(1) Analysis and analysis of common machine tool workpiece pattern
Material, shape, size, accuracy, blank shape and heat treatment requirements of the workpiece. , to determine whether the parts are suitable for machining on CNC machine tools, or which type of CNC machine tools are suitable for machining. Only those parts with small batch, complex shape, high precision and short production cycle are suitable for NC machining. At the same time, the content and requirements should be clear.
(1) Determine the processing technology of ordinary machine tools.
On the premise of comprehensive analysis of parts drawings, the processing methods (such as fixture and clamping positioning method), processing routes (such as tool alignment, tool change point and feed route) and cutting parameters (such as feed speed, spindle speed, cutting width and cutting depth) of parts are determined. When making NC machining technology, besides considering the rationality and economy of NC machine tools, the following factors must also be considered: the fixture used should be easy to install and coordinate the dimensional relationship between workpiece and machine tool coordinate system; The tool alignment point should be selected in the position where it is easy to find the right well and check it when machining; The feed route should be as short as possible to facilitate numerical calculation and safe and reliable machining. ?
(3) Numerical calculation of common machine tools
According to the workpiece diagram and the determined machining route and cutting parameters, the input data required by the NC machine tool are calculated. Numerical calculation mainly includes calculating the base point and node coordinates of the workpiece contour.
(4) Write the processing program sheet of common machine tool parts.
According to the machining route, the coordinate values of tool path are calculated, the cutting parameters and auxiliary actions are determined, and the parts machining program sheet is written segment by segment according to the instruction code and program segment format specified by the numerical control device. Programmers must be very familiar with the performance, programming instructions and codes of the CNC machine tools used in order to correctly write processing programs.
(5) ordinary machine tool program input numerical control system.
After the program list is compiled, it needs to be input into the numerical control system through certain methods. There are three commonly used input methods: ① Manual data input. According to the contents of the program sheet, the number, letter and symbol keys on the keyboard of the numerical control system are used for auxiliary input, and the contents are displayed by CRT for inspection. In other words, the contents of the program table are directly manually input into the numerical control system through the keyboard of the numerical control system. ② Input with control medium. The control media are mostly perforated paper tape, magnetic tape, magnetic disk, etc. The program code on the perforated paper belt is input into the numerical control system through the photoelectric reader to control the work of the numerical control machine tool. Magnetic tapes and disks are input into the numerical control system through tape recorders, disk drives and other devices. ③ Input through machine tool communication interface. Through the cable connected with the communication interface controlled by the machine tool, the NC machining program is directly and quickly input into the NC device of the machine tool.
(6) Proofreading the processing program of ordinary machine tools
Usually, after the NC machining program is input, it needs to be checked for errors. Generally, the machining information on the machining program is inserted into the numerical control system for idle running inspection, or a pen can be used to replace the cutter on the numerical control machine tool, and a drawing paper can be used to draw a simulation diagram of machining instead of the workpiece to check the correctness of the movement and trajectory of the machine tool.
(7) Trial machining of the first ordinary machine tool
After proofreading the machining program, it is impossible to determine the machining error caused by inaccurate programming calculation or improper tool alignment. Therefore, it is necessary to carry out practical inspection through the first piece trial cutting method, further investigate the correctness of the program sheet, and check whether the workpiece meets the machining accuracy requirements. According to the trial cutting situation, modify the program sheet and take size compensation measures in turn until the parts that meet the requirements are processed.
Structure of extended data NC machining program
1. Composition of the program: composed of multiple program segments.
o 000 1； O (Fanuc-O, Ab8400-P, Sinumerik 8m-%) can specify program numbers, and each program number corresponds to a workpiece.
n 0 10 G92 X0 Y0； A semicolon indicates the end of a program segment.
2. Program segment format:
1) word address format: such as n020g 90g00x50y60;
The most commonly used format, modern CNC machine tools use it. Address n is the program segment number, and the word address consisting of address g and number 90 is the preparation function.
References:
Baidu Encyclopedia-NC Machine Tool Programming