Deformation Analysis On Plastic Injection Mould Based On Boundary Element Method

The centre issue of injection moulding analysis has long been focused on the simulation of the product profile, and the mould system is commonly supposed to so rigid that they have no deformation. In fact, however, the deformation can influence the dimensions of the product, especially in nowadays plastic injection industry, the high-quality and precision are strongly demanded; Meanwhile, the structural strength of injection moulds determines their operating life, which is also an important factor to economic basis in industry.Therefore, this paper is to predict the injection mould's structural deformation under injection pressure. The 3.dimensional elastic boundary element method is applied to model the problem numerically. The key challenges have been solved such as: 1). To deal with the singularity of boundary integral, a newly method of local oblique coordinate is employed; 2). Based on point-surface contact model, the highly efficient contact search algorithm is presented, as well as simplified uncompromising meshing contact algorithm; 3). The specified solution according to different facet element the vertex belong is employed to deal with the un-continuous boundary conditions of surface pressures.As a result, an integrated analysis software system to calculate the injection mould deformation is developed. It can be directly integrated with the plastic injection analysis system HSCAE by importing the latter's analysis result of injection pressure field as boundary condition. Then it can calculate the assembly injection moulds'stress and strain field under the injection pressure by what we can control the moulds'deformation in order to limit the product undesired offset, as well as to optimize the structural design of moulds to lower the cost.It should note that in cases that real injection moulds which commonly have very complex die cavity, the general structural analysis systems have their limit to predict the real deformation the injection moulds experience because they have no way to automatically obtain the pressure field on die cavity. Meanwhile manually applying the pressure field is too roughly to reflect the real boundary condition the injection moulds experience. This problem can be solved by the specialized system developed in this paper. It has as simple user-interface as possible and the result compared with ANSYS shows the numerical model this paper presented is of effective, practical basis in engineering application.