机械加工厂强调机械加工要满足一定的精密度，是指钢件在机械加工后的实际上几何图形主要参数与零件图纸所要求的理想化值的相一致的水平。而他们中间不相一致的水平，则称之为生产加工偏差。

 

机械加工厂生产加工精密度包含3个层面：一方面是规格精密度，限定生产加工表层两者之间标准标准间规格偏差不超出必须的范畴；另一方面几何图形样子精密度，限定生产加工表层的宏观经济几何图形样子偏差，如圆度、圆柱度、平行度和直线度等。

 

还有一方面则是互相部位精密度，限定机械加工厂生产加工表层两者之间标准间的互相部位偏差，如同轴度、平整度和平行度等。生产加工精密度是生产加工后零部件表层的实际上规格、样子、部位几种几何图形主要参数与工程图纸规定的理想化几何图形主要参数的合乎水平。

 

理想化的几何图形主要参数，对规格来讲，是说均值规格；对表层几何图形样子来讲，是说的圆、圆柱体、平面图、球面和平行线等；对表层中间的互相部位来讲，是说的平行面、竖直、同轴输出、对称性等。

 

机械加工厂生产零部件实际上几何图形主要参数与理想化几何图形主要参数的偏移标值称之为生产加工偏差。生产加工精密度与生产加工偏差全是点评生产加工表层几何图形主要参数的专业术语。生产加工精密度用公差等级考量，等級值越小，其精密度越高；生产加工偏差用标值表达，标值越大，其偏差越大。

Machining plant emphasizes that machining must meet certain precision, which means that the actual geometry parameters of the steel parts after machining are consistent with the idealized values required by the part drawings. The level of inconsistency between them is called production-processing bias. There are three levels of manufacturing precision in a machining plant: On the one hand is the precision of the specifications, which limits the standard deviation between the production and the processing surface to be within the necessary range; on the other hand is the precision of the geometric patterns, limit the appearance deviation of macro-economic geometries, such as roundness, cylindricity, parallelism and straightness. On the other hand is the precision of each other's parts, limit the deviation between the two standard parts, such as coaxiality, flatness and parallelism, etc. . The precision of production processing is that the main parameters of the actual specification, shape and position of the surface layer of the parts are in line with the main parameters of the idealized geometry stipulated in the engineering drawings. The main parameters of an idealized geometric figure are, in the case of a specification, mean size; in the case of a surface geometric figure, circles, cylinders, plans, spheres, and parallel lines; and in the case of the mutual parts between the surfaces, it is said that the parallel plane, vertical, coaxial output, symmetry and so on. The offset of the main parameters of the actual geometry and the idealized geometry of the parts produced by the machining plant is called the production deviation. Production processing precision and production processing deviation is the evaluation of the production process surface geometric parameters of the main terms. The production process precision is considered by tolerance grade, the smaller the grade value, the higher the precision, and the production process deviation is expressed by standard value, the larger the standard value, the greater the deviation.