ENGINEERING CONCEPTS

What are the ejection techniques in injection moulding

Ejection is a process of removing the plastic material from the mold.

This are of different types to remove the material from mold.

EJECTION

Ejection techniques:

  • Pin ejector:
  • Simplest and most economical method .
  • Location and number of ejector pins depends on component shape and size.

D-shaped ejector pin:

  • Flat sided ejected pin.
  • Made by machining of flat on standard ejected pin.
  • Blade ejector :
  • Basically a rectangular ejector pin.
  • Slender parts such as ribs are ejected by this method.

blade ejection

  • Sleeve ejector :
  • Molding by means of hallow ejector pin or sleeve.
  • Ejections of small cylindrical Molding.
  • Provide positive ejector around a local core pin in forming and hole in the mold.
  • Value ejector :
  • Large diameter ejector pin.
  • Used for ejections of large component.
  • Ejector applies ejector force on to the inside surface of the molding
  • Air ejector:
  • Ejector force is supplied by compressed air.
  • Stripper bar ejector:
  • Ejector element pushes against the bottom at the molding.
  • Effective area of ejection is greater.
  • Suitable for walled box type moldings.
  • Stripper plate ejector :
  • Mold adopted for ejecting circular box moldings with thin wall sections.