Jetting (injection moulding defect)
Appearance
Jetting is an moulding defect that can occur in the manufacturing process of injection muolding. Jetting is a snake-like stream which occurs when polymer melt is pushed at a high velocity through restrictive areas.[1]
Effect
- Surface blemishes
- Part weakness
Prevention methods
- Design a feed system to direct the melt against the metal surface of mould (see example of edge gate and overlap gate)
- Use an optimized ram speed profile so that melt front velocity is initially slow. [2]