Check ring is the non-return valve in a co-rotating twin screw extruder machine. Please make this a point to clean check ring every time you clean the screw and the barrel. This maximizes the performance of your purging compounds.
Twin screw extruders are heavy duty machines and when used continuously, the check rings get prone to the build up of carbon, additives and other degraded materials. It becomes tough to remove the contamination in these areas and if neglected, often show up after re-starting following a colour or material change.
After thoroughly cleaning the screw and barrel, perform a few air shots to clean the check ring assembly. Rotate the screw back to about half or two-thirds of the shot size. Manually decompress, followed by manually inject fast air shots. Increase fill rate if necessary, and repeat 2-3 times. The goal is to force as much purge compound through the check assembly as possible. This action will help to insure the check ring assembly being as clean as the rest of the screw and barrel.
Finish purging the remaining compound from the screw and barrel. Load the next production material and you will be ready for a fast, low scrap start-up. For more details call us or write to us.