xiehe model

The machining accuracy and machining error of CNC parts are terms for evaluating the geometric parameters of the machining surface. However, the actual parameters obtained by any processing method are not absolutely accurate. From the perspective of the function of the part, as long as the machining error of the part is within the tolerance range required by the part drawing, the machining accuracy can be considered.

Accuracy refers to the degree to which the actual geometric parameters (size, shape and position) of the processed part are consistent with the ideal geometric parameters. The difference between them is called machining error. The machining error reflects the machining accuracy. The larger the error, the lower the machining accuracy, and the smaller the error, the higher the machining accuracy.

The following briefly introduces 7 methods to improve the machining accuracy of CNC parts:

Process system adjustment:

1. The adjustment of the trial cutting method is through a series of processes of "trial cutting - measuring size - adjusting the cutting amount of the tool - cutting - re-cutting", which can be repeated until the required size is reached. However, this method has low production efficiency, so it is mainly used for single piece and small batch production.

2. Adjustment method The adjustment method is to obtain the required size by pre-adjusting the relative positions of the machine tool, fixture, workpiece and tool. However, due to its high productivity, this method is mainly used for large-scale production.

3. To reduce the error of the machine tool, in order to improve the manufacturing accuracy of the main shaft parts, the rotation accuracy of the bearing should be improved:

① Select high-precision rolling bearings.

② High-precision multi-oil wedge dynamic pressure bearings are used.

③ High-precision hydrostatic bearings.

4. Improve the accuracy of bearing accessories:

① It can improve the machining accuracy of the box support hole and the main journal.

② It can improve the machining accuracy of the bearing mating surface.

③ By measuring and adjusting the radial runout range of the corresponding parts, errors can be compensated or offset.

5. Rolling bearings need to be properly preloaded:

① The gap can be eliminated.

② Improve bearing rigidity.

③ The uniform rolling element is wrong.

6 Reduce the transmission error of the transmission chain:

① Fewer transmission parts, short transmission chain, high transmission precision.

② The use of deceleration transmission is an important principle to ensure transmission accuracy. The closer the transmission pair is to the end, the smaller the transmission ratio.

③ The precision of the end piece needs to be higher than that of other transmission components.

In order to reduce tool wear, it is necessary to regrind the tool before the tool size wear reaches the sharp wear stage.