Refer pic 1
Criteria for decision
If it occurs white dust about 2 times per roll, we accept it.
If it occurs white dust every 20-30 meters per roll, we reject it.
Solving method
To Check all actual temperature to be correct with all set temperature
To reduce temperature each 3-5 degree F then monitor the result
Refer pic 2
Cause of it is
1. Temperature of zone5 is not enough(it should be 430 O F) which it will make incomplete material melting
2. Air pressure at head of nozzle is less than 4 bar
Refer pic 3
Cause of it is
1. Temperature of zone3,4 are over heat
2. Insufficient Material flows into screw barrel
3. Die plugging