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FITTER - CITS

4 M03: Spindle on Clockwise (CW) - Starts the spindle rotation in the clockwise direction, usually used for
machining operations.
5 M04: Spindle on Counter clockwise (CCW) - Starts the spindle rotation in the counter clockwise direction, if
supported by the machine.
6 M05: Spindle Stop - Stops the spindle rotation, ending the machining operation.
7 M07: Mist Coolant On - Activates the mist coolant system, which delivers a fine spray of coolant to the cutting
area to lubricate and cool the tool and workpiece.
8 M08: Flood Coolant On - Activates the flood coolant system, which floods the cutting area with coolant to
remove chips and dissipate heat during machining.
9 M09: Coolant Off - Deactivates the coolant system, stopping the flow of coolant to the cutting area.
10 M10/M11: Chuck Open/Close - Controls the opening and closing of the chuck jaws, used for workpiece
clamping.
11 M16: Spindle Orientation - Rotates the spindle to a predefined orientation, aligning specific features of the
workpiece with the tool.
12 M18/M19: Tailstock Retract/Advance - Controls the movement of the tailstock, used for workpiece support and
centring.
13 M20: Tool Change - Initiates an automatic or manual tool change process, allowing the operator to replace
cutting tools.
14 M27/M28/M29: Return Home - Commands the machine to return to the home position or reference point.
15 M72/M73: Program Stop/Cycle Start - Pauses or resumes program execution, commonly used for manual
intervention or automatic operation.

16 M88/M89: Bar feed Control - Controls the operation of a bar feeder for automatic loading of workpieces.
17 M98/M99: Subprogram Call/Subprogram End - Calls a subprogram (a separate section of code) or marks the
end of a subprogram.
• co-ordinate system G90 and G91:

In CNC (Computer Numerical Control) machining, G90 and G91 are G-codes used to specify the coordinate
system mode for programming tool movements and machining operations. They
control how coordinates are interpreted and used to define the tool’s position relative to the workpiece.
Here’s a breakdown of G90 and G91:
1 G90 - Absolute Programming:

• When G90 is activated, it sets the machine to use absolute coordinates for positioning.
• In absolute programming mode, coordinates specify positions relative to a fixed reference point, typically the
origin (0,0) of the machine’s coordinate system.
• Each coordinate value represents the exact position of the tool or workpiece in relation to the reference point.
• Absolute programming mode is useful for specifying precise positions and movements, as coordinates are
defined in relation to a known starting point.
2 G91 - Incremental Programming:
• When G91 is activated, it sets the machine to use incremental coordinates for positioning.
• In incremental programming mode, coordinates specify distances or movements relative to the tool’s current
position.
• Each coordinate value represents a change in position or movement from the tool’s current location, rather
than an absolute position.
• Incremental programming mode is useful for specifying relative movements and distances, as coordinates are
defined based on the tool’s current position.

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