In China, the growth of Plastic products still reached 12% in 2006, the sales of plastic resins increased by 10.1%, and the sales volume of plastic machinery increased by 10.6%. However, the rising prices of plastic raw materials and steel products have brought severe challenges to the plastics processing industry and the plastics machinery industry. , Further improving the precision and quality of the extrusion machinery is an inevitable trend in the development of the plastics industry.
Extruder Overview
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. There are many different types and sizes of screw extruders. The most commonly used extruder is a screw extruder. Adopting the extruder main drive of the Ampun letter E11 AC frequency converter can fully meet the process requirements of the extruder and achieve the necessary process control indexes. After years of actual operation, the operation is stable and the product has strong adaptability. Obvious economic benefits.
Traditional extruder drive features
Extrusion equipment components
An extrusion device is usually composed of a host (extruder), an auxiliary machine, 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.
Traditional screw extruder control
1) In a conventional 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 there is a slippage of the belt, the belt will cause a certain amount of 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 higher, the initial cost of DC motor is also higher.
Application of Shanyu SY8000Z Series Frequency Converter on Precision Extruder
The SY6000 series inverters are used in extrusion equipment and have high-quality operating characteristics. This is determined by the good product performance that the Shanyu SY6000 series inverters can provide.
1> Fast Processor Provides Higher Frequency Response
Shan Yu SY6000 inverter built-in processor, providing 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> Automatic energy-saving control to optimize motor efficiency
The main drive motor of the extruder drives the screw to rotate mainly through the deceleration of the parallel shaft helical gear reducer, and the constant torque speed is adjusted when the operating speed is changed below the fundamental frequency.
Yamatake SY6000 series inverters have automatic energy-saving control function, which can automatically adjust the voltage according to the load conditions, so that the motor runs at the highest efficiency.
3> Torque limit and slip compensation
Torque limit and slip compensation function make the output torque constant, small torque fluctuations, to meet the product process requirements.
Conclusion
The use of Shanyu's new generation of speed sensorless vector inverters on precision extruders not only saves energy, but also more importantly improves the process, improves product quality, and enhances the product's competitiveness.
Nantong Boxin Electronic Technology Co., Ltd. , https://www.bosencontrols.com