For CNC machining, programming is very important, which directly affects the processing quality and efficiency. I believe everyone loves and hates programming. So how do you quickly master CNC machining center programming skills? Let’s learn with the editor below!
pause command
G04X(U)_/P_ refers to the tool pause time (feed stops, spindle does not stop), and the value after the P or X address is the pause time. The value after
However, in some hole system processing instructions (such as G82, G88 and G89), in order to ensure the accuracy of the bottom of the hole, there is a pause time during which the tool processes to the bottom of the hole . be expressed by the address P. If the address
Differences and connections between M00, M01, M02 and M03
M00 is an unconditional pause instruction for the program. When the program is executed, the feed stops and the spindle stops. To restart the program, you must first return to JOG state, press CW (forward spindle) to start the spindle, then return to AUTO state, press START key to start the program.
M01 is a selective program pause instruction. Before the program is executed, the OPSTOP button on the control panel must be activated. The effect after execution is the same as M00. The program must be restarted as above. M00 and M01 are often used for inspection or chip removal of workpiece dimensions during processing.
M02 is the main end-of-program instruction. When this command is executed, the feed stops, the spindle stops, and the coolant is cut off. But the program cursor stops at the end of the program.
M30 is the main end of program command. The function is the same as M02, the difference is that the cursor returns to the position of the start of the program whether or not there are other program segments after M30.
Addresses D and H have the same meaning
Tool compensation settings D and H have the same function and can be interchanged as desired. They both represent the address name of the compensation register in the CNC system, but the specific compensation value is determined by the address of the compensation number behind them. However, in machining centers, in order to avoid errors, it is generally artificially stipulated that H is the tool length compensation address, the compensation number is 1 to 20, D is the address tool radius compensation and the compensation number starts at No. .21 (a tool magazine with 20 tools).
Mirror control
Mirror image processing instructions M21, M22, M23. When only the X axis or Y axis is reflected, the cutting sequence (climb and up milling), tool compensation direction and arc interpolation direction will be opposite to the actual program. When the X and Y axes are reflected at the same time, the tool feeding sequence, tool compensation direction and arc interpolation direction remain unchanged.
Note: After using the mirror command, you must use M23 to cancel it to avoid affecting subsequent programs. In G90 mode, when using the mirror image or undo command, you must return to the origin of the part coordinate system before you can use it. Otherwise, the CNC system will not be able to calculate the subsequent movement trajectory and random movement of the tool will occur. At this point, a manual return to origin operation should be performed to resolve the issue. Spindle rotation does not change with mirror image control.
Arc interpolation command
G02 is clockwise interpolation, G03 is counterclockwise interpolation. In the XY plane, the format is: G02/G03X_Y_I_K_F_ or G02/G03X_Y_R_F_, where X and Y are the coordinates of the end point of the arc, and I and J are the start of the arc. point to the center of the circle. The incremental value on the X and Y axes, R is the arc radius and F is the feed amount.
When arc cutting, please note that when q≤180°, R is a positive value; when q>180°, R is a negative value, I and K can also be specified with R. When both are specified at the same time; the R command has priority and I, K is invalid; R cannot perform full circle cutting, and full circle cutting can only be programmed with I, J, and K, because there are countless circles with the same radius passing through the same point. . When I and K are zero, they can be omitted; Regardless of G90 or G91 mode, I, J and K are programmed based on relative coordinates during arc interpolation, G41/G42 tool compensation instructions cannot be used.
Advantages and disadvantages between G92 and G54~G59
G54~G59 is the coordinate system set before processing, and G92 is the coordinate system set in the program. After using G54~G59, there is no need to use G92 again, otherwise G54~G59 will be replaced and should be avoided.
Note: (1) After G92 is used to set the coordinate system, using G54~G59 again will have no effect unless the system is powered off and restarted, or G92 is used to define the new required part coordinate system. (2) After the program using G92 is completed, if the machine tool does not return to the origin set by 92, restart the program and the current position of the machine tool will become the new origin of the workpiece coordinates, subject to accidents. . So I hope readers will use it with caution.
Programming tool change routine
On a machining center, tool changes are inevitable. However, the machine tool has a fixed tool change point when it leaves the factory. If it is not at the tool change position, the tool cannot be changed. In addition, before tool change, tool compensation and cycle must be canceled, the spindle. stops and the coolant is cut off. There are many conditions. If these conditions have to be ensured before each manual tool change, it will not only be error-prone but also inefficient. Therefore, we can compile a tool change program to save it and then use M98 to call it. perform the tool change action in one go.
Taking the PMC-10V20 machining center as an example, the program is as follows:
O2002; (program name)
G80G40G49 (Cancellation of canned cycle and tool compensation)
M05 (spindle stops)
M09; (coolant shutdown)
G91G30Z0 (Z axis returns to the second origin, which is the tool change point)
M06 (Tool change)
M99; (End of subroutine)
When you need to change tools, you only need to type “T5M98P2002” in the MDI state to replace the required T5 tool, avoiding many unnecessary errors. Readers can compile the corresponding tool changing routines according to the characteristics of their own machine tools.
other
Sequence number of the program segment, represented by address N. Typically, the CNC device itself has limited memory space. To save storage space, the sequence numbers of program segments are omitted. N only represents the program segment label, which can make it easier to find and edit the program. It has no effect on the machining process. The sequence number can be increased or decreased and continuity of values is not required. However, it cannot be omitted when using certain loop instructions, jump instructions, subroutine calls and mirror instructions. In the same program segment, for the same instruction (same address character) or the same group of instructions, the one that appears later will take effect.
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