CNC machining is a process that is widely used in the machining industry, which refers to the process of machining parts on CNC machine tools. CNC machining, CNC machine tools will be used, CNC system, CNC machine tool is a kind of computer to control the machine tool, and CNC system instructions by the programmer based on the workpiece material, processing requirements, machine tool features and systems A set of instructions prepared by the prescribed instruction format.

1. CNC machining advantages and disadvantages

advantage:

(1) a substantial reduction in the number of tooling, machining complex shape parts do not require complex tooling. To change the shape and size of parts, only need to modify the parts processing procedures, for new product development and modification.

(2) stable processing quality, high precision, high repetition accuracy, to meet the processing requirements of the aircraft.

(3) The high production efficiency in many varieties and small series can reduce the time of production preparation, machine adjustment and process inspection, and reduce the cutting time by using the best cutting amount.

(4) Machinable complex surfaces that are difficult to machine in conventional methods, and even unobservable machining parts.

Disadvantages: expensive machine tools and equipment, maintenance personnel required a high level.

2. CNC machining technology

(1) Dimensioning should be consistent with the characteristics of CNC machining

In NC programming, the size and position of all points, lines and planes are based on the programmed datum. Therefore, the best parts of the map directly to the size of the coordinates, or as much as possible with the same benchmark cited size.

(2) The conditions of geometric elements should be complete and accurate

In programming, the programmer must have full knowledge of the geometric element parameters that make up the contour of the part and the relationships among the geometrical elements, since all the geometric elements of the part outline are defined during automatic programming, and each node is calculated manually Of the coordinates, no matter what point is not clear or uncertain, programming can not be carried out. However, due to poor or neglected parts designers in the design process, the parameters often appear incomplete or unclear, such as arcs and straight lines, arcs and arcs are tangential or intersect or phase separation. Therefore, in the review and analysis of drawings, we must carefully and find the problem in a timely manner with the designer.

(3) Reliable positioning

In CNC machining, machining processes tend to be more focused on the same benchmark positioning is very important. Therefore often need to set some auxiliary benchmarks, or increase in the blank some process boss.

(4) uniform geometric type or size

Parts of the shape, the cavity is best to use a uniform geometric type or size, so you can reduce the number of tool change, but also may apply control programs or special procedures to shorten the length of the program. The shape of the part is as symmetrical as possible to facilitate the use of the mirror-processing functions of CNC machines to save programming time.

3. CNC machining order of arrangement principle

(1) The processing of the upper working procedure can not affect the positioning and clamping of the lower working procedure.

(2) first inside and outside, that is, the first internal cavity processing, after the shape of the processing.

(3) The same process of installing or using the same tool is best done continuously.

(4) In the same installation, should be carried out on the workpiece less rigid process.