影响精密铸造件尺寸精度的因素 The factors affecting precision casting precision are edited 一般情况下，精密铸造件尺寸精度是受铸件结构、铸件材质、制模、制壳、焙烧、浇注等多方因素影响的，其中任何一个环节设置、操作不合理都会使铸件的收缩率产生变化，导致铸件尺寸精度与要求有偏差。以下是可造成精密铸件尺寸精度缺陷的因素： In general, precision casting parts dimensional accuracy is influenced by structure of casting, casting material, moulding, shell making, roasting, pouring the influence of various factors, such as any one link set, unreasonable operation can make the casting shrinkage rate of change, has led to the deviation of dimension accuracy of castings and requirements. Here are some factors that can cause precision casting dimensions: （1）铸件结构的影响：a. 铸件壁厚，收缩率大，铸件壁薄，收缩率小。 b. 自由收缩率大，阻碍收缩率小。 (1) the effect of casting structure: a. The casting wall is thick, the shrinkage rate is large, the casting wall is thin, and the shrinkage rate is small. B: the free systolic rate is large and the shrinkage rate is small. （2）铸件材质的影响：a. 材料中含碳量越高，线收缩率越小，含碳量越低，线收缩率越大。 b. 常见材质的铸造收缩率如下：铸造收缩率K=(LM-LJ)/LJ×100%， LM为型腔尺寸，LJ为铸件尺寸。K受以下因素的影响：蜡模K1、铸件结构K2、合金种类K3、浇注温度K4。 (2) the effect of the casting material: the higher the carbon content in the material, the lower the line shrinkage, the lower the carbon content, and the greater the line contraction. The casting shrinkage rate of common materials is as follows: the casting shrinkage ratio K = (LM - LJ)/LJ * 100%, LM is the size of the cavity, LJ is the casting size. K is affected by the following factors: wax modulus K1, casting structure K2, alloy type K3, casting temperature K4. （3）制模对铸件线收缩率的影响：a.射蜡温度、射蜡压力、保压时间对熔模尺寸的影响以射蜡温度最明显，其次为射蜡压力，保压时间在保证熔模成型后对熔模最终尺寸的影响很小。 b.蜡(模)料的线收缩率约为0.9-1.1%。 c.熔模存放时，将进一步产生收缩，其收缩值约为总收缩量的10%，但当存放12小时后，熔模尺寸基本稳定。 d.蜡模径向收缩率仅为长度方向收缩率的30-40%，射蜡温度对自由收缩率的影响远远大于对受阻收缩率的影响(最佳射蜡温度为57-59℃，温度越高收缩越大)。 (3) the influence of the molding shrinkage of casting line: a. wax wax temperature, pressure, the influence of the holding time of molten mould size to wax mould temperature is the most obvious, followed by radiation pressure of wax, the holding time in melt after mould for casting the influence of the final size is very small. The rate of shrinkage of wax is about 0.9 to 1.1%. When the mold is deposited, it will contract further, the contraction value is about 10% of the total shrinkage, but after 12 hours, the mould size is basically stable. D. wax models of radial shrinkage rate was only about the length direction shrinkage rate of 30-40%, shooting wax temperature effect on the free shrinkage rate is much greater than stuck to the influence of shrinkage (optimum temperature for 57 ℃, 59 - the higher the temperature the greater the shrinkage).