A starting point for the most common injection molding defects — always confirm with a DOE, but this narrows the field:

• Sink marks — insufficient packing time/pressure, thick sections, high melt temperature.
• Flash — clamp force too low, injection speed/pressure too high, worn parting line.
• Short shots — venting, material shortage, injection speed too slow, melt temp too low.
• Silver streaks / splay — moisture in resin, degraded material, excessive shear.
• Warpage — differential shrinkage, non-uniform cooling, residual stress, unbalanced packing.
• Burn marks / dieseling — trapped air, poor venting, too-fast fill.
• Weld lines weak or visible — melt/fill temperature too low, merge angle, venting at junction.

Post your specific case with machine data and we will dig in.