Stepped Casting System Process Optimization And Analague Study Of Injection Base

As the main large parts in the injection system of the injection molding machine,the injection base must require high mechanical properties.In order to ensure the injection base castings in ultrasonic inspection to meet the level 2 standard,this paper combines the structural characteristics of injection base with the actual situation of the production site,preliminary determination of design stepped casting system,feeding system and casting process parameters,the mold filling process and solidification process are simulated by Flow 3D software,and a reasonable design process scheme is selected according to the final simulation results.This paper studys the casting defects of the liquid metal flow in the stepped casting system and the injection base casting.By establishing a general model,analysis of the flow of liquid metal gate than the order and the influence of flow state,optimizing the reasonable proportion of components step gating system.To determine the influence of the filling velocity of turbulent flow state,adjust the best casting process parameters,given the high quality castings.According to the velocity field,pressure and the time-velocity curve of the inner gate injection in the filling process,determine whether the metal liquid splashing phenomenon occurs in the early filling period,whether the premature overflow or backflow phenomenon occurs in the middle filling period,and whether the casting erosion phenomenon occurs.Change the number,shape and distribution position of the bottom ingate,increase the sprue base,and thicken the middle ingate.After optimization,the speed of the ingate is more stable,and the filling sequence is more reasonable.Reduce the pouring speed,judge state of turbulent flow and filling time for the influence of the entrained air and the secondary oxidation slag.In order to study the formation of air entrapped,oxidized slag entrapped and shrinkage cavity,the Flow 3D software was used to calculate the flow state during the mold filling process,it based on the parameters of air entrained model,surface defect tracking model and shrinkage cavity model,analyses the position and probability of these three kinds of casting defects.Analysis of different schemes shows that:The casting system of plan 2 is more reasonable and can effectively reduce the possibility of porosity and slag inclusion defects.In the plan 3,the longer pouring time reduces the turbulent state,but increases entrained air volume fraction and free surface defect concentration.For the injection base of thick ductile iron with stepped casting system,the turbulence velocity criterion in filling process is not accurate enough.For the solidification process of castings,retained melt modulus criterion is close to the actual shrinkage phenomenon,and the design of the shrinkage supplement system can effectively reduce the probability of the formation of shrinkage defects.This paper put forward the judgment of a variety of defects through Flow 3D simulation calculation and combination with the practical production of the factory,using the optimized gating system and the casting process parameters,could effectively reduce the probability of defects,improve the production rate of the injection base,reduce the production time,provides reliable theoretical guidance for the casting production practice.