# Exchange spindles in coordinated motion (# CAX, #CAX OFF)

This "basic mode" is required in particular for C axis machining on lathes because in this case the position-controlled spindle has to be converted into a rotary path axis (e.g "C").

## Notice

C axis machining can also be executed on milling machines or machining centres which are designed with rotary workpiece fixtures (e.g. turntable). In this case, it is not necessary to select #CAX.

The three physical axes X, Y, Z and the C axis replaced in coordinated motion can be directly programmed. Linear axes are programmed in Cartesian coordinates and the C axis in angle units.

Radius and diameter programming depends on G52/G51.

Two linear axes define the main plane: ZX (G18) or YZ (G19).

Syntax:
#CAX [ [ [<main_spindle_name>, ] <C_axis_name> ] ]

<main_spindle_name> | Only the main spindle name can be programmed according to P-CHAN-00053. If a spindle other than the C axis is used, it must first be declared as the main spindle (see programming example in Section [PROG// Changing the main spindle]). Otherwise, an error message is output.
<C_axis_name> | Freely definable name of the C axis in the NC program. If no C axis name is programmed, the default name from P-CHAN-00010 is used.

The main plane (circular interpolation, tool radius compensation, etc.) remains the same as before activation of the C axis.

An error is generated if a command for this spindle (M3, M4, M5, etc.) is programmed although the axis is still declared as a C axis in the coordinated motion.

The C axis is deselected, i.e. the axis is released to the spindle interpolator, by the following:

Syntax:
#CAX OFF

## Programing Example

C axis machining

Exchange spindles in coordinated motion

;…

#CAX ; Assuming: default C axis is "C"

G01 G90 X50 Z10 C90 F200

#CAX OFF ; deselect C axis mode

;...

#CAX[S, C] or #CAX[C] ; Assuming: main spindle is "S"

G01 G90 X50 Z10 C90 F200

#CAX OFF

;...

#MAIN SPINDLE [S2] ; “S2” becomes new main spindle “S”

#CAX[S, C] ; select C axis mode

G01 G90 X50 Z10 C90 F200

;...

#CAX OFF ; deselect C axis mode

;...

#CAX[S3, C]; Error, “S3“ is not the main spindle