| Rheology is an important indicator of PVC and other plastic materials in the processing process,it is of great significance to study the performance and mold design of such materials.The rheometer's analysis of the material,the guiding role of the mold design can only provide qualitative guidance through comparative experiments,and can not provide an accurate and quantitative guidance.Therefore,the tredn of R & D is accurate and timely analysis of the rheological properties of the rheometer,obtaining rheological properties timely and accurately is a very important part of mold design and adjustment.In order to be able to measure the rheological properties of PVC material in the process of material production and processing,this paper designs a PVC rheological on-line analysis system to measure the rheological properties of the material during the extrusion process,and the change trend of shear viscosity of material under different pressure and shear stress was obtained.In this paper,the rheological on-line analysis system of PVC is needed to develop the pressure gradient curve of PVC in the flow channel,the shear thinning ratio and the shear viscosity pressure coefficient are analyzed.The main research contents of this subject include:(1)Research on rheological extrusion theory,the flowability of PVC in the melt from the solid state to the melt state to the polymer melt state was analyzed,carried out the quantitative mathematical analysis of the polymer melt state of the material in the flow channel of mold,the calculation method of shear viscosity,shear dilution ratio and shear viscosity pressure coefficient is given.(2)Design the rheology on-line analytical system for PVC,based on the analysis of the influence of the basic structure,working process and process parameters on the molding effect of PVC.According to the type of physical quantity,the range of indication and the corresponding working conditions,a system platform consisting of extruder,condition monitoring module and data acquisition module is set up.Through the configuration of a variety of sensors,to achieve the temperature,speed and other parameters of the collection and control,and detect the flow channel pressure function,and upload data to the host for display and processing functions.(3)Developed the system analysis software based on the LabVIEW platform.According to the functional requirements of the system,the process of software measurement is planned and the software part of the system is completed.According to the mathematical model of the flow in the PVC extrusion process,the appropriate curve fitting algorithm is selected to finally analyze the on-line analysis of PVC rheological properties.(4)Analys the rheology of PVC on – line based on the built-up system.Through the actual detection and analysis of the experimental data,the results obtained by comparison with the experimental results of PVC extrusion slices were compared to verify the system reliability,stability and test accuracy. |
PDF Full Text Request