Research On Cooling Process Of Extrusion Blowing Products Under The Condition Of Condensed Water Film

The phenomenon of condensed water film on surface of mould cavity is a special phenomenon during the extrusion blow molding process, which has a significant impact on the cooling process of extrusion blowing products. We have research on cooling mechanism of extrusion blowing products under the conditions of water film. And the three-layer composite model of mould-water film-product (MWP model) is established based on the formation mechanism of condensed water film in this paper. The influence of temperature distribution in the cooling process is obtained through numerical analysis of different cooling methods, different initial temperature and different thickness of the extrusion blowing products. And we analyze the effect of the cooling time and cooling uniformity of extrusion blowing products under the conditions of water film. The function modules of cooling analysis of extrusion blowing products is developed. It not only improves the accuracy of analysis of the cooling process, but also is conducive to the realization of designing optimization of extrusion blowing products and mold.The main contents of the dissertationare include:The first chapter introduces the research background and gives a brief overview of the technology and equipment, particularly describes the cooling equipment of the plastic extrusion blow molding process. It reviewed current research of analysis technology in the cooling process and blowing mold design techniques and methods. The problems were proposed in accordance with of the existing research work on the deficiencies of the judgment.And ultimately the contents and framework of the paper are determined.In the second chapter, we study the formation mechanism of condensed water film on surface of mould cavity under large temperature difference. The formation of water film is described through the mold cavity surface thermodynamic functions and the solid-liquid-gas adsorption model. We focus on the properties of water film and impact of the cooling process of extrusion blowing products according to mechanism of water film and existence of physical and chemical properties based on the solid surface thermodynamic theory and solid-liquid-gas adsorption theory, which provides the evidence for cooling analysis and optimization of process parameters.The third chapter introduces the cooling process of extrusion blow molding. The MWP model of cooling boundary element model is established based on simplifying assumptions and considering the water film. It describes in detail the process of the finite element model and sets the boundary conditions. Finally, mathematical methods of solving the cooling problems of extrusion blowing products are introduced and the calculation parameters are set up.In the forth chapter, we have a complete simulation of cooling process of extrusion blowing products. The influence of temperature distribution in the cooling process is obtained through numerical analysis of different cooling methods, different initial temperature and different thickness of the extrusion blowing products, which is expected to provide analytical basis for optimization and the development of cooling process simulation analysis system. Meanwhile, it analyzes the effect of the cooling time and cooling uniformity of extrusion blowing products under the conditions of water film. We analyze the temperature field with the presence or absence of water film in order to show the advantages and availability of water film ultimately.In the fifth chapter, the function modules of cooling analysis of extrusion blowing products is developed according to the water film theoretical model and analysis method proposed. And also gives the analysis of the cooling process engineering application of 125ml hollow bottle.In the sixth chapter, the main content, research achievements and innovations of this paper were summarized and the further research is put forward.