Friday, 14 August 2020

What is the use of gates in creation of plastic?

Main Topics

Gates is an a orifice connecting the runner with the impressions its cross sectional area is very small compared with the rest of the feed system. Smaller cross sectional area is necessary.


Gate can freeze soon after the impressions are filled and prevent material to flow back from the mold. When screw is withdrawn the De gating is simple and heat.

Only a small de gating mark will remain the component is not spoiled. Multi impressions mold can be filed with better control.

Types of gates:

Sprue Gate:

  • Where molding is feed directly from sprue.
  • Dis – Advantage of this gate, It leaves large de gating mark on the molding.

Rectangular Gate:

  • Cross section is rectangle and easy to machine.
  • Gate Dimensions can be easily and Quikly modified.
  • All general plastics can be molded through this gate.

Pin Gate:

  • A circular gate of relatively small diameter and is used for feeding into the base of the component.
  • Used in 3 plate mold and hot runner molds. (Where automatic de gating is done.)

Submarine gate: 

  • Submarine gate is circular or oval gate.
  • It submerges and feeds into the impression below the parting surface of the mold.
  • Gate is sheared from the molding during its ejection.

Submarine gate

  • A very small de gating mark is left in the component.
  • Used in 3 plate molds and hot running molds.
  • Where automatic de gating is done.