How to Avoid Short Shot in Plastic Products?

1. Phenomenon

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

2. Cause

• 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

3. Measures

• 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.