The entry position of the inner gate in the lost mold casting
The cutting position of the inner gate of disappearing die casting is not whether it can achieve smooth filling and avoid turbulence. Smooth filling may not be beneficial to the disappearing die casting, because the foam mold is the gas material, so it is impossible not to produce gas, and it is impossible for the gas it produces not to enter into the liquid metal. It is important to enter the liquid metal gas and gasification is not completely some residues, to smoothly, to achieve this purpose, sometimes need artificial manufacturing, turbulence, the liquid metal shock, create gas and slag floating and discharge liquid level conditions, also turbulence for obtaining high quality of disappear die casting is not harmful.
In the design of the inlet position of the casting, the liquid metal can realize the reasonable distribution of the thermal field and the sequential solidification or synchronous solidification, in other words, the heat distribution of the liquid metal. The flow field is only the process, but the hot field is the end.
In order to further explain the principle of the entry position of the inner gate, we should understand the gasification characteristics of foam type. Among the many gasification characteristics of foam model, the temperature has the greatest influence. Under high temperature conditions, the foam gasification speed is fast, the gasification is complete, and no residue is produced. The reaction is also the same in the casting, where the temperature is high (high temperature area), there is no residue, no foam gasification defect; where the low temperature (low temperature area), the residue is left, the gasification defect will occur.
Therefore, the disappearing die casting realizes the reasonable distribution of the thermal field of the inner gate through the design of the entry position of the inner gate. The important purpose is to make all liquid metals can contact the foam mold and assume the responsibility of heating to the foam type, rather than a certain liquid metal alone assuming the heating function of the foam mold gasification. The foam type of each part has contact with high temperature metal liquid without touching low temperature metal liquid; all have completely gasification at high temperature rather than leaving residue at low temperature.
