| Flow Lines | |
| Possible Cause | Suggested Remedy |
| Melt temperature too low | Increase melt temperature |
| Mould temperature too cold | Increase mould temperature |
| Gate size too restrictive, causing jetting | a. Increase gate size b. Decrease injection rate |
| Material impinging on cavity wall or core | a. Decrease injection rate b. Relocate gate |
| Non-uniform wall thickness | Redesign part to obtain a more uniform wall thickness to provide for optimum filling |
| Insufficient mould venting | Improve mould venting |