This kind of precision machining method reports the working size of the wool or the last process processing is divided into n groups according to the size of the error, and the size error range of each group of parts is reduced to the original /n; Then adjust the position of the tool relative to the workpiece according to the error range of each group, so that the center of the size dispersion range of the named component is basically the same.

In order to greatly reduce the size dispersion range of the whole batch of workpieces. This method is often more economical and easier than increasing the accuracy of vigilance. For example, when finishing the tooth shape, in order to ensure the coaxiality of the tooth ring and the inner hole of the gear after processing, the matching gap between the gear and the mandrel should be reduced.

In the production, it is often grouped according to the size of the gear, and then matched with the corresponding group mandrel, which evenly divides the original error caused by the gap, and improves the position accuracy of the gear ring. This method is essentially to transfer the geometrical errors, mechanical deformation and thermal deformation of the process system to the direction that does not affect the machining accuracy.

For example, for a multi-station process with indexing or transposing or a process processed by a transposing tool holder, the indexing and transposing errors will directly affect the processing accuracy of the relevant surface of the part. In processing and equipment matching, some accuracy involves the relationship between parts and components, which is quite complex.

If you blindly improve the accuracy of the parts themselves, sometimes it is not only difficult or even impossible, but the use of local processing can solve this problem. The main points of local processing: To ensure the position relationship between the parts, use a part to install a tool to process a part in such a position relationship. For example, in the manufacture of hexagonal laths, the axis of the large holes of the six mounting tool holders on the turret must ensure that the machine tool and the spindle rotation line coincide, and the end face of the large holes must be perpendicular to the spindle rotation line.