562,566 active members*
2,720 visitors online*
Register for free
Login
IndustryArena Forum > Machine Controllers Software and Solutions > Fanuc > The method of comparing the actual spindle speed with the set point speed
Results 1 to 8 of 8
  1. #1
    Member
    Join Date
    Oct 2022
    Posts
    12

    The method of comparing the actual spindle speed with the set point speed

    Hello, I have a Dusan milling machine with fanuc 18m control. When the connection between the spindle motor and the spindle is disconnected, the tool collides with the work piece without rotating the spindle and causes the tool to break. How to activate the spindle non-rotation alarm?????

  2. #2
    Registered
    Join Date
    Dec 2009
    Posts
    795

    Re: The method of comparing the actual spindle speed with the set point speed

    Look for a parameter called SAR taht will look for the spindle arrival rotation request
    do you have belt between motor and spindle?
    Do you have ecnoder attached to spindle shaft or a proximity sensor?

  3. #3
    Member
    Join Date
    Oct 2022
    Posts
    12

    Re: The method of comparing the actual spindle speed with the set point speed

    I did not find the mentioned parenter. The connection between the motor and the spindle is through a gear and a position coder is used to display the speed of the spindle. Can you help me more?

  4. #4
    Member
    Join Date
    Oct 2022
    Posts
    12

    Re: The method of comparing the actual spindle speed with the set point speed

    I checked the 3708 parameter, the sar parameter only checks the rotation of the spindle motor, I need to check the actual speed of the spindle with the setpoint speed

  5. #5
    Member
    Join Date
    Aug 2007
    Posts
    790

    Re: The method of comparing the actual spindle speed with the set point speed

    SAR - is an output signal of spindle VFD and it must be procceded in ladder. Usually there is the M-command, which activates this function.
    You should put it after SxxxM4(3) block

  6. #6
    Member
    Join Date
    Oct 2022
    Posts
    12

    Re: The method of comparing the actual spindle speed with the set point speed

    thank you. I checked that sar only checks the rotation of the motor and does not check the difference between the setpoint speed and the actual spindle speed. In other words, if the spindle speed is lower than the setpoint value, the program It executes G01 and causes tool failure.
    I want the device to alarm and stop if the mechanical connection between the spindle and the motor is broken or the speed difference between the spindle and the motor is too large.

  7. #7
    Member
    Join Date
    Aug 2007
    Posts
    790
    Quote Originally Posted by Electrify View Post
    thank you. I checked that sar only checks the rotation of the motor and does not check the difference between the setpoint speed and the actual spindle speed. In other words, if the spindle speed is lower than the setpoint value, the program It executes G01 and causes tool failure.
    I want the device to alarm and stop if the mechanical connection between the spindle and the motor is broken or the speed difference between the spindle and the motor is too large.
    Then you should use spindle encoder and command feed per routine.
    I would advise you take additional gauge with comparator, but where will you get reference? - because your cnc uses serial spindle most likely.
    Are your belts getting broken often?

  8. #8
    Member
    Join Date
    Oct 2022
    Posts
    12

    Re: The method of comparing the actual spindle speed with the set point speed

    Our spindle has a position coder, can't we use it?

  9. #9
    Member
    Join Date
    Aug 2007
    Posts
    790
    Quote Originally Posted by Electrify View Post
    Our spindle has a position coder, can't we use it?
    May be your spindle encoder intended for rigid tapping?
    If so, i'm not sure if it is coupled all the time.
    Or you can observe real spindle speed during machining?

  10. #10
    Member
    Join Date
    Oct 2022
    Posts
    12

    Re: The method of comparing the actual spindle speed with the set point speed

    The encoder counts all the actual revolutions of the spindle.

  11. #11
    Member
    Join Date
    Aug 2007
    Posts
    790
    Quote Originally Posted by Electrify View Post
    The encoder counts all the actual revolutions of the spindle.
    So why don't you use feed per revolution Mode (G95)?

  12. #12
    Member
    Join Date
    Oct 2022
    Posts
    12

    Re: The method of comparing the actual spindle speed with the set point speed

    Can you explain more?

  13. #13
    Member
    Join Date
    Aug 2007
    Posts
    790
    Quote Originally Posted by Electrify View Post
    Can you explain more?
    If your spindle stops axis wil stop as well

    https://www.kennametal.com/in/en/resources/engineering-calculators/miscellaneous/speed-and-feed.html

  14. #14
    Member
    Join Date
    Aug 2019
    Posts
    142

    Re: The method of comparing the actual spindle speed with the set point speed

    You could look at G26 speed fluctuation detection. There are a few parameters to configure for the function but it works well.
    There are a few engine manufacturers that require this function to be setup on any machines that produce certain parts. Another option would be a ladder modification to use interlock and SAR via an alarm.
    SAR check via parameter has its pitfalls as it is easily bypassed using Dry Run and if memory serves it is only examined at the start of a block vs continuously.
    And as mentioned in earlier posts feed per rev. is another option.

    I know the manuals state it is T control only. But I have seen it used on M controls. I'm not sure if it is software version dependent or what control series support it.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •