The lost foam mold, also known as the white mold, is the mold used for casting castings. The lost foam mold is obtained by casting foam beads after curing and foaming. When the mold is made, it will also be damaged for some reasons, such as lost foam. After the mold is formed, it is found that there is a shortage of material, so what is the reason for this phenomenon?

1. Poor bead pre-development

Under normal circumstances, when the air pressure is constant, the capacity of the pre-expanded beads decreases with the prolongation of the ventilation time, and the density of the pre-expanded beads decreases with the increase of the vapor pressure when the ventilation time is unchanged. Before pre-blasting, if the beads are not screened completely, the coarse and fine particle sizes are uneven, or the stirring speed is too fast, the beads are heated unevenly, which will result in insufficient pre-blasting and uneven density of some beads. This will cause the phenomenon of molding material shortage.

2. Poor ripening effect

The reason for the poor ripening effect may be that the steam pressure supply is insufficient. In order to facilitate the bonding of the molding process, the pre sent beads must be ripened. Therefore, the effect of ripening is great, which is closely related to the lack of material.

3. Insufficient material supply

 When the mold is made, the insufficient material supply is mostly due to the "bridging" phenomenon at the feeding port, which will lead to insufficient material injection, resulting in the phenomenon of molding shortage.

4. Poor mold exhaust

Check whether there is a cold material cavity, or whether the position is correct. For a mold with a deep cavity, an exhaust groove and an exhaust hole should be added at the undershot part, and an appropriate size exhaust groove can be opened on the clamping surface. The exhaust hole should also be set at the final filling of the cavity. If the exhaust port is unreasonable, it will cause the filling to be short of material.