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IndustryArena Forum > MetalWorking Machines > Okuma > Okuma LB15 - chuck clamping issues / solenoid.
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  1. #1
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    Okuma LB15 - chuck clamping issues / solenoid.

    When trying to switch from inside clamping to outside clamping i get an Alarm in the controller when trying to close the chuck.. (Alarm A, chuck open/close)

    When flipping back to inside clamping it clamps and unclamps just fine..

    So looking at the solenoids in the rear i realize the left one of the pair dont activate as it should.

    Outside clamping "On" results in this.
    Attachment 470064

    Inside clamping On and Clamped results in:
    Attachment 470066

    Inside clamping On and Unclamped results in:
    Attachment 470068

    The left solenoid in the picture missing a light is "cold" to the touch, and the other three "ends" of the two solenoids are warm to the touch so i think it might be dead or a fuse or a relay..

    Do anybody know if these are relay activated?? And or if they have a fuse? its a 1A solenoid so not sure why it would be fused.. but relays for sure.

    Kindly // A

  2. #2
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    Re: Okuma LB15 - chuck clamping issues / solenoid.

    I also found this electric schematic (on vellum paper) for my "SMW Autobloc" chuck.
    Attachment 470078

  3. #3
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    1982

    Re: Okuma LB15 - chuck clamping issues / solenoid.

    I didn't got your question. Where the problem is?
    Since jaws are moving to both directions there is nothing wrong with solenoids.
    Check your setup.
    To be short, I will explain you the clamping philosophy related to setup of limit swithes.
    1. OD clamping. Chuck open means draw bar is advanced forward and the respective LS is activated.
    Chuck clamped means draw bar is pulled back and no limit swith is activated.
    Workpiece lost is when draw bar is pulled back and the limit switch activated. Means - the drawbar travelled full way back and there is no workpiece in the jams. Alarm, machine stop instantly.

    2. ID clamping. Chuck open means draw bar is pulled back and the respective LS is activated.
    Chuck clamped means draw bar is advanced forward and no limit swith is activated.
    Workpiece lost is when draw bar is advanced forward and the limit switch activated. Means - the drawbar travelled full way forward and there is no workpiece in the jams. Alarm, machine stop instantly.

  4. #4
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    Re: Okuma LB15 - chuck clamping issues / solenoid.

    Quote Originally Posted by Algirdas View Post
    I didn't got your question. Where the problem is?
    Since jaws are moving to both directions there is nothing wrong with solenoids.
    Check your setup.
    To be short, I will explain you the clamping philosophy related to setup of limit swithes.
    1. OD clamping. Chuck open means draw bar is advanced forward and the respective LS is activated.
    Chuck clamped means draw bar is pulled back and no limit swith is activated.
    Workpiece lost is when draw bar is pulled back and the limit switch activated. Means - the drawbar travelled full way back and there is no workpiece in the jams. Alarm, machine stop instantly.

    2. ID clamping. Chuck open means draw bar is pulled back and the respective LS is activated.
    Chuck clamped means draw bar is advanced forward and no limit swith is activated.
    Workpiece lost is when draw bar is advanced forward and the limit switch activated. Means - the drawbar travelled full way forward and there is no workpiece in the jams. Alarm, machine stop instantly.
    Well it only moves in both direction when the chuck clamping direction is set to ID clamping

    And there is two bi-directional solenoids controlling this. When its set in ID clamping the solenoids works as expected as it uses the ports of upper left, right and down right. So it cycles fine.
    When you flip the switch to OD clamping it reverses the switching order. and it should be upper right, down right and down left.. solenoid that gets activated in open vs. closed mode.

    The solenoid on the down left side is not active - its not turned on at all.
    Which begs the question, is the solenoid itself fried or is the relay driving the solenoid fried.

  5. #5
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    Re: Okuma LB15 - chuck clamping issues / solenoid.

    Got it! A bit different hydraulics design. What I would do I would just swap the control cables. This will explain if the problem lays in control side.
    Next check: the relay interface block, which is inside the control cabinet.

  6. #6
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    Re: Okuma LB15 - chuck clamping issues / solenoid.

    After some investigating.. my assumption from my clickin buttons is seemingly wrong.

    The 2C circuit of the solenoid is whats clamping the ID and the 1C of the solenoid is what clamping OD
    The solenoid is spring returned, so question is if its activated when clamping or activated when opening.

    If one thinks of the above images this means this diagram needs to be rotated 180. But its only one solenoid driving the chuck
    Attachment 470110

    From these diagrams tho i cannot figure out what relay is turning on and off the 1C side of the solenoid.
    Attachment 470112
    Attachment 470114

    Anyone better at me reading analog diagrams? I guess the "cross over switch" is the key switch in the control panel.
    And that is connected to a relay somewhere in the cabinette, that in turns closes the circuit or turns on and off the 1C solenoid side of the bidreictional solenoid valve.

  7. #7
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    Re: Okuma LB15 - chuck clamping issues / solenoid.

    Your explanation is a bit messy and I hardly relate it to illustrations you presented here.
    some simple questions:
    1. Where you see the "cross over switch" in the diagram?
    2. Did you find the hydraulic diagram ( the one with actuators = valves )?
    3. When the draw bar is in action ( when the chuck clamping direction is set to ID clamping ) are both LS activated as must? ( =at the very end of te draw bar stroke )
    4. What is status of hydraulic pressure and draw bar LS when OD clamp is selected?
    The solenoid is spring returned, so question is if its activated when clamping or activated when opening
    disconnect the wires to see the answer.
    Let's make some description of clamping / releasing, opening / closing. In case of OD clamping closing the chuck = clamping. In case when ID clamping selected opening the chusk is = clamping.

  8. #8
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    Re: Okuma LB15 - chuck clamping issues / solenoid.

    1)
    As far as i can see is that the cross over switch is called CH3(F12) in the first chart on the C2 circuit on the right side.

    2)
    No

    3)
    No, when its in ID clamping its the 2C of the chuck solenoid that controls the activation, when its not activated it returns on spring pressure.

    4)
    My pressure sensor on the back side seems to be broken it never reports any pressure anywhere, ever.. but everything else works..


    Actually when the F12 switch is flipped to ID, "Opening" the chuck will make it close up, and vice versa. The pedals change direction with the cross over switch.

  9. #9
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    Re: Okuma LB15 - chuck clamping issues / solenoid.

    I would advice to place limit switches where they belong to first.
    Maybe after MDI command chuck clamp / chuck release the informative error message will pop- up ?
    cross over switch is called CH3
    we speak different languages. I see CH3 is the "chuck unclamp command" only :-(

  10. #10
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    Re: Okuma LB15 - chuck clamping issues / solenoid.

    Ah well as soon you as hit M83 or M84 or any of the pedals when im in OD mode of the chuck it alarms right out - nothing else happens. "ERROR - A: Chuck Open/closing"

    when i flip back to ID and clear the error it works just fine again.

  11. #11
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    Re: Okuma LB15 - chuck clamping issues / solenoid.

    What if you will try to place limit switches so, that they are activated at the end of pull bar stroke respectivelly?
    When the workpiece is clamped in the chuck none of LS should be activated.

  12. #12
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    Re: Okuma LB15 - chuck clamping issues / solenoid.

    Would you happen to have a picture of the limit switches you would be speakin of? cuz the ones i got in the rear is not really getting triggered at all when the chuck is opening and closing. Not entirely sure what they are for to be honest.

    The only two i can see in the rear of the spindle sits just on the right and below and has a "push" rod coming out that isnt really moving when the chuck draw tube is.

    afaik the triggering is happening thru pressure switches for the chuck not the normal roller type limit switches?

  13. #13
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    Re: Okuma LB15 - chuck clamping issues / solenoid.

    1. Take away external jaws out of chuck ( the jaws who holds the workpiece ). Then we will gt the maximum draw bar stroke lenght
    2. Go to the back end of draw bar.
    3. Make chuck open and close
    4. See what is moving there
    So the moving part should be equipped with big washer - a flag, which is seen by limit switches. Make the limit switches detect that flag at the both ends of stroke.
    I was looking for the pictures on google and the best I found is Flag and LS are not indicated in this picture.

  14. #14
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    Re: Okuma LB15 - chuck clamping issues / solenoid.

    ok, yeah there is two limit switches back there but not seeing anything getting triggered..

    To be complete sure; there isnt a parameter setting / tolerance in the parameters pages that has anything todo with the chuck right?!

  15. #15
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    Re: Okuma LB15 - chuck clamping issues / solenoid.

    forget the parameters for the moment.
    Place your limit sensors where they needs to be.

  16. #16
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    Re: Okuma LB15 - chuck clamping issues / solenoid.

    Quote Originally Posted by Algirdas View Post
    forget the parameters for the moment.
    Place your limit sensors where they needs to be.
    So this is what i think is the limit switches for the chuck.. that round metal part that is supposed to trigger the swithces.. that thing aint effing moving to be honest. And on second note.. those look like airlines
    but there is no pressured air for this thing..

    Attachment 470202

    Anyway with the limit switches both unscrewed, the problem persists.. ID clamping works, OD clamping does not.. and yeah that solenoid **** is not moving in any sense of the word..

  17. #17
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    Re: Okuma LB15 - chuck clamping issues / solenoid.

    Attachment 470212
    Attachment 470214

    Anyone knows what this knob does ?? is it for pressure monitoring or what is that selector for?

    the chuck pressure switch seems to have died off .. but as said the chuck still runs in ID mode..

  18. #18
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    Re: Okuma LB15 - chuck clamping issues / solenoid.

    Im starting to think that those micro switches i found is for the Gear shifter on the machine and not the chuck clamping limit.

  19. #19
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    Re: Okuma LB15 - chuck clamping issues / solenoid.

    After some figuring i realized i may be in the SMW chuck mode.. even tho i wonder where the "Air" part in that comes from.

    In the cabinette there is 3 relays that in concert would control the live support and the chuck depending on key changes..


    And thus im trying to figure out where to set clamping pressure thinking it might be set to low and thus not allowing it to clamp in OD mode.

    Click image for larger version. 

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  20. #20
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    Re: Okuma LB15 - chuck clamping issues / solenoid.

    Does anybody knows where to set the chuck clamping pressure on the machine?! i suspect something is off with the hydraulics tbh.

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