Plastic Extruder Temperature Control
Plastic Extruder Temperature Control
Temperature control in the plastic extrusion machine production process is undoubtedly a very important process control, temperature control is a direct impact on product quality.
Heater heating (external heat): The current Plastic Extruder is the use of electric heating, clean, effective, easy to control the heating method. That is, with electric heaters (with resistance wire) packaged in the barrel, through the power of heat, due to heat conduction, convection, radiation, the role of heating and heating materials. The current heater is usually a mica heater, ceramic heater, cast aluminum heater, cast copper heater, cast iron heater, the effectiveness of a variety of heaters have some differences, mica heater low cost, easy processing, The use of shorter life; ceramic heater, cast iron heater power, heating up quickly, can rise to 300 ℃ or higher, relatively short life, longer than the mica heater. Cast aluminum heater, copper heater due to high thermal efficiency, good insulation properties, long life and the most commonly used.
Plastic Extruder Extrusion Process Cracking Friction (Internal Heat): During the extrusion process, the shape of the plastic particles is deformed by the strong extrusion pressure, resulting in plastic particles and between the particles and the barrel And the friction between the screw and the heat generated. In the process of heating temperature inertia, heating in the heating process, no matter what kind of heating, stop heating, because the temperature rise inertia, the temperature will continue to rise, then need to watch the temperature control instrument control parameters, accuracy and so on. Plastic extrusion process of shear friction heat (heat), the resulting heat to the processing temperature rising, breaking the characteristics of the material, resulting in materials become waste.
Electrical Plastic Extruder thermocouple failure can be divided into two kinds. The first is not installed in place, or the installation hole there is a slight short circuit of debris and thermocouple lines, can not accurately convey the barrel temperature, often showing the temperature below the set temperature caused by continuous heating, so that the actual material temperature is high material. The second is the thermocouple circuit (open circuit), this time will make the display temperature to full scale or directly show the disruption, resulting in the heating controller to stop the output heating instructions, the heater will be broken due to contactor to stop heating, slow Slow material will be due to no external heating and can not continue to produce
Plastic Extruder The electric heater coil part or the connection with the wire due to poor contact and heat burned, the actual power of the heater becomes smaller or directly to zero power, showing the temperature is low. Due to the feed section of the heating ring opening and closing more frequent or even long-term work, this phenomenon often occurs. Mold section is often disassembly, wiring worse than the situation. AC contactor due to open frequently, and each opening and closing will produce arc, arc temperature is very high, we can think of welding welding machine, is the use of arc typical example. The arc sometimes causes the surface of the AC contactor to melt the clutch to cause the clutch to dry, causing the electric heater to work continuously, showing a high temperature; prolonged repeated adhesion, mechanical force to disengage, and then the adhesion will gradually burn the contact Causing the circuit breaker to make the heater work, indicating that the temperature is below the set temperature.
Plastic Extruder Heating Main Line Insurance Open circuit or circuit breaker trip, mostly due to the rear line or heater short circuit caused by instantaneous high current caused. At this time although the heating indicator light, showing heating, but the instrument shows the number or pointer does not rise up and down, indicating the temperature is getting lower and lower. Improper installation of the heating ring: improper installation of the heating ring, and the barrel or die contact is not close, there is a gap, so that the heat loss of the heating ring, can not be passed to the barrel or die, heating ring does not stop working, indicating that the temperature is still low , Affecting the material plastics. In this case there is the danger of burning the heater, the installation of the heater should be caused enough attention.