How to Avoid Short Shot in Plastic Products?

About the short shot

1. Phenomenon of short shot

An incomplete phenomenon in which the resin is not completely filled. And this is called short shot.

2. Causes of short shot

  • Overly runner/gate diameter
  • Long runner
  • Large flow resistance in cavity
  • Poor degassing of sprue and runner
  • Insufficient air escape in the mold
  • Lack of supply
  • Insufficient injection pressure
  • Slow filling speed
  • Low resin temperature
  • Low mold temperature
short shot

3. Measures to avoid short shot

  • Increase runner/gate size
  • Review runner placement
  • Change the position of the gate
  • Provide sufficient gas venting to the sprue and runner
  • Vent the unfilled part
  • Degas just below the sprue part and at the runner end.
  • Increase the air vent near the final filling part of product.
  • Optimum material supply
  • Increase injection pressure, injection speed, cylinder temperature, mold temperature
  • It occurs when it is difficult to fill due to vent clogging.
  • By taking good venting measures with the mold, there is no air resistance in the mold and molding at low pressure is possible.

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