CNC machining is a process that is widely used in the machinery industry. It refers to the process of machining parts on CNC machine tools. In CNC machining, CNC machine tools, CNC systems, etc. are used. CNC machine tools are computer-controlled machine tools. The instructions of the CNC system are determined by the programmer according to the material of the workpiece, the machining requirements, the characteristics of the machine tool and the system. A set of instructions prepared in the prescribed instruction format.
1. Advantages of CNC machining
(1) A large number of tooling reductions are required, and complicated tooling is required without machining complicated shapes. 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 new product development and modification.
(2) The processing quality is stable, the processing precision is high, the repeating precision is high, and it is suitable for the processing requirements of the aircraft.
(3) High production efficiency in multi-variety and small-volume production, which can reduce the time for production preparation, machine tool adjustment and process inspection, and reduce cutting time due to the use of the best cutting amount.
(4) It is possible to process complex profiles that are difficult to machine by conventional methods, and even process parts that cannot be observed.
2. CNC machining process
(1) Dimensions should conform to the characteristics of CNC machining
In NC programming, the size and position of all points, lines, and faces are based on the programmed origin. Therefore, it is best to give the coordinate size directly on the part drawing, or try to use the same reference size.
(2) The conditions of geometric elements should be complete and accurate
In programming, the programmer must fully understand the geometric feature parameters that make up the contour of the part and the relationship between the geometric features, because all geometric elements of the part's outline are defined during automatic programming, and each node is calculated during manual programming. The coordinates of the coordinates, no matter which point is not clear or uncertain, programming can not be done. However, due to the inconsistency or neglect of the part designer during the design process, the parameters are often incomplete or unclear, such as arcs and lines, arcs and arcs are tangent or intersect or separate. Therefore, when reviewing and analyzing drawings, be sure to carefully check the problems and contact the designer in time.
(3) Reliable positioning criteria
In CNC machining, the machining process is often concentrated, and positioning with the same reference is very important. It is therefore often necessary to set up some auxiliary references or to add some process bosses to the blank.
(4) Unified geometry type or size
The shape and inner cavity of the part are preferably of a uniform geometry type or size, which reduces the number of tool changes, and may also use a control program or a dedicated program to shorten the program length. The shape of the part is as symmetrical as possible, which is easy to program with the mirror machining function of the CNC machine to save programming time.
3. The principle of sequential arrangement of CNC machining
(1) The processing of the previous process cannot affect the positioning and clamping of the next process.
(2) First, inside and outside, that is, the internal cavity is processed first, and then the shape is processed.
(3) It is preferable to carry out the same process of installing or using the same tool, preferably continuously.
(4) In the same installation, the process that has less influence on the rigidity of the workpiece should be performed first.