Method for producing sheath of nylon cable and extrusion die thereof

Abstract

The invention relates to a method for producing a sheath of a nylon cable and an extrusion die thereof. The method comprises the following steps of: predrying, forming a primary polyethylene (PE) sheath, forming a primary waterproof tape, forming a glass fiber layer, forming a secondary waterproof tape, forming a secondary PE sheath, and the like, wherein the secondary PE sheath is molded by a semi-extrusion die; a cable core covered by the secondary PE sheath is dried and preheated; and the nylon sheath is molded by a double-core inner die. In the semi-extrusion die, the axial length of an inner die extrusion part is not more than 5mm, and the axial length of an extrusion hole of an outer die is not more than 3mm. An inner die of the double-core inner die consists of a cable core heat-insulation supporting tube and an inner die core, wherein the cable core heat-insulation supporting tube is supported in a supporting hole in the center of the inner die core through a plurality of supporting ribs which are distributed on the circumference of the front end; the extrusion part at the front end of the inner die core passes through the extrusion hole to extend out of a corresponding end face of the outer die for 1 to 1.5mm; and the difference between the pore diameter of the extrusion hole and the outer diameter of the extrusion part is 2.8mm to -4.0mm. The invention has the advantages that: the adhesive strength between nylon and the PE sheath is greatly improved; therefore, the bending index and other properties of finished products are effectively improved.

Description

technical field [0001] The invention relates to the technical field of optical cable production, in particular to a method for producing a sheath of a nylon optical cable and an extrusion die thereof. Background technique [0002] Nylon optical cable is a special optical cable, which has the characteristics of anti-rat, anti-termite, high mechanical strength, heat resistance, wear resistance, oil resistance, weak acid resistance, good electrical insulation, etc., and has a wide range of uses. The structure of this kind of optical cable is as follows Figure 4 . Its production mainly goes through three processes of plastic covering, layer twisting and sheathing. The plastic coating process mainly covers several primary coated optical fibers 1 to form a loose tube to improve the mechanical properties of the optical fiber such as tensile strength and bending resistance 3; Close it on the central strengthening member 6, put the tape 5 on its outer side, and fill the tape with ...

AI Technical Summary

Problems solved by technology

Because the cable core before the second PE sheath is a non-metallic cable core, the surface is covered with glass filaments and water-blocking tape, and the thickness of PE is only 1.2mm. If the treatment is not good, the yarn tie marks will be obvious and the appearance will not be round.

Therefore, the optical cables produced by the existing production process and molds often have surface bubbles and wrinkles. In addition, the bending performance of the optical cables is poor, and bending and cracking are prone to occur during construction, so that the qualified rate of mass production of finished products is low. , the above problems have not been well resolved

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