Screw type and form

1, conventional injection screw:

General injection molding machine with a standard diameter screw, matched with two conventional high and low pressure screw can be applied to a wide range of general-purpose plastics and engineering plastics processing. This screw is also three-stage: feeding section, compression section, homogenization section. Are considered injection molding machine plastic injection molding and processing of materials to work characteristics.

2, extended injection screw:

Extended plastic injection screw is a universal plastic screw extruder with better plasticizing ability. Compared with conventional screw, it has the features of large aspect ratio (20 ~ 25), long measuring section (30%), Shallow (0.04 ~ 0.05D), the compression ratio is relatively large (0.11 ~ 012D), it is conducive to plasticizing the mixing effect.

3, the type of hard PVC injection screw:

The characteristics of this screw are: the aspect ratio is small, the metering section and the delivery section is shorter, the compression section longer; metering section of the deep groove, the compression ratio is small, suitable for hard PVC and other poor thermal stability of plastic For injection molding. In order to reduce the effects of strong shearing and stocking and to prevent overheating, this screw is suitable for use with a "Z" type screw head with a melt flow void.

4, non-metric section injection screw:

Non-metering section of injection molding screw, also known as "ZM" screw, which is characterized by no metering section, only the feeding section and the transition section, so this is a two-stage screw. Because of the non-metering section can reduce the melt overheating, increase the plasticizing ability and mixing effect, it is suitable for injection molding ABS and prevent cutting overheating of other non-crystalline materials, such as used to process flame-retardant impact polystyrene, Polycarbonate, filled polystyrene, polyvinyl chloride, and filled nylon. Non-metering section of the screw length-diameter ratio is generally 20, the length of the feeding section and the transition section of each 50%, each section recommended screw deep

5, separate injection screw:

(BM screw) Separation of injection molding screw called "BM" screw, has been widely used in injection molding, the main type of screw features in the melting section (transition section, compression section) to add a secondary thread, the main thread groove In two parts, when the screw rotates, the melt film scraped by the main thread flows into the thread groove of the sub-thread from the gap between the screw rib and the barrel wall to separate the solid bed from the molten pool so as to keep the solid bed and the inner wall of the barrel well Good contact, easy to transport and heat transfer.

6, wavy screw (HPM screw):

Wavy screw has a "single wave" and "double wave" of the points. Single-wave screw is characterized by two adjacent groove bottom diameter is equal, but it is eccentric, and the eccentricity is equal, and open the screw axis symmetry. As the depth of the groove changes periodically along the wavy direction in the axial direction, the material is strongly sheared and strongly sheared during the pre-molding process, absorbs a large amount of mechanical energy and performs energy conversion. When the material reaches the trough, the material relaxes and the energy is balanced Homogenization of each temperature. The molten polymer will soon pass through the strong shear zone, and the remaining solid material will be forced to undergo periodic changes by strong shear to accelerate disintegration and melting of the solid bed. Double-wave screw can not only improve the plasticizing ability, but also increase the mixing effect. For materials with filler, pigment and foaming agent injection molding, can get uniform components; also apply injection of hard PVC and other heat-sensitive materials, can reduce the degradation.

7, mixing type injection screw:

Molded plastic injection screw is characterized by setting the mixing section at the metering section. Based on the analysis of normal screws, it was shown that the polymer initially melted during the transitional period and a melt film was also formed at the trailing edge of the thread. So the entire solid bed is actually surrounded by the melt film, reducing the melting efficiency. Therefore, in the transition zone, it is still appropriate to emphasize the stable melting and conveying. After the material has been completely melted in the transition section, a further mixing section is added and mixing elements are set in the mixing section to further mix and homogenize the material. There are three types of mixing elements. Pin-type mixing elements (IKV mixing elements); Barrier-type mixing elements (straight groove mixing elements also known as Maddook elements); Other barrier-type mixing elements )

8, the combination of screw:

Combination of the screw is used in the metering section of the mandrel, according to the different nature of the material to install different functions of the mixing element group. The mixing element is made in the form of a key and is connected by keys and minds. The face of the sleeve must be precision-matched to prevent the melt from entering.