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Pre-NGC Haas Continuous 4th Axis

Andrew Preisler

Plastic
Joined
Jan 8, 2024
Hey all,

I need some assistance getting continuous 4th axis rotation on my Haas Super Mini Mill (pre-NGC). I have converted my 4th axis into a rotary table for lens grinding and need it to rotate continuously as a grinding tool sweeps across the surface and OD of a lens.

I have seen posts that recommend using jog lock which only works temporarily as movement stops once I switch out of the jog screen and over to the program screen.
The controller doesn't recognize the G33 continuous rotary motion command either.
Here is a snippet of the code, I have included where the 4th should start rotating and where the cutter disengages from the part and starts moving to the next pass.

Thanks for your help.

(Trace4)
---------------------------------START ROTATION HERE-------------------------------------------------
N6845 M1
N6850 T1 M6
N6855 S8000 M3
N6860 G54
N6865 G17 G90
N6870 M8
N6875 G1 X-6.7848 Y0. F500.
N6880 G0 G43 Z0.6 H1
N6885 T15
N6890 G0 Z0.2
N6895 G1 Z-2.1758 F2.
N6900 Z-2.2558
N6905 Z-3.5058
N6910 X-6.7856 Z-3.5184
N6915 X-6.788 Z-3.5308
N6920 X-6.792 Z-3.5428
N6925 X-6.7974 Z-3.5543
N6930 X-6.8042 Z-3.5649
N6935 X-6.8123 Z-3.5746
N6940 X-6.8216 Z-3.5832
N6945 X-6.8318 Z-3.5906
N6950 X-6.843 Z-3.5966
N6955 X-6.8547 Z-3.6012
N6960 X-6.867 Z-3.6042
-------------------------------------------TOOL FINISHES PASS AND MOVES TO NEXT CUTTING POSITION HERE---------------------------------------------
N6965 X-6.8796 Z-3.6057
N6970 X-6.8922 Z-3.6055
N6975 X-6.9047 Z-3.6038
N6980 X-6.9169 Z-3.6005
N6985 X-6.9286 Z-3.5957
N6990 X-6.9396 Z-3.5894
N6995 X-6.9497 Z-3.5819
N7000 X-6.9588 Z-3.5731
N7005 X-6.9667 Z-3.5632
N7010 X-6.9733 Z-3.5524
N7015 X-6.9785 Z-3.5409
N7020 X-6.9822 Z-3.5288
N7025 X-6.9843 Z-3.5163
N7030 X-6.9848 Z-3.5058
N7035 X-6.9864 Z-3.4668
N7040 X-6.9871 Z-3.428
N7045 X-6.987 Z-3.3895
N7050 X-6.9862 Z-3.3513
N7055 X-6.9847 Z-3.3136
N7060 X-6.9825 Z-3.2765
N7065 X-6.9799 Z-3.24
N7070 X-6.9767 Z-3.2043
N7075 X-6.9731 Z-3.1695
N7080 X-6.9692 Z-3.1356
N7085 X-6.965 Z-3.1029
N7090 X-6.9606 Z-3.0713
N7095 X-6.956 Z-3.0409
N7100 X-6.9514 Z-3.012
N7105 X-6.9421 Z-2.9587
N7110 X-6.9333 Z-2.912
N7115 X-6.9253 Z-2.8716
N7120 X-6.8296 Z-2.3934
N7125 X-6.8228 Z-2.3592
N7130 X-6.8156 Z-2.3229
N7135 X-6.8081 Z-2.2858
N7140 X-6.8005 Z-2.2496
N7145 X-6.7929 Z-2.2161
N7150 X-6.7855 Z-2.187
N7155 X-6.7786 Z-2.1639
N7160 X-6.7722 Z-2.1488
N7165 X-6.7693 Z-2.1446
N7170 X-6.7679 Z-2.1436
N7175 X-6.7672 Z-2.1433
N7180 X-6.7666 Z-2.1431
-------------------TOOL STOPS TOUCHING PART AND MOVES TO NEXT CUTTING PASS HERE-----------------------
 
You’re moving in X and Z already. Throw an A on each line then the rotary will move. It can only make a limited number of 360 rotations before its all wrapped up and needs to unwrap.
Lol sounds like the software guys don't understand how gears works. Would you just put A9999 or should I time how long the cut path takes and put in a corresponding A value? (i.e. the cut path takes 45 seconds during which I count how many revolutions the rotary can make and then input that value.... 455 degrees during that time so put A455)
 
Lol sounds like the software guys don't understand how gears works. Would you just put A9999 or should I time how long the cut path takes and put in a corresponding A value? (i.e. the cut path takes 45 seconds during which I count how many revolutions the rotary can make and then input that value.... 455 degrees during that time so put A455)
You're not understanding: the machine executes a single block of code at a time. All the axes are addressable but, the machine will not move to the next X, Y or Z until A has also completed its move. It's exactly what @Booze Daily posted: every line has to have the A move it's supposed to execute on that line.

If you just want a spinning platter to hold a piece of optics while you do XYZ motion, the rotary axis won't do that. The closest you might get is by purchasing an outboard rotary control box, programming it to do relative motion and whatever number of degrees, then trigger it from an M-relay wire and no finish signal.
 
Hey all,

I need some assistance getting continuous 4th axis rotation on my Haas Super Mini Mill (pre-NGC). I have converted my 4th axis into a rotary table for lens grinding and need it to rotate continuously as a grinding tool sweeps across the surface and OD of a lens.

I have seen posts that recommend using jog lock which only works temporarily as movement stops once I switch out of the jog screen and over to the program screen.
The controller doesn't recognize the G33 continuous rotary motion command either.
Here is a snippet of the code, I have included where the 4th should start rotating and where the cutter disengages from the part and starts moving to the next pass.

Thanks for your help.

(Trace4)
---------------------------------START ROTATION HERE-------------------------------------------------
N6845 M1
N6850 T1 M6
N6855 S8000 M3
N6860 G54
N6865 G17 G90
N6870 M8
N6875 G1 X-6.7848 Y0. F500.
N6880 G0 G43 Z0.6 H1
N6885 T15
N6890 G0 Z0.2
N6895 G1 Z-2.1758 F2.
N6900 Z-2.2558
N6905 Z-3.5058
N6910 X-6.7856 Z-3.5184
N6915 X-6.788 Z-3.5308
N6920 X-6.792 Z-3.5428
N6925 X-6.7974 Z-3.5543
N6930 X-6.8042 Z-3.5649
N6935 X-6.8123 Z-3.5746
N6940 X-6.8216 Z-3.5832
N6945 X-6.8318 Z-3.5906
N6950 X-6.843 Z-3.5966
N6955 X-6.8547 Z-3.6012
N6960 X-6.867 Z-3.6042
-------------------------------------------TOOL FINISHES PASS AND MOVES TO NEXT CUTTING POSITION HERE---------------------------------------------
N6965 X-6.8796 Z-3.6057
N6970 X-6.8922 Z-3.6055
N6975 X-6.9047 Z-3.6038
N6980 X-6.9169 Z-3.6005
N6985 X-6.9286 Z-3.5957
N6990 X-6.9396 Z-3.5894
N6995 X-6.9497 Z-3.5819
N7000 X-6.9588 Z-3.5731
N7005 X-6.9667 Z-3.5632
N7010 X-6.9733 Z-3.5524
N7015 X-6.9785 Z-3.5409
N7020 X-6.9822 Z-3.5288
N7025 X-6.9843 Z-3.5163
N7030 X-6.9848 Z-3.5058
N7035 X-6.9864 Z-3.4668
N7040 X-6.9871 Z-3.428
N7045 X-6.987 Z-3.3895
N7050 X-6.9862 Z-3.3513
N7055 X-6.9847 Z-3.3136
N7060 X-6.9825 Z-3.2765
N7065 X-6.9799 Z-3.24
N7070 X-6.9767 Z-3.2043
N7075 X-6.9731 Z-3.1695
N7080 X-6.9692 Z-3.1356
N7085 X-6.965 Z-3.1029
N7090 X-6.9606 Z-3.0713
N7095 X-6.956 Z-3.0409
N7100 X-6.9514 Z-3.012
N7105 X-6.9421 Z-2.9587
N7110 X-6.9333 Z-2.912
N7115 X-6.9253 Z-2.8716
N7120 X-6.8296 Z-2.3934
N7125 X-6.8228 Z-2.3592
N7130 X-6.8156 Z-2.3229
N7135 X-6.8081 Z-2.2858
N7140 X-6.8005 Z-2.2496
N7145 X-6.7929 Z-2.2161
N7150 X-6.7855 Z-2.187
N7155 X-6.7786 Z-2.1639
N7160 X-6.7722 Z-2.1488
N7165 X-6.7693 Z-2.1446
N7170 X-6.7679 Z-2.1436
N7175 X-6.7672 Z-2.1433
N7180 X-6.7666 Z-2.1431
-------------------TOOL STOPS TOUCHING PART AND MOVES TO NEXT CUTTING PASS HERE-----------------------

Would a simple on off switch for rotation work?
Wire up a plug that sends voltage through the 2 correct pins. Toss it on a dc power supply and it will run forever till you turn it off or burn out the servo.
(Next question is what is the duty cycle of these servos…..)
Alternately you could pull the servo right off and toss a pulley on any ac or dc motor of your choice
Ultimately it’s just a precision worm gear reducer.
 
Just program in G91 and be done with it. That way you can rotate A past it's 360 as many times as you want. So X,Y and A movements in the same line in G91
 
What @Stirling said could work, sort of. I doubt you're using a Brush-type rotary. The good news is that on the brushless rotaries, Haas already broke out the motor wires in one of the two cables. It's nothing but the three motor phases, two brake wires and ground.

You could buy a VFD, provide a variable speed signal to the three motor phases and be sure to unlock the brake first. Buy a used Haas motor axis cable as a spare, build your own external power box to run it and it's a straight plug-in option.

The second cable is strictly for the encoder that keeps track of the axis position. Since that doesn't matter to you, it will stay unplugged.
 
What @Stirling said could work, sort of. I doubt you're using a Brush-type rotary. The good news is that on the brushless rotaries, Haas already broke out the motor wires in one of the two cables. It's nothing but the three motor phases, two brake wires and ground.

You could buy a VFD, provide a variable speed signal to the three motor phases and be sure to unlock the brake first. Buy a used Haas motor axis cable as a spare, build your own external power box to run it and it's a straight plug-in option.

The second cable is strictly for the encoder that keeps track of the axis position. Since that doesn't matter to you, it will stay unplugged.
My bad. I ASSumed the servos where dc.
If ac a dirt cheap vfd would be the ticket

The break is powered by air. If you don’t need it at all just don’t connect it to air.

I will mention again duty cycle.
I’m not sure how long u can spin it for if/when overheating the servo

Again, it’s just a worm gear on a pulley. You can strap any motor to the belt if rotation is the o key desirable motion.
 








 
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