Mumbai University > Mechanical Engineering > Sem 5 > production process 3

Marks: 10M

Year: May 2016

Ejector System:

• The system which facilitates the positive ejection of the molding after it solidifies known as the ejection system.
• The ejector system can be actuated automatically and mounted behind the moving half.
• It consist of the following system:
  • Ejector Grid.
  • Ejector Plate Assembly.
  • Methods of Ejection.

1) Ejector Grid:

• The ejector grid is the part of ejection system which support the mould plate.
• Also it provide space for ejector plate assembly.
• The ejector grid consist of a back plate and support block.

• There are following three types of ejector grid:

  • In-Line Ejector Grid.
  • Frame type Ejector Grid.

  • Circular support block grid.

    a) In-Line Ejector Grid:

• It consist of two rectangular support blocks mounted on the back plate as shown in fig.
• The ejector plate assembly is mounted between the two support blocks.
• This type of design is suitable for small moulds where space available is less.
• Extra support blocks may be added to support the mould plate and avoids its distortion due to injection force.

b) Fram- Type Ejector Grid

c) Circular Support Pillar Grid:

• Above fig shows the circular support pillar grid which consist of circular support pillars mounted on the back plates.
• The grid is attached to the mould plate by socket headed screws. The ejector plate assembly can move freely in the support pillars.
• This type of grid is used for large moulds.