The structural characteristics of several types of barrel screws are as follows: (The material selection of the barrel screw is 38CrMoAlA)

Date:Nov 04, 2019

1, conventional, low filler, high filler structure difference

(1) spigot, groove geometry and matching relationship

Less CaCO3 content: larger between the spiral edge and the spiral edge

More CaCO3 content: the gap between the spiral edge and the screw edge is smaller, the purpose is to increase the shear force and increase the plasticization.

(2) The role of each regional segment. The screw is generally divided into: feed section, compression section, block section, mixing section, exhaust section, metering section.

Feeding section: Generally, the conveying edge has a large gap and the conveying speed is fast, and vice versa. It is also related to the formulation, CaCO3 composition.

Compression, block material, mixing: The main influence is the plasticizing ability. If there is no material before compression, plasticization can be increased. If a material is provided, it is not suitable for high calcium, mixing and compression. Set together, generally only suitable for low calcium.

Exhaust section: The plasticizing ability of the material can be observed from the vacuum port, which is granular, powdery, and strip-shaped.

Metering section: the gap of the screw edge is large, the extrusion is fast, and vice versa.

2, low filler, high filler structure features: low filler screw feed section, compression, mixing is linked together, the last section of the feed section becomes smaller during the machining process into a compression section, and then the compression section is opened Slot, add 2 turns of material, thus increasing plasticization, the rear exhaust section, the metering section is larger than the pitch clearance; the high-fill screw structure consists of the feed section, the material, the compression, the material, the mixing, the exhaust section , the metering section, the gap between the feed section and the metering section is small.

3, screw, barrel thermostatic control structure introduction

Internal circulation: automatic circulation of distilled water

External circulation: screw temperature control can be set, the material temperature can be controlled, the screw can be protected during the startup process and during the production process, and the production can be stabilized. If not used, the article is discolored for the processing of the profile.

Barrel temperature control: There are two kinds of air cooling and oil cooling. Relatively speaking, the oil cooling temperature control accuracy is greater than the air cooling temperature control accuracy, but the oil circuit is easy to prevent during use, and the failure rate is higher than air cooling.

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