I've been reading plenty of lathe tool offset threads - however, the older fanuc 6t-b does not have G54 or G10. It has G50 and that's it.
This is a new machine to me and I'm trying to wrap my head around how to setup the tool changer with coordinate systems that don't need to be changed much part to part: e.g. if I put in a new piece that sticks out of the chuck 4" instead of 2.1", I don't want to redo all my tool offsets.
Right now (as was on machine delivery to me) all of the tool offsets are large negative numbers. for example T0101 is x: -8.7770", z: -9.5000".
I first put the machine in the ref position (turret up against the furthest x/z travels away from the axis and chuck face / most upper right position). I then set 'U' 'ORIGIN', 'W' 'ORIGIN which puts u and w both at zero.
I measured the offset for this tool by taking an OD skim and measuring the diameter (off a 1" bar), and using a z-axis setter/depth gauge (2" block with a dial indicator built in so when the dial reads zero you're exactly 2.0000" from bottom to top of that gauge) placed on the chuck jaw face. I then go to MDI mode and set x0z0 using 'G50 X 0.9945, Z2.0' After this, I put the control in ref. mode and manually jog to the reference point
At this point, the u, w reads zero because I'm back at the ref point. X and Z read X = 8.7770, Z = 10.4000. Both values are positive values. The X reads identical to the stored x offset, except positive, and the Z is a bit different because who knows what Z they were using at the time.
I then go into the OFFSET page and set this tool T0101 with my new / similar values (because that's how they were doing it before) Xoff -8.7770, Zoff -10.4000.
I do this for the tools that I will use in my program - in this case for my first simple program I only use tools 1 and 7 so I setup the offsets 1 and 7 as described above.
I then load up my program and use tool 1 to set Z (absoulte) zero. I do this by using my Z depth gauge again against the chuck jaw. (I setup the program with the chuck face as zero, stock will need to stick out about 2.5" + 0.02"). I get tool 1 against the gauge at exactly 2.0000", then I go to MDI mode and program G50 Z2.0.
All is reading well in X and Z. I put the machine back in the ref. position, then I loadup the program and hit cycle start - at which point the tool changes to tool 7 (the first tool used) by the code:
T0700
G28 U0 W0
G00 T0707
At this point, the turret procedes to rapid towards the chuck face, the tool goes exactly on centerline, but during the move, the X and Z readouts change to some seemingly random numbers (maybe subtracted the tool offset values??) and I have to mash the E-Stop to stop it from rapiding right through the chuck.
Clearly I need to rethink or learn how the tool offsets are currently setup and intented for use, and how I want to do it.
I want to use the chuck jaw as Z0 everytime and just allow some error in the placement of the stock which I face in the program to the correct size.
Any tool offset / fanuc wisdom out there? Don't start talking G54/G55, or G10 - those are not available on the 6T.
Some additional info:
the parameters for automatic coordinate shifting are set to 0000 so its not that.
Do I need to setup the z0 in a different menu screen before running the programs?
I'll be back in the shop working this out in a few hours, but any help would be very much appreciated!! :drowning:
buying a new (to me) machine is a hell of a thing, as usual. This is my first lathe, and first CNC lathe that I've ever used. I have a mill - I wish that every part could be done on my mill right now. Darn lathe is difficult! Subtract an axis, add a tool turret that can crash chuck jaws that aren't cut just right... etc., etc., etc. wow.