Warm Global Customers
With China Plastic Machinery
With China Plastic Machinery
The injection molding process of common plastics requires reasonable temperature and pressure parameter configuration. The following introduces the specific parameter configuration under different environments.
1. High-density polyethylene (HDPE)
Barrel temperature feeding zone 30¡«50¡æ (50¡æ)
Zone 1 160¡«250¡æ (200¡æ)
Zone 2 200¡«300¡æ (210¡æ)
Zone 3 220¡«300¡æ (230¡æ)
Zone 4 220¡«300¡æ (240¡æ)
Zone 5 220¡«300¡æ£¨240¡æ£©
Nozzle 220¡«300¡æ£¨240¡æ£©
The temperature in brackets is recommended as the basic setting value, the stroke utilization rate is 35% and 65%, and the ratio of mold flow length to wall thickness is 50:1 to 100:1
Melt temperature 220¡«280¡æ
Barrel constant temperature 220¡æ
Mold temperature 20¡«60¡æ
Injection pressure has good flow performance, avoid using too high injection pressure 80¡«140MPa (800¡«1400bar); except for some thin-walled packaging containers, it can reach 180MPa (1800bar)
The holding pressure shrinks to a high degree, and the product needs to be held under pressure for a long time. Dimensional accuracy is the key factor, which is about 30% to 60% of the injection pressure
Back pressure 5 to 20MPa (50 to 200bar); places where the back pressure is too low are prone to uneven product weight and dispersion
Injection speed High injection speed is required for thin-walled packaging containers, and medium injection speed is often more suitable for other types of plastic products
High screw speed (linear speed of 1.3m/s) is allowed, as long as the plasticizing process is completed before the end of the cooling time; the torque requirement of the screw is low
Metering stroke 0.5 to 4D (minimum to maximum); 4D metering stroke is very important to provide a sufficiently long residence time for the molten material. The residual material volume is 2 to 8mm, depending on the metering stroke and screw diameter
Recovery rate can reach 100% recovery
Shrinkage rate 1.2~2.5%; easy to twist; high shrinkage; will not shrink after 24h (shrinkage after molding)
Gating system point gate; heating hot runner, insulation hot runner, inner sleeve; the cross-sectional area is relatively small, which is enough for thin-section products. There is no need to use other materials for special cleaning during the machine downtime period; PE is resistant to temperature rise
Standard screw for barrel equipment, standard three-stage screw; for packaging container products, the mixing section and shear section have special geometric shapes (L:D=25:1), straight nozzle, check valve
II. Polypropylene (PP)
Barrel temperature feeding zone 30~50¡æ (50¡æ)
Zone 1 160~250¡æ (200¡æ)
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