What Are the Process Parameters of PP Injection Molding?

1. The temperature of PP injection moulding plastic cylinder

Feeding area 30 ~ 50℃ (50℃)

Zone 1: 160 ~ 250℃ (200℃)

Zone 2: 200 ~ 300℃ (220℃)

Zone 3: 220 ~ 300℃ (240℃)

Zone 4: 220 ~ 300℃ (240℃)

Zone 5: 220 ~ 300℃ (240℃)

Nozzle: 220 ~ 300℃ (240℃)

It is suggested that the temperature in brackets is the basic setting point.The stroke utilization is 35% and 65%.And the ratio of mold flow length to wall thickness is 50:1 to 100:1.

2. The melt temperature and injection pressure of PP injection moulding

The melt temperature is 220 ~ 280℃, the temperature of the plastic cylinder is 220℃, and the mold temperature is 20 ~ 70℃. It has good flow performance, avoiding using too high injection pressure of 80 ~ 140MPa. Expect some thin-wall packaging containers, it can reach 180MPa.

3. The pressure of PP injection moulding

Avoid product shrinkage, it needs a long time to keep the product pressure (about 30% of the cycle time), about 30% ~ 60% of injection pressure. The back pressure is 5 ~ 20MPa.

Injecting speed. High injecting speed (with accumulator) is required for thin-walled packaging containers. Medium injection speeds are often more suitable for other types of plastics.

4. The screw speed of the PP injection moulding

High screw speed (linear speed of 1.3m/s) is allowed as long as the plasticizing process, which is completed before the end of the cooling time.

Measuring stroke: 0.5 ~ 4D (minimum ~ maximum).The 4-D metering stroke is important to provide a long dwell time for the melt.

The residue of PP injection moulding: 2 ~ 8mm, depending on the measuring stroke and screw speed.

Pre-drying: not required. If the storage conditions are not good, it can be dried at 80℃ for 1h.

5. The PP injection moulding recovery

100% recovery