auto-tool measurement problems

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05 Apr 2021 09:00 #204867 by sibelius
Good evening everyone

I was trying understand the tool change macro and I have a few questions.
Before going into that I want to explain what I have tried to achieve.

When I change the tool in my Chinese spindle in the middle of a g code, the z of the tool change, so I was trying to follow this link auto-tool measurement because I think that is exactly my problem.

So i manage to adapt the new tool-change code to my machine and when I call the tool from MDI, the tool is measured and the off set is stored in the tool table file.
My reference point is the top of my tool setter.
To get the figure 120.141 of the parameter called
<_Ztravel> = 120.141		( distance between machine zero and touch off sensor )
I removed the collar nut of my spindle and jog z down on the tool setter checking when the sensor light up to stop and register this figure.
I also change all the coordinate accordingly with my tool setter's fixed position and seems ok.
Now when i was trying experimenting , axis was on machine touch off to workpiece (probably wrong).
Anyway what I did was to create a simple file in freecad to test the tool change procedure and my steps were:

1) after I fixed my piece of wood to the machine table I touch off x and y to the piece with G54 value 0.
2) with my first tool in the spindle, from MDI, I type T3M6 (my first tool is called T3) and the tool was measured.
3) the spindle after the measure was stationary above the tool setter
4) G0 G21 X0 Y0 to go back to my piece
5) at this point I was jogging the z to the top of my piece of wood and than touch off G54 set to 0.

At this point i was running my freecad gcode and before getting to the next tool right at the beginning, the spindle was trying to move under the level of the top of the wood piece crashing.

Can anyone point me in the right direction?
Thanks in advance for any help.

Regards,
V.

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06 Apr 2021 00:59 #205013 by andypugh
It doesn't really matter what you use as your reference, but you need to be consistent.

You might want to consider making or choosing a "touch-off-tool" that you use to locate the work surface and that all other tools are referenced relative to.

This _could_ be your spindle with the collet removed, if that is convenient.

The trick is to set the workpiece reference to to that with "touch off" and then set your tool lengths relative to that.

Note that "touch off" can set either the the tool length or the working coordinates. Basicallly it comes down to understanding the 4 different variants of the G10 command. (in the docs)

I don't expect this to be a complete answer, more an invitation to ask for further clarification.
The following user(s) said Thank You: sibelius

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06 Apr 2021 10:58 #205071 by sibelius
Hi
Thanks for your answer.
I think I need to read a bit more on the topic so I can avoid trying to hit a nail on the wall inside a dark room with my soldering helmet on.
But at least my tool setter wiring is correct.

I will update after some result.

Regards,
V.

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08 Apr 2021 00:46 #205301 by sibelius
Hello to everyone,

Finally I got the concept, now is working like I was expecting.
There is nothing better than a good twenty minutes sitting on the toilet reading papers to sorted out problems.
Bad for legs circulations but seems working for me.

So basically what I do when I start my work is:

1) load a piece of wood
2) remove the nut of my spindle (this is my fix z zero)
3) go to touch off the point on my piece of wood x=0 y=0
3) touch off Z with dowel thickness
4) run my gcode

Twenty minutes, is the right time.

Regards,
V.

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