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Hello Folks:

I am having trouble with the Touch Off function on my mill, I must be doing something wrong. The following is the procedure I am using.
I am using a vise which is mounted on the table and my Z axis 0 would be about 3 inches above the table.
Procedure
I load program that I want to use,
Open it up, axis displays the tool path, the programs run flawlessly when cutting air.
Home X, Y, Z.
Then I perform the touch off function, I use a feeler gauge., I set the offsets in the appropriate box and push OK.
I use G54 for my coordinate, I have also inserted G54 into the preamble of my program.
This is where it gets troublesome,
When I push the run function,
The Z axis moves down and settles out below the bottom of the work, also the X and Y, zero positions do not go to the Touch Off positions.
Obviously there is something I am missing, in the initial setup of EMC2 is there something I should have done and did't.
Am I doing the Touch Off correctly.
Any thoughts would be greatly appreciated.

The latest (2.5) version has options in the touchoff window to select the coord system
(G54, G55, etc.) that will be set. If your program has any G10 L2 Px commands in
it, it will change the coord system and nullify your touchoff setting. And, of course, if
you use G41, G42 or G43 commands, that will offset from the coordinate system
by tool radius or length settings.

I'm wondering why you home after loading the program, I always home when I
start LinuxCNC.

Jon

Chipmunk wrote:
Can you post the first dozen or so lines of your G-code?

Bear in mind that when typing in a number in the touch-off box you are saying what you want to call the current position. So, if your G-code is written with the top of the work as Z=0 then if you have a 0.3mm feeler gauge, when the tool tip is touching the feeler gauge, that is a Z-touch-off value of 0.3mm in G54. If you put the offset in the tool table (T instead of G54 in the touch-off box) then it will set the tool length such that the current axis position is Z = +0.3mm

My guess is you have not loaded the tool length offset before touching off. I cobbled up a short tutorial for setting up material in a mill.

Seems I need to write on homing as well... oh wait is it in the general section.

John

Thanks you Folks for getting back to me.

Here is the first few lines of the code as it comes from my CAM program. I have not modified it in any way.
%
G20 G40 G49 M6 T1
G17
M7
G0Z0.7874
G0X0.0000Y0.0000S7000M3
G0X-0.0938Y0.5159Z0.2362
G1Z-0.0625F0.5
G1Y1.0309F3.0
G2X0.0000Y1.1247I0.0938J0.0000
G1X0.7976
G1X0.8354
G1X0.8420Y1.1247
G1X0.8491Y1.1247
G1X0.8565Y1.1247
G1X0.8643Y1.1248
G1X0.8725Y1.1250
G1X0.8809Y1.1252
G1X0.8895Y1.1255

ps When I start up the CNC program it always diverts back to the splash screen showing the carving of the old Logo. Is this normal or have I failed to do something on the original installation?

Thanks for getting back to me.

In answer to your question, I just thought that that was the way it was done. The reason I thought that was every time I start up LinuxCNC I get the splash screen showing the carving of the original Logo. I thought it would be better if the splash screen showed my project while I was touching off.