HOW TO PURGE
1. Check that all the zones are in the proper temperature range for the grade of ASACLEAN™ being used.
2. Retract the injection unit, run the barrel empty, wiper clean the hopper fee throat and nozzle.
3. Dose the required amount of ASACLEAN™ into the hopper. Approximately 1 or 2 barrel capacities of ASACLEAN™ is required for a typical moulding machine. The actual amount depends on the difficulty of the application and the condition of the equipment. Start with one barrel capacity.
4. With screw completely forward increase the back pressure to maximum safe level, approximately 90% of maximum.
5. Increase RPM 90% of maximum and purge out of the barrel.
6. Drop the back pressure after the ASACLEAN™ coming out of the nozzle is clear.
7. Retract the screw and perform high velocity injection shots
8. Repeat steps 1-7 if contamination is still visible.
9. Once ASACLEAN™ is visibly clean, introduce the next polymer to be used or increase temperatures if necessary.
1. Check that all zones are in the proper temperature range for the grade of ASACLEAN™ purging compound being used.
2. Run the barrel empty. Wipe the hopper and feed throat.
3. For unfilled grades of ASACLEAN™, screens and dies may be left in place for purging. If the machine is heavily contaminated and using our glass-filled grade (EX, PX and NF) – remove the screen pack to prevent plugging. Remove the die as well, if necessary. Note: Feed one to two barrel capacities of ASACLEAN™ into the extruder. Note: Feed ASACLEAN™ into the barrel at a rate which allows for filling the flights of the screws as best as possible.
4. 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 ASACLEAN™ to sit for a few minutes. Resume screw rotation at maximum screw speed.
5. Continue until most of the ASACLEAN™ is purged from the barrel.
6. Visually inspect the purge pile. The machine is clean and purging is complete when ASACLEAN™ coming from the machine is visually free of contamination.
7. Repeat steps 4 through 7 if contaminants are still visible.
8. Displace the ASACLEAN™ with the next resin, again, at the maximum safe screw speed.
1. Raise the temperatures of the die about 20°C – 30°C.
2. Extrude the remaining resin from the system.
3. Clean the hopper and feed throat.
4. For unfilled grades of ASACLEAN™ purging compound, screens and dies may be left in place for purging.
5. If the machine is heavily contaminated and our glass-filled grades (EX, PX2, NF) are required, remove the screen pack to prevent plugging. Remove the die as well, if necessary (recommended for highly polished surfaces).
6. Feed the required amount of ASACLEAN™ purging compound into the hopper.
7. Start purging at low screw speed first; increase the screw speed to the maximum safe level after material begins coming out from the head.
8. Periodically stop the screw and allow the ASACLEAN™ purging compound to sit for a few minutes. Resume screw rotation at maximum safe screw speed.
9. When the purge is free of contamination, displace the remaining ASACLEAN™ purging compound with the next processing resin, using the same procedure above.
10. Change the machine parameters back to normal processing conditions.
11. Replace the screen pack with a clean one.
Hot Runner Systems with mould plates open:
1. After the screw and barrel have been cleaned thoroughly using the ASACLEAN™ purging compound, set the nozzle into the mould.
2. Open the mould plates.
3. Set up a safety-approved surface for collecting the purgings.
4. Verify that the mould safety door is closed.
5. Add enough ASACLEAN™ purging compound into the hopper to fill the barrel approximately ½ full.
6. Extrude the ASACLEAN™ purging compound through the hot runner system starting at a medium velocity. Increase screw speed to the maximum safe level for maximum cleaning. Once ASACLEAN™ is flowing adequately through all of the gates, perform injection shots (air shots) with mould plates open.
7. Visually inspect purgings for colour and/or carbon contamination.
8. If contamination remains, repeat steps 5 through 7 until the ASACLEAN™ purging compound is visually free of colour and/or carbon contamination and has returned to a clean appearance.
9. Purge out any remaining ASACLEAN™ using the maximum safe screw speed. Adjust the temperatures in the barrel and hot runners to the processing conditions for the next resin to be processed.
10. Flush the system with the next resin to be processed using the maximum safe screw speed until the next resin is visually free of the ASACLEAN™ purging compound.
11. Resume production using normal production settings.
Hot Runner Systems with mould plates closed:
1. After the screw and barrel have been cleaned thoroughly using ASACLEAN™, set the nozzle into the mould.
2. Verify that the mould safety door is closed.
3. To reduce the small possibility of ASACLEAN™ purging compound parts getting stuck in the hot runner cavities, reduce cooling time and spray the cavities with mould release.
4. Remove pack and hold pressures and velocities. Inject ASACLEAN™ purging compound using short-shot moulding (use only as much shot as is needed to safely remove parts from cavities – no more than 90% shot size).
5. Eject parts immediately, while they are still warm.
6. Visually inspect parts for colour and/or carbon contamination until parts are clean.
7. If contamination still remains, repeat steps 4 through 6 until the ASACLEAN™ purging compound is visually free of colour and/or carbon contamination and has returned to a clean appearance. Purge out any remaining ASACLEAN™ using the same method as above. Adjust the temperatures of the barrel and hot runners to the processing conditions for the next resin to be processed.
1. Follow the basic ASACLEAN™ purging instructions to clean the barrel and screw with an ASACLEAN™ purging compound before a temporary or extended shutdown. Please note: A filled grade of ASACLEAN™, such as EX Grade, cannot be used for sealing the machine.
2. When using ASACLEAN™ EX or NF Grade for purging the barrel and screw, use with ½ barrel capacity of a sealing grade. When using ASACLEAN™ PX2 Grade for purging, displace with ASACLEAN™ PF Grade for sealing.
3. Empty the barrel. Feed one barrel capacity of the same grade of ASACLEAN™ at a slow screw speed. For injection moulding machines, it is best to shut down with 1/3–1/2 barrel capacity of melted ASACLEAN in front of the screw. To ensure that the barrel is full, check that the feed throat is still filled with ASACLEAN™.
4. Turn off the heaters.