"Why M-Codes Used in CNC Programming"

M-Codes

M-codes are Non-Axis movement command and also called as machine codes which control the miscellaneous functions of machine excluding the axis movement of the machines.M-Code is the Letter “M” Followed by the Numbers which control the machine functions.Example: M03 à Controls the spindle to rotate along clockwise direction.

-->   M-code can be used to initiate a miscellaneous function not related to tool movement.
--> M-code Usually acts like a switches that stay ON until they are turned OFF by another M code
-->M-code is always allowed one per block of code.
--> Some M-codes are used in conjunction with other address, M06 tool change is always called with the conjunction with a T word.

-->The machine tool manufacturer often provides many additional M-Codes, many of these codes are non-         standard, and therefore we should consult the user manual of machine before making assumptions while using M-codes in the CNC program.

M Code Modal Groups

Group 2 = [M26, M27} - axis clamping

Group 4 = [M0, M1, M2, M30, M60] - stopping

Group 6 = [M6] - tool change

Group 7 = [M3, M4, M5] - spindle turning

Group 8 = [M7, M8, M9] - coolant

Group 9 = [M48, M49] - feed and speed override bypass