īut, it must be parameter dependent which operator's manual does not mention. So, I thought M51/M50 might be a standard codes like M00, M01. The operator's manual does mention that there is a parameter for spindle clamp M-code (M31 here), but it is silent on M code for spindle-indexing mode (M51/M50 here). 1' above work zero.Īs you know Sinha I have been wrong many times before so take my post with a grain of salt. If you were to look at it in the standard it would be Z is the distance from your work zero to the bottom of the hole, not R plane to bottom. The Z to W I think would be incremental in W. I would think there should be no difference in relation to the X,C,Z,R etc. It would suck if I had to because some of the parts I drill have 150+ holes on a BC and if I had to clamp and unlcamp at every rotation it would triple my machining time.Ĥ. I can not speak to this 100% because I have only been using this on a few machines recently and on MY machines it is not needed to clamp the spindle all the time. If I have to do some heavy milling then I will clamp the spindle. I do not clamp my spindle when I am doing light work like bolt circle drilling. So I would think that if you want to index the main spindle you have to use M51-rotate-then M50ģ. I ass u me that if you are using index modes you are trying to mill which then you are indexing the spindle and not running it at a constent. I have an M51 on one of my machines which is thru the spindle coolant on #4. The M51 will probably be the same if it is the same MTB. Your typical M3, M1, M8 things of this sort are usually typically across most machines. M-codes like M51 are typically MTB dependant. I believe, the given ststements are correct in system B and C, with G91.ġ. Is it correct, with reference to G-code system A? R_ is the distance from the initial level to R-point level. Z_ is the distance from R-point to the bottom of the hole, The manual gives this syntax (apparently for G-code system A, since U, H and W are there) : M31 (for C-axis clamp) must necessarily be used with these cycles, even in repeated calls in subsequent blocks.

With M50 (C-axis index mode OFF), M03 would start the main spindle, and with M51, it would start the live spindle. Is the number 51 always same on all the machines or do we specify a desired number in some parameter?Ģ.

M51 is given to be for C-axis index mode ON. I have to depend on Fanuc manual only which is often not very clear. Since my machine does not have live tooling, I cannot experiment on the machine for analyzing how the cycles behave.

M51 code on cnc