Study On Micro Injection Molding Process Of Polymeric Stent

In recent years, the incidence of cardiovascular and cerebrovascular diseases is increasing with the improvement of life condition and pace, and has the trend of rejuvenation. Interventional therapy, as a kind of effective treatment, has been widely used to cure cardiovascular, cerebrovascular and other diseases. Stent, as the main medical apparatus for treating hemadostenosis, plays an important role in the treatment of cardiovascular disease, and so the manufacturing molding technology of it has been a research hotspot. The subject of this paper is to study on the mold design and process technology of the polymeric stent manufactured by micro injection molding, and get the ideal injection molding process parameters through the simulation. The main works of this paper are as follows:Firstly, the injection molding process of stent is simulated by using finite element method, during which, the filled flow status in different injection molding process parameters is studied and the influence of each parameter on filling is analyzed. The result of researching shows that the temperature of mold and the pressure and velocity of injection have apparent impact on filling rates which can be improved by raising them.Secondly, for the knockout difficulty of the polymer stent’s micro injection molding, the elements which can impact the success of knockout in the cavity and ejection mechanism are analyzed. The cross-section shape of mold cavity and ejection mechanism have been redesigned and assembled. And in the later molding experiments, the problem during the demoulding progress is obviously solved.At last, the experiment of polymer stent’s micro injection molding has been carried out by using orthogonal experimental method. The influence of different molding process parameters on filling rates are analyzed and compared. Through the experiment, considering the melt temperature, mold temperature and injection speed have significant influences on the plastics stent filling rate, especially, the melt temperature had the greatest influence. And fill rates while also along with the increase of injection pressure and holding pressure increase, but its influence is not significant; Finally, the ideal injection process parameters are obtained.