大型铸件精确度的问题具有极大的实际意义.现在工业上所采用的制造方法还不能保证大型铸件获得一定程度的尺寸精确度和表面光洁度.假如能够的话那末将可大大地减少机械加工的数量.由于上述原因,铸件上的机械加工余量与名义尺寸允许偏差将导致大量的金属消耗,因之也增加了铸件的重量. The problem of large-scale casting accuracy is of great practical importance, and the manufacturing methods used in industry today do not yet guarantee a degree of dimensional accuracy and surface finish for large castings, which would greatly reduce the number of machining Due to the above reasons, the allowable deviation of the machining allowance from the nominal size of castings will lead to a large amount of metal consumption, thus increasing the weight of the castings.