Blown film extrusion processors deal with the same processing issues as everybody else. When processing thermoplastics in a blown film process, carbon will eventually begin to show up. Typically, it will accumulate downstream of the extruders and most commonly in the die. Little black specks will appear in the film creating scrap and if severe enough create holes causing you to lose the bubble.
If your processing a LDPE, LLDPE or similar and decide to use a purging compound rather that manually tear down and clean, you may have concerns. Carbon removal will require increasing heat in the affected area and a purge with a stiff carrier resin. After the machine is clean, how do you remove the purge compound when coming in with a significantly less viscous production material?
A chemical purge, one that creates steam in the cleaning process is a great solution. The steam will not only aid in the cleaning process to help remove the specks but also reduce the viscosity of the purge’s carrier resin after the cleaning process is complete. The steam essentially makes it easier to remove the purge compound.
After cleaning, lower your temperatures to operating conditions and begin to run your LD or LLDPE. This will displace the remaining purge effectively in a short period of time. You’ve just cleaned your system of contamination without spending countless hours of a manual cleaning.
Ready to reduce your production downtime to protect your profits? Learn more about how purging compounds and process efficiency work in tandem.