This information is taken from: Blow Molding Handbook, Rosato, Rosato, DiMattia (2003)
“It has always been a necessary “evil” that at the end of a production run the plasticator has to be cleared of all its plastics in the barrel/screw to eliminate barrel/screw corrosion or contamination; this is also required when a change of material occurs.
According to these authors, the following table (briefing from its original) show us what to do:
Guidelines for Plastic Changes | ||||
Material in Machine | Material Changing to | Mix with rapid purge and soak | Temperature bridging material | Follow with |
ABS | PP | ABS | ——– | PP |
ABS | SAN | SAN | ——– | SAN |
ABS | Polysulfone | ABS | PE | Polysulfone |
ABS | PC | ABS | PE | PC |
ABS | PBT | ABS | PE | PBT |
Acetal | PC | Acetal | PE | PC |
PE | PP | PE | ——– | PP |
PE | PE | PE | ——– | PE |
PP | ABS | ABS | ——– | ABS |
PVC | Any Material | LLDPE or HDPE | ——– | New Material |
PVC | PVC | LLDPE or HDPE | ——– | PVC |
PPS | PVC | PPS | PE | PE |