Preheating Device For Plastic Granulator

Preheating of the cable core is necessary for both insulation extrusion and sheath extrusion. For insulation layers, especially thin layer insulation, the presence of pores is not allowed. The core can be thoroughly cleaned of surface moisture and oil stains by high-temperature preheating before extrusion. For the extrusion of the sheath, its main function is to dry the cable core and prevent the possibility of air holes in the sheath due to moisture (or moisture from the wrapping layer). Preheating can also prevent the residual internal pressure of plastic during extrusion due to sudden cooling.
During the plastic extrusion process, preheating can eliminate the significant temperature difference caused by the cold wire entering the high-temperature head and coming into contact with the plastic at the mold mouth, avoiding fluctuations in plastic temperature and extrusion pressure, thereby stabilizing the extrusion volume and ensuring extrusion quality. Electric heating wire core preheating devices are used in extrusion molding units, which require sufficient capacity and ensure rapid heating to achieve high efficiency in wire core preheating and cable core drying. The preheating temperature is limited by the wire release speed and is generally similar to the head temperature.