Flow Balance Design In The Injection Mold

The runner system in the injection mold serves to convey the plastic melt coming from the nozzle of the injection molding machine to the cavity. It can be divided into common runner system and the one without runner, and the pressure loss and heat loss of the melt in the runner are decided by arrangement and size of runner.To improve the manufacture efficiency, multi-cavity injection molds are usually employed to produce the medium and pint-sized plastic products. In order to guarantee uniform product weight and performances, flow balance of the runner system must be considered and all the cavities can be filled simultaneously under the same pressure.After the cavity and runner layout and gate sizes are designed, a flow runner diameter inversion model, aiming at the requirement of flow balance from product, is founded based on the numerical simulation in this article. A Bregman regularization method is proposed to solve the problem. A relevant programme was developed, using numerical examples, to justify the feasibility of the arithmetic.This paper includes four chapters, as briefly reviewed follow:In chapter 1, background of this paper, with the review of literature, is introduced. First, the runner system in the injection mold is introduced briefly, and then the history and current research on flow balance are illustrated, after that, the development of CAE technology for injection mold is reviewed, finally, the research of this paper is proposed based on the above.Chapter 2 provides the numerical simulation during injecting process, with the control equations of forward problem, which is the base of inversion problem in this paper.Chapter 3 begins with the introduction of inverse problems, and establishes a runner inversion model for flow balance in unbalanced mold.Chapter 4 focuses on the solution of runner diameter inversion. By using a D-function as regularization functional, a new runner design method is proposed, viz. Bregman regularization for runner diameter inversion. The numerical examples embodies that the method is feasible and it can be expanded to other optimization problems like process parameter design.Chapter 5 gives a summary of this thesis and some possible future work with reference to this paper.