How to do technical analysis of CNC precision machined parts

The extensive application of CNC precision machining technology in China’s manufacturing industry has made more and more precision machining practitioners pay more attention to this. However, due to the complexity of CNC machining technology, operators need to learn in advance. In particular, the machining process analysis of CNC parts has a wide range of aspects. This paper analyzes the possibility and convenience of CNC precision machining.

First, the size data on the part drawing should be given in accordance with the principle of convenient programming.

1. The dimensioning method on the part drawing should be adapted to the characteristics of CNC machining.

On the NC machining part drawing, the same reference engraving size or directly giving the coordinate size, this marking method is very helpful for the convenience of programming, and also contributes to the coordination between the dimensions. In particular, it is very convenient to maintain the consistency of design basis, process reference, test reference and programming origin setting.

CNC precision machining

Since the part designer generally takes into account the use characteristics such as assembly in the process of dimensioning, the partial dispersion labeling method has to be adopted, which brings a lot of inconvenience to the process arrangement and the numerical control processing. Since the numerical control machining precision and the repetitive positioning accuracy are high, the use characteristics are not destroyed due to a large accumulation error, so the local dispersion notation method can be changed to the same reference engraving size or the coordinate method directly giving the coordinate size…

2. The conditions for the geometric elements that make up the contour of the part should be sufficient

When doing manual programming, you need to calculate the base point or node coordinates. In the case of automatic programming, the geometric elements that make up the contour of the part are defined. Therefore, in the analysis of the part drawing, it is necessary to analyze whether the conditions given by the geometric elements are sufficient.

For example, an arc and an arc are tangent to the pattern, but according to the dimensions given in the figure, when the tangency condition is calculated, it becomes an intersecting or dissociating state. Because the conditions that make up the geometry of the part are not sufficient, programming can’t be done. This situation needs to be negotiated with the part designer.

Second, the structural processability of each processing part of the part should meet the characteristics of CNC machining

1. The internal cavity and shape of the part are preferable of uniform geometry and size. This can reduce the tool size and the number of tool changes, making programming easier and improving production efficiency. Precision machining

2, the size of the inner groove rounding determines the size of the tool diameter, so the inner groove fillet radius should not be too small. The quality of the part is related to the height of the contour to be machined and the radius of the adapter arc.

3. When the part is ground in the bottom plane, the corner radius of the groove bottom should not be too large.

4. It is best to use a uniform standard positioning. In CNC machining, if there is no uniform reference positioning, the contour position and size of the two faces after machining will be uncoordinated due to the re-installation of the workpiece.