Thread cutting with endlessly rotating spindle (G33)

Syntax example for ZX plane (longitudinal axis Z, feed axis X):

G33 Z<expr> K<expr> [ <spindle_name>OFFSET[ = ]<expr> ]                                                  (modal)

G33

Thread cutting with endlessly rotating spindle. The G33 function is modal. The next motion block with a modal block type (G00, G01, G02, G03, spline, polynomial) deselects thread cutting.

Z<expr>

Target point ("thread length”) in [mm, inch]

K<expr>

The thread pitch is programmed with active thread cutting in the unit [mm/rev, inch/rev] without a mathematical sign using the address letters I, J and K. They are assigned to the X, Y and Z axes according to DIN 66025.

The thread pitch is modal up to program end and should not be zero on when G33 is selected. The feed is not programmed using the F word but results from the spindle speed and the thread pitch.

The pitch of longitudinal or tapered threads at an inclination angle less than 45° is specified by the address letter K if the Z axis is the longitudinal turning axis. With facing or tapered threads with an inclination angle greater than or equal to 45°, the pitch is specified by I if the X axis is used as the face turning axis, and by J if the Y axis is used. The figure below shows examples for specifying thread pitch using the address letters in the Z-X plane.

<spindle_name>.OFFSET=<expr>

Thread offset angle in [°] in spindle modulo range. Only required as an option for multi-turn threads. The offset angle is modal up to program end. Spindle name according to P-CHAN-00053. The "=” character is optional.

Pitch values I, K with longitudinal thread

Value of thread pitch for longitudinal thread
Value of thread pitch for longitudinal thread

Pitch values I, K with tapered thread

Value of thread pitch for tapered thread
Value of thread pitch for tapered thread

Programing Example

prg_example

Thread cutting with endlessly rotating spindle (G33)

Illustration of geometry example
Illustration of geometry example

Cutting a longitudinal thread (M70x1.5) with several cuts:

%L longit_thread

N100 G33 Z48 K1.5                 ;Cut thread turn

N110 G00 X72                      ;Retract and move

N120 Z105                         ;to start position

N130 M29                          ;Subroutine end

%G33 (thread depth 0.92 mm)

N10 G51                           ;Select diameter programming

N15 T1 D1 M03 S400                ;Select tool, start spindle

N20 G00 X72 Z105                  ;Start

N25 G01 X69.54 F1000              ;Position at 1st cutting depth

N30 LL longitudinal thread              ;1. Cut thread

N35 G01 X69.08                    ;Position at 2nd cutting depth

N30 LL longitudinal thread              ;2. Cut thread

N35 G01 X68.62                    ;Position at 3rd cutting depth

N30 LL longitudinal thread              ;3. cutting thread

N35 G01 X68.16                    ;Position at final depth

N30 LL longitudinal thread              ;4th cutting thread

N35 G01 X68.16                    ;Reposition at final depth

N30 LL longitudinal thread              ;Empty cut

N60 M05 X150 Z200              ;Moving to end position

N65 M30                      ;Program end

Cut a 2-turn longitudinal thread (M70x1.5)

%G33_2 (2-turn thread, thread depth 0.92 mm)

N10 G51                           ;Select diameter programming

N15 T1 D1 M03 S40                ;Select tool, start spindle

N20 G00 X72 Z105                  ;Approach

N25 G01 X68.16 F1000              ;Position at thread depth

N30 G33 Z48 K1.5                  ;Cut 1st thread turn

N35 G00 X72                      ;Retract and move

N40 Z105                          ;to next

N45 G01 X68.16                    ;start position

N50 G33 Z48 K1.5 S.OFFSET=180     ;Cut 2nd thread turn at 180°

N55 G00 X72                      ;Retract and move

N60 M05 X150 Z200              ;to end position

N65 M30                      ;Program end

Cutting a tapered thread

%L tapered thread

N010 N010 G33 X1 I5.0                 ;Cut thread turn (reference I)

; N010 N010 G33 Z90 X1                 ;Cut thread turn (reference K)

N020 G00 X72                      ;Retract and move

N030 Z105                         ;to start position

N040 M29                          ;Subroutine end

%G33

N050 G00 X0 Y0 Z0

N060 G18

N070 G51                           ;Select diameter programming

N080 D1 M03 S1                ;Select tool, start spindle

N090 G00 X105 Z105                  ;Start

N100 G01 X100 F1000              ;Position at 1st cutting depth

N110 LL tapered thread              ;1st thread cut

N120 M05 X150 Z200              ;Move to end position

N130 M30                      ;Program end