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C-axis positioning on turn-mill lathe

Message 1 of 3
593 Views, 2 Replies

C-axis positioning on turn-mill lathe

Hi. I have a multispindle lathe with C and Y-axis, and Siemens 840D controller. When I post programs I can not get the C-axis to index the way it should. Enclosed are a test file to show the problem.


In the program you can see on line 74 where it positions the C-axis for the first milling operation, giving SPOS[1]=0, which is fine. But when I do the other side, it also posts SPOS[1]=0, (line 410). This should be SPOS[1]=180, since it is on the opposite side. I have changed the tool orientation, but I can not figure out how to get the code correct from Fusion. Is it something wrong with how I do the tool orientation? Any tips would be appreciated. 



Lars Olav 

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Message 2 of 3
in reply to: lars.olav.tveito

Hi @lars.olav.tveito 


Thanks for raising your concern via forum.


I think this issue is with your customized post which you attached.  I checked with Siemens Mill turn post from F360 post library and its giving the expected output.


If you want to modify the existing one then open post file in a 'Visual Studio Code' or 'Notepad++' to do the required modifications.


1. Search ' machineState.cAxisIsEngaged = true; '

2. Put '//' in front of 

//return "SPOS[" + (currentSection.spindle == SPINDLE_PRIMARY ? mainSpindleAxisName[1] : subSpindleAxisName[1])+ "]=" + abcFormat.format(0);

3. Remove '// from  "return "";


4. Goto line number 1153 and add ' writeBlock( '

Technical Consultant - Post Processor
Message 3 of 3
in reply to:



Thank you for your reply. That pushed me in the right direction, so I could modify the post to make it work. I made your changes, but in addition I had to change the spindle names to make it work. Neither of my Siemens controllers accept SP1 as spindle name, so I changed it to SPOS[1]. This might be an incorrect way of doing it, but I have not seen any other use of this spindle name than C-axis positioning. Siemens only (as far as I know) indexes C with the SPOS-command. 



If this can cause any other problems down the line please let me know. 

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