What is the concept of CNC machining precision parts?

The machining accuracy of CNC machining center is the main concern of customers. The machining accuracy of a CNC machining center refers to the degree of precision of the produced product. In the machining industry, machining accuracy and machining error are both terms for evaluating the geometric parameters of the machined surface of the part. Machining accuracy is measured by tolerance grade, the smaller the grade value, the higher the accuracy. The machining error is expressed by a numerical value. The larger the numerical value, the greater the error. It can usually be understood that the machining accuracy is high, and the machining error is small at the same time.

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There are 20 tolerance grades for parts processing using CNC machining centers from IT01, IT0, IT1, IT2, IT3 to IT18. IT01 indicates the highest machining accuracy of the part, and IT18 indicates the lowest machining accuracy of the part .

The actual parameter results obtained by any machining method in the machining industry are not 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, the machining accuracy can be considered qualified.

2. What’s included in the machining accuracy of the machining center

1) Dimensional accuracy of parts
Refers to the degree of conformity between the actual size of the part processed by the machining center and the center of the tolerance zone of the part size.

2) Shape accuracy
Refers to the degree of conformity between the actual geometric shape of the surface of the part processed by the machining center and the ideal geometric shape.

3) Position accuracy
Refers to the difference in actual position accuracy between the relevant surfaces of the parts processed by the machining center.

4) Mutual relations
Generally, when designing machine parts and specifying the machining accuracy of parts, attention should be paid to control the shape error within the position tolerance, and the position error should be less than the dimensional tolerance. Or it can be understood as a precision part or an important surface of a part. The shape accuracy requirement should be higher than the position accuracy requirement, and the position accuracy requirement should be higher than the dimensional accuracy requirement.