Optimization And Research In Gate Number Of Injection Molds

Injection molding is an important polymer processing technique. According to the statistics, every year 30 percent of the plastic products are injection products, 50 percent of the molds are injection molds. Therefore the injection molding technique acts a vital role in plastic industry. Since the gate number and location are two critical parameters in mold design, the corresponding optimal research is a very important subject.This thesis presents an optimization model for gate number and its location, employs the Kriging method and Moldflow software, optimize the filling time difference, so as to realize the effect of filling balance and obtain the optimal gate number and their locations. The main contents of this thesis are list as follows:In chapter 1, we first introduce the engineering background in injection molding, the traditional mold design methods, and the application of injection CAE technique. Then we summarize the recent research situation in gate optimization. Finally, we give a depiction of this paper and the corresponding Kriging method and K-means clustering method.In chapter 2, we discuss the Kriging method in detail, based on this we present a gate location optimization model. The model is proposed to achieve the balance filling, the objective function is expressed as the time difference of the maximum and minimum times at the extremities of the cavity, the coordinates of gate locations are chosen as design variables, apply Moldflow software to calculate the filling time, employ the Kriging method to build the mapping relationship between time difference and gate coordinates, necessary iteration is executed to obtain the gate locations.In chapter 3, we specify the multi-gates location optimization, when the gate number is designated. First we utilize the K-means clustering method, using flow length to cluster the FEM mesh of injection mold, partition the FEM mesh into appointed regions. Then we consider every region as a gate design space, choose the balance filling as the ultimate result, to optimize the multi-gates locations with Kriging method when the gate number is designated.In chapter 4, we analyze the results, construct a weighted objective function to quantify the product's quality, comprehensively consider the injection condition (such as the property of injection machine, the volume of the injection product, the style of the product) to adjust the weight coefficient, compare to obtain the optimal gate number and their locations.In chapter 5, we summarize the whole thesis to discuss its advantages and limitations, prospect the possible research directions in the future.