It is known as a small CNC milling machine. It is a new type of machining equipment. Machine itself configuration of high accuracy electronic control unit and the feed system, by performing the workpiece processing program, can complete including complex curved surface and sphere of each type of artifacts, such as a variety of concentration processes. The workpiece machining, a line of processing personnel don't have to be actual manipulation of the machine tool, just after the machine to complete a process, change is suitable for processing of next working procedure of cutting tool can, until the final completion of discharge.
Thus it can be seen that the workpiece on the small CNC milling machine processing, the factors that affect the final machining precision and machining efficiency, is no longer a line processing personnel handling capacity and processing experience, and the quality of workpiece processing program is using. In a nutshell, workpiece numerical control programming can be divided into manual programming and computer-aided programming, which is also called automatic programming, depending on the programming approach.
Manual programming requires a lot of operation and code entry, so it is only suitable for nc machining of some simple or single parts. At present, automatic programming is its main method. It is accomplished through computer and special programming software, and the commonly used programming software is CAD/CAM programming software. This kind of software has a weak post-processing capability, so optimizing automatic programming is necessary. This paper briefly introduces the principles and methods of automatic programming optimization of nc machining program for small numerical control milling machines.
The principle of automatic programming optimization should be followed
We know that the small nc milling machine performs the entire process by executing the workpiece's processing program. A good machining procedure can not only guarantee the machining of the required workpiece, but also give full play to the function of the machine and make it safe, reliable and efficient. Now, the processing program developed by CAD/CAM software requires some optimization due to the limitations of the software itself. The purpose of optimization is to ensure the final machining accuracy, machining efficiency and the processing performance of the machine. Therefore, the following principles should be followed:
Firstly, the optimization should ensure the correctness of the processing procedure, so that the quality of the workpiece is stable. Secondly, the processing procedure should be easy to debug and modify, readability should be high; The stability of the program should be good. When the tool radius changes or the position of the workpiece changes, the whole procedure should not be modified. In addition, the optimization should ensure that the application of the processing procedure, when there is an artifact similar to the processing shape, can be used with only a few key dimensions.
2. Automatic programming optimization method
CAD/CAM automatic programming is now small CNC milling machine CNC processing main preparation methods, in addition to automatically generate the program code, it is that it has a strong graphics mathematical processing function, dispense with the manual programming in the tedious mathematical calculation, reduces the programming operation of labor, at the same time you can prepare some complex shaped workpiece of artificial hard to finish the CNC program. We mainly focus on the following methods:
1. Make use of the system space tool radius compensation function
CAM software generally generates the machining procedure of the straight line motion of the blade when the small nc milling machine is processed in the complex surface. If you want to change the tool, you must change the program, causing inconvenience to the processing. The CAM software should generate the core vector at the same time as the surface generation program, the actual position of the knife center is calculated by the system. In this way, the tool radius is adjustable within a certain range and is convenient for processing.
2. Try to replace linear approximation with arc interpolation function
In surface machining, CAM software is generally used in the machining process of generating workpiece. If symmetrical shape is used, the number of program segments will decrease sharply and improve efficiency.
3. Simplified programming using subroutine functions
Generally, CAM programming software has the function of subroutine processing program, which is programmed by the nc system and the function of subroutine call. There is a large amount of numerical computation work in the subroutine, which can be completed by CAM software. This can reduce the programming amount of the processing program, which is beneficial to the machining efficiency of small CNC milling machine.