| Burn Marks | |
| Possible Cause | Suggested Remedy |
| Melt temperature too high | a. Decrease melt temperature b. Lower back pressure c. Lower screw RPM |
| Air entrapped in mould | a. Vent cavity at final point of fill b. Decrease first stage pressure or injection speed c. Relocate gate d. Clean vents and/or enlarge vents e. Reduce clamp pressure to allow parting line vents to work |
| Injection rate too fast | a. Decrease injection rate b. Decrease first stage pressure c. Decrease boost time d. Enlarge gates |
| Moisture in material | a. Review material handling to eliminate moisture pick up b. Dry material prior to moulding c. Utilize hopper dryers |