Excellent Rubber Extruder


1. Plunger type

The rubber extruder originated in the 18th century. The manual piston extruder used to manufacture seamless lead pipes manufactured by Joseph Bra mah of England in 1795 is considered to be the first extruder in the world. . From then on, in the first 50 years of th

.

 

1. Plunger type

The rubber extruder originated in the 18th century. The manual piston extruder used to manufacture seamless lead pipes manufactured by Joseph Bra mah of England in 1795 is considered to be the first extruder in the world. . From then on, in the first 50 years of the 19th century, extruders were basically only used in the production of lead pipes, the processing of macaroni and other foods, the brick making and ceramic industries.

In the development process of the extruder as a manufacturing method, the first clear record was R. B ro o o m an applied for a patent in 1845 for the production of Gutebo glue wires with an extruder. H. B e w l g y subsequently improved the extruder, and in 1851 used it to wrap the copper wire of the first submarine cable between Dover and Carais. In the following 25 years, the extrusion method 13 became more important, and the extruder operated by electric motors quickly replaced the previous manual extruder. The early mechanically operated plunger extruder produced thousands of kilometers of insulated wires and cables, which firmly established the position of extrusion for the production of cables. The early extruders for cable production were all plunger types, whether they were manual, mechanical or hydraulic. In this production process, the plunger presses the hot gutta-percha into the die with the copper wire, and the gutta-percha is extruded from the die, thus covering the copper wire to form an insulating layer.

2. Screw type

The rubber extruder that appeared in 1870 was a hot feed extruder. The rubber material it feeds must be hot-melted, and the feed is uniform, stable, and constant, and the material temperature is maintained at 50 ~ 70 ℃. The screw is short, the thread groove is deep, and the homogenization effect is not ideal. Since the 1970s. At one time, the aspect ratio became smaller. Because the hot-feeding extruder can continuously extrude, the operation is simple, the production efficiency is high, and the shape of the extruded product is stable, in the production process of many products, the hot-feeding extruder is still used. In tire production, it is used for the extrusion of various treads and various types of rubber, as well as for the extrusion of rubber and rubber blanks in the production of hoses, cables and other rubber products.
3. Ordinary

The cold feed extruder appeared in the 1940s, and began to be promoted and popularized in the 1960s, and became the mainstream of development in the 1980s. By the early 1990s, products produced by cold-feed extruders in developed countries such as Europe and the United States accounted for 95% of total production. Separate screw extruder, baffle screw extruder, cavity screw extruder, transfer mixing extruder, pin screw extruder and multi-channel transfer mixing screw (MC T) extruder Wait.

From the perspective of equipment structure, cold-feed extruders generally have a longer body than hot-feed extruders, with an aspect ratio (L/D) of 8-20, and a shallower thread groove. Due to its long body, multiple functions and low feed temperature, its power is much larger than that of a hot-feed extruder, which is about 2 to 4 times that of a hot-feed extruder of the same specification. For example, the power of the cold feed extruder with a diameter of 250 ram produced by the German Berstorff Company is 500 kw, while the hot feed extruder of the same specification is only 105 kw, but the production capacity But it is lower than the heat-feed extruder. The appearance of the cold feed extruder simplifies the production process. The rubber material fed no longer needs to be heated, and the rubber material is fed into the extruder at room temperature to obtain product rubber embryos of various shapes. It can completely replace the hot-feed extruder, and can omit the rubber hot-smelting process, simplify the production process, and enable the die to build up a higher pressure, which has a certain effect on improving the quality of extruded products. It has been widely used in the production of products.

However, the screw with the main and auxiliary thread structure designed for better plasticizing effect of the rubber compound affects the extrusion output and requires a large driving power, which limits its use in some production processes. The main and auxiliary thread cold feed extruder appeared in 1970. Its main thread is the same as that of an ordinary screw. The main structure is that a secondary thread with a certain height difference is set in the main thread groove, and the secondary thread is in the pitch There is a change in the height of the spiral ridge, only allowing the rubber to be transported forward through the narrow slot, which effectively eliminates the "dead zone" of the rubber in the ordinary screw groove and strengthens the effect of plasticization and mixing. The mixing quality of the rubber material is not uniform, and the energy consumption is large.

4. Cold feed type

The emergence of the cold feed venting extruder stems from the design of the vacuum extruder screw proposed by Ber nha t d t in 1956. According to the flow state of the screw groove in the narrow compression section of the rubber, the screw used can be divided into an ordinary cold row screw and a strong shear type cold row screw. The screw of the cold feed exhaust extruder is divided into feeding section, compression section, throttling section, exhaust section and extrusion section. The throttling section adopts shallow grooves and equal-distance equal-depth threads, which can make the rubber material obtain higher shear and stable conveying process, and also improve the exhaust effect. In the cold feed screw extruder, the rubber strip at room temperature is added to the extruder. Rubber extruders are often classified according to whether they are used for exhaust.
5. Pin type

In the continuous exploration of extrusion technology, that is, the research of pin technology began in the late 1960s and early 1990s. The pin was inserted into the screw thread groove radially from the circumference of the barrel, and the flowing rubber Perform shearing and stirring. The rubber material becomes a melt and flows in the screw thread at a low shear rate, gradually forming a continuous viscous fluid, which destroys the laminar flow and agglomeration of the rubber material in the extrusion process, breaks the rubber block, and achieves The rubber material has good plasticization, low rubber temperature and energy saving effects, which simplifies the production process.

This technology was patented in the United States in 1979. The emergence of the pin-type cold feed extruder has greatly developed and improved the technology of the cold feed extruder. This kind of extruder not only has a great improvement in the screw structure, but also because of the addition of pins on the barrel, it has a great plasticization performance on the rubber, the compactness of the extruded product, and the extrusion volume. It can meet the extrusion requirements of a variety of production processes. At the same time, due to the improved screw structure, its driving power is reduced, and the unit energy consumption is significantly reduced. Because of its good plasticizing performance, low debinding temperature, and large extrusion volume, it has been widely used in rubber industrial production.

6. Compound type

In the rubber industry, the compound extruder is mainly used for the extrusion of tire compound treads, automobile sealant strips, colored tire treads, rubber hose compounding and rubber-plastic compounding, and multi-layer co-extrusion of rubber sheets. The composite extrusion production process is an advanced technology in the rubber industry. It can use different formulations and properties of rubber according to the different performance requirements of the product. The composite extrusion equipment can save materials and meet a variety of properties. Products on demand.

 

 

257 Views