used to soften the plastics and joining by pressing together.