With the development of industrialization, rubber sheathed soft cable with its electrical performance stability, excellent mechanical and physical properties, especially the characteristics of soft, has been a variety of mobile occasions the use of the main equipment installation cable. At present, in the mining process of large opencast and metal mines, will often appear large gravel and sharp objects hit the cable, the cable in the process of large-scale mining equipment is often subjected to a lot of drag, so towed rubber cable rely on a special structural design to reduce the external torsional force on the sheath material impact,

Therefore, the use of cable to improve the life of the installation of equipment to drag occasions preferred. In the often drag, friction occasions, cable life is often reduced from the wear and tear from the outside to the inside of the insulation core caused by damage, so the life of the sheath directly affect the life of the cable.

The tow-cable adopts the traditional sheath thickness in two, in the two-layer sheath to increase the structure of the woven layer to increase the binding force of internal and external sheath, woven layer with a certain degree of elasticity of the material to cushion the cable sheath in the process of the reaction to improve cable life. The previous implementation of the sheath is divided into two times to achieve, the nature of each layer of sheath thickness will be thin, greatly improve the process to achieve the difficulty, therefore, rubber materials in the extrusion mold choice is particularly important. In general, the general rubber sheath cable production, through the mold core and the proportion of the mold to provide greater pressure will be filled into the cable core to achieve, general mold core will choose a larger angle, reduce the angle of the die set (see Figure 1), the mold core and the angle of the mold sleeve general control around 15 ℃, through the angle difference control rubber material extrusion pressure, The material is compacted in the case of extrusion on the cable core surface.

Towing cable of the internal and external protection thickness is relatively thin, rubber material production is extrusion production, in the production of external protection, rubber material in the extrusion die at the core, when the pressure is too large, easy to cause the accumulation of internal sheath extrusion caused by the card mode phenomenon. In order to solve the above Kamo, we have many theoretical design and practical demonstration, through the improvement of the mold core and the angle of the die sets, can be a good solution to the external protection pressure caused by the accumulation of card mold, greatly improve the continuous production capacity of this kind of cable.