When I and K are zero, they can be omitted; regardless of G90 or G91 mode, I, J, K are programmed according to relative coordinates; when circular interpolation, tool compensation instruction G41 / G42 cannot be used.
- Advantages and disadvantages between G92 and G54-G59
G54-G59 is the coordinate system set before machining, while G92 is the coordinate system set in the program. If G54-G59 is used, there is no need to use G92 again, otherwise G54-G59 will be replaced and should be avoided, as shown in Table 1.
Table 1 difference between G92 and working coordinate system`
Note: (1) once G92 is used to set the coordinate system, G54-G59 will not work unless the system is restarted after power failure or G92 is used to set the required new workpiece coordinate system. (2) After using G92 program, if the machine tool does not return to the original point set by G92, the program will be started again, and the current position of the machine tool will become the new workpiece coordinate origin, which is prone to accidents. Therefore, we hope that readers will use it carefully.
- Compile tool changing program.
In the machining center, tool change is inevitable. However, there is a fixed tool change point when the machine tool leaves the factory. If it is not in the position of tool change, it is impossible to change the tool. Moreover, before changing the tool, the tool compensation and circulation must be cancelled, the spindle is stopped and the coolant is turned off. There are many conditions. It is not only easy to make mistakes but also inefficient to ensure these conditions before each manual tool change. Therefore, we can compile a tool change program to save the memory and MDI status
Under the call of M98, the tool change action can be completed at one time.
Taking pmc-10v20 machining center as an example, the program is as follows:
O2002; (program name)
G80g40g49; (cancel fixed cycle, cutter compensation)
M05; (spindle stop)
M09; (coolant off)
G91g30z0; (Z axis returns to the second origin, i.e. tool change point)
M06; (tool change)
M99; (end of subroutine)
When the tool needs to be changed, just type “t5m98p2002” in MDI state to replace the required tool T5, thus avoiding many unnecessary mistakes. According to the characteristics of their own machine tools, the majority of readers can work out the corresponding tool change program.
- Others
The sequence number of the program segment is represented by address n. Generally, the memory space of NC device itself is limited (64K). In order to save storage space, the sequence number of program segment is omitted. N only means the segment label, which is convenient to find and edit the program, and has no effect on the processing process. The sequence number can be increased or decreased, and the continuity of the value is not required. However, some loop instructions, jump instructions, calling subroutines and mirror instructions can not be omitted.
- In the same program segment, the later occurrence of the same instruction (the same address symbol) or the same set of instructions takes effect.
For example, tool change procedure, t2m06t3; instead of T2, T3 is replaced;
G01g00x50.0y30.0f200; G00 is executed (although there is f value, G01 is not executed).
If the instruction codes are not in the same group, the effect is the same if they are exchanged in the same program segment.
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