What are the relationship issues between precision parts processing errors and accuracy

The machining accuracy of precision parts refers to the degree to which the actual size, shape, and position of the machined part surface meet the ideal geometric parameters required by the drawing. The ideal geometric parameter, in terms of size, is the average size; For surface geometry, it refers to absolute circles, cylinders, planes, cones, and straight lines; For the mutual positions between surfaces, it means absolute parallelism, verticality, coaxiality, symmetry, etc.

Processing accuracy is mainly used to produce products, and both processing accuracy and processing error are terms used to evaluate the geometric parameters of the processed surface. The machining accuracy is measured by tolerance level, and the smaller the level value, the higher its accuracy; The machining error is represented by numerical values, and the larger the numerical value, the greater the error. High machining accuracy means small machining errors, and vice versa.

There are a total of 20 tolerance levels from IT01, IT0, IT1, IT2, IT3 to IT18. Among them, IT01 represents the highest machining accuracy of the part, and IT18 represents the lowest machining accuracy of the part. Generally, IT7 and IT8 are of medium machining accuracy.

The actual parameters obtained by any machining method will not be absolutely accurate. From the perspective of the function of the part, as long as the machining error is within the tolerance range required by the part drawing, it is considered to ensure the machining accuracy.

The quality of a machine depends on the machining quality of the parts and the assembly quality of the machine. The machining quality of precision parts includes two major parts: machining accuracy and surface quality.