CNC Operating Modes

by Helman Jr.

Every CNC machine has couple of Modes or I call it Standard Working Modes , such as Auto Mode, Single Block Mode, MDI (Manual Data Input) and Jog Mode and there will be more modes but those mostly will be CNC machine or CNC control specific modes.

CNC Operating Modes Jog Mode MDI Mode Auto Mode Single Block Mode

CNC Operating Modes Jog Mode MDI Mode Auto Mode Single Block Mode

Lets know actually what these CNC Modes are and what they do.

CNC Machine Jog Mode

CNC machine Jog mode is one of the most used CNC mode. Jog mode is mostly used to travel the CNC machine carriage ( or CNC machine Slide) such as cnc machine’s axis movement e.g. x-axis z-axis. These axis movement can be via axis specific keys or through the cnc machine hand wheel.

CNC Machine MDI Mode or MDA Mode

The cnc machine MDI (Manual Data Input) mode or MDA (Manual Data Automatic) mode can be called a semi automatic mode. The cnc MDI or MDA mode is mostly used to index tools, or to execute one block of cnc code (on some models of cnc such as sinumerik 840D you can execute multi block cnc program in MDA mode ). The cnc M-Codes can be executed in MDI or MDA mode. You can even rotate the cnc machine spindle to a specific RPM in MDI or MDA mode.

CNC Machine Single Block Mode

The cnc program consists of cnc program blocks. The cnc program blocks are numbered such as N10, N20, N30 and so on. In cnc machine single block mode when you press the cycle start button on the cnc machine control panel only one block of the cnc program will be executed and the machine slide or cnc machine carriage will stop or you might say that the cnc machine cutting tool feed will be at hold but remember that this does not mean that cnc machine fully stops, only cnc machine axis movement will be at hold and all the othe functions like coolent will continue to flow and the spindle will continue to rotate. In short the cnc machine single block mode will not affect the machine spindle rotation but it will only hold the tool feed after the cnc program block is executed. And if you press the cycle start button again the next program block of the cnc program will be executed and the machine will again be at hold after that block completion.

CNC Machine Auto Mode or Automatic Mode

You will rarely see a production shop cnc machine out of cnc machine auto mode. The most used mode on a cnc machine (on some controls like Sinumerik 840D the machine control panel has a setting key which when switched off the machine will only be in auto mode and you can’t change the modes). In cnc machine auto mode when you press the cycle start button on the machine control panel the whole cnc program will be executed. To run the cnc machine in auto mode there are some conditions on some cnc machine such as the cnc machine safety guard door must be closed.