In order to study the relationship between the main process parameters and the cell size,the mathematical model of cell growth of microcellular foaming injection process is built.Then numeric simulation is employed as...In order to study the relationship between the main process parameters and the cell size,the mathematical model of cell growth of microcellular foaming injection process is built.Then numeric simulation is employed as experimental method,and the Taguchi method is used to analyze significance of effect of process parameters on the cell size.At last the process parameters are focused on melt temperature,injection time,mold temperature and pre-filled volume.The significance order from big to small of the effect of each process parameters on cell size is melt temperature,pre-filled volume,injection time,and mold temperature.On the basis of above research,the effect of each process parameter on cell size is further researched.Appropriate reduction of the melt temperature and increase of the pre-filled volume can optimize the cell size effectively,while the effects of injection time and mold temperature on cell size are less significant.展开更多
Mathematical model of filling disk-shaped mold cavity in steady state was studied.And the mathematical model under vibration field was developed from the model in steady state.According to the model of filling disk-sh...Mathematical model of filling disk-shaped mold cavity in steady state was studied.And the mathematical model under vibration field was developed from the model in steady state.According to the model of filling disk-shaped mold cavity in steady state,the filling time,the distribution of velocity field and the pressure field were obtained.The analysis results from rheological analytic model were compared with the numerical simulation results using Moldflow software in the powder injection molding filling process.Through the comparison,it is found that it is unreasonable to neglect the influence of temperature when calculated the pressure changing with the time at the cavity gate,while it can be neglected in other situations such as calculating the distribution of the velocity fields.This provides a theoretical reference for the establishment of correct model both in steady state and under vibration force field in the future.展开更多
An intelligent model employing case-based reasoning（CBR） and fuzzy inference was constructed in terms to the system characteristics of plastic injection molding and considering the molding personnel＇s thought durin...An intelligent model employing case-based reasoning（CBR） and fuzzy inference was constructed in terms to the system characteristics of plastic injection molding and considering the molding personnel＇s thought during the molding trial-runs. The model describes the complex process of injection molding with a view to the characters and advantages of CBR and fuzzy theory. And it can be used to determine the initial process parameters and optimize the process parameters on-line. The key implementation technologies of the model are described in detail, including determining the initial process parameters based on CBR, correcting defects, optimizing process parameters based on fuzzy inference, etc. A corresponding intelligent system was developed which is integrated with injection machine by communicating with the controller.展开更多
Plastic injection molding is a very complex process and its process planning has a direct influence on product quality and production efficiency. This paper studied the optimization of injection molding process by com...Plastic injection molding is a very complex process and its process planning has a direct influence on product quality and production efficiency. This paper studied the optimization of injection molding process by combining the numerical simulation with back-propagation(BP) networks. The BP networks are trained by the results of numerical simulation. The trained BP networks may:(1) shorten time for process planning;(2) optimize process parameters;(3) be employed in on-line quality control;(4) be integrated with knowledge-based system(KBS) and case-based reasoning(CBR) to make intelligent process planning of injection molding.展开更多
Quick material change is often encountered for the different colors or kinds of polymer in hot runner injecting molding process. Time costing and incompleteness of material change process often affects the quality and...Quick material change is often encountered for the different colors or kinds of polymer in hot runner injecting molding process. Time costing and incompleteness of material change process often affects the quality and productivity of products. In the practical production, multi injection or white material as the transition material is often adopted for quick material change. Based on the rheological behavior of the new and the previous plastic melt, the researches on the related problems were carried out. The concept of drag material change was originally presented. The physical and mathematical model on the simultaneous flow process of the new and the previous plastic melt in hot runner were built up, which can well explain the influence of the injection speed, pressure, viscosity difference, temperature and mold structure on the drag material change efficiency. When temperature in different position in the mold was increased and adjusted, the viscosity difference between the two kinds of melt can be controlled. Therefore the material change ability can be greatly improved during the whole material change process, getting rid of more and more difficult changing in the late stage.展开更多
文摘In order to study the relationship between the main process parameters and the cell size,the mathematical model of cell growth of microcellular foaming injection process is built.Then numeric simulation is employed as experimental method,and the Taguchi method is used to analyze significance of effect of process parameters on the cell size.At last the process parameters are focused on melt temperature,injection time,mold temperature and pre-filled volume.The significance order from big to small of the effect of each process parameters on cell size is melt temperature,pre-filled volume,injection time,and mold temperature.On the basis of above research,the effect of each process parameter on cell size is further researched.Appropriate reduction of the melt temperature and increase of the pre-filled volume can optimize the cell size effectively,while the effects of injection time and mold temperature on cell size are less significant.
基金The authors would like to thank the research group that took part in the study for their generous cooperation. Project 50965003 supported by National Natural Science Foundation of China.
基金Project(10672197) supported by the National Natural Science Foundation of ChinaProject(07JJ1001) supported by the Natural Science Foundation of Hunan Province for Distinguished Young Scholars,China
文摘Mathematical model of filling disk-shaped mold cavity in steady state was studied.And the mathematical model under vibration field was developed from the model in steady state.According to the model of filling disk-shaped mold cavity in steady state,the filling time,the distribution of velocity field and the pressure field were obtained.The analysis results from rheological analytic model were compared with the numerical simulation results using Moldflow software in the powder injection molding filling process.Through the comparison,it is found that it is unreasonable to neglect the influence of temperature when calculated the pressure changing with the time at the cavity gate,while it can be neglected in other situations such as calculating the distribution of the velocity fields.This provides a theoretical reference for the establishment of correct model both in steady state and under vibration force field in the future.
基金Supported by New Century Excellent Talents in University of China(NCET-040-0718) and Young Scholars of Hubei Province(2005ABB04)
文摘An intelligent model employing case-based reasoning（CBR） and fuzzy inference was constructed in terms to the system characteristics of plastic injection molding and considering the molding personnel＇s thought during the molding trial-runs. The model describes the complex process of injection molding with a view to the characters and advantages of CBR and fuzzy theory. And it can be used to determine the initial process parameters and optimize the process parameters on-line. The key implementation technologies of the model are described in detail, including determining the initial process parameters based on CBR, correcting defects, optimizing process parameters based on fuzzy inference, etc. A corresponding intelligent system was developed which is integrated with injection machine by communicating with the controller.
文摘Plastic injection molding is a very complex process and its process planning has a direct influence on product quality and production efficiency. This paper studied the optimization of injection molding process by combining the numerical simulation with back-propagation(BP) networks. The BP networks are trained by the results of numerical simulation. The trained BP networks may:(1) shorten time for process planning;(2) optimize process parameters;(3) be employed in on-line quality control;(4) be integrated with knowledge-based system(KBS) and case-based reasoning(CBR) to make intelligent process planning of injection molding.
文摘Quick material change is often encountered for the different colors or kinds of polymer in hot runner injecting molding process. Time costing and incompleteness of material change process often affects the quality and productivity of products. In the practical production, multi injection or white material as the transition material is often adopted for quick material change. Based on the rheological behavior of the new and the previous plastic melt, the researches on the related problems were carried out. The concept of drag material change was originally presented. The physical and mathematical model on the simultaneous flow process of the new and the previous plastic melt in hot runner were built up, which can well explain the influence of the injection speed, pressure, viscosity difference, temperature and mold structure on the drag material change efficiency. When temperature in different position in the mold was increased and adjusted, the viscosity difference between the two kinds of melt can be controlled. Therefore the material change ability can be greatly improved during the whole material change process, getting rid of more and more difficult changing in the late stage.
