Injection Molding Purging Instructions for Transitions from High Heat Resins to Other Resins using Asaclean PX2 Grade Above 360°C (680°F) to below 300°C (570°F)
- Upon completion of the production run, extrude the high heat resin from the machine, emptying the barrel. Clean the hopper and feed throat.
- Purge out of first resin prior to dropping temps.
Note: ASACLEAN PX2 should not be left idle in the machine for ANY period of time at ANY temperature.
- Drop temps to next resin processing temperature.
- Feed about 1 barrel capacity of ASACLEAN PX2 into the hopper.
- With the screw completely forward, increase back pressure to the maximum safe level.
- Start to extrude the ASACLEAN PX2 at a slow screw speed. When it starts coming out of the nozzle, increase the screw speed to the maximum safe level.
Note: If processing temperatures are at or near the maximum recommended temperature for the PX2 Grade, start with low to medium backpressure and screw speed. Backpressure and screw speed can be increased at lower temperatures within the recommended range to maximize cleaning.
- Continue to drop all of the temperatures to 280°C – 300°C (535°F – 570°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.
- Begin feeding a lower-temperature ASACLEAN grade. After all of the ASACLEAN PX2 has been displaced by the lower-temperature grade, leave the barrel full and stop the screw. The lower-temperature grade will have a slightly different appearance. The lower-temperature grade should not be left at temperatures above 300°C (570°F), for more than 30 minutes as decomposition may occur.
- When the temperature drops into the processing range of the lower heat resin, empty the ASACLEAN from the barrel.
- Then start feeding the next resin to be processed, and displace the ASACLEAN with the next resin following the standard purging procedure, using the maximum safe back pressure and screw speed with the screw completely forward.
- Begin production under normal operating conditions.