fanuc 18i programming with tool changes

[krustykrab]

Hi,

I have a friend that has a Fanuc 18i controller who wants to start running programs with multiple tool changes.

On my Fanuc 20, I pick up each tool and enter the value in the tool offset page for the length. The value I get is from the Relative Z location, which, seems to be relative to the machine home position.

However, when he picks up his tools, the Relative Z location is relative to the Absolute location. Is there some kind of parameter to change so that his Relative position is relative to the machine absolute position?

I'm not sure if this makes any sense to anyone, but I hope so.

What I do on the fanuc20, is first pick up my X0Y0 location on the job and enter the machine absolute position in the G54 table. Then I reference my Z pickup to a block and whatever that number turns out to be (like z=-206mm), then I enter a value in the G54 table Z=206.
So, then I go and pick up each tool on that block and type in the "relative" Z value....which is the SAME as my Machine absolute value. These will be the H values when each tool is called up in the program.

This has always worked for me....mostly self taught. Is it wrong? And why does the 18i Relative position reflect the Absolute position?

I'm guessing that I have to cancel the G54 before picking up the tools?

[krustykrab]

If I'm speaking in circles then let me know......but otherwise any help would be great.

[maktiel]

First of all, before I touch off any tools I zero return all my axis and clear out my relative position. That way relative and absolute are the same and there's less chance of messing anything up.

Now I'm not sure I understand what your asking about the tool changes.
Are you redefining your G54 Z position each time you change your tool?
Are you defining seperate Tool Length Offsets and calling them up using a G43H? or is that what you asking how to do?

[krustykrab]

each tool gets called up during the program using g43 H#

So, I zero out the machine, go pick up each tool at my pick up block.
Then I add any offset required in the g54 z value?

[bob in windsor]

I do it the same way as you on the 16m that I run.At power on, I home the machine with g91 g28 zo,then g91g28 x0y0.After its homed, I set the relative z position to zero and then do exactly as you do.This way the relative will match.Maybe he isn't setting it the same way.

[psychomill]

There is a parameter that controls the absolute position display at 'reset'. I think its at 1201.

Then there are parameters to control relative positions at 3104. I think he may be hitting reset at some point of picking up tool lengths and the display changes position and its relativity. If he zeros out his relative Z (when the machine is at machine position "0") it should stay. If he hits reset and the Z changes, then either stay off the reset button (and maybe MDI) or change the parameter (3104 bit 3 I think controls the relative and absolute values for each other). Do you have a book?

[krustykrab]

ok, we'll try zero out the relative after home position and then re-pick up the tools. I'll let you know how goes as soon as I can.

thanks all!!

[hangslot]

With some machines there is a switch or a keep relais called "manual absolute"
Be sure to switch this function on!

[Bent]

"What I do on the fanuc20, is first pick up my X0Y0 location on the job and enter the machine absolute position in the G54 table. Then I reference my Z pickup to a block and whatever that number turns out to be (like z=-206mm), then I enter a value in the G54 table Z=206.
So, then I go and pick up each tool on that block and type in the "relative" Z value....which is the SAME as my Machine absolute value. These will be the H values when each tool is called up in the program."

As i understand it then you are changing the H values in TOOL OFFSETS everytime you are running a new program ?????????? Is that right

Bent

[Gncc50]

Boy am I glad you asked this question. I think we are having the same trouble.

When I touch off my tool or to a block and enter that figure into G54. I then set the rest of my tools. My tools are set right but if I bring each tool down to 0.000 (material top) the display reads the differnce between the tools and doesn't dispay 0.000 Is this the same problem you are having? My machine (Fanuc OMD) had lost alot of it's parameters because it sat too long bitween battery changes. Could this be the problem??? I apologize if I am butting in on your thread. I hope this isn't bad manners. I am new to the Forum.

Anxious to find out also. Pete