ASACLEAN PF GRADE INJECTION MOLDING PURGING INSTRUCTIONS for High Heat Resins (280°C – 420°C or 535°F – 790°F)
Notes before purging:
- The following procedures are for the non glass-filled PF grade. If using the glass-filled PX or PX2 grade, follow our standard injection molding purging procedures.
- ASACLEAN PF Grade should not be left idle in the machine at temperatures above 370°C (700°F), for any period of time.
- Keep the barrel full of ASACLEAN PF Grade at all times to prevent oxygen from entering the barrel – excess oxygen will accelerate material decomposition / carbon formation.
- While purging, it is recommended that a bucket of water be kept near the machine. Place ASACLEAN purge piles in water immediately upon exiting the nozzle.
- For nozzle hang-up or check ring cleaning (carbon and/or color deposits) use short, high velocity shots.
- Upon completion of the molding operation, run the high heat resin from the machine, emptying the barrel. Purging must begin as soon as possible. Clean the hopper and feed throat. Feed about 1 barrel capacity of ASACLEAN PF Grade into the hopper.
- With the screw completely forward, increase backpressure to a moderate level (enough to keep the screw forward).
Note: If processing temperatures are at or near the maximum recommended temperature for PF Grade, low to medium backpressure and screw speed are recommended. Backpressure and screw speed can be increased at lower temperatures within the recommended range to maximize cleaning.
- Start to extrude the ASACLEAN PF Grade at a slow screw speed. When it starts coming out of the nozzle, increase the screw speed to a moderate level (about 50% of maximum).
- Continue adding ASACLEAN PF Grade following the above instructions until the purge pile is clean.
- After the machine is clean (with the barrel still full of PF Grade) run the barrel empty of ASACLEAN PF, and begin feeding the next resin to be processed. Displace the PF with the next resin following the same procedure above (using increased backpressure and screw speed with the screw completely forward).
- After all ASACLEAN has been displaced, begin production using normal processing conditions.