Tool offsets for CNC



  • I'm trying to implement semi automatic tool changing -- where my mill will using a know machine coordinate to measure the tool length using a fixed position button, then i will keep work coordinates relative to my stock independent of that -- mostly, zero on Z is zero in work coordinate system, will be based of an arbitrary tool which will be zero tool offset. Then when I need to change tools, I'll run a macro --which will turn the spindle off, move the toolhead for manual change, and with a few M291 commands to prompt me to change to the next tool -- that is pretty easy to accomplish, then once I confirm I've done so the machine will move to the probe point, measure the tool and adjust the offset. That, I don't know how to record. I can do an G38.2 to get to the probe, but then using a G10 L20 or something similar will mess up my work coordinates which are set relative to the stock, so now I just want to record the tool offset. Is there something like that available, i keep reading through new RRF3 additions and still can't find it.


  • administrators

    G10 P# with no L parameter, or with L1, will set the tool offsets without touching the workplace offsets.



  • @dc42 yep -- just figured out I need to use G10 P0 -- that works. The tricky part now is how do I set it automatically, I don't know what Z offset will be, it will be measured when G38.2 does it's probing of the new tool. Basically assume it was Z0 -- then I probe the tool height, and I want to set the offset based on that difference.



  • @dc42 I think M585 does it -- I just tried it -- and it looks like it set my offset correctly. Will make a rigid mount for my button and do more tests.


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