Five common problems in the production of PVC cable pellet extrusion and the solutions
Five common problems in the production of PVC cable pellet extrusion and the solutionsPVC wire and cable materials play a vital role in cable production, PVC cable particle extrusion will directly affect the use of cable. It will also directly affect the quality of the wire and cable materials produced. Today we give five examples of common problems of PVC cable pellet extrusion.
1. Scorch phenomenon when PVC cable particles are extruded
The exit of the mold is heavily smoked, the odor is intensely affected and there is crackling noise; there are particles of scorch on the plastic surface; there are consecutive bubbles at the meeting place.
1. The screw is used for a long time, the screw is not cleaned, and the accumulated char is brought out; the screw can be removed and cleaned thoroughly.
2. The heating time is too long, the plastic is aging and scorch; shorten the heating time, check whether there is a problem with the heating system, and timely repair.
2. Poor extrusion plasticization of PVC cable particles
The appearance of plastic is toad skin, the appearance is black, and there are small cracks or small particles that have not been plasticized. There is a remarkable trace at the meeting place.
1. The temperature is too low; just make appropriate progress.
2. During granulation, the plastic is mixed unevenly or there are particles in the plastic that are difficult to plasticize; the mold sleeve can be properly equipped with a smaller one to increase the pressure of the glue outlet.
3. The screw and traction speed are too fast, and the plastic has not been completely plasticized; the speed is appropriately slowed down to extend the temperature of the plasticizing time and improve the plasticizing effect.
4. Material problems; refueling.
Third, the appearance of PVC cable particles is not good
1. The resin that is difficult to be plasticized is extruded without plasticization, forming small crystal points and particles on the surface, scattered around the surface; the temperature should be appropriately increased or the traction linear speed and screw speed should be reduced.
2. Impurities are mixed in when feeding, and there are impurities on the surface; when feeding, the impurities should be prevented from being mixed. If the impurities are mixed, the machine head should be sorted out immediately, and the glue in the screw should be discharged.
3. The surface of the mold bushing diameter is not lubricated or notched, or plastic differentiation is accumulated on the die opening, which makes the appearance traces; when selecting the mold, you should carefully check whether the diameter of the bearing diameter is lubricated, and properly reduce the temperature of the die opening. The deposits should be removed immediately at the die opening.
4. The cable core is too heavy, the pay-off tension is small, and the plastic appearance is wrinkled simply when the cooling is not good; the former should increase the tension, the latter should reduce the traction line speed to ensure the cooling moment.
Fourth, uneven extrusion thickness and slub shape
Because of the instability of the screw and traction, the uneven thickness of the product is formed, because of the problem of the tension ring, the simple occurrence of the slub, the mold is too small, or the outer diameter of the cable core changes greatly, resulting in a thickness fluctuation.
often check the traction, screw, and retractable wire tension equipment or speed, adjust in time; choose the appropriate mold to avoid pouring; often monitor the change of outer diameter.
Fifth, the cable material extruded pores and bubbles
1. The temperature control part is too high; found that the temperature should be adjusted in time and strictly controlled.
2. The plastic is caused by moisture or water ingress; if it is found, it should be stopped in time and drained away.
3. Baking equipment should be added; the material should be used after drying.
4. The core of the wire should be preheated when it gets wet.
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