Extrusion Process Purging Procedures
Sealing, Shutdowns, Start-Ups
Most thermoplastic resins, when left in the barrel – even for a short time – are likely to degrade and cause product contamination.
To prevent contamination or deposit formation in your plastic injection molding machines, use an ASACLEAN purging compound to clean the barrel and screw and displace resins from the machine completely.
Purging Instructions For Shutdown And Sealing
Follow these step-by-step instructions when using an ASACLEAN purging compound for shutting down and sealing your plastic injection molding machines:
- Follow the basic ASACLEAN purging instructions to clean the barrel and screw with an ASACLEAN purging compound before a temporary or extended shutdown. For grade selection, refer to the ASACLEAN Grade Selection Guide or contact a Purging Process Expert at ASACLEAN. Please note: A filled grade of ASACLEAN, such as EX Grade, cannot be used for sealing the machine.
- When using ASACLEAN EX or NF Grade for purging the barrel and screw, use with ½ barrel capacity of a sealing grade. When using ASACLEAN PX2 Grade for purging, displace with ASACLEAN PF Grade for sealing.
- Empty the barrel.
- Feed one barrel capacity of the same grade of ASACLEAN at a slow screw speed. For injection molding machines, it is best to shut down with 1/3–1/2 barrel capacity of melted ASACLEAN in front of the screw. To ensure that the barrel is full, check that the feed throat is still filled with ASACLEAN.
- Turn off the heaters.
Purging Instructions For Extrusion Start-Up
Follow these step-by-step instructions when using an ASACLEAN purging compound for starting up your plastic injection molding machines:
- Set the heaters to 230°C (450°F).
- When ASACLEAN has completely melted, feed a small amount of fresh ASACLEAN to displace the previously charged ASACLEAN. Verify the material is free of contamination.
- If contamination persists, continue purging until the contamination is eliminated.
- Set heats to production levels.
- When desired production conditions are reached, begin production.
For further insight into our recommended purging procedures, visit the Purging Process Resource Center. This page offers you training videos, guidelines, technical documentation and more to help answer your purging compound questions.
Ready to learn even more about ASACLEAN purging compounds and services? Click here to schedule your free, 10-minute consultation with a Purging Process Expert at ASACLEAN.