Injection Molding Simulation And Process Optimization Of Guiding Sheath Based On Moldflow

With the continuous development of medical technology,the clinical requirements for the innovation and performance of medical devices are getting higher and higher.At the same time,the variety of polymer materials has increased,and the performance has been improved.Biocompatible medical-grade plastics have been widely used in the medical device industry.High-performance medical device products have complex structures and high dimensional accuracy,and more and more plastic parts are produced by injection molds.With the increasing maturity of injection mold CAE technology,the application of plastic parts of medical device products is more and more widely used,which avoids the tedious process of traditional injection mold design through personal experience and continuous modification of molds and mold trials,and the developed products have the advantage of the short cycle,low cost,and high efficiency.Therefore,the application of injection mold CAE technology in the development and design of medical device products has profound significance.Through Moldflow’s mold flow analysis,the following conclusions and production reference opinions are drawn: 1)There may be air pockets and filling problems in the injection molding of the sheath hub.In the subsequent production,the filling of the buckle position of the sheath hub should be mainly considered.When designing the mold,it is necessary to increase the exhausting slot at this position.And focus on control by filling time and pressure during mold test.2)There may be cavitation problems in the injection molding of the hub cap,and the exhausting slot of the hub cap should be mainly considered in the subsequent production.When designing the mold,it is necessary to increase the exhausting slot at this position.And focus on control by filling time and pressure during mold tryout.3)The main problem of the clip injection is deformation.In the subsequent production,the deformation of the clip should be mainly considered,and focus on control by extending the cooling time during mold test.Besides,through the actual production verification of the injection molding process parameters recommended by the numerical simulation of the Moldflow software,it is found that it can produce qualified parts,but the production qualification rate may not meet the production requirements of the manufacturer.On this basis,the orthogonal test method was used to study the influence of injection molding process parameters on the qualified rate of parts.Combined with the range analysis,the primary and secondary sequence of process parameters and the optimal combination of process parameters that affect the qualified rate of parts were obtained.1)The primary and secondary order of the injection molding process parameters that affect the production pass rate of the sheath joint is as follows: Mold temperature >melt temperature > holding pressure time > holding pressure > injection pressure.The optimal combination of process parameters: Mold temperature is 80 ℃.The melt temperature: the first step is 300 ℃,the second step is 295 ℃,the third step is 290℃,the fourth step is 280℃.The holding pressure: the first step is 105 bar,the second step is 100 bar,the third step is 90 bar.The holding pressure is 60 bar,and the holding pressure time is 4 seconds.2)The primary and secondary order of the injection molding process parameters that affect the production pass rate of the hub cap is as follows: melt temperature >holding pressure > injection speed.The optimal combination of process parameters:melt temperature of the injection nozzle is 295℃,of the first step is 305℃,of the second step is 295℃,of the third step is 285℃.The injection pressure: the first step is100 bar,the second step is 130 bar,the third step is 80 bar.And the injection speed: the first step is 40mm/s,the second step is 30mm/s,the third step is 20mm/s.3)The primary and secondary order of injection molding process parameters that affect the production qualification rate of the clip is as follows: cooling time > mold temperature > holding pressure time > melt temperature > holding pressure.The optimal combination of process parameters: the cooling time is 10 seconds,the mold temperature is 50℃,the holding pressure is 25 bar,the holding pressure time is 4seconds,the melt temperature: the first step is 310℃,the second step is 290℃,the third step is 285℃,the fourth step is 275℃ and the fifth step is 270℃.Finally,the batch production verification is carried out on the optimal process parameter combination,and the product qualification rate meets the production requirements of the manufacturer,which verifies the reliability and practicability of the optimal process parameter combination.