Rapid movements following a G77...
Close
Login to Your Account
Results 1 to 7 of 7
  1. #1
    Join Date
    Feb 2016
    Country
    UNITED STATES
    State/Province
    Indiana
    Posts
    5
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    0

    Question Rapid movements following a G77...

    I suddenly experienced an issue with rapid movements (G00) following a g77 p# line on our Charmilles wire machine. I havent ever experienced this in the past so its confusing that its suddenly happening and why.

    I am burning halfway around a round part after a 3 point center find. Generally I would find the 3 points manually but lately running more than 2 or 3 parts, i've been writing in the the block of code for locating into the beginning of the program so i can hit go and walk away.

    After manually locating the first one and setting Points 1, 2 and 3, I wrote this into the beginning of the program:

    G77 P1
    G70 B0
    G74 P13
    G00 Y1.0
    G77 P2
    G70 B270
    G74 P14
    G00 X1.0
    G77 P3
    G70 B180
    G74 P15
    G79 P10 B0
    M50
    G77 P10
    G92 X0 Y0

    The rapid movements in Bold are having issues. The first one (G00 Y1.0) gets completely ignored (no, its not already at Y1.0) and skips right to the G77 P2 movement. Even when I put it in single block. The second rapid movement (G00 X1.0) is even more odd. Instead of going from X-0.01145 (Point 2's X coordinate) to X1.0, It goes to X1.98855 which is 2 inches incrementally from where it started. So not only is it ignoring the first rapid all together, Its also moving incrementally when the machine is in absolute mode AND adding an inch to that movement. I made sure the main and sub programs do not have a G91 anywhere so i dont know why its moving incrementally. Not to mention the extra inch of movement. And it is actually an extra inch not just a scaling issue. I plugged in G00 X2.00 and it went to X2.98855 which is incrementally 2 inches from where it left (X-0.01145) plus an extra inch. I tried writing a completely new main program and had the same issue. I wrote another new program just for locating in a different directory all together and still had the same issues. I erased all of the G70's and G74's and still the same issue:

    G77 P1
    G00 Y1.0
    G77 P2
    G00 X1.0
    G77 P3

    This still did the exact same thing. Once I erased the G77's the rapid movements did what they were supposed to do. Then I tried this:

    G77 P10
    G00 X-1.0 Y0

    When I ran it, it ended up at X-2.0 Y-1.0.....

    If I type a G77 movement into the MDI line, and then a rapid movement, It works fine. Just not in a program. I added G91 in front of the rapid movements in the location block of code and it ran exactly like it should. This is my current solution. But if I remove the G91's or replace them with G90's it has the original problem. Using incremental movements in the location block of code works fine and is the easy quick solution. I just prefer to always program in absolute mode to avoid confusing myself and make the programs themselves easier for me (and others) to read and figure out what exactly its doing. Plus I want to know what is going on here and why. I would appreciate any input. Thanks.

  2. #2
    Join Date
    Feb 2016
    Country
    UNITED STATES
    State/Province
    Indiana
    Posts
    5
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    0

    Default

    Forgot to mention that I also plugged in several G00 Y1.0 lines in after the first one in case it was a read ahead issue...Ignored all of them...

  3. #3
    Join Date
    May 2005
    Location
    Republic of Arizonia
    Posts
    1,448
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    381

    Default

    I’m not familiar with your machine.
    On a makino , I’ll input the hole size that I’m looking for and the degrees per touch off and how many edge find cycles to average.

    If you have the manual with the G codes.

    What does it read for center finding on a circle?

  4. #4
    Join Date
    May 2005
    Location
    Republic of Arizonia
    Posts
    1,448
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    381

    Default

    Maybe it’s a

    G77 X,Y ,angle , number of tries...

    If X,Y are greater in length then your radius

    Or

    G77 with a length longer then hole size.

    This would be irrelevant to the coordinates.

  5. #5
    Join Date
    May 2005
    Location
    Republic of Arizonia
    Posts
    1,448
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    381

    Default

    Maybe what you need is to set 0,0 in the coordinates.

    Example:
    G54G77 etc etc....

  6. #6
    Join Date
    Jan 2013
    Location
    Plainfield, Indiana, USA
    Posts
    1,578
    Post Thanks / Like
    Likes (Given)
    1156
    Likes (Received)
    822

    Default

    Try a 'G90' in front of your G00 . . . makes sure your are back in Absolute coordinates.

  7. #7
    Join Date
    May 2005
    Location
    Republic of Arizonia
    Posts
    1,448
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    381

    Default

    Did some reading.

    A makino uses G77 for finding center in a hole, but doesn’t change coordinates...

    So you would use G91 when using G77

    A G83 is a hole measurement and coordinates are set to the center of the hole...

    Makino

    Example:

    Start in a work group say G54 Program

    The some where along the line a G55G91G83
    and define the additional information for G83.

    Another line of code after finding center sets coordinates to that center...

    Probably specific to your machine, if it has a G83 available.


Tags for this Thread

Bookmarks

Posting Permissions

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