Headpiece and mould: the nose consists of alloy steel inner sleeve and carbon steelcoat, inside the nose with molding mold.It is the role of head rotation movement of the plastic melt into a parallel straight line, import the die set is steady, and give necessary to plastic molding pressure.Plastic plasticizing compaction in the barrel, is approved by the flow of porous filter plate along a certain head neck into the head forming die, die core die set appropriate coordination, the formation of cross section and decreases the annular space, make the plastic melt around the conductor to form a continuous solid tubular cladding layer.In order to ensure the nose in plastic flow is reasonable, eliminate accumulated plastic corner, placed tend to have a split sleeve, to eliminate the plastics extrusion pressure fluctuations, also has a set of equalizing ring.The nose is also equipped with mold correction and adjustment device, easy adjustment and correction of mold core and mold set of concentricity.Extrusion molding machine according to the head material flow direction and the Angle of the center line of the screw, will head into bevel head Angle of 120 o and crosshead.The nose of the shell is bolted on the fuselage, the mold has a mold core inside the head, with a nut fixed in the nose into the line port, the front of the mold core cities with mold core, mold core and mold core of the center hole, used by conductor;In the front of the nose with equalizing ring for balanced pressure;Extrusion molding package part is composed of die sleeve and die set, the location of the die set can be made of bolt support to adjust, to adjust the die set of the relative position of mold core, easy to adjust the uniformity of extrusion cladding thickness.Starting from an external is equipped with heating device and temperature measuring device.2. The role of the transmission system transmission system is a screw driver, and supply the screw in the required torque and rotational speed in the process, usually composed of motor, reducer and bearing, etc.3. The screw rotation speed regulation of screw rotation speed and stability of the control of is one of the important technological requirements of the host transmission.The screw rotation speed directly decide the quantity of glue and the speed, the normal production always wanted to achieve the highest rotational speed and achieve high yield as much as possible, the screw rotation speed to squeeze molding machine requirement from starting work to the required speed, speed range that can be used.And demand is high, to the stability of the speed because the rotation speed fluctuations will lead to the fluctuation of impact extrusion quality, so in the case of traction linear speed did not change, can cause the change of the cable diameter.Large fluctuations in the same way as traction device wire speed can cause the change of the cable diameter, screw and traction linear velocity can be reflected on the corresponding instrument, should be closely observed when it is squeezed, ensure good quality and high yield.
Plastic extruder control system including heating system, cooling system and the process parameters measurement system, is mainly composed of electrical appliances, instruments and actuators (i.e., control panel and work station).Its main role is: control and adjustment of the main auxiliary drive motor, the output meet the technological requirements of speed and power, and can make the main auxiliary coordination;Testing and adjusting temperature, pressure and flow of the plastic in the molding machine;Implementation of the entire unit control or automatic control.Extrusion unit electrical control is roughly divided into drive control and temperature control of two parts, realize the extrusion process including temperature, pressure, screw revolution, cooling, cooling, machine barrel screw products control, cooling and diameter and drawing speed, neat row line and ensure the line plate from the line in empty plate to a plateful of constant tension control.1. Squeeze molding machine host the temperature control of wire and cable insulation and sheath of plastic extrusion is based on the characteristics of thermoplastic deformation make of viscous flow.Except for screw and barrel external heating, to the plastic melt extrusion, but also the screw extrusion plastic itself fever, temperature requirements of the host should consider from overall, therefore, should not only consider the heater heating on and off, and to consider the screw of the factors of cooling the heat, to be effective cooling facilities.And requires correct and reasonable to determine the location of the measuring element thermocouple and installation method, can from the temperature control meter reading to reflect the actual temperature of the host's components.And require the precision of temperature control instrument and system cooperate well, the whole host fluctuations in temperature control system stability reached the requirements of all kinds of plastic extrusion temperature.2. Squeeze molding machine pressure control in order to reflect the extrusion of the nose, need to detect the head pressure of extrusion, because domestic squeeze molding machine head no pressure sensor, is generally after the screw extrusion force of alternative head pressure measurement, screw load table (ammeter or a voltmeter) can correctly reflect the size of the extrusion pressure.Extrusion pressure fluctuations, also is one of the important factors of instability caused by extrusion quality, extrusion pressure fluctuations and the use of the extrusion temperature, cooling device, closely related to factors such as the length of the continuous operation time.When abnormal phenomenon occurs, can eliminate quickly ruled out, must reorganize the production should be decisive stop, not only can avoid the waste, can prevent the happening of the accident.By measuring the pressure gauge reading, can know when plastic extrusion stress, generally take after thrust limit alarm control.
