G96 & G97 ....Again

[Terence Toh]

Hey guys,

As this is my first post, and i am willing to hear and learn from all of you...Below is my situation...


What will happen to the thread if the programmer use G96 instead of G97?
Will the thread pitch out? or any abnormal outcome by using G96 to cut the thread.

PS: This is a straight thread.

N8850 G00 M41
N8860 G50 S0083
N8870 T0002
N8880 G96 S0100 M03
N8890 G00 X40.0 Z1.0 M08
N8900 X28.077
N8910 Z-23.542
N8920 X27.977 Z-23.561
N8930 G92 X27.8671 Z-31.051 F0.5
N8940 X27.8574
N8950 X27.8479
N8960 X27.8384
N8970 X27.8291
N8980 X27.82
N8990 X27.811
N9000 X27.8021
N9010 X27.7934
N9020 X27.7849
N9030 X27.7764
N9040 X27.7681
N9050 X27.76
N9060 X27.752
N9070 X27.7441
N9080 X27.7364
N9090 X27.7289
N9100 X27.7214
N9110 X27.7141
N9120 X27.707
N9130 X27.7
N9140 X27.6931
N9150 X27.6864
N9160 X27.6799
N9170 X27.6734
N9180 X27.6671
N9190 X27.661
N9200 X27.655
N9210 X27.6491
N9220 X27.6434
N9230 X27.6379
N9240 X27.6324
N9250 X27.6271
N9260 X27.622
N9270 X27.617
N9280 X27.6121
N9290 X27.6074
N9300 X27.6029
N9310 X27.5984
N9320 X27.5941
N9330 X27.59
N9340 X27.586
N9350 X27.5821
N9360 X27.5784
N9370 X27.5749
N9380 X27.5714
N9390 X27.5681
N9400 X27.565
N9410 X27.562
N9420 X27.5591
N9430 X27.5564
N9440 X27.5539
N9450 X27.5514
N9460 X27.5491
N9470 X27.547
N9480 X27.545
N9490 G00 X28.977 Z-23.561
N9500 Z1.0
N9510 M09
N9520 T0000 M05



Hope someone can help to clear my doubt...Thanks !!!

[Superman]

For theading, you must use G97, the machine starts feeding at a timed point of spindle rotation, if you alter the RPM between cuts, then the relationship between the timing signal and the feed engagment will also alter, resulting in multiple threads

if G96 is used, this is in effect changing the RPM between cuts

[dcoupar]

The spindle speed will fluctuate up and down with every pass. I would put G97 in a block after the approach move to clamp the RPM.

N8920 X27.977 Z-23.561
N8925 G97
N8930 G92 X27.8671 Z-31.051 F0.5

[sinha_nsit]

In fact, the control should have automatically disabled G96 in case of threading. It could even alarm out. It is better not to do something instead of doing it incorrectly.