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IndustryArena Forum > Machine Controllers Software and Solutions > Fanuc > A axis not tanking negative values.
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  1. #1
    Junior Member
    Join Date
    Nov 2018

    A axis not tanking negative values.

    Hello, i've been looking at the forum for some time now, but this is my first post.

    In my work we have a 3+2 mill machine made for styrofoam. The machine works fine, but we have some issues with the post processor.

    We are currently using FANUC 5x Mill which was given to use, but its doenst work the way we want to. So we started our mission to make it work like it should.

    The first problem was that it made some wind ups when it should. We manage to fix that, but to verify it we made some half cylinders and mill them in various directions, to test if it was working like it should. A clarification is that our machine is a head/head type and both C and A axis have -105° to -105° angles.

    But the problem is that there is one direction of milling it that it makes wind ups in every past. We know for sure that in this direction and position of the machine and axis it shouldnt make any wind ups. We know why it makes them, we just cant find what it is in the POST, we tried changing everything that we look online but nothing worked.

    Ill try to describe what it does: The half cylinder is lay down on the machine bed, and the direction of the cylinder is in Y axis, so.. it makes half circles in X axis rotating the A axis which is the one with the tool. The problem comes when it reaches 0°, it comes from 90° all the way down to 0° and then it wind ups instead of going continuously down to -90°. Its like it wont take any negative values on A axis. The weird thing and makes us wonder a lot, is that in all other positions of the cylinder what we have tried it (all the other 5 ones) it works just fine.

    Ill really appreciate if anyone has any type of suggestion or something to look at.

    Thanks to all.

    Some clarifications: We are currently using Mastercam 2018 and we check things with CIMCO.
    Im adding our PST in case someone wants to check some value and i added a jpg file with the view from CIMCO where you can see the little wind ups that it makes and the position of the cylinder, and it shows clearly that it have the capacity to go further but it wont. 
    Regards from Argentina.
    Attached Thumbnails Attached Thumbnails Wind Ups.jpg  
    Attached Files Attached Files
    Last edited by Fxsm12; 11-15-2018 at 01:27 PM. Reason: Wrong file

  2. #2
    Junior Member
    Join Date
    Jan 2014
    I'll take a stab at it. You said you have been trying to make it work like it should?
    Sounds like it's doing an incremental move when you want it to be absolute? From 90 to -90..
    Maybe it's a program issue, I haven't even looked at the program since I am not a CNC programmer. But you could check parameter 3401 MAB. Make sure it is set to (0) so that what sounds like the rotary axis (A) can move a cording to the G90-G91.
    If anything it's worth a look.

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