What is CNC Machining Accuracy?

CNC Machining accuracy is the conformance between the actual size, shape, position of the processed parts surface and the drawing requirements. So according to the actual situation and the ideal parameters, it can be divided into dimensional accuracy, form accuracy and positional accuracy.

Usually in the design of machine parts and specify the machining accuracy of parts, especially precision parts and important surfaces of parts, the requirement of form accuracy should higher than positional accuracy，and the requirement of positional accuracy should higher than dimensional accuracy.

The deviate value of the actual and ideal geometric parameters of parts is called machining error. Machining accuracy and machining error are both terminology for evaluating geometric parameters of machined surfaces. Grade of tolerance was divided into a total of 20 levels from IT01, IT0, IT1, IT2 to IT18. Among them IT01 express the highest machining accuracy, and the IT18 is the least. Machining accuracy is measured by tolerance grade. The smaller the grade value is, the higher the accuracy is. Machining error is represented by numerical value. The larger the numerical value is, the larger the error is. So High machining accuracy means small machining error and vice versa.

The actual parameters obtained by any machining method are not absolutely accurate. So for the function of the parts, as long as the machining error is within the tolerance range required by the part drawing, it is consider that the processing accuracy is guaranteed.