Injection Molding Machine Screws

Screws can be selected according to the functions and requirements of the injection molding machine.

Commonly used screws are: Reciprocating screw (three-stage screw)

Reciprocating screws (three-stage screws) are divided into gradual-change type, model-change type, and general-purpose type.

Screws for the production of imitation marble products.

Screw for exhaust type injection molding machine.

Preplasticizing injection molding machine screw.

Mixing screw.

1、Conventional injection molding screw: the general injection molding machine with a standard medium diameter screw, with two high and low pressure of the conventional screw, can be applied to a wide range of general-purpose plastics and engineering plastics processing, this screw is also a three-stage: charging section, compression section, homogenization section, are to consider the injection molding machine pre-molding and injection processing of the material's working characteristics to determine.

2, lengthening injection screw: is a higher plasticizing capacity of the better mixing role of the general-purpose injection molding butterfly rod, compared with the conventional screw is characterized by: L/D ratio (20 ~ 25), metering section is long (30%), the metering section of the groove is shallower (0.04 ~ 0.05D), compression ratio (0.11 ~ 012D), so it is conducive to the plasticization of the temperature of the cooperative action.

3, type of hard PVC injection molding screw: this screw is characterized by: L/D ratio is small, measuring section and conveying section is shorter, compression section is longer, i metering section of the screw groove is deeper, compression is relatively small, suitable for hard PVC and other thermally unstable plastics injection molding, in order to reduce the strong shear effect and storage of materials, to prevent overheating and decomposition, this screw is suitable for matching with the melt - the flow of the empty "Z", the melt, the melt, the melt, the melt, the melt, the melt, the melt, the melt, the melt, the melt, the melt, the melt, the melt, the melt, the melt, the melt, the melt and the melt. In order to reduce the strong shearing effect and material storage, and to prevent overheating and decomposition, this kind of screw is suitable to be equipped with a "Z" type screw head which has -melt flow space.

4, no metering section of the injection screw: light metering injection 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, due to the non-metering section can reduce the melt overheating, increase the plasticizing capacity and mixing effect, so it is suitable for injection molding of ABS and to prevent overheating of shear of other non-crystalline materials.

Such as for the processing of flame retardant impact-resistant polyethylene, polycarbonate, filled polyethylene, polyvinyl chloride, and filled nylon, etc., non-metering section screw L/D ratio is generally 20, charging section and the length of the transition section of 50% each, each section of the recommended depth of the screw groove.

5、Separate injection screw: ( BM screw ) Separate injection screw called "BM" screw, has been widely used in injection molding, the main kind of screw is characterized by the melt section ( transition section, consolidation section ) to increase a water sub-thread, the main thread groove into two parts, when the screw rotates the main thread scraping down the molten film from the gap between the spiral prongs and barrel into the sub-thread of the thread, and the main screw is used to scrape down the molten film. When the screw rotates, the molten film scraped off by the main thread flows into the screw groove of the sub-thread from the gap between the screw prong and the barrel, which separates the solid bed from the molten pool and thus maintains a good contact between the fixed body bed and the inner wall of the barrel for easy transportation and heat transfer.

6, corrugated screw (HPM screw): Corrugated screw has a "single wave" and "double wave" points, single wave type screw is characterized by the bottom diameter of the adjacent slot is equal, but is eccentric, and eccentric distance is equal, and symmetrical open screw axis. Due to the depth of the screw groove along the axial wave periodic changes, so the pre-molding of the material is subject to strong extrusion of the strong shear effect, absorbing a large amount of mechanical energy and energy conversion; injection molding should be vinyl chloride and other heat-sensitive materials, you can reduce the role of degradation.

7, mixing type injection screw: mixing type injection screw is characterized by the location of the metering section set up mixing elements. Based on the analysis of the ordinary screw shows that; in the transition section, the polymer initial melting, in the threaded back edge also formed a molten film, so the whole homogeneous bed is actually surrounded by a molten film, reduces the melting efficiency, so in the transition zone, still emphasize the role of stable melting and conveying appropriate, in the material after the transition section of the whole, after the melting, the barrier-type kneading element ( straight groove kneading element also known as the Maddook element) Other barrier type mixing element, (manifold mixing element also known as DIS-shaped mixing element)

8, combined screw: combined screw is mostly used in the screw metering section of the heart pumping, according to the different nature of the material to install different functions of the mixing element group, the mixing element to do into the form of the key, and the key and the heart of the idea of connecting, the end of the set should be precision fit, in order to prevent the melt to enter.