Taiwan Shihlin Inverter SH (Sensorless Vector Control) Series Inverters Applied to Extrusion Machinery The plastic is plasticized by the extruder into a uniform melt, and under the effect of the pressure established in the plasticization, the screw is continuously set at a constant temperature, quantitatively, and at a constant pressure to extrude the head. Most thermoplastics use this method. Screw extruders come in many different models and sizes. The most commonly used extruders are screw extruders. The extruder main engine drive using SH series AC frequency converter can fully meet the technological requirements of the extruder and achieve the necessary process control indicators. After years of actual operation, the operation is stable, the product adaptability is strong, and the economic benefits are obvious. Providers: Changzhou Ganma Technology Development Co., Ltd. Author: Wei Qing / contact number fax
First, the characteristics of the extruder drive Extrusion equipment components An extrusion equipment is usually composed of the host (extruder), auxiliary engine and its control system. Usually these components are collectively referred to as extrusion units.
1. The main machine of an extruder consists of three parts: extrusion, transmission, and heating and cooling.
The extrusion system is mainly composed of screw and barrel, which is a key part of the extruder.
The role of the drive system is to drive the screw, to ensure that the screw in the working process has the required torque and speed;
The heating and cooling system is mainly used to ensure the temperature control of the material and the extrusion system in the molding process.
2. The composition of the auxiliary machine for the auxiliary machine extrusion equipment depends on the type of product. Generally speaking, the auxiliary machine is composed of the agent-defining device, the cooling device, the traction device, the cutting device, and the coiling or stacking device of the product.
3. The control system of the control system extruder consists mainly of electrical appliances, meters and actuators. Its main role is:
(1) Control the drive motor of the main and auxiliary engines to meet the speed and power required by the process requirements, and ensure that the main and auxiliary machines can operate in a coordinated manner.
(2) Control the temperature, pressure, flow rate and product quality of main and auxiliary engines.
(3) to achieve the automatic control of the entire unit.
Second, the control of the traditional screw extruder 1) In the traditional screw extruder system, the screw is driven by a DC motor. In the case of direct transmission, the screw is directly driven by the gearbox; in the case of indirect transmission, the screw is driven by the belt and the traction disk. The traditional DC motor itself has certain drawbacks: for example, the brush of a DC motor needs to be replaced once a month. In a multi-dust or corrosive environment, the DC motor needs to be cleaned frequently, and sometimes even a DC motor is needed outside the workshop. Into the clean cooling air.
2) The disadvantage of the indirect drive screw extruder is that it exists in the slippage of the belt, the belt will cause a certain energy loss, and more mechanical devices increase the wear and the possibility of failure. The biggest drawbacks of DC motors are excessive noise, brush ignition, rotor contamination, high motor temperature, insufficient exhaust gas, and motor vibration. Therefore, the use of DC motor screw extruder maintenance costs are higher, the original cost of the DC motor is also higher. Third, the Shihlin SH series inverter in the extruder application SH inverter for extrusion equipment, high-quality operation The characteristic, which is determined by the good product performance that the vector control type inverter itself can provide.
1> Fast Processor Provides higher frequency response The built-in processor of the SH drive provides high control accuracy, fast response frequency and good dynamic performance. The process requirements of the extruder are mainly to control the pressure at the outlet. When the equipment is just starting to work, it controls the speed. When the demand pressure is reached, it must be switched to pressure control. The switching process should have no impact, requiring high control accuracy of the frequency converter to connect the pressure signal.
2> Vector control provides high torque at low frequency output The main drive motor of the extruder drives the screw to rotate mainly through the reduction of the speed of the parallel shaft helical gear reducer. When the operating speed is changed below the fundamental frequency, it is the constant torque speed regulation.
In the past, V/f control type inverters were used. To consider the starting torque of the load, the corresponding torque boost level should be set. If the torque boost setting is too high, the excitation will be too large at low-frequency light load, and it is easy to cause The motor is extremely hot and affects the stable operation of the equipment.
The use of vector control type SH frequency converter, using the self-learning function to observe the motor parameters, not only can ensure a good output characteristics of the motor at low frequencies, SH's automatic energy-saving operation function will reduce the output current with the torque change, not only can save Electrical energy can better eliminate the possibility of the above-mentioned working hidden dangers.
3> Torque limit and slip compensation, speed control accuracy up to five thousandth