1. The advantages and disadvantages of CNC machining
(1) The number of tooling is greatly reduced, and machining of parts with complex shapes does not require complicated tooling. If you want to change the shape and size of the part, you only need to modify the part processing program, which is suitable for the development and modification of new products.
(2) The processing quality is stable, the processing accuracy is high, and the repeat accuracy is high, which is suitable for the processing requirements of the aircraft.
(3) The production efficiency is higher in the case of multiple varieties and small batch production, which can reduce the time for production preparation, machine tool adjustment and process inspection, and the cutting time is reduced due to the use of cutting volume.
(4) It can process complex profiles that are difficult to process with conventional methods, and even process some unobservable processing parts.
Disadvantages: machine tool equipment is expensive, requiring maintenance personnel to have a high level.
2. The technology of CNC machining
(1) The dimensions should be consistent with the characteristics of CNC machining
In CNC programming, the size and position of all points, lines, and areas are based on the origin of the programming. Therefore, the coordinate dimensions are given directly on the part drawing, or the dimensions are quoted with the same reference as far as possible.
(2) The conditions of geometric elements should be complete and accurate
In the process of programming, programmers must fully grasp the parameters of the geometric elements that constitute the part outline and the relationship between the geometric elements, because all the geometric elements of the part outline must be defined during automatic programming, and each node must be calculated during manual programming The coordinates of, no matter what point is unclear or uncertain, programming can not be carried out. However, due to inadequate consideration or neglect in the design process of the part designer, the parameters are often incomplete or unclear, such as whether the arc and the straight line, the arc and the arc are tangent or intersecting or separated. Therefore, when reviewing and analyzing the drawings, you must be careful, and if you find a problem, contact the designer in time.
(3) Reliable positioning reference
In CNC machining, the processing procedures are often concentrated, and positioning on the same reference is very important. Therefore, it is often necessary to set some auxiliary benchmarks or add some process bosses on the blank.
(4) Uniform geometry type or size
The shape and internal cavity of the parts adopt a unified geometric type or size, which can reduce the number of tool changes, and may also use control programs or special programs to shorten the length of the program. The shape of the parts is as symmetrical as possible, which is convenient for programming using the mirror processing function of the CNC machine tool, so as to save programming time.