1. Screw diameter (D)

1. The screw diameter should be proportional to the plasticizing power and inversely proportional to the injection pressure.

2. It has a lot to do with the amount of injection. The calculation of the injection volume can be obtained by a formula, which is 1/4*π*D2*S*0.85.

2. Measurement section

1. The residence time of heat-sensitive plastics cannot be long, and the two ends can be ignored or a relatively short measuring section can be selected.

2. If the metering section is long, the result of mixing will be better, but if the metering section is too long, it will easily be thermally differentiated.

3. In order to ensure a balanced mixing ratio, it generally accounts for 20% to 25% of the length.

Three, compression section

1. Usually the compression section needs to account for more than 25% of the working length of the screw.

2. If it is a nylon screw, the length of the compression section accounts for 15% of the working length of the screw.

3. The screw made of PVC material accounts for all the working length of the screw.

4. Feeding screw groove depth, measuring screw groove depth

1. The depth of the feed groove is proportional to the conveying volume, and the depth of the metering groove should not be too shallow to avoid discoloration of the plastic.

2. The calculation formula for measuring the depth of the groove: KD=(0.03'0.07)*D, if D increases, then K should choose a small value.