Reply with QuoteIf you are using G90 in your part program then you are positing off of the Absolute position and not the Relative. The CNC doesn't look at the Relative while it is running a program.
Fanuc: Relative Position and Tool Setting
Hi guys-
Machine is a Robodrill Mate with a Oi-MC
I'm using a master tool (a Haimer) to set G54 and such in my machine, and I'm using it as my master tool.
1- I touch it off on my gauge block, go to Position > Relative Position and set Z0 as the origin.
2- I touch my tools off on that surface, and set their offsets with Input C in the Offsets page.
3- Everything works... UNTIL I turn the machine on/off again. The relative coordinates change...
So do I need to go grab my master tool and touch off *every single time* my relative position changes or the machine restarts?
Thanks!
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Re: Fanuc: Relative Position and Tool Setting
If you are using G90 in your part program then you are positing off of the Absolute position and not the Relative. The CNC doesn't look at the Relative while it is running a program.
I'm using G54 in my programs. But all my tools are zeroed off of Relative because that seems to be how Fanuc wants it (touch a master took off of reference, zero the relative, use InputC to plug relative values into all the other tools).Originally Posted by drdos
That's fine with me, I don't plan on ever changing Relative- but it resets every time the machine powers down.
Re: Fanuc: Relative Position and Tool Setting
The relative position will always change on the FANUC controls.
I don't set the tool lengths off of a master tool here. I use the end of the spindle nose with no tool. That way every tool length is calculated from the same reference point every time.
Just touch the spindle on what ever surface you can and set relative zero there. Then load the tool and set length by touching of the same surface and use the "INPUT C" on offsets page.
Re: Fanuc: Relative Position and Tool Setting
Just so it's out there, this is actually a parameter on the OiD control. 3104#3 turns on/off resetting relative position on power up. I checked the book and this is not the case for the OiC.
Try putting the distance from the tip of your zero master to part zero in the external work coordinate. That way it's saved and won't clear on power down. Then touch your tools off to part zero the same as you are now. So you're basically measuring the difference between the master and subsequent tools, and that's your offset.
I'm with amorhous, I like setting the spindle nose to the table, that way you have positive offsets and can always double check with a quick glance or with a scale to make sure it's not bogus!
Re: Fanuc: Relative Position and Tool Setting
I would love to to do the spindle to the table thing, but the only problem is that the Robodrill (and most other BT30 drill-tap centers) have a lot of distance from the spindle to the table at the lowest Z height - like 5.5". They design these machines for doing serious serial production work, so they assume you're going to have big work holding on the table (hydraulic fixtures, pallet changers, etc).
Re: Fanuc: Relative Position and Tool Setting
Everybody uses his own method of offset setting. And every method is correct if it works.
I prefer the use of a master tool for work offset. length offsets are the differences in length from the master tool. The advantage is that any serious error in length offset would be obvious, because one can see and estimate the length differences.
