In the process of production, there will be a lot of faults, but some of them are unavoidable, so we should prepare some methods to deal with them when we are working. So, under casting of die castings is also a common problem. What are the causes of under casting of die castings?
- The filling condition is poor, and there is irregular condensed metal in the under cast part;
When the pressure is insufficient, the metal in the active front solidifies too early, resulting in under casting at the corner, deep concave, thin wall (even thinner than the average wall thickness) and cylindrical hole wall. The results show that the mold temperature is too low, the alloy pouring temperature is too low, and the location of the inner gate is not good, resulting in large moving resistance.
- It is difficult to set up the part of overflow system because of gas obstruction and lubrication on the surface of under cast part, which makes it difficult to set up an overflow system. When molten metal moves, turbulent flow is violent and gas entrapment occurs.
- There is residue in the cavity of plastic mold
The amount of coating or spraying method is improper, resulting in local coating deposition.
When filling, the metal will run into the metal when filling. After the casting is pulled out, it can not be brought out completely and the flake is clamped on the gap. When the sheet metal (the thickness of the metal sheet is the size of the gap) is more convex on the surrounding mold surface, the height of the projection will be changed into the wall thickness of the casting under the condition of closing the mold, so that the future casting will have a groove penetrating (for the wall thickness). This penetrating groove is a special form of under casting. This kind of under cast phenomenon often occurs in the case of deep cavity composed of mosaic.
These are the reasons for the under casting of die castings
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