Why are ejector pins made of hard yet shock resistant materials? ...

[Arii_bell]

Why are ejector pins made of hard yet shock resistant materials?
 
  What will be an ideal response?

Question 2

What feature in a mold will allow a hollow, cylindrical part to be made?
 
  What will be an ideal response?

[mceravolo]

Answer to Question 1

Ejector pins can meet resistance when ejecting a part that is stuck in the mold. This resistance can cause some impact forces on the pins which, if they were brittle, could cause them to break. In normal use, the ejector pins must be strong enough to push out the part. Furthermore, the constant sliding of the long ejector pins requires certain strength to keep from breaking and excessive wearing.

Answer to Question 2

Hollow parts are made by inserting a core into the mold so that the material will flow around the core, displacing the resin from the volume to be hollow. When the mold is opened and the part is removed, the core is withdrawn and the solid, hollow part is created. Normally the withdrawal of the core occurs simultaneously with the opening of the mold.

[Arii_bell]

Wow, this really help

[nguyenhoanhat]

TYSM