What Are The Extrusion Methods

The extrusion process mainly includes hot refining of rubber (cold feed extrusion does not need to go through hot refining), rubber supply, extrusion, cooling, cutting, connecting and parking processes. Extrusion process is divided into hot feed extrusion method and cold feed extrusion method according to the form of feeding.

The extrusion operation in which the rubber feed is hot tempered to reach the required temperature is called hot feed extrusion. Cold feed extrusion is the extrusion of cold feed extruder, which does not need to heat the rubber before extrusion, and directly feeds the rubber strip or sticky rubber material at room temperature for extrusion. Compared with hot feed extrusion, the rubber material has a distinct feeding section in the extruder. The cold feeding extruder used has a large length-diameter ratio, generally 8~16, which is equivalent to more than twice that of the ordinary extruder, and the compression ratio is large, generally 1.7~1.8, to strengthen the shearing and mixing of the screw, so that the rubber material can obtain uniform temperature and plasticity.

There are two kinds of screw threads, single thread and double thread, the former is used to extrude hard rubber material, the latter is used to extrude high plastic rubber material. The thread structure is generally equal distance and unequal depth. In order to facilitate automatic feeding, the cold feeding extrusion has the following advantages compared with the hot feeding extrusion under the feeding port: the buckling system is natural

1 Because the rubber material does not need hot refining, it simplifies the process, saves manpower and equipment labor can save more than 50%;

2 The overall energy consumption of the extrusion process is less, and the facility covers a small area;

3 Wide range of applications, greater flexibility, there is no influence of hot smelting process on the quality of semi-finished products, so that the shape of extruded semi-finished products is more consistent, and not easy to produce coke phenomenon;

4 High degree of automation and continuity, but there are defects such as rough surface of extruded semi-finished products and expensive extruder