Cleaning of Screw for Extrusion
- Check that all zones are in the proper temperature range for the grade of ASACLEAN being used. ASACLEAN is effective within the entire service temperature range. It is not necessary to adjust the extruder temperatures if the temperatures are within the service range.
- Run the barrel empty. Wipe the hopper and feed throat.
- For unfilled grades of ASACLEAN, screens and dies may be left in place for purging. If the machine is heavily contaminated and our glass- filled EX Grade is required, remove the screen pack to prevent plugging. Remove the die as well if necessary.
- Feed the required amount of ASACLEAN into the hopper. About one to two barrel capacities of ASACLEAN is required for purging a typical extruder. The actual amount required depends on the difficulty of the application and the condition of the equipment. Start with about one barrel capacity.
NOTE: For twin-screw extruders, feed ASACLEAN into the barrel at a rate which allows for filling the flights of the screws as best as possible.
- Start purging at low screw speed; after material begins coming out from the head, increase the screw speed to the maximum safe level. Periodically stop the screw and allow the ASACLEAN to sit for about a minute (a few minutes if possible). Resume screw rotation at maximum screw speed.
- Continue until most of the ASACLEAN is purged from the barrel.
- Visually inspect the purge pile. The machine is clean and purging is complete when ASACLEAN coming from the machine is visually free of contamination.
- Repeat steps 4 through 7 if contaminants are still visible.
- Displace the ASACLEAN remaining in the machine with the next resin, again, at the maximum safe screw speed.
- ASACLEAN does not work by chemical reaction. No soak time is required for an effective purge.
- For maximum performance, ASACLEAN should not be diluted with other materials.
- ASACLEAN is most effective when pressure within the barrel is maximized.
Temperature Range
| Grade | °F | °C |
| SA | 350-680 | 180-360 |
| UP | 340-570 | 170-300 |
| UE | 350-570 | 180-300 |
| SX | 570-735 | 300-390 |
| Grade | °F | °C |
| E | 320-530 | 160-270 |
| EX | 390-680 | 200-360 |
| U | 350-680 | 180-360 |
Tips to target specific areas of the extruder
These techniques should be used after performing the above procedures
Vented Barrels
Special procedures may be required to effectively clean extruders with vented barrels. If you cannot plug the vents, contact Technical Service to discuss the most appropriate method for your situation.
Dies
Raising the temperature of the die about 60-86°F (15-30°C), while remaining within the service temperature range for both the resin and ASACLEAN grade being used may help remove material deposits more quickly. If using a highly-polished or textured die, contact us before running the glass-filled EX Grade.
“I love to pass some
ASACLEAN through my
machines prior to screw
removal - it makes the job a lot easier and best
of all, faster! Our
service technicians pull
screws from time to time
and ever since they’ve
done the first screw-pull
with ASACLEAN,
they won’t pull
any more screws
without it!”
- A molder in Canada
