1. Dimensional annotation should comply with the characteristics of CNC machining

In CNC programming, all dimensions and positions of points, lines, and surfaces are based on the programming origin. Therefore, the coordinate dimensions should be directly provided on the part drawing, or the dimensions should be annotated with the same reference as much as possible.

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

In programming, programmers must fully grasp the geometric element parameters that make up the contour of the part and the relationships between each geometric element. Because all geometric elements of the part contour need to be defined during automatic programming, and the coordinates of each node need to be calculated during manual programming. Regardless of which point is unclear or uncertain, programming cannot proceed. However, due to inadequate or overlooked consideration by part designers during the design process, incomplete or unclear parameters often occur, such as whether the arc is tangent, intersecting, or apart from the line or arc. So when reviewing and analyzing drawings, it is important to be careful and promptly contact the design personnel if any problems are found.

3. Reliable positioning reference

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

4. Unified geometric type or size

The appearance and inner cavity of the parts adopt a unified geometric type or size, which can reduce the number of tool changes, and may also apply control programs or specialized programs to shorten the program length. The shape of the parts should be as symmetrical as possible to facilitate programming using the mirror oriented machining function of CNC machine tools, in order to save programming time.