xiehe model

The wide application of precision CNC machining technology in my country's manufacturing industry has made more and more precision machining practitioners pay more attention to it. However, due to the complexity of CNC machining technology, operators need to learn in advance. In particular, the analysis of the machining process of cnc parts involves a wide range of areas. This paper analyzes the possibility and convenience of CNC precision machining.

First of all, the dimension data on the part drawing should be given according to the principle of programming convenience.

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

On the part drawing, the same reference engraving size or the coordinate size is given directly. This marking method is very helpful for the convenience of programming and 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.

Since part designers generally take into account the use characteristics such as assembly in the process of dimensioning, they have to adopt the method of partial scattered labeling, which brings a lot of inconvenience to process arrangement and CNC machining. Due to the high precision of CNC machining and repeated positioning, the use characteristics will not be destroyed due to the large cumulative error, so the local dispersion notation can be changed to the same reference engraving size or the coordinate method that directly gives the coordinates.

2. The conditions of the geometric elements constituting the outline of the part should be sufficient

During manual programming, the base point or node coordinates need to be calculated. In the case of automatic programming, define the geometric elements that make up the outline of the part. 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 array, but according to the dimensions given in the figure, when the tangent condition is calculated, it becomes either intersected or separated. Programming cannot be done due to insufficient conditions that make up the part geometry. This situation requires consultation with the part designer.

3. The structural machinability of the parts processing parts should conform to the characteristics of CNC machining

(1) The cavity and shape of the part should preferably have a uniform geometry and size. This reduces tool size and tool changes, making programming easier and increasing productivity.

(2) The size of the rounded corner of the inner groove determines the diameter of the tool, so the radius of the rounded corner of the inner groove 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 coupling arc.

(3) When the parts are ground on the bottom surface, the corner radius of the groove bottom should not be too large.

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