As an enterprise that operates CNC machine tools to produce and process parts, most of his employees must know what I said about CNC machining, which can make us more clear and understand us Own machine tool, you can also take a lot of detours
1. General operation steps of CNC machining
(1) Before writing or programming processing, first compile the machining program of the workpiece, if the machining program of the workpiece is long and complicated At the time, it is best not to program on the machine tool, but to use a programming machine or computer programming, so as to avoid occupying the machine, short programs should also be written on the program list. It is best to wait for the trial after the editing is completed to avoid unnecessary waste caused by formal processing.
(2) Generally, the machine is turned on first and then the system is turned on. In some designs, the two are interlocked, and the machine cannot display information on the CRT without power. In addition, as soon as the system is turned on, it is easy to have a problem that the previously written program runs as soon as it is turned on, which may be potentially dangerous. Its like a car igniting after its in gear, which is very dangerous.
(3) Reference point return For machine tools with incremental control systems (using incremental position detection elements), this step must be performed first to establish a movement reference for each coordinate of the machine tool.
(4) Adjust the processing program According to the storage medium of the program (paper tape or tape, disk), you can use a paper tape reader, cassette tape drive, programming machine or serial communication input. If it is a simple program, you can directly use the keyboard in Input on the CNC control panel, if the program is very simple and only one piece is processed, the program is not necessary to save. MDI mode can be used to input and process each segment. In addition, the workpiece origin, tool parameters, offsets, and various compensations used in the program must be lost before processing. Of course, our average person refuses to process only one workpiece.
(5) Editing the program If the input program needs to be modified, it needs to be edited. In the meantime, the machine must be tentatively set. At this time, put the mode selection switch in the edit position, and use the edit key to add, delete, and change. Refer to the corresponding manual for the editing method.
(6) The machine is locked and running the program. This step is to check the program. If there is an error, it needs to be edited again.
(7) Manual incremental movement is used for the upper workpiece and alignment tool setting, continuous movement or hand wheel is used to move the machine tool. Align the starting point to the beginning of the program and align the tool reference.
(8) Starting coordinate feed for continuous machining is generally a program machining in memory. This method has a lower failure rate than processing on paper tape. The feed rate during processing can be adjusted by the feed override switch. During processing, you can press the feed hold button to pause the feed movement, observe the processing status or perform manual measurement. Press the cycle start button again to resume processing. To ensure that the program is correct, it should be reviewed again before processing. When milling, for plane curved workpieces, you can use a pencil instead of a tool to outline the workpiece on the paper, which is more intuitive. If the system has a tool path simulation function, you can use it to check the correctness of the program.
(9) Operation display Each screen of the CRT is used to display the position of the workbench or tool, the program and the state of the machine tool, so that the operator can monitor the processing situation.
(10) After the output of the program is finished, if it is necessary to save the program, it can be left in the CNC memory. If the program is too long, the program in the memory can be output to an external device (such as a punching machine). Save it on tape (or tape, disk, etc.).
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2. Precautions during CNC machining operations
(l) Before turning on every time, check whether the lubricating oil in the lubricating oil pump behind the Milling machine is sufficient, whether the air compressor is turned on, and whether the mechanical oil used in the cutting fluid is sufficient.
(2) When starting, first turn on the main power, then press the start button in the CNC power supply, turn the emergency stop button clockwise, after the Milling machine has detected all functions (a row of red indicators on the lower operation panel Lights off), press the machine button to reset the Milling machine, and it is in the standby state.
(3) During manual operation, always be aware that the Z axis must be in the knife lifting position before moving in the X and Y directions. During the movement, you can't just look at the change of the coordinate position in the CRT screen, but to observe the movement of the tool. After the tool moves into place, look at the CRT screen for fine adjustment.
(4) In the programming process, for beginners, try not to use G00 commands as much as possible, especially in the three-axis linkage of X, Y, Z, more attention should be paid. When the knife is empty, the movement of the Z axis should be separated from the movement of the X and Y axes, that is, more knife lifting and less oblique insertion. Sometimes due to oblique insertion, the tool will hit the workpiece and the tool will be destroyed.
(5) When using a computer for serial communication, it is necessary to turn on the Milling machine first and then the computer; turn off the computer first and then turn off the Milling machine. Avoid the Milling machine impacting the computer due to the instantaneous change of current during the switching process.
(6) When using the DNC (computer and Milling machine to transfer programs between each other) function, pay attention to the memory capacity of the Milling machine. Generally, the total number of program bytes transferred from the computer to the Milling machine should be less than 23kB. If the program is relatively long, it must be processed by the computer while transmitting, but the program segment number must not exceed N9999. If there are more than 10,000 program blocks, you can use the program editing function in MASTERCAM to cancel the program block number.
(7) When an alarm occurs on the Milling machine, it is necessary to search for the cause according to the alarm number, and then remove the alarm, and do not turn off the power, otherwise it will still be in the alarm state after the power is turned on. Using the edge finder to set the knife, the detailed steps are as follows:
(1) X, Y direction tool setting
1 Install the workpiece on the machine table through the fixture. When clamping, the four sides of Precision parts should be Set aside the measurement position of the edge finder.
2 Quickly move the table and the spindle, so that the edge finder probe is close to the left side of the workpiece;
3 Change to fine-tuning operation, let the probe slowly touch the left side of the workpiece, until the edge finder is illuminated, remember At this time, the X coordinate value in the machine coordinate system, such as -310.300;
4 Raise the edge finder to the upper surface of the workpiece, quickly move the table and the spindle, and make the probe close to the right side of the workpiece;
5 Change to fine-tuning operation, let the probe touch the left side of the workpiece slowly until the edge finder glows, and record the X coordinate value in the mechanical coordinate system at this time, such as -200.300;
6 If the probe diameter is 10mm , The length of the workpiece is -200.300-(-310.300)-10=100, according to which the X coordinate value of the origin W of the workpiece coordinate system in the machine tool coordinate system is -310.300+100/2+5= -255.300;
7 Similarly, the Y coordinate value of the origin W of the workpiece coordinate system in the machine coordinate system can be measured.
(2) Remove the edge finder in Z direction tool setting 1 and install the tool used for processing on the spindle;
2 Place the Z axis setting device (or fixed height tool setting block, the same below) on the workpiece On the upper plane;
3 quickly moves the spindle to bring the tool end face close to the upper surface of the Z-axis setter;
4 changes to the fine-tuning operation so that the tool end face slowly touches the upper surface of the Z-axis setter until it The pointer indicates the zero position;
5 record the Z value in the machine coordinate system at this time, such as -250.800;
6 If the height of the Z axis setter is 50mm, the workpiece coordinate system origin W is in machine coordinates The Z coordinate value in the system is -250.800-50-(30-20)=-310.800.
(3) Input the measured X, Y, Z values into the storage address of the machine tool workpiece coordinate system (generally use G54-G59 code to store the tool setting parameters).
4. Precautions The following issues should be noted during the tool setting operation:
(1) Use the correct tool setting tool to control the tool setting error according to the processing requirements;
(2) During the tool setting process , Can be adjusted by changing the fine-tuning feed to improve the accuracy of tool setting;
(3) need to be operated carefully, especially pay attention to the moving direction to avoid the risk of collision;
(4) the tool setting data must be Store the storage address corresponding to the program to prevent serious consequences due to call errors. 2. Input and modification of tool compensation value According to the actual size and position of the tool, the tool radius compensation value and tool length compensation value are input to the storage location corresponding to the program. It should be noted that the correctness of the compensated data, the correctness of the symbol, and the correctness of the address where the data is located will threaten the processing, resulting in a collision hazard or processing scrap.

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