Air venting simulation for multiphase flow of polymers and air in the cavity of a mold

Air venting is important in the polymer shaping process, which uses the cavity of a mold. Inadequate air venting invokes a short shot and bum marks in the product. Therefore, it is necessary to evaluate and predict the venting performance according to the vent location and size when the material is introduced into the cavity. In this study, a computer simulation was performed considering the multiphase flow to examine the venting phenomena when the material flows into the cavity, which is equipped with varying venting hole. The computer simulation predicted the interface variation between the material and air as a function of time. The air venting phenomena was analyzed when the occupying material pushed air into the cavity. The suitability of venting can be evaluated using pressure and velocity distribution of air in the venting region.