Effect of Ventilation Direction and Position on Demolding Force of Cup-Shaped Parts Using Breathable Injection Mold

In injection molding, elucidating the demolding phenomenon and reducing demolding resistance are very important issues from the viewpoint of ensuring product quality and improving productivity. In our previous study, a breathable mold for a cup-shaped molded product by embedding porous inserts in the core mold was proposed to reduce demolding resistance and its effectiveness was verified experimentally. In this paper, in order to optimize mold design, the influence of the verification direction and position on the demolding force was experimentally investigated. As a result, it was confirmed that end ventilation can reduce the total energy, and side ventilation can reduce the peak value of the demolding force. It was also confirmed that it is effective to set the position of ventilation close to the bottom of the cup shape.