ASACLEAN PURGING INSTRUCTIONS for Shutdown/Sealing/Start-up of High Heat Resins using PX2 Grade Above 360°C (680°F)
- Upon completion of molding or extrusion run, purge the machine with ASACLEAN PX2 following the standard purging procedures.
- Purging out of the first resin should be completed prior to dropping the temperatures to 280°C (535°F). 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 PX2should not be left idle in the machine for ANY period of time at ANY temperature.
- Continuously displace the PX2 with a fresh barrel capacity of PX2 and continue to decrease temperatures. Before 280°C (535°F) is reached, displace PX2 with a non-glass filled grade of ASACLEAN (U, UP, or E). When all of the PX2 Grade has been removed, ensure that the barrel is full of the non-glass filled ASACLEAN grade and turn off heaters.
- Do not allow the temperatures in the barrel to drop below 280°C (535°F) with ASACLEAN PX2 in the barrel as overloading of the screw may occur during rotation.
- Turn on the heaters and wait until the temperature of ASACLEAN in the barrel reaches 280°C (535°F). Allow adequate time for all of the ASACLEAN to plasticize, including material far from the thermocouple at the barrel wall, before turning the screw (to prevent damage).
- For injection molding: with maximum safe back pressure and the screw completely forward, start feeding PX2 Grade to displace the non-glass filled ASACLEAN grade after temperatures are above 280°C (535°F). (Do not allow the temperatures in the barrel to drop below 280°C (535°F) with ASACLEAN PX2 in the barrel as overloading of the screw may occur during rotation.)
- When PX2 comes out from the nozzle or die, increase the screw speed to maximum safe level.
- Continue to increase the temperature in the barrel to the processing range of the high heat resin. ASACLEAN PX2should not be left idle in the machine for ANY period of time at ANY temperature.
- Begin feeding the next resin.
- For injection molding: Use maximum safe back pressure and screw speed until the next resin starts coming out from the nozzle and all of the ASACLEAN is displaced. For extrusion: Use maximum safe screw speed until all of the ASACLEAN is displaced.
- Begin production under normal processing conditions for the next resin.