The Design And Research Of Rubber Continuous Mastication Machine

Natrual rubber mastication is the foundation of other production process. In the traditional intermittent mastication, rubber is unevenly masticated. The open mixer is is not efficient and not automatic. The internal mixer with large floor space costs much. Consequently, we have to seek more advanced technique to solve the problems above. Gradually, it turns to continuous production. Although it comes to the automatically and continuously operating by the single-screw extruder, but the application of single-screw mastication extruder is restricted, because there is"half-baked"phenomenon, and the temperature is too high. As a result, the popularization of the machine is limited. There are many reasons for these phenomenons in the single-screw mastication extruder, it includes 5 points:①irrational knife in the barrel: rubber is teared and chafed and produces a lot of heat, which leads to a temperature rise and even over-refining;②irrational screw designing: plain screw thread without mastication element is adopted. Consequently, raw rubber is piled out without enough mastication, which leads to"half-baked"phenomenon;③irrational feeding installation: rubber is drove by an air cylinder which results in large deformation and heat;④irrational cooling systems: barrel is cooled, while it turns out just the opposite, the viscosity goes up higher, which in turn leads to fierce friction and temperature build-up;⑤the flow resistance is obstinate, which causes friction and temperature rise.In view of existing situation, we propose a new rubber contionuous mastication machine—rubber single-screw mastication extruder, which provides smooth and steady unvulcanized rubber continuously and efficiently, and which will realize continuously mixing technique in the future and solve the problems better. The machine designed in this paper will improve the quality, reduce the costs and energy consumption, which will break down the technical barrier, resolve the key technical problems above, and promote technological process. In this thesis—rubber continuous mastication machine, the main works include:1,In this thesis,the special pin is applied firstly in the mastication machine. On one hand,"drop point"pin is adopted to provide powerful shearing action for natrual rubber and cut it into small cubes, which will lay a sound foundation for mastication; on the other hand, traditional pins depending on elastic deformation are replaced, which decreases the resistance and realizes low temperature shearing.2,In this thesis,mixed mode screw is adopted firstly to raw rubber mastication. Characteristics of screw parameters are theoreticaly analyzed in detail, and overall designing of the screw is carried out. The special cone-shape screw is combined with new fashioned short shear cut technology. Firstly, the root load capacity of the screw is enhanced by using the cone-shape screw; and the production capacity is improved as well; secondly, short shear cut screw thread adopted in the fluxing zone redoubles the level of mastication. Hence, the screw designed in the thesis makes valuable contributions to reduce the temperature of unvulcanized rubber and to realize low temperature squeezing. And it is essential for receiving high-quality and high-efficiency unvulcanized rubber products.3,In this thesis,meshed spiral feeding device is introduced in the feeding segment. As a result, continuously and stably feeding of natrual rubber bulk materiel without significant temperature rise is guaranteed. At the same time, forceful thrust is produced, which is operative for squeezing press. The device provides advantaged base of raising the production capacity and low temperature squeezing.4,In this thesis,a most up-to-date generation of high efficiency energy saving heat exchange facility is adopted for the temperature control. It keeps the temperature constant, brings about stable properties for rubber, and improves the quality of the mastication goods. Besides, it offers the technologist a simple, easy operated technique with high efficiency as well. What is more, it cuts down the difficulty and intensity and improves their efficiency.5,In this thesis, the nose is designed rationally. With ANSYS finite element method, flow field and pressure analysis of handpiece are optimized,which further enhances mastication effect, and maintains the shape and squeezing output stable. In summary, there is a very bright future for the development and application of rubber single-screw continuous mastication machine, which will bring us both significant economic and social benefits.