Research On Temperature Control Method Of Low Pressure Casting Mould

Low pressure casting technology was used in industrial production in the 1940 s.It is an anti-gravity casting technology.At present,low pressure casting mainly USES aluminum and magnesium alloy materials to produce castings.The principle of low pressure casting is to pressurize the holding furnace containing the molten aluminum alloy.Under the action of pressure,the liquid aluminum alloy enters into the mold cavity from the liquid lift tube,and finally the casting solidifies under the action of pressure.In low pressure casting,the combination of runner and shrinkage channel under lower pressure can improve the stability of mold filling,solve the problem of unreasonable shrinkage and greatly improve the quality of casting.In addition,low pressure casting technology also has the advantages of high shrinkage pressure and large temperature gradient,which can improve the casting quality.In order to meet the demand of modern production,casting production technology and process need to be improved continuously.Low pressure casting technology has obvious advantages and application prospects in satisfying the requirements of lightweight casting parts.In the process of low pressure casting,the mold temperature not only affects the forming quality of the casting,but also affects the service life of the mold.The mould temperature control system has the characteristics of non-linearity and large time delay.Therefore,the research on mold temperature control method has important theoretical research significance and engineering application value.Paper main research content is in the process of low pressure casting mold cooling,using ProCAST casting simulation software is used to numerically simulate the low pressure casting process simulation,get the hub of cooling system and a cooling system has been casting,low pressure casting process simulation results with and without cooling system are analyzed influence on casting quality,and the design of the mould of internal cooling channels,cooling water circulation scheme is proposed.By analyzing the mould cooling system,the mould temperature control system is established and the main components are selected.On this basis,the mold temperature control algorithm is studied.By comparing the traditional PID control algorithm,fuzzy PID control algorithm and Smith pre-estimation method,the Smith fuzzy PID control algorithm is proposed.Matlab/Smulink module was used to establish the PID control system,fuzzy PID control system,Smith fuzzy PID control system model,and the simulation results were compared and analyzed.The results show that Smith fuzzy PID algorithm has higher precision and better robustness than traditional PID control algorithm and fuzzy PID control algorithm.