Tuesday, 26 May 2020
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.