During the filling phase, the conventional venting will have an increasing over pressure. The air and gases can’t be in a short time completely pushed out of the venting lines.

Depending on the venting application and the injection force, pressure in the cavity already increases during the first injection stage up to 3000 mbar. In the second stage, these values can be doubled and even tripled.

The additional vacuum venting will produce an depression in the cavity. The air and gases will be evacuated until the mould cavity is completely filled. This way, pressure in the cavity rarely exceeds 200 mbar.