Molding Interview Questions & Answers

- Mar 18, 2018-

  1. What Is The Important Characteristics Of Plastics?

    Answer :

    It can be molded into finished product by application of heat and pressure.


  2. What Are The Advantages Of Plastics Over Metals?

    Answer :


    • Low weight 

    • Corrosion resistance 

    • Insulation properties

    • Electrical properties

    • Cheaper 

    • Easy to handle 

    • Surface properties 

    • Reusable

  3. Explain The Disadvantages Of Plastics?

    Answer :


    • Low strength 

    • Low heat resistance

    • Poor mechanical properties

    • Difficulty to repair

  4. How To Classify The Plastics?

    Answer :


    • Natural : milk of rubber tree, cellulose

    • Semi synthetic

    • Synthetic

  5. Types Of Plastics Based On Chemical Behavior?

    Answer :


    • Thermo plastics 

    • Thermosetting plastics

  6. Difference Between Thermo Set And Thermo Plastics?

    Answer :

    Thermoplastics:

    Thermo set plastics:


    • Cannot be re softened and reused

    • Chemical changes during heating etc.

    • In powder form

    • Cross linked structure 

    • Hard and brittle 

    • Can be re softened and reused

    • No chemical changes during heating.

    • In granular form

    • Needle structure 

    • Hard but not brittle

  7. Give Example Of Thermoplastics?

    Answer :

    ABS, PP, CA, PMMA, PS, PC, POM etc.


  8. Perspex Is The Trade Name Of ---- ?

    Answer :

    CA


  9. Nylon Is The Trade Name Of ---- ?

    Answer :

    PA


  10. Delrin Is The Trade Name Of ---- ?

    Answer :

    POM



  11. Teflone Is The Trade Name Of ……….?

    Answer :

    PTFE


  12. What Is Mfi?

    Answer :

    Flow capacity of different grades of thermoplastics are inversely proportional to molecular weight.


  13. About Abs?

    Answer :

    Shrinkage 0.5%. It is heat resistant, provides good insulation and exhibit electrical properties. Examples are general purpose safety helmets, pipe fittings, television, radio etc.


  14. About Ca ?

    Answer :

    Shrinkage 0.3-0.8%. Its main properties are transparency and surface texture. Examples are Tool handle, goggles, TV screens.


  15. About Hdpe?

    Answer :

    Shrinkage 3-4%. Main features of HDFE are high density, rigidity, strength, hardness and chemical resistance. Examples are milk bottle crates, fish boxes etc.


  16. About Ldpe?

    Answer :

    Shrinkage 0.8-1.5%. It is crystalline and not available in transparent form. Examples are shopping baskets, waste baskets etc.


  17. About Pa?

    Answer :

    Shrinkage 0.7-1.5%. It is tough and high rigid. Examples are light duty gears, sprockets, bearings etc.


  18. About Pc?

    Answer :

    Shrinkage 0.5-0.7%. It is known optical transparency, rigidity and toughness. Examples are goggles, lenses, safety helmets etc.


  19. About Pp?

    Answer :

    Shrinkage 1-3%. It is flammable and degradable in sun light and stable. Examples are air cleaner, garden furniture etc.



  20. About Ps?

    Answer :

    Shrinkage 0.2-0.8%. It is clear, brittle and it can be easily molded. Examples are toys, house hold appliances, electronic housings etc.