Auxiliary Equipment For Plastic Extruders

The auxiliary equipment of the plastic extrusion unit mainly includes a pay-off device, a straightening device, a preheating device, a cooling device, a traction device, a meter counter, a spark tester, and a wire take-up device. The use of the extrusion unit is different, and the auxiliary equipment used for matching is also different, such as cutters, blow dryers, printing devices, etc.
Straightening Device
The most common type of plastic extrusion waste is eccentricity, and various types of bending of the wire core are one of the important reasons for insulation eccentricity. In sheath extrusion, scratches on the sheath surface are also often caused by bending of the cable core. Therefore, straightening devices in various extrusion units are essential. The main types of straightening devices are: drum type (divided into horizontal type and vertical type); pulley type (divided into single pulley and pulley block); winch type, which also plays multiple functions such as dragging, straightening, and stable tension; Pressure wheel type (divided into horizontal type and vertical type), etc.
Preheating Device
Core preheating is necessary for both insulation extrusion and sheath extrusion. For the insulation layer, especially thin-layer insulation, the existence of air holes cannot be allowed. The moisture and oil on the surface can be completely removed by preheating the wire core at high temperature before extrusion. For the extrusion of the sheath, its main function is to dry the cable core to prevent the possibility of air holes in the sheath due to the action of moisture (or moisture surrounding the cushion). Preheating also prevents the residual internal pressure of the plastic during extrusion due to sudden cooling. In the process of extruding plastic, preheating can eliminate the temperature difference formed when the cold line enters the high-temperature machine head and contacts the plastic at the die, and avoid the fluctuation of the extrusion pressure caused by the fluctuation of the plastic temperature, thereby stabilizing the extrusion volume and ensuring Extrusion quality. The electric heating wire core preheating device is used in the extrusion unit, which requires sufficient capacity and ensures rapid temperature rise, so that the efficiency of wire core preheating and cable core drying is high. The preheating temperature is restricted by the pay-off speed, which is generally similar to the head temperature.
Cooling Device
After the molded plastic extruded cladding leaves the machine head, it should be cooled and shaped immediately, otherwise it will be deformed under the action of gravity. The cooling method usually adopts water cooling, and can be divided into rapid cooling and slow cooling according to different water temperatures. Quenching is the direct cooling of cold water. Quenching is beneficial to the shaping of plastic extrusion cladding, but for crystalline polymers, due to sudden cooling, internal stress tends to remain inside the extruded cladding tissue, resulting in cracks during use. Generally, PVC The plastic layer is quenched. Slow cooling is to reduce the internal stress of the product. Water of different temperatures is placed in the cooling water tank in sections to make the product gradually cool down and shape. The extrusion of PE and PP is carried out by slow cooling, that is, through hot water, warm water, and cold water. Three stages of cooling.