Process analysis

The NC machining process of machined parts involves a wide range. The following puts forward some main contents to be analyzed and reviewed in combination with the possibility and convenience of programming.

1. The dimensions shall conform to the characteristics of NC machining

In NC programming, the dimensions and positions of all points, lines and surfaces are based on the programming origin. Therefore, the coordinate dimensions shall be directly given on the part drawing, or the dimensions shall be introduced with the same datum as far as possible.

2. The conditions of geometric elements shall be complete and accurate

In programming, programmers must fully grasp the geometric element parameters constituting the part contour and the relationship between various geometric elements. Because all geometric elements of part contour should be defined during automatic programming, and the coordinates of each node should be calculated during manual programming. No matter which point is unclear or uncertain, programming cannot be carried out. However, due to the poor consideration or neglect of part designers in the design process, there are often incomplete or unclear parameters, such as whether arc and straight line, arc and arc are tangent or intersecting or separated. Therefore, when reviewing and analyzing drawings, we must be careful and contact the designers in time if any problems are found.

3. Reliable positioning datum

In NC machining, the machining processes are often concentrated, and it is very important to locate with the same benchmark. Therefore, it is often necessary to set some auxiliary benchmarks or add some process bosses on the blank.

4. Uniform geometric type or size

The shape and inner cavity of parts adopt unified geometric type or size, which can reduce the number of tool changes. Control programs or special programs may also be applied to shorten the program length. The shape of the parts shall be as symmetrical as possible, which is convenient for programming by using the mirror machining function of the NC machine tool, so as to save programming time.