CNC lathe wont read cam max speed

Hi all!

I am trying to use constant surface speed in Fusion360 CAM to use in a cnc lathe with Mach3 turn. The problem is that the lathe wont read the max rpm that I have set up in fusion360 and just increase the chuck speed to the max speed possible when approaching the minor diameter of the part. I have tried different combinations but wont work. Any idea what could it be?.



This is an example of the code


%
(7041)
N10 G90 G94 G18
N11 G21
N12 G28 U0.
N13 G28 W0.

(2 ROUGHING)
N14 T0101
N15 G54
N16 G94
N17 G97 S410 M3
N18 G0 X36.1 Z5.
N19 M48 S410
N20 G96 S200 M3
N21 G0 Z6.
N22 X18.1
N23 G1 X15.1 F150.
N24 Z-53.8
N25 X18.1
N26 X20.1 Z-52.8
N27 G0 X25.1
N28 Z-48.8
N29 G1 Z-53.8 F150.
N30 X12.6
N31 Z-52.572
N32 G90 G18 G2 X12.151 Z-50.825 I-6.9
N33 G1 X12.1 Z-50.729
N34 Z-26.249
N35 G2 X12.3 Z-25.079 I-6.8 K1.17
N36 G1 Z-12.955
N37 G2 X12.1 Z-11.785 I-6.9
N38 G1 Z6.
N39 X9.1
N40 Z-7.627
N41 X11.313 Z-10.393
N42 G3 X12.1 Z-11.785 I-6.406 K-2.563
N43 G1 X14.1 Z-10.785
N44 G0 X21.599
N45 Z-7.627
N46 X12.1
N47 G1 X9.1 F150.
N48 X6.1 Z-3.877
N49 Z6.
N50 X3.1
N51 Z-1.418
N52 G3 X5.177 Z-2.723 I-1.654 K-2.382
N53 G1 X6.1 Z-3.877
N54 X8.1 Z-2.877
N55 G0 Z-1.418
N56 X6.1
N57 G1 X3.1 F150.
N58 X2.898 Z-1.351
N59 X2.691 Z-1.288
N60 X2.688 Z-1.287
N61 X2.686
N62 X2.65 Z-1.276
N63 G2 X0.75 Z-0.94 I-1.429 K-2.524
N64 G1 Z6.
N65 X-1.6
N66 Z-0.9
N67 X-0.208
N68 G3 X0.75 Z-0.94 K-2.9
N69 G1 X2.75 Z0.06
N70 G0 X22.3
N71 Z-26.249
N72 X15.1
N73 G1 X12.1 F150.
N74 G3 X11.907 Z-26.714 I-6.8 K1.17
N75 G1 X10. Z-30.623
N76 Z-46.716
N77 X12.1 Z-50.729
N78 X14.1 Z-49.729
N79 G0 Z-46.716
N80 X13.
N81 G1 X10. F150.
N82 X8.232 Z-43.338
N83 G3 X7.9 Z-42.047 I4.934 K1.291
N84 G1 Z-35.54
N85 G3 X8.191 Z-34.332 I5.1
N86 G1 X10. Z-30.623
N87 X12. Z-31.623
N88 G0 X36.1
N89 Z5.
N90 G97 S410 M3

N91 G28 U0.
N92 G28 W0.
N93 M30
%

The Artsoft website seems to be down, so no access to the forums right now.

Just for fun try replacing the M48 with a G50, that seems to be the standard for the CSS spindle speed limit for a number of other controllers. Be careful, not sure what will happen.

N17 G97 S410 M3
N18 G0 X36.1 Z5.
N19 G50 S410
N20 G96 S200 M3
N21 G0 Z6.

Hi Jim, thanks for your reply.

Changing M48 with G50 wont make a difference. One thing I have noticed is that, the program starts normal, but at line N23, the program appears to stop, but the feed speed just slows so much that is almost imperceptible. If it wasnt for the last decimal in the DRO changing very slow, I would not have notice there is movement at all.