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Key points of ceramic silicone rubber cable insulation sheath extrusion process
Ceramic silicone rubber cable insulation and sheath using a new material 'ceramic silicone rubber ', this material is a new type of polymer composite material. Under the condition of flame ablation at 750 ℃ × 90 min, not only will it not be burned into powdery Ashes, but it can also form a hard ceramic shell, which plays a role in insulation and fire prevention. And the higher the temperature, the longer the burning time, the harder the shell. The material is used as a cable refractory layer and can withstand certain spraying and impact effects. And has excellent electrical properties, good mechanical properties and other characteristics, according to the special process properties of this kind of material, we trial production in silicone rubber extruder. In the process of trial production, we found through many tests that there are always unqualified situations in tensile strength and elongation at break. Therefore, in the trial production, we adjusted its key operations many times, and finally succeeded after repeated debugging and testing. Ceramic silicone rubber cable insulation and sheath extrusion process should pay attention to the following points: 1, extrusion die extrusion cable its appearance quality is good, the surface is smooth and round. According to the properties of ceramic silicone rubber material, after repeated tests, it is finally decided to adopt extrusion mold production. The length of the molding section is smaller than that of ordinary rubber, and the length of the molding section is recommended, length of small section wire shaping section 1. 5-3mm, length of large cross-section cable alignment section 2-5mm. 2, mold polishing, in order to improve the appearance quality of cable extrusion, ceramic silicone rubber mold must be polished before extrusion. If the extrusion surface is rough and not smooth after polishing, adjust the distance between the extrusion die sleeve and the die core, and at the same time, the extruded rubber should be slightly larger than the diameter of the finished product line, the mold sleeve should be slightly smaller than the ordinary silicone rubber wire and cable, and finally the actual production of on-site debugging shall prevail. 3. Cold extrusion shall be adopted for extrusion. The temperature of the Screw, nose and fuselage of the extruder shall be lower than 30℃, and the maximum shall not exceed 50℃. The lower the cooling water temperature, the better; Body temperature too high compound self-sulfur jam head. 4. Heat the oven or oven according to the temperature of the first section: 160 ~ 180 ℃, second stage temperature 165 ~ 185 ℃, the temperature of the third section is 170 ~ 175 ℃, the fourth section temperature 175 ~ 180 ℃, last section 200 ~ The temperature is set and heated at 230 ℃, and the vulcanization temperature of each section can also be set according to different types of equipment and cables with different structures. The principle is that there are no micropores in the product section and no bubbles in the longitudinal direction of wires and cables, if bubbles are generated, the temperature of the first and second segments should be reduced by 5 ~ 10 ℃, reduce the temperature by 5 ~ 10℃ until no bubbles are generated. 5. The production speed is a key parameter, which directly affects the degree of vulcanization. According to the repeated verification of Vulcanization curve data, it is better to determine it as about 10 m/min, and the extrusion should be slow at the beginning, then slowly speed up. The physical and mechanical properties can be guaranteed to be qualified.