摘要 |
In a mould forming machine comprising a moulding chamber, a movable squeeze plate and a pattern, the filling of selected parts of the pattern with compressible mould material is improved by applying vacuum to said selected parts. By applying the vacuum separately to different parts of the pattern at different periods, of time during the filling step, the vacuum application can be applied during shorter periods only when needed, thereby reducing the drying out of the mould material and reducing the amounts of air to be removed by the vacuum system. |