金属型和砂型，在性能上有显著的区别，如砂型有透气性，而金属型则没有；砂型的导热性差，金属型的导热性很好，砂型有退让性，而金属型没有等。金属型的这些特点决定了它在铸件形成过程中有自己的规律。
There are significant differences in performance between metal mold and sand mold, such as sand mold has air permeability, while metal mold has no; sand mold has poor thermal conductivity, metal mold has good thermal conductivity, sand mold has yielding property, and metal mold has no. These characteristics of metal mold determine that it has its own rules in the forming process of castings.
型腔内气体状态变化对铸件成型的影响：金属在充填时，型腔内的气体必须迅速排出，但金属又无透气性，只要对工艺稍加疏忽，就会给铸件的质量带来不良影响。
The influence of the change of the gas state in the mold cavity on the casting molding: when the metal is filled, the gas in the cavity must be quickly discharged, but the metal has no air permeability. As long as the process is slightly neglected, it will bring adverse effects on the quality of the casting.
铸件凝固过程中热交换的特点：金属液一旦进入型腔，就把热量传给金属型壁。液体金属通过型壁散失热量，进行凝固并产生收缩，而型壁在获得热量，升高温度的同时产生膨胀，结果在铸件与型壁之间形成了“间隙”。在“铸件一间隙一金属型阳雕刻 手套生产设备 果树反光膜 北京纯水设备 保定网站制作 排水槽模具 ”系统未到达同一温度之前，可以把铸件视为在“间隙”中冷却，而金属型壁则通过“间隙”被加热。
The characteristics of heat exchange in the solidification process of castings: once the liquid metal enters the mold cavity, the heat is transferred to the metal mold wall. The liquid metal loses heat through the mold wall, solidifies and shrinks. The mold wall obtains heat and expands at the same time when the temperature rises. As a result, a "gap" is formed between the casting and the mold wall. Before the "casting gap metal mold" system reaches the same temperature, the casting can be regarded as cooling in the "gap", and the metal mold wall is heated through the "gap".
金属型阻碍收缩对铸件的影响：金属型或金属型芯，在铸件凝固过程中无退让性，阻碍铸件收缩，这是它的又一特点。
The influence of metal mold hindering shrinkage on Casting: metal mold or metal core has no yielding property during casting solidification, which hi