The causes of casting defects and technology-related aspects of classification

China has the causes of casting defects and technology-related aspects of classification, the general classification of the following ways: 
The first one is so poor design, and design work flawed because it is produced by a part of a collapsed when not reach this part of the time, tooling manufacture casting a flawed product. 
The second is a material and melting, when they are different when defects are inevitable, melting the metal and alloy steel products manufacturing, rational performance reduction is relatively large, the thermal cracking will large, when the increase in internal and external defects, casting techniques can also cause mistakes. 
One aspect of casting defects caused by technical knowledge, then cracks and holes it? Sand probability may be defective operation step, the shape of the defect classification and casting defects negligent waste. Such as forgetting to lower the weight and ultra-poor part of the core, carrying the box using the case of defects cause trachoma, moderate control is king.