With the rapid development of science and technology, society has higher and higher requirements for the structure, performance, precision, efficiency, and variety of mechanical products and the proportion of single and small-batch products is increasing. Traditional general-purpose and special-purpose machine tools and process equipment can not meet the requirements of high quality and diversified processing.
And NC machine tool as the electronic information technology and traditional machining technology combined with the product of modern precision machinery, computers, communications, hydraulic pneumatic, such as photoelectric co., LTD. Is a multidisciplinary technology, can effectively solve the complex, precision, small-batch and changeable parts processing, can meet the high quality, benefit, and many varieties, small batch mode of flexible production requirements, adapt to the needs of all kinds of mechanical products quickly upgrade, represents the trend and trend in today’s machining technology.
Because of its high precision and high flexibility, CNC lathe has been widely used in the mechanical manufacturing industry and has become one of the widely used CNC machine tools. However, to give full play to the role of CNC lathe, the key is programming, that is, according to the characteristics of different parts and precision requirements, the preparation of a reasonable, processing procedures. The commonly used NC programming methods are manual programming and automatic programming. Manual programming refers to the programming process which is mainly completed by a human from the parts drawing analysis process, data calculation, programming sheet, input program to program verification.
It is suitable for point processing or geometric shape is not too complex parts processing, and the calculation is relatively simple, the program section is not much, the programming is easy to achieve the occasion. For parts with complex geometric shapes and parts with a large amount of programming which are not complicated geometric elements, manual programming is difficult to complete, so automatic programming is adopted.
According to different requirements and combined processing drawings, traditional processing can not meet the requirements of sufficient accuracy. For example, in the processing requirements of high precision with the parts, this is often in the CNC machine to complete processing. Special attention should be paid to the fitting tolerance when the matching parts are programmed manually. The so-called tolerance means that after finishing the processing, the machining accuracy is within the range specified in the drawing, and the parts can be combined. Therefore, we should pay attention to the following questions when programming manually:
(I) correct selection of program origin
In numerical control turning programming, the first point on the workpiece is selected as the origin of the numerical control program, and based on the origin to establish a workpiece coordinate system. The reasonable determination of the coordinate system of the workpiece is very important to the workpiece alignment in NC programming and machining. The selection of program origin should meet the requirements of simple programming, small size conversion, and small machining error. In order to improve the machining accuracy of parts, convenient calculation, and programming, we usually set the program origin at the intersection of the workpiece axis and the workpiece front end face, back end face and the front end face of the jaw, try to make the programming benchmark coincide with the design and assembly benchmark.
(2) reasonable choice of feeding route
Feed route is the movement path of the tool in the whole machining process, that is, the tool starts from the point of feed movement, until the end of the machining program back to the point and the path, is one of the important basis for programming. It is very important to choose the feed route reasonably for NC machining
Accurately grasp the various circular cutting instructions
(3) of the processing characteristics and the impact of the workpiece machining accuracy, and make a reasonable choice in FANUC0 – TD in the CNC system, CNC lathe more than ten cutting circulation processing instruction, each order has its processing characteristics, the machining precision of workpiece processing after is also different, their programming method is different also, when we are choosing to careful analysis, a reasonable choice, strive for the processing of high precision parts
(4) flexible use of special G code to ensure the processing quality and accuracy of parts