ASACLEAN INJECTION MOLDING PURGING INSTRUCTIONS for the removal of high heat resins for pre-maintenance cleaning (Above 360°C, 680°F)
- Upon completion of the molding operation, extrude the high heat resin from the machine, emptying the barrel. Clean the hopper and feed throat.
- Begin dropping the temperature in the barrel to below 370°C (700°F) while purging with the ASACLEAN SX. ASACLEAN SX should not be left at temperatures above 370°C (700°F) for more than 30 minutes as decomposition may occur.
- Feed about 1 barrel capacity of ASACLEAN SX into the hopper.
- With the screw completely forward, increase back pressure to a moderate level (enough to keep the screw forward). Note: If processing temperatures are at or near the maximum recommended temperature for the SX 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 SX at a slow screw speed. When it starts coming out of the nozzle, increase the screw speed to a moderate level (about 50% of the maximum).
- Continue adding ASACLEAN SX, following the above instructions until the purge pile is clean.
- When all temperatures are below 370°C (700°F) stop the screw. Leave the barrel completely full of ASACLEAN SX to prevent oxygen from entering the barrel. Add more ASACLEAN SX if necessary to fill the barrel. Oxygen will accelerate material decomposition and carbon formation.
- Continue to drop all of the temperatures to between 600°F – 620°F (315°C – 325°C). Make sure you do not allow the temperatures in the barrel to drop below 570°F (300°C) with ASACLEAN SX in the barrel as overloading of the screw may occur when screw rotation resumes.
- Begin feeding ASACLEAN EX into the machine to further remove deposits from the screw and barrel and to make it easier to pull the screw. Follow the standard “ASACLEAN PURGING INSTRUCTIONS for PRE-MAINTENANCE CLEANING and SCREW PULL.” An unfilled grade of ASACLEAN, such as ASACLEAN U, can be used to clean the screw and barrel, instead of the EX grade, but may not be as effective at removing stubborn deposits.