injection parameter of PP material
suggested set heating temperature
Feeding zone of Barrel temperature 30～50°C (50°C)
Zone 1 160 ~ 250 ° C (200 ° C)
Zone 2 200 ~ 300 ° C (220 ° C)
Zone 3 220 ~ 300 ° C (240 ° C)
Zone 4 220 ~ 300 ° C (240 ° C)
District 5 220 ~ 300 ° C (240 ° C)
Nozzle 220 ~ 300 ° C (240 ° C)
The temperature in parentheses is recommended as the basic setting, the stroke utilization is 35% and 65%, and the ratio of module flow length to wall thickness is 50:1 to 100:1.
Melt temperature 220～280°C
Barrel constant temperature 220 ° C
Mold temperature 20～70°C
Injection pressure has good flow performance, avoiding excessive injection pressure of 80 ~ 140MPa (800 ~ 1400bar);
Except for some thin-walled packaging containers up to 180MPa (1800bar)
Holding pressure Avoiding the shrinkage of the product, it takes a long time to hold the product (about 30% of the cycle time); about 30% to 60% of the injection pressure
Back pressure 5～20MPa (50～200bar)
Injection speed requires high injection speed (with accumulator) for thin-walled packaging containers; medium injection speeds tend to be more suitable for other types of plastic products
Screw speed High screw speed (line speed 1.3m/s) is permissible, as long as the plasticizing process is completed before the end of the cooling time
Metering stroke 0.5 ~ 4D (minimum ~ maximum); 4D metering stroke is very important to provide a long enough residence time for the melt
Residual material amount 2～8mm, depending on metering stroke and screw speed
Pre-drying is not required; if the storage conditions are not good, it can be dried at 80 ° C for 1 h.
Recovery rate can reach 100% recycling
Shrinkage rate 1.2 to 2.5%; high degree of shrinkage; no shrinkage after 24h (shrinkage after molding)
Gate system Point gate or multi-point gate; heated hot runner, insulated hot runner, in-situ sleeve; gate location is at the thickest point of the product, otherwise it is prone to large shrinkage
during Machine downtime ,no special cleaning work with other materials; PP can bearing temperature rise.
Barrel equipment Standard screw, standard three-stage screw; special for packaging container products, mixing section and shear section geometry (L: D=25:1), straight-through nozzle, check valve.