Molding - Manufacturing and Industrial Engineering Interview Questions

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31. Define drooling ?

Leakage of plastic material through the nozzle in between shots.
32. What is injection capacity or short capacity?

Maximum volume material injected by the screw during one cycle of operation.

33. What is plasticizing capacity ?

It is the amount of material that can be processed by the machine per hour. It is expressed in kg/h.

34. What is injection pressure?

It is the maximum pressure by which the material is injected through the nozzle. It is given in kg/cm2.

35. What is Injection rate or Injection velocity ?

It is the maximum rate at which the screw can inject or shoot materials from the barrel during one shot.

36. What do you meant by clamping force?

It is the maximum force that the clamping system can exert on the mold or it is the maximum force by which the mold halves can be closed together. It is given in ton or kilo Newton.

37. What is maximum daylight?

It is the maximum distance that the machine platen can be separated from each other and it can be obtained by adding the maximum mold thickness to the maximum opening stroke.

38. What is a mold ?

It is a custom build tool in which we converts plastic raw material into finished product.

39. What are the main elements of mold ?

The main parts of molds are core and cavity.

40. What are the general types of mold ?

Injection molds, compression molds, transfer molds.

41. What  are the types of injection mold ?

  • Two plate mold 
  • Three plate mold 
  • Hot runner mold 
  • Insulated runner mold 
  • Hot manifold mold 
  • Stacked mold 

42. What  is two plate mold ?

Mold which consists of core and cavity situated in plates. It is logical type tool where component require large gate. For simple type components there is only one daylight.

43. What  is 3 plate mold?

It consists feed plates with core and cavity.

44. What  is hot runner mold?

In this, runner kept hot to keep the molten metal into fluid state also called runner less mold. In this, runner contained in a plate of its own runner section of the mold is not opened during molding cycle.

45. Note down the advantages of runner mold ?

  • No molded side products 
  • No separating of gate
  • Cycle time can be reduced

46. What  is insulated runner mold ?

 It is a variation of hot runner mold in this type of molding. The outer surface of the material in the runner acts as a insulator.

47. What is hot manifold mold ?

This is a variation of the heated hot runner and not the runner plate. This is done using electric cartridge.

48. What do you meant by stacked mold? 

A stacked mold is a multiple two plate mold with mold placed one over the other. A stacked mold construction doubles the output from a single molding machine and requires the same clamping force.

49. Explain about injection molding?

 In this process, the plastic material is injected in to the mold through a sprue bush by means of a screw plunger. This process can be used for both thermosetting and thermoplastic materials.

50. What  is compression molding?

In this process, the plastic material is placed in the cavity and use a force for compressing the compound as the mold closes, these molds are generally used for thermosetting materials. 

51. What  is transfer mold?

In this process, the plastic materials is transferred from a transfer pot and then forced in to the cavity by means of plunger. This method is used for molding thermosetting materials only.

52. Write a short note about blow molding ?

Blow molding is very much like compression molding because the blow mold generally closes on a hollow shape that has been deposited in between the halves of the mold. Air or gas pressure is introduced at the center. This internal pressure causes a flow of the heated material in to intimate contact with the relatively cold mold sections. Here the plastic material solidifies and is subsequently ejected.

54. Explain vacuum molding?

The mold used for this process is similar that of the female half of the compression or blow mold auxiliary equipment on the machine heats the material and drags it over the cavity as indicated by the precise technique chosen.

55.Elaborate about rotational molding?

The machine provides the means of holding the mold and rotating it about two axis at the same time. This rotation causes the powdered material that was loaded in to the mold before it was clamped in to the machine to solidify and cling to the wall of the mold.

56. What  is impression ?

Gap between core and cavity is called impression. Impression provides the shape of the component.

57. What  do you meant  cavity?

Female portion of the mold and it gives external form.

58. What  is core ?

Male portion of the mold and it gives internal form.

59. What  is sprue bush?

Connecting member between register ring and runner.

60. What  is register ring ?

It is used to align the mold with machine platen.

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