Short Shot (Incomplete Fill)

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Short Shot (Incomplete Fill)

Last updated on Jul 22, 2026

Definition

(1) What is a Short Shot? (Visual Defect)

A short shot means the molten resin cannot fully fill the mold cavity.

Acceptable parts fully replicate the mold geometry, whereas parts with short shot fail to achieve the designed shape.

Short shot occurs when resin fluidity is inadequate or the metered shot volume is insufficient.

Figure 1: Appearance of Short Shot Gate

Short Shot | Good Part

Main Causes

🔹 Poor resin flow Low melt temperature, poor resin fluidity, excessive additives resulting in high flow resistance.

🔹 Insufficient shot volume Inadequate injection volume, inaccurate metering or low injection pressure, preventing melt from reaching the part extremities.

🔹 Difficult filling at part extremities Uneven wall thickness, improper runner/gate design and poor venting, which obstruct filling at the end sections of the part.

Inspection Criteria (Inspection Steps)

☑ Check incomplete forming at part extremities

☑ Compare with the contour of acceptable parts

☑ Confirm whether melt flow reaches all end regions

☑ Keep defective samples for retention