G90 G-Code Command
G90 is a CNC programming code used in CNC machining to set the machine’s absolute programming mode. In absolute programming mode, the coordinates specified in the program are interpreted as absolute coordinates, with respect to the machine’s reference point or home position. This means that the machine will move to the exact position specified in the program, regardless of its current position.
G90 is often used at the beginning of a CNC program to ensure that the machine is in the correct mode, and that subsequent movements are interpreted correctly. It is also used to specify the position of the machine’s reference point, which is typically set during machine setup or calibration.
How G90 G-Code Command Is Used
Here’s an example of how G90 might be used in a CNC program:
O1000 (Main Program) G90 (Set to Absolute Programming Mode) G00 X0 Y0 Z10 (Rapid Move to Pre-Position) G01 X10 Y20 Z5 F100 (Linear Move to Position) G02 X30 Y20 I10 J0 F200 (Circular Move to Position) G03 X30 Y40 I0 J20 F200 (Circular Move to Position) G01 X10 Y40 Z10 F100 (Linear Move to Position) M30 (End of Program)
In this example, the program starts with a comment indicating that it is the main program. The first line of code sets the machine to absolute programming mode using G90. The next line moves the machine to the start position, which is specified as X0, Y0, Z10.
The program then makes a linear move to position X10, Y20, Z5 at a feed rate of 100 units per minute. This is followed by two circular moves, one clockwise and one counterclockwise, using G02 and G03 respectively. The circular moves are specified using the center point I10, J0 and I0, J20, and a feed rate of 200 units per minute.
Finally, the program makes another linear move to position X10, Y40, Z10 at a feed rate of 100 units per minute, before ending with the M30 code.