Design And Experimental Study On The Monitoring System Of Extruder Melt Temperature And Pressure

Extrusion line consists of host,auxiliary equipment and control system,which is a device for producing plastic pipes,plates,sheets,films and some opposite material,among them,the extruder screw is an important part of the plastic to the appropriate temperature and pressure extrusion.It is easy to bring the problems such as low temperature control precision and unstable pressure fluctuation in the production,which has an adverse effect on the output and quality of extrusion.Aiming at the problem that the output of LDPE material produced by single screw extruder is poor and the temperature measured by the temperature sensor on the barrel can not accurately express the intermediate melt temperature,this paper based on the analysis of the screw structure and extrusion process,designed a set of temperature and pressure monitoring program based on Labview,realized the accurate measurement,description,control and storage of pressure data,increased the output of LDPE and ensure its quality,through the experimental study and analysis,obtained the temperature variation trend of the intermediate melt in the extruder.It provides a reliable basis for improving the output and quality of extrusion products.The main contents of this paper include:First of all,this paper based on the analysis of the current situation of the single screw structure and the temperature sensor on the barrel of the extruder LDPE,and proposed to detect the melt temperature in the spiral groove by installing a temperature sensor on the screw.Second,this paper designed the whole scheme for the temperature and pressure monitoring system of single screw extruder.Using Auto CAD software to design the improved screw structure and design the shape and size of the sleeve,through the slip ring,detected the temperature through the temperature sensor in the spiral groove,the strength of the screw was analyzed by Workbench software according to the actual working conditions.Third,according to the influence of LDPE extrusion process parameters yield(i.e.speed and temperature),used the orthogonal test,according to the transmission protocol and structure characteristics of Z-Tio temperature control module,on the basis of the Z-Tio protocol and the structure characteristics of the temperature control module,using Labview software and MODBUS communication protocol to deal with the collected temperature signal,Then through the temperature control module came with its own PID control to the heating barrel,realized temperature monitoring,and then get the temperature curve of the melt in the district.Fourth,used orthogonal test to study the effect of temperature and rotational speed on the output of extruded products.and used INSTRON universal mechanical and ISO 527-1 plastic tensile property test method to check orthogonal test's extrusion quality,from extrusion quality and yield to analyze the optimum temperature of the metering section,with the help of NI USB 6009 data acquisition card and Labview program collect the numerical value of the pressure sensor,obtained optimal pressure value.Fifth,through theoretical analysis to obtain theoretical analysis of the formula on the radial distribution of the melt metering section,according to the temperature data of the inner wall of the cylinder and the melt in the screw groove,the radial temperature curve of the melt in the metering section of the extruder is fitted by the formula of Origin software,according to the inner wall of the barrel and the layer temperature data of spiral groove melt,using the Origin software of formulas of radial temperature curve of the extruding measurement part of the melt and fitting equation editor module,analyzed the irrationality of the theory on the intermediate layer melt temperature curve to represent the actual melt temperature.