Overhauling of Extruders
Cleaning prior to a maintenance shutdown can require significant time and effort. Using ASACLEAN prior to a maintenance shutdown will greatly reduce the resources required to perform this task.
- Remove as much resin as possible from the barrel by extruding the material from the system.
- Purge following the standard "Cleaning of Screw for Extrusion".
A. For cleaning just the screw and barrel, if there is no die attached, use ASACLEAN EX for maximum deposit removal. A glass-filled grade of ASACLEAN (EX Grade) should not be run through polished dies. Contact Technical Service for procedures to run a filled grade of ASACLEAN through dies with tight clearances.
B. For cleaning extruders with a die attached, it is best to use an unfilled grade of ASACLEAN to purge all of the resin from the screw, barrel and die. After removing the die, clean the barrel again, this time with ASACLEAN EX. An unfilled grade of ASACLEAN can be used to clean the screw and barrel, but may not be as effective at removing stubborn deposits.
- For easiest screw removal and maximum cleaning effect, the screw and barrel should be purged with a melt temperature between 43O°F, (220°C) and 570°F, (300°C). For low temperature resins, use ASACLEAN SA, E or UE to remove the low temperature resin, then increase the temperature to 430°F, (220°C) for further cleaning with ASACLEAN EX.
- After the ASACLEAN purge pile appear clean, continue extruding the remaining ASACLEAN until no material is coming from the machine. Do not introduce any new material into the machine prior to manual breakdown.
- Turn off the heaters. If purging with ASACLEAN EX, wait until the temperature drops to between 430°F, (220°C) and 460°F, (240°C), then pull the screw. Melt temperatures outside this range will result in more effort being required to pull the screw. For unfilled grades of ASACLEAN the optimum temperature to pull the screw is between 380°F, (195°C) and 400°F, (205°C).
- Continue following approved breakdown procedure. Exercise proper safety precautions such as the use of safety glasses and protective gloves to prevent thermal burns and other injuries.
BENEFITS from using ASACLEAN for pre-maintenance cleaning:
- The force required to pull the screw from the cylinder will be significantly reduced.
- ASACLEAN can remove almost all deposits from the screw and inner wall of the barrel, so only a minimum of effort will be required to complete the cleaning. Any remaining deposits or ASACLEAN residue can be easily removed by a wire brush or other standard cleaning tools.
