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  1. #1
    Cuda is offline Hot Rolled
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    Default Lathe running too fast with G96?

    I noticed today our Daewoo Puma 400 with Fanuc 21Ti control was running way too fast on large dia. parts, I was turning some 18.5" dia. wear rings made from super duplex and was wanting to turn 125 surface feet per min. that should be about 26 RPM, however the machine was running 50 RPM at 18.5 Dia. with a G96 S125 speed command??? The funny thing is if you manually move the tool down in X after starting the program the speed would remain at 50 RPM until the tool reached about 10" then the chuck would start increasing speed and at that point it would have the correct RPM for the dia. it was at. The only way I could make the parts was to use a G97 code to force 26 RPM. I think it may be a parameter issue?

  2. #2
    Xjenderfloip is offline Stainless
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    How coincidental ! Last days i was running big SS parts on a puma 700 and i had the exact same problem.
    Only i didnt notice the 50 rpm right away, and kept changing surface speed in the program, untill i saw it.
    Took me a few extra inserts tho.
    I just manually do override the rpm to a lower % right now, but if anyone knows of a parameter setting i would be glad to hear aswell.

    What kind of puma 400 do you run, a LMA LMB or LMC?

    You manually moved the tool to 10", that was the diameter where your SFM was 125, from there it catches up.
    I noticed the same when facing the parts.

  3. #3
    Tonytn36 is offline Diamond
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    That is probably the minimum spindle speed allowed by the MTB, and it is almost certainly set in a parameter. Unfortunately, going lower under load may cause overheating of the motor.

  4. #4
    Heinz R. Putz is offline Hot Rolled
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    Default Lathe running too fast with G96?

    Can you post the beginning of your program, especially where you tell it how fast to turn?
    Do you have a gear range, like M41, M42, etc.?
    Heinz.
    www.doccnc.com

  5. #5
    Cuda is offline Hot Rolled
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    Quote Originally Posted by Xjenderfloip View Post
    What kind of puma 400 do you run, a LMA LMB or LMC?
    It's a 400 LC with 21" chuck and 12 station turret, and I don't just run it, I also do the set up and programs.

    Quote Originally Posted by Heinz R. Putz View Post
    Can you post the beginning of your program, especially where you tell it how fast to turn?
    Do you have a gear range, like M41, M42, etc.?
    Heinz.
    www.doccnc.com
    The machine has Low range M41 and High range M43
    Program sample would look something like this...
    N0001 G50 S300
    (ROUGH O.D. WNMG432)
    M41
    G99
    G0T0101
    G54
    G96 S125 M3
    G0X18.5 Z.04 M8
    G1Z-2.8 F.012
    X18.55
    G0 Z.04
    X20 Z12. M9
    T0100
    M1

  6. #6
    Heinz R. Putz is offline Hot Rolled
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    Default Lathe running too fast with G96?

    The program looks fine, I see nothing that should mess up your speed.
    There is a guy at Daewoo, his name is Kaspar, I am sure he can help you.
    Why don't you give him a call.
    I just made a 40" part on a different machine, but the same control for a shop in Detroit and we had no problem.
    The only thing different in the program was no G0 with the tool call, so it was T0101 by itself.
    I have no clue if that has anything to do with it, but you might try it.
    Do you know what the minimum RPM for your machine is?
    The best of luck: Heinz.
    www.doccnc.com

  7. #7
    Empireweld's Avatar
    Empireweld is offline Aluminum
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    When I use G96 on my Seimens 840C I use G92 to set upper limit on
    spindle speed.

    Doug Walker

  8. #8
    Cuda is offline Hot Rolled
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    Quote Originally Posted by Empireweld View Post
    When I use G96 on my Seimens 840C I use G92 to set upper limit on
    spindle speed.

    Doug Walker
    G50 does that on Fanuc controls like this Daewoo has, and G92 is a thread cutting cycle.

  9. #9
    alphonso is offline Stainless
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    Quote Originally Posted by Cuda View Post
    N0001 G50 S300
    (ROUGH O.D. WNMG432)
    M41
    G99
    G0T0101
    G54
    G96 S125 M3
    G0X18.5 Z.04 M8
    G1Z-2.8 F.012
    X18.55
    G0 Z.04
    X20 Z12. M9
    T0100
    M1

    This is the way I program this sequence:

    T0101
    M41
    G97 M3 S25
    G0 X18.5 Z.04 M8
    G50 S300
    G96 S125
    WORK
    G97 (sometimes I add S value here)
    M9
    T0100
    G0 Z.04
    X20 Z12.
    M1

  10. #10
    gcodeguy is offline Cast Iron
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    Tony is the man! Low gear on our Daewoo Puma is 50-1300.

  11. #11
    Cuda is offline Hot Rolled
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    Quote Originally Posted by Tonytn36 View Post
    That is probably the minimum spindle speed allowed by the MTB, and it is almost certainly set in a parameter. Unfortunately, going lower under load may cause overheating of the motor.
    My boss is going to HIGHLY upset if that's the case, he bought that machine to do heavy big work and that sometimes requires less than 50 RPM on big dia., I've been running it a lot on these big rings at 26 RPM @ .150/.200 depth of cut and .01 to .012 feed with only 20 to 30% spindle load showing and not a sign of bogging. I would think if 50 RPM was the min. it would not run any slower under any condition, we have a Mori Seiki SL25 and it won't run less than 35 RPM even if you tell it to run G97 S10

  12. #12
    Xjenderfloip is offline Stainless
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    Quote Originally Posted by Cuda View Post
    It's a 400 LC with 21" chuck and 12 station turret, and I don't just run it, I also do the set up and programs.


    The machine has Low range M41 and High range M43
    Program sample would look something like this...
    N0001 G50 S300
    (ROUGH O.D. WNMG432)
    M41
    G99
    G0T0101
    G54
    G96 S125 M3
    G0X18.5 Z.04 M8
    G1Z-2.8 F.012
    X18.55
    G0 Z.04
    X20 Z12. M9
    T0100
    M1
    Sorry if i offended you by asking what machine your run, i do mean by running a machine programming, setup, making your own fixtures, fix your own problems, knowing how to align your turret, aligning the headstock and tailstock, fix the sheets when needed, replace bearings of the steady rest if available, align steady rest, keep coolant healty, change own filtermist, make programs while it runs, help other collegues with programming issues, make macros, program C-axis if available, setting up a toolsystem from the ground, knowing the inserts for turning milling and boring tools on the different materials, being able to make a big shaft fully automatic from a rough blank without any program interruption, shifting, placing steadyrest in the program, aswell as the tailstock, ect...

    Oh wait i think i lost track, yes only running a machine like in pushing the green button is different.

    I do like this

    O0001(drawing number+customer)
    G50 S300
    G54
    N1G00X...Z..G40G99
    T0100(ROUGH O.D. WNMG432)
    M41
    G96 S125 M3
    G00X18.5 Z.04T0101 M8
    G01Z-2.8 F.012
    G01X18.55
    G00 Z.04
    G00X.. Z..G40 T0. M9
    M01[/QUOTE]

    actually i leave out G54 when i didnt call a diff offset, because standard on our pumas the G54 is modal.

  13. #13
    Xjenderfloip is offline Stainless
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    Quote Originally Posted by Heinz R. Putz View Post
    The program looks fine, I see nothing that should mess up your speed.
    There is a guy at Daewoo, his name is Kaspar, I am sure he can help you.
    Why don't you give him a call.
    I just made a 40" part on a different machine, but the same control for a shop in Detroit and we had no problem.
    The only thing different in the program was no G0 with the tool call, so it was T0101 by itself.
    I have no clue if that has anything to do with it, but you might try it.
    Do you know what the minimum RPM for your machine is?
    The best of luck: Heinz.
    www.doccnc.com
    Minimum programmable speed is 1 RPM that goes for Puma 230-Puma 240-Puma 350-Puma 400 and Puma 700

  14. #14
    Xjenderfloip is offline Stainless
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    Cuda how is the backlash on your machine when miling with a C-axis?
    I found that the pumas with a gearbox are having a big backlash when milling circular on bigger diameters.

  15. #15
    WILLEO6709's Avatar
    WILLEO6709 is offline Diamond
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    I'd be getting the parameter manual out and going through how its set up. It sounds like mightbe a simple way of incorrect diameter/ radius setup in the parameters.

  16. #16
    g-coder05's Avatar
    g-coder05 is online now Stainless
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    This is the way I program this sequence:

    T0101
    M41
    G97 M3 S25
    G0 X18.5 Z.04 M8
    G50 S300
    G96 S125
    WORK
    G97 (sometimes I add S value here)
    M9
    T0100
    G0 Z.04
    X20 Z12.
    M1

    I think Alphonso nailed it there with the G50
    However will your control will take a G1000 to make sure the spindle is at the correct RPM before the tool re-engages after a rapid move? Ive noticed this seems to be my number one cause of insert failure in the past. Other wise you could always use a G4 after each rapid.

  17. #17
    Cuda is offline Hot Rolled
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    Quote Originally Posted by Xjenderfloip View Post
    Cuda how is the backlash on your machine when miling with a C-axis?
    I found that the pumas with a gearbox are having a big backlash when milling circular on bigger diameters.
    No C-axis on this machine.

  18. #18
    gcodeguy is offline Cast Iron
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    Quote Originally Posted by g-coder05 View Post
    I think Alphonso nailed it there with the G50
    However will your control will take a G1000 to make sure the spindle is at the correct RPM before the tool re-engages after a rapid move? Ive noticed this seems to be my number one cause of insert failure in the past. Other wise you could always use a G4 after each rapid.
    Sorry, but I don't see how limiting max rpm to 300 is going to help with the machine not running less than 50 rpm with a G96 block. I second the opinion to call Kasper. He is a nice guy who knows his machines.

  19. #19
    alphonso is offline Stainless
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    Quote Originally Posted by gcodeguy View Post
    Sorry, but I don't see how limiting max rpm to 300 is going to help with the machine not running less than 50 rpm with a G96 block. I second the opinion to call Kasper. He is a nice guy who knows his machines.
    I use the G50 S "whatever" as a safety device to prevent over-speeding the spindle. Has nothing to do with minimum spindle speed.

    Not familiar with a 21i control. 0TC has a parameter (0551) for "minimum spindle speed in G96", enter a value. Also has a parameter (0556) for max spindle speed in G96/G97 SCLMP (spindle speed clamp), enter a value.

  20. #20
    Xjenderfloip is offline Stainless
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    I just changed #3771 from 50 to 5. CCS min (Fanuc 21it)
    So minimum is 5 now, with 0 unlimited is asumed, so do anything above zero!
    BTW turning at zero rpm would be silly also.
    I dont think the drive will overheat, because in the Doosans the torque, drive heat, powerconsumption and whatsmore are used to caulculate general motorload.
    And if it overheats, it will trip out anyway.

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