How to ensure machining accuracy in machining?(2)

The error of the fixture mainly refers to:

(1) positioning elements. Tool guiding elements. Indexing mechanism, clamping specific and other manufacturing errors;

(2) fixture assembly, the relative dimensional errors between the working surfaces of the above components;

(3) fixture in the process of use of the work surface wear;

(4) process error refers to the workpiece in the process of processing.

If these deformations are not taken into account during the machining process, they will affect the workpiece coordinate system that has been adjusted in the process system.

How to improve the accuracy of machining

1, Adjust the process system. Through the test cut measurement size to adjust the tool cutting and then test cut, so repeatedly until the required size. This method of low production efficiency, mainly for single-piece small batch production. By pre-adjusting the machine tool, fixture workpiece and the relative position of the tool to obtain the required size. This method of high productivity, mainly for mass production.

2, reduce machine errors: (1) improve the manufacturing accuracy of spindle components. Should improve the rotary accuracy of the bearing, should improve the accuracy of the bearing accessories. (2) the rolling bearing appropriate preload: ① can eliminate clearance; ② increase bearing stiffness; ③ homogenize the rolling body error. (3) so that the spindle rotation accuracy is not reflected to the workpiece.

3, reduce transmission chain drive error. The number of transmission parts is small, the transmission chain is short, and the transmission accuracy is high;

4, Reduce tool wear. The tool must be resharpened before the tool size wear reaches the sharp wear stage;

5, Reduce the deformation of the process system mainly from: (1) improve the stiffness of the system, especially to improve the stiffness of the weak link in the process system; (2) reduce the amount of tool holding, according to the material of the workpiece to choose a reasonable amount of tool eating.

As can be seen, the accuracy of each link in machining cannot be ignored, but the accuracy of the tool accounts for a large part of it. Therefore, it is important to ensure the original accuracy of the tool and the wear resistance of the tool. If only the original accuracy of the tool is high, but in the process of use, due to tool wear and frequent tool changes, the workpiece accuracy will also be affected.