[dpaulson]

I'm new at VMC. I am trying to set up tool offsets and the work offset(g54). I turn on the VMC jog each axis and home all axis. If there is any valves in the relative position display other than 0, i reset them to 0. I have a tool setter height gauge that I set on the table. I install a tool, and jog down till tool tips touches the z setter gauge. I install the number into the offset that I assigned to that tool with EOB Z and insert. Repeat for each tool. All z values are - values which make sense because z is below or - direction from the machine 0. Now on to setting the work offset. I can jog over and get the X and Y values right, but the z still is puzzling. I jog the z to the top of the work piece. relative position is -4.3265 or +3.4339 above the Z setter height for the tool that I am using (tool offset is -7.7604). I am think I am to put +3.4339 into the work offset z value. I go into MDI and enter with the correct tool number and H offset selected input a z0 command. the Z wants to move upwards which is an over travel error. I get all axis back to machine 0. set the work offset to -3.4339. Back to MDI. Input z0. Tool moves down to a position 3/4" off table or 3.4339 below the z tool setter height. (which makes sense because i set the work offset to -3.4339 I can cycle though all the tools and the Z0 will always be 3/4 off the table or 3.4339 below the tool setter height. So I assume that the tool offsets are correct, just the work offset isn't correct. Anyone can see what I am doing wrong. G54 and G43 are selected.

[cjfisher]

D,

Take a look at this post:
http://www.cnczone.com/forums/fanuc/...ml#post1762320
Superman (Post #9) talks about setting up the overall machine offsets. Post #5 is code from one of my machines and should give you some ideas about how to set up your code. I have cut sections out of the code to shorten it. What remains is the code relevant to tool changes.

Charles

[dpaulson]

Is there a reason that the tool setting height must be above the work the work offset height.

[Superman]

Is there a reason that the tool setting height must be above the work the work offset height.

Those are 2 different items, like apples & oranges

Work offset height is the distance from the spindle face ( or from the end of a referencing tool ) to the Z origin that you have programmed your part around
Tool length is the distance from the tool tip to the spindle face ( or to the end of the referencing tool ) if using G43 H#
Tool length is the distance from the spindle face ( or to the end of the referencing tool ) to the tool tip, if using G44 H#
( NOTE how these are worded, this gives you the correct sign to input with the distance )

Normally a tool setter is calibrated using a reference tool ( known length from the spindle ) when gauging, it should return a length distance that can be physically measured, ie from the gauge line on the taper ( very near to the spindle face ) to the tip of the tool


What values are you getting from your tool setter Vs ruler measurement ? are they nearly the same ??


Do not zero out the RELATIVE positions after homing, it is displaying the current position of the spindle / tool with respect to the active co-ord system ( normally G54 )
( you can zero the RELATIVE position when using manually, ( or setting up a job ), but homing again resets the values in respect of the G54 origin

[sinha_nsit]

If you want to understand the theory behind offset setting, pm me your email. I would send you some material.

Sinha

[Third-Gen]

The tool offsets are based on the NEGATIVE difference from all your tools, starting from the LONGEST.

So here:
tool 1: length 7.5
tool 2: length 4.5
tool 3: length 6.5 (also axis probe)

You would set your offset of tools:
Tool 1: 0
Tool 2: -3.0
Tool 3: -1.0

Basically the distance that the Z axis has to "fill" when it changes tools. When you go from a 7.5" tool to a 6.5" tool, the Z will correct with the H offset of -1.00, and will correct accordingly. Ive broken a LOT of end mills when I first got my OM-B running, a 4x4 piece of wood is your friend when trying to set up tooling the first time.

[Third-Gen]

Keep in mind also when setting your Z0 point on your work to have G43 and whatever tool number H offset active, so if its tool 20 (like I have mine), go to MDI and type G43, input, Shift, H, 20, input, Output start, the Z axis will move a little bit to offset from your currect Z offset to your Tool Offset, so beware. Then, touch off your part, set G54 or G92, and then let her rip.

[dpaulson]

I have gotten to a point that I can use the machine, so as I set up for different jobs, eventually it'll start to make sense.

[sinha_nsit]

Good progress!
The offset thing is so logical. One only needs to understand the theory behind it which is not a rocket science.

[marsheng]

I have an OMD.

G43 H# moves the axis immediately to the preset value. Can be quite dangerous if at Machine 0

I'm tying to move the Z to a safe point before implementing G43 or cancelling it G49.

Any idea on what registers holds the current tool and the new tool length.

I want to move the Z to G53 + or - offset length then do the change length thing.

Remove current tool length

G53 Z????
G49

ATC Change tool

New tool length.

G53 Z????
G43 H#20 (#20 is my tool number)