584,858 active members*
4,688 visitors online*
Register for free
Login
Results 1 to 11 of 11
  1. #1
    Join Date
    Feb 2005
    Posts
    116

    Absolute and Incremental Toegether

    I am cutting a constant pitch screw with varying root diameter with constant pitch on my mill using the 4th axis .
    The screw has a major root diameter (.325") for 6 turns and then transitions to a minor diameter (.265 ") for 8 turns.
    From there the screw is cut an additional 6 turn at the minor diameter.
    Right now I am cutting in one direction from left to right .
    After completing the pass I am raising the spindle up to a clearance height and then moving X and A back to there initial
    starting position to the left..
    A lot of time is wasted returning A axis back to 0,0 to start the next pass.
    Right now every line is written in absolute mode.
    Can I combine G90 and G91 on the same command line such that X and Z moves would be in absolute and
    A moves would be in incremental ?

  2. #2
    Join Date
    Feb 2006
    Posts
    1792

    Re: Absolute and Incremental Toegether

    I do not think so.
    G90 and G91 belong to the same G-code group, and only one code from a group remains active at any time.
    You may, however, experiment and let us know the result: G90 G00 X_ Z_ G91 A_

  3. #3
    Join Date
    Jan 2005
    Posts
    15362

    Re: Absolute and Incremental Toegether

    Quote Originally Posted by johnd View Post
    I am cutting a constant pitch screw with varying root diameter with constant pitch on my mill using the 4th axis .
    The screw has a major root diameter (.325") for 6 turns and then transitions to a minor diameter (.265 ") for 8 turns.
    From there the screw is cut an additional 6 turn at the minor diameter.
    Right now I am cutting in one direction from left to right .
    After completing the pass I am raising the spindle up to a clearance height and then moving X and A back to there initial
    starting position to the left..
    A lot of time is wasted returning A axis back to 0,0 to start the next pass.
    Right now every line is written in absolute mode.
    Can I combine G90 and G91 on the same command line such that X and Z moves would be in absolute and
    A moves would be in incremental ?
    No you can't have the 2 active at the same time but you could use them on any individual lines one will cancel the other
    Mactec54

  4. #4
    Join Date
    Jun 2015
    Posts
    4131

    Re: Absolute and Incremental Toegether

    hy johnd

    A lot of time is wasted returning A axis back to 0,0 to start the next pass
    is the rapid of the 4th axis really-really slow ? what is it's rapid speed ?

    repositioning movement is done in feed or in rapid ?

    during threading, is the 4th axis used in positioning mode ( degrees / minute ), or like a spindle ( rpms / minute ) ?

    if your code works in positioning mode ( degrees / minute ), then have you tried to "start" and "end" at same spindle phase ? so to eliminate the need to reposition the 4th axis between passes ?

    Can I combine G90 and G91 on the same command line such that X and Z moves would be in absolute and A moves would be in incremental ?
    it is possible to achive this somehow ( by using a soubroutine, etc ), but i don't believe that you really need this trick

    i hope that all those questions listed above will light a spark / kindly
    Ladyhawke - My Delirium, https://www.youtube.com/watch?v=X_bFO1SNRZg

  5. #5
    Join Date
    Sep 2010
    Posts
    1230

    Re: Absolute and Incremental Toegether

    Quote Originally Posted by sinha_nsit View Post
    I do not think so.
    G90 and G91 belong to the same G-code group, and only one code from a group remains active at any time.
    You may, however, experiment and let us know the result: G90 G00 X_ Z_ G91 A_

    Quote Originally Posted by mactec54
    No you can't have the 2 active at the same time but you could use them on any individual lines one will cancel the other
    Hello sinha and mactec54,
    In the way you can combine Absolute and Incremental with a lathe control, (G00 X100.0 W-30.0) so are you able to do the same with a mill control using G90 and G91 in the same Command Block. The following example is quite legal and results in a combined Absolute move to X100.0 and an Incremental move of Y-10.0.

    G00 G90 X100.0 G91 Y-10.0

    One caution that should be observed is that on completion of the above example Block, the control will be in G91 (Incremental) Mode.


    Regards,

    Bill

  6. #6
    Join Date
    Jun 2015
    Posts
    4131

    Re: Absolute and Incremental Toegether

    hello angel

    G00 G90 X100 G91 Y-10
    same (iso) code may perform differently, depending on control brand

    each code line ( block , etc ) has different words inside it, and some controls may be sensitive to words order; in such a case, that code will work

    a conflict may appear on controls that are not sensitive to words order, because there are at least 2 words that belong to the same family

    G00 X100 W-30
    such a code may be executed identicaly on both types of controlers, because G90 is "modal", while W is "one shot"

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

  7. #7
    Join Date
    Sep 2010
    Posts
    1230

    Re: Absolute and Incremental Toegether

    Quote Originally Posted by deadlykitten View Post
    hello angel



    same (iso) code may perform differently, depending on control brand

    each code line ( block , etc ) has different words inside it, and some controls may be sensitive to words order; in such a case, that code will work

    a conflict may appear on controls that are not sensitive to words order, because there are at least 2 words that belong to the same family



    such a code may be executed identicaly on both types of controlers, because G90 is "modal", while W is "one shot"

    kindly
    I see you're still demonstrating your lack of knowledge.

    Attachment 404548

    G90/G91 are from the same G Code Group

    Attachment 404550

    Yet they can be combined in the same Block. The above are extracts from a Fanuc Manual, but Haas, Mazak, Yasnac and many other controls are the same. It is, however, not allowed to program G90/G91 in the same Block with an Okuma control.

  8. #8
    Join Date
    Jun 2015
    Posts
    4131

    Re: Absolute and Incremental Toegether

    Yet they can be combined in the same Block. Haas, Mazak, Yasnac and most controls are the same
    because the controller is sensitive to words order

    It is, however, not allowed to program G90/G91 in the same Block with an Okuma control
    because the controller is not sensitive to words order, at least for g-codes


    please, will you share the full list of those G groups ? kindly
    Ladyhawke - My Delirium, https://www.youtube.com/watch?v=X_bFO1SNRZg

  9. #9
    Join Date
    Jun 2015
    Posts
    4131

    Re: Absolute and Incremental Toegether

    hey angel, are there angels in heaven ?

    is there life after death ?

    why do you believe that okuma does not behave ok with both G90 & G91 on same block, while many other controllers allows it ? is it okuma old-fashioned ?

    who created fanuc ?

    is it possible for an okuma programmer to switch easy to other brands ?

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

  10. #10
    Join Date
    Sep 2010
    Posts
    1230

    Re: Absolute and Incremental Toegether

    Quote Originally Posted by deadlykitten View Post
    hey angel, are there angels in heaven ?

    is there life after death ?

    why do you believe that okuma does not behave ok with both G90 & G91 on same block, while many other controllers allows it ? is it okuma old-fashioned ?

    who created fanuc ?

    is it possible for an okuma programmer to switch easy to other brands ?

    i am just curious / kindly
    You purport to be some sort of Okuma Guru (skeptical), but again in this Post you display your lack of knowledge and of being a jerk.

  11. #11
    Join Date
    Jun 2015
    Posts
    4131

    Re: Absolute and Incremental Toegether

    i am far from being a guru, and my lack of knowledge is as deep as a black hole ...

    sometimes i smell the roses; roses are always there ... let it go; help others to gain knowledge, by enlighten them, not by making them fools

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

Similar Threads

  1. Replies: 5
    Last Post: 07-18-2013, 10:59 AM
  2. From incremental to Absolute,
    By CharlieM in forum BobCad-Cam
    Replies: 2
    Last Post: 12-03-2010, 02:33 PM
  3. Incremental Vs Absolute mode
    By chilly2k in forum Mach Wizards, Macros, & Addons
    Replies: 4
    Last Post: 03-06-2009, 11:54 PM
  4. Absolute or Incremental
    By mikede in forum Haas Mills
    Replies: 1
    Last Post: 02-04-2007, 12:02 AM
  5. Absolute and Incremental
    By ACME in forum G-Code Programing
    Replies: 3
    Last Post: 09-04-2004, 11:45 PM

Tags for this Thread

Posting Permissions

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