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  1. #1
    Junior Member
    Join Date
    Sep 2018
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    2

    Limit loads on axis travel

    This is my first post to this forum, so forgive me if I leave out any important info.

    I am working on a HAAS DS-30 running continuous operation on lengths of stainless steel pipe. Bar stock feeds through main spindle, ends are machined, part is passed to sub and held by dual spindles while a parting operation runs, sub pulls out and the other end of stock is machined, repeating the cycle until the end of the bar.

    When parting tools break, the machine does not sense and will pull along the pipe, subsequently crashing the next tool into the stock. I am trying to add a load limit on the B axis travel that will output a #3000 - user defined alarm to indicate an impending crash when travel loads exceed expected values. I have scoured operator's manuals and forums but cannot find a machine variable for current B-axis load, even though there is a load value displayed on the controller. I have found variable #1068 which indicates the maximum load value since last restart.

    My current solution allows the machine to pull the sub spindle to its final position, then checks the value of #1068, outputting the above alarm if it exceeds expected values, but I would like to continuously monitor the current load during pullout and stop during the execution of motion as soon as the limit is tripped. This seems like a parameter I should be able to set on the controller but I can't find any load limits other than spindle load. My next idea is to simply monitor tool loads and trip my alarm based on those, but our incoming material has wildly inconsistent hardness and this may not be reliable.

    Any help or suggestion is appreciated

  2. #2

    Re: Limit loads on axis travel

    If the Haas has a user configurable input to the controller, a prox sensor or maybe a photo eye would work to sense the presence or absence of the material at the correct time. Monitoring the load might be nebulous at best. A call to Haas tech support might be helpful, they may have a broken tool detection option for that machine.

    On my single spindle machine I solved the problem by putting a pusher in a tool holder and run a cycle that pushes the bar back into the chuck to the proper start position. That way in the case of a broken parting tool it will just keep cutting the same part without crashing. Then hopefully someone will catch it before it cuts the same part 500 times. Not sure if this would work on a sub-spindle machine.
    Jim Dawson
    Sandy, Oregon, USA

  3. #3
    Member
    Join Date
    Jun 2015
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    2930

    Re: Limit loads on axis travel

    hy protocell

    - maybe there is a higher quality parting tool, so to decrease the frequency of this event; i am using kyocera gdm3020n-030ph pr1225

    - after the 2nd spindle clamped the part, move it a bit to right, and after that start cutting : in this way, you should avoid compressing the cutting insert, which may lead to shorter tool life, etc; you can find how much is required to "move to right before cutting" by inspecting the "load monitor value" or the "diff value"; this movement to right has to be done in feed, not in rapid

    - after the 2nd spindle has moved to it's safe position, index the turret to a " rod post ", and check if the material is where it should be, by using " load monitor " or "torque limit check"; this check should be in feed, not in rapid :
    ... among X, somewhere between the spindles, so to be sure that there is an empty space
    ... maybe also among Z, towards the 1st spindle or towards the 2nd spindle, so to check if the material face is where it is suposed to be

    i don't know how many of those functions are available for haas; if you wish, discuss them with someone who knows your control

    if you succed in implementing them, you will have much more piece of mind, and feeling comfortable when you are not near the machine / kindly
    Ladyhawke - My Delirium, https://www.youtube.com/watch?v=X_bFO1SNRZg

  4. #4
    Member
    Join Date
    Jun 2015
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    2930

    Re: Limit loads on axis travel

    hello again, during cutting, use " no-load-detect function "

    i have observed on some toolholders, after the insert was broken, that damaging the toolholder occurs at a much lower load : thus the machine feels the insert, but does not feel the toolholder ( because it is softer )

    if you are afraid that the load will increase after the insert is broken, simply use " load monitor "

    depending on control capabilities, you may have both functions activated during cutting ( no-load detect & load monitor )

    kindly
    Ladyhawke - My Delirium, https://www.youtube.com/watch?v=X_bFO1SNRZg

  5. #5
    Junior Member
    Join Date
    Sep 2018
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    2
    Thank you, I'll give that a try today

  6. #6
    Member
    Join Date
    Jun 2015
    Posts
    2930

    Re: Limit loads on axis travel

    hy proto there are also other methods :

    1) after the cutting tool finished, move the 2nd spindle towards left : travel should be insert_width-a_bit : if there is no gap, the machine should sense this, and stop

    2) after the 2nd spindle has gone to its home position, with both chucks clamped, trigger a dual comand, at same moment, each one for each spindle : like "break" on 1st spindle + "orientation" on 2nd spindle

    if the material was not cut, the machine should raise an error, and the stress on spindles should be minimal





    but don't you receive an error for chuck un-clamped ? if the cut-off tool failed, then the 2nd spindle should not be able to move, because the part is clamped also by the 1st spindle; or does the material slides inside the jaws ?

    what happens when the cut-off fails ? is the material pulled by the 2nd spindle, and jaws from 1st spindle are damaged ? if the material remains in 1st spindle, you can simply trigger an rpm comand for the 2nd chuck, after it has gone to home position, and this should raise the chuck not-clamp error

    kindly
    Ladyhawke - My Delirium, https://www.youtube.com/watch?v=X_bFO1SNRZg

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