Need Help! LINUX CNC 4 AXIS WON'T RECOGNIZE THE BOTTOM SECTION OF MY PART


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Thread: LINUX CNC 4 AXIS WON'T RECOGNIZE THE BOTTOM SECTION OF MY PART

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    Default LINUX CNC 4 AXIS WON'T RECOGNIZE THE BOTTOM SECTION OF MY PART

    Hello, I just started using a 4th axis. I use bobcad v31. When I post my gcode of my part in on my machine. It shows the top 50% of my part fine.The bottom 50%shows up above my part in the top of my parameters. I zero and touch off. Then the top of the part is milled fine. Then my part rotates 180 and I get a z height error and machine shuts down. The bottom section is still above my top and high in z plane.
    What could it be, I have tried machine setup, new indexes etc. As always on this journey it will be something simple. Any help would be appreciated.

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    Default Re: LINUX CNC 4 AXIS WON'T RECOGNIZE THE BOTTOM SECTION OF MY PART

    Quote Originally Posted by unionoutfitt View Post
    Hello, I just started using a 4th axis. I use bobcad v31. When I post my gcode of my part in on my machine. It shows the top 50% of my part fine.The bottom 50%shows up above my part in the top of my parameters. I zero and touch off. Then the top of the part is milled fine. Then my part rotates 180 and I get a z height error and machine shuts down. The bottom section is still above my top and high in z plane.
    What could it be, I have tried machine setup, new indexes etc. As always on this journey it will be something simple. Any help would be appreciated.
    are you setting zero at the 4th axis center of rotation or the top surface of the part???

    Zero should be the center of the 4th....



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    Default Re: LINUX CNC 4 AXIS WON'T RECOGNIZE THE BOTTOM SECTION OF MY PART

    solved, my machine is to simple for true 4 axis. i have to create a g55 to machine the lower part of the model.



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    Default Re: LINUX CNC 4 AXIS WON'T RECOGNIZE THE BOTTOM SECTION OF MY PART

    Quote Originally Posted by unionoutfitt View Post
    solved, my machine is to simple for true 4 axis. i have to create a g55 to machine the lower part of the model.
    Linux CNC will certainly do 4 axis, it will currently control up to 9 axis so there should be no problems with a simple 4th axis 180 degree index.

    I agree with Burrman that it is likely that you have not set the 4th axis correctly in BobCAD and it is producing a Z height offset on your G43 line that when added to the tool length being called is likely trying to send the head on the machine up instead of down based on the Z height set in your G54.

    I have seen the same issue with Mach3/4 and simCNC and it is usually down to the generated code being incorrect on the G43 line after the index move, I have done exactly the same using BobCAD V28 3 axis Pro and the BCx3X Post processor, because I was only working with 3 axis sofware and a 3 axis Post Processor so it couldn`t output the different Z height offset required after the 4 axis index move, setting a new Work Offset for everything after the index worked perfectly and is an easy workaround
    So are you using the 4 axis version of BobCAD V31 and a 4 axis Post Processor and as Burrman has suggested in your other thread can you upload your BobCAD file (Zipped up) ????

    Regards
    Rob



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    Default Re: LINUX CNC 4 AXIS WON'T RECOGNIZE THE BOTTOM SECTION OF MY PART

    Thanks for all your help. When I create a part in 4 axis it does not rotate.
    Here is a file of a simple part.
    g54 works fine. But there is no A180 on my post to flip part when it goes to g55.
    is this a definition on CAM DEFAULTS / MULTIAXIS POSTING.
    I have also included the post file line g55 has a value of a0. line 598. It needs to go to a180 to flip part.
    It is probably a simple toggle in bobcad.
    Any help would be appreciated.
    Thanks
    jc

    Attached Files Attached Files


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    Default Re: LINUX CNC 4 AXIS WON'T RECOGNIZE THE BOTTOM SECTION OF MY PART

    jc

    Looking at you file you don`t appear to have enabled an index move for your second (bottom) feature, see images below.

    LINUX CNC 4 AXIS WON'T RECOGNIZE  THE BOTTOM SECTION OF MY PART-rotary-selection-jpg LINUX CNC 4 AXIS WON'T RECOGNIZE  THE BOTTOM SECTION OF MY PART-rotary-selection-180-jpg

    As I only have the Demo version of V31 I am not able to generate the whole code and I don`t have the machine Configuration or the Post Processor you used so I can`t duplicate exactly what you are trying to do, needs someone with a full version to have both your machine configuration and post processor so i am afraid that`s all I have for you for now

    Regards
    Rob

    Attached Thumbnails Attached Thumbnails LINUX CNC 4 AXIS WON'T RECOGNIZE  THE BOTTOM SECTION OF MY PART-rotary-selection-jpg   LINUX CNC 4 AXIS WON'T RECOGNIZE  THE BOTTOM SECTION OF MY PART-rotary-selection-180-jpg  


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LINUX CNC 4 AXIS WON'T RECOGNIZE  THE BOTTOM SECTION OF MY PART

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