1 manual method
By manual cutting or punching, the rubber compound is made into certain specifications and shapes, such as various types of rubber rings, mats and the like. The manual forming method is to make the hot-melted rubber material into a certain shape and specification by punching or manual cutting, and some need to be cut into a certain specification rubber strip, and then bonded into a rubber ring or other by hand or by means of a tool. shape. The manual method is original and simple, and is still widely used. However, the regularity of the size and shape of the semi-finished product after molding is poor, and the compactness of the rubber compound is poor, which may easily cause some defects after vulcanization of the product, such as lack of glue, bubbles, and impurities.
2 extrusion molding
The rubber compound is made into a certain cross-sectional shape through an extruder, and the denser strip or the rubber tube is cut into a semi-finished product of a certain shape, and is mainly applied to a rotary shaft lip seal (oil seal) with high sealing performance requirements. , 0-rings and various rubber strips that are squeezed and vulcanized, hoses, etc.
Extrusion is a typical molding process. Under the extrusion of the screw of the squeezing machine, the rubber material is continuously extruded into strips or hoses of various cross-section shapes through different mouth shapes, and then cut into semi-finished products by final cutting, and finally vulcanized in the model. . With the calendering process. Compared with the advantages of simple operation and high production efficiency; it can play the role of further kneading and replenishing the kneading. After extrusion, the rubber has high compactness and good uniformity; less bubbles and stable semi-finished products; It can squeeze a variety of semi-finished products of various cross-section shapes and sizes, and has a wide application range; the equipment has a small footprint, the structure of the extrusion machine is simple, and the equipment investment is small; the appearance and internal quality of the semi-finished product after molding are excellent, and the appearance of the finished product is bright, physical and mechanical High performance.
The rubber compound needs to be heated 1 to 2 times before being fed into the extruder. In order to ensure that the hot rubber compound can be continuously extruded to prevent disjointing or bending, the amount of rubber supplied by the hot rubber compound should be compatible with the amount of glue used in the crushing machine. When using the extrusion return compound, it should be noted that the blending ratio is 20%~30%, and it needs to be fully heated before it can be used. When refining, it should also prevent over-refining, so as to avoid poor molding after extrusion. Therefore, the time and extent of heating should be controlled.