| Short Shot | Part not filled, local short shot, incomplete edges | Low melt/mold temp, insufficient injection pressure and speed, small gate, poor venting. | Raise melt/mold temp and injection speed/pressure; optimize gate and runner; improve venting. |
| Flash | Resin Flake at Parting Line / Insert | Insufficient clamping force, poor platen parallelism, excessive melt temp, excessive injection pressure, mold wear. | Increase clamping force, verify platen parallelism, lower melt temp and pressure, repair worn parts. |
| Sink Mark | Surface Dent on Thick Wall / Rib | Insufficient holding, excessive melt temp, uneven wall, gate freezing too early. | Extend hold, raise holding pressure, optimize wall thickness and cooling, delayed gate. |
| Warpage | Warped / Twisted Part Out of Tolerance | Uneven filling and cooling, anisotropic shrinkage, uneven ejection force, rib design. | Optimize gate position, balance cooling channels, adjust process window, apply sound rib design. |
| Weld Line | Visible Line at Flow Merge | Low melt temp, poor venting, multi-gate confluence, low material flowability. | Raise melt/mold temp, add venting, adjust gate; use high-gloss process if needed to remove it. |
| Silver Streak / Gas Mark | Silver Streak or Cloudy Surface | Material moisture/volatiles, degradation from excessive melt temp, poor venting, insufficient back pressure. | Dry fully, lower melt temp, improve venting, raise back pressure. |
