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IndustryArena Forum > MetalWorking Machines > Okuma > Multus B300W Sub Spindle Center issues.
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  1. #1
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    Jun 2006
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    59

    Multus B300W Sub Spindle Center issues.

    After receiving basically no help from our local Okuma tech guy I'm resorted to come here. I'm trying to turn a 5.25in diameter 28in long inconel shaft. I clamped a dead center into the sub spindle and synced the spindles. Ive already had to cheat using my M151, because one chuck has to be open to sync the spindles so I lied to it and said I was ID clamping on the sub spindle and moved the sensor just enough to be "unclamped" .

    I am aware there is a g29 torque command which I want to run to keep a constant pressure on my W axis. Without it I've noticed while turning my W axis load starts to lower and I'm affraid to leave the machine while it's taking 2.5 hours to do this part.

    The problem is when I run this code the program alarms and stops at the G29 line.

    (********************)
    (Turn Rough1)
    NT2
    MT=05101 (DVJNL-164C VNMG-432*)
    M321
    NAT1
    M247
    M151(SYNC SPINDLES)
    G29 PW=50
    G97S300M3
    G00 X6. Z.1427 TL=01051051 BT=1 M602
    G96 S850 M03


    What am I doing wrong here?

  2. #2
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    Jun 2005
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    142
    what is the alarm?

  3. #3
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    372
    Sorry to say that the machine alarms out as it is not made to be used like this. Using the Sub spindle as a tail stock can effect the preload on the spindle bearings. However it can be done;

    - After power on Run M151 in MDI. The machine will need to rotate the 2 spindles to get the zero points

    - Load the part

    - In manual mode drive the Sub spindle into the part, Remember that the W axis motor has a duty cycle so do not exceed it

    - Change the M151 to this M151 M883 M210

    NT2
    MT=05101 (DVJNL-164C VNMG-432*)
    M321
    NAT1
    M151 M883 M210
    G97S300M3
    G00 X6. Z.1427 TL=01051051 BT=1 M602
    G96 S850 M03

  4. #4
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    Apr 2009
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    1156
    G29 is the torque limit command which only sets the Max that your W can push. You may want that higher - more like PW = 85.

    Then use the G22 command to feed the W into your part and "push" up to a certain load before stopping.

    G94
    G22 W0 D.1 L.1 PW=50 F50
    G95

    W= Target position
    D= Distance before target to slow feed
    L= Distance past target before alarm occurs
    PW= load to push to (as % of duty cycle)
    F= Feed in IPM (since spindle is not running)

    The other thing that can get you is if there is no parameter max setting for your G29 value. But since you did not say what the alarm is, I'm only guessing here...

    Alarm # and description would be helpful.

    Best regards,

    PS: forgot to tell you about VCHIO. It can change your chucking from OD to ID in the program without having to cheat, but budgieW's way ignores the orientation, so that works too.

  5. #5
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    Make sure both spindles are in the same gear

  6. #6
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    Aug 2012
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    Check out this center from Riten made specifically for this type of application.

    http://www.riten.com/news/product-releases-linear.html

    Its a little pricey but it will keep the tension that you lack from mot having a hydraulic quill. There is a less expensive way to go but for the size and weight of your part I would be very careful.

    Riten Industries: Spring-Loaded, "Greber"Live Centers

    Since the center is live you wouldn't have to turn the right spindle. I'm not sure if it would give an alarm if it rotated a little just from the friction in the bearings.

  7. #7
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    Nov 2006
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    174

    live centre

    We use a live centre without a problem. The sub spindle is free to spin and doesn't cause an alarm (it hardly moves, anyway)
    We wind in the W axis manually and run it with 25% load on the W axis. It does creep up as the part is machined to around 50% on the load monitor.
    A spring loaded centre was bought at first and the W axis load reached 80% before the spring started to compress.
    This would normally be fine but our part was 900mm long and 320mm diameter. We are only gripping on 3mm of the part and the centre had 3mm of travel on it. I wasn't prepared to risk running the job with the possibilty of the job working it's way out. So we got an unsprung live centre and the job runs fine. I don't think 25% load on the W axis is excessive. 50% is only reached briefly and I don't think this is excessive either.
    Attached Thumbnails Attached Thumbnails live centre.jpg  

  8. #8
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    You don't even need a live centre.
    I've used a bit of scrap turned into a dead centre (we don't have a pipe centre).
    Turning and milling worked fine.
    Attached Thumbnails Attached Thumbnails g3.jpg  

  9. #9
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    Sep 2006
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    213
    Centre with spring works really fine. You can find it with load meter also.

  10. #10

    Re: Multus B300W Sub Spindle Center issues.

    I’m having a similar issue on a transfer on a Multus b300II when transferring the part from g141 to g140 I’m getting “2277-01 alarm-b data word torque limit a side 3”

    On the g29 PW=60

    When I changed it to G29 PW=0 and ran it through machine lock it didn’t alarm but the machinist I was working with didnt want to do that. I’m not a programmer by any means so I’m just looking for some advice.

  11. #11
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    Jun 2015
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    3458

    Re: Multus B300W Sub Spindle Center issues.

    hy if you use g29 pw=60, then 60 must be smaller then the parameter value from attached images; for example, for your code, the minimal value for the parameter should be 61, but transfering with pw=60 may be a bit too much, but still ok if your final feeding is slow (like 30 mm/min ); common pw values are a bit over 30, but one may need to increase them as part's dimension increases, and/or machine alignment is poor, etc

    if you are in doubts, set parameter to 35, and use 30 inside your program; if 30 is too little, then tranfer position will no longer be consistent consistency increases with higher values, but so does stress inside the machine, so try to target consistency with minimal stress

    most nasty things may happen during transfer :
    ... chips may gather between part and :
    ...... chuck face, thus your part will be clamped, but a bit too far away from the chuck; this means that Z0 for 2nd chuck is no longer ok one method to prevent, is by checking 2nd spindle position/W axis, right after clamping
    ...... jaws, thus your part will be clamped excentric, it's axis no longer aligned as it shoud visual check should be fine, or you may consider methods that lead safety, but cycle time will increase
    ... 2nd spindle may begin the transfer sequence with a part still in it, yet in an unclamped state
    ... and others

    When I changed it to G29 PW=0 and ran it through machine lock it didn’t alarm ... I’m not a programmer
    machine didn't alarm because g29 can not be actually simulated in lock mode, thus the machine simply jumpes over it, but it gave you a 'false' ok; it is designed to do so

    pw=0 is never used in real practice, but it didn't alarm out, because your parameter value is >=0 and <60 / kindly
    Attached Thumbnails Attached Thumbnails 02.png  

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