ASACLEAN PURGING INSTRUCTIONS for Shutdown/Sealing/Start-up of High Heat Resins (Above 360°C, 680°F)
- Upon completion of the molding or extrusion operation, purge the machine with ASACLEAN SX following the standard purging procedures.
- Begin dropping the temperatures to below 600°F (315°C), before purging. The barrel should be left full of Asaclean to prevent the entry of oxygen into the barrel that will accelerate material decomposition and carbon formation. ASACLEAN SX should not be left idle in the machine at temperatures above 700°F (370°C), for any amount of time as decomposition may occur.
- If it takes longer than 30 minutes to drop temperatures below 600°F (315°C), displace the SX with a fresh barrel capacity of SX and continue to decrease temperatures. Leave the barrel filled with ASACLEAN SX at all times. Stop the screw and turn off the heat.
- Turn on the heaters and wait until the temperature of ASACLEAN in the barrel reaches 680°F (360°C). Allow adequate time for all of the ASACLEAN to plasticize, including material far from the thermocouple at the barrel wall. Excess residue may appear in parts if enough time is not allowed for the ASACLEAN to completely plasticize.
- Continue to increase the temperature in the barrel to the processing range of the high heat resin. ASACLEAN SX should not be left idle in the machine at temperatures above 700°F (370°C), for any amount of time as decomposition may occur.
- Add one barrel capacity of fresh SX to the hopper and extrude through the barrel using moderate backpressure (enough to keep the screw forward).
- Purge all of the ASACLEAN SX from the machine. If the ASACLEAN purge pile is badly contaminated, purge the machine again with ASACLEAN SX. Begin feeding the next resin.
- For injection molding: Use low back pressure and screw speed until the next resin starts coming out from the nozzle, then increase to moderate back pressure and moderate screw speed until all of the ASACLEAN is displaced. For extrusion: Use low screw speed until the next resin starts coming out from the die, then increase to moderate level until all of the ASACLEAN is displaced. Begin production using the normal processing conditions for the next resin.