Practical question during use

[Hessel Oosten]

Hi James. Art, Others,

Produced my first little PCB today and all went well.
But I encoutered a practical problem for which I didn't have a quick solution.

After the probing I adjusted the Z height for the engraving mill and started the real milling process.
It was not quite deep enough to my liking, so I stopped the process. No problem.

But now the question: Do I need every time when trying a new Z-height the probing again and again and again, or do I miss here a more clever solution ? Of course I realise that when getting more experience, this will occur less frequent.

Thanks,

Hessel

[Country_Bubba]

"After the probing I adjusted the Z height for the engraving mill and started the real milling process.
It was not quite deep enough to my liking, so I stopped the process. "

If you mean "adjusted the Z" means you moved the head or tool up or down, then yes, you will have to re-probe. If, however, you stopped the program and changed the Z depth in the gcode only and resumed the execution, then I don't think you will need to re probe.

[daedelus]

Just to add to Art's reply...

If you change the Z height in the gcode and make no other changes, then the variables used should be exactly the same and you should be able to load the new gcode and resume from the line after the probe section.

However, I think this is dependent on the control software you use. I tried this once in LinuxCNC and all the variables that stored the probe values were reset between sessions so I did need to re-probe each time. In theory Mach3 should fare better but I havnt tried.

We were just discussing the possibility of logging the probe values so they can be re-loaded whenever you mill / re-mill for any control software (take a look at the "Forgot to mention" thread in the "General discussion" topic).

[Hessel Oosten]

Hi Both,

Thanks for the help. 'Think its more clear now. My problem presentation was a little bit "cloudy".
Using MACH3 here.

After the probing (with a broken mill upside down) there was no problem to replace that "poor man's probing tool" with the V cutter. The new/adjusted height is taken without problem.

Than during the engraving I interupted the process. I gave in MACH3 in the Dig Read Out a new (better) Z height and tried to "RUN FROM HERE". Well, that was the problem because the new AL-file refuses that. I HAVE to rewind the code, but in that case ... new probing necessary. Variables gone seemingly.

If I undertood it well, I now can try:

1. To change/edit in the code e.g. G1 Z[#100 + -0.15] F60 --->>>> G1 Z[#100 + -0.18] F60 and save.
2. And after that try to "RUN from HERE" just after/in the characteristic AL pause.

Is that right ?
Will report trials because I expect .... that after editting the G code (above) and saving it, it will NOT run from the point were I left it. After saving it's always rewinded and starts so obligatory at the beginning.

Thanks again !

Hessel

[Country_Bubba]

OK, I'll take a whiz upwind in a hurricane as I don't use Mach.
However, from what I have read; when you do a "run from here", it goes through the code from the start BUT doesn't do anything until it gets the the "new" starting point.
I can be all wet, and probably am; but that is the way I understand it.

[daedelus]

I am not a Mach user either so I may also get wet
However, if the variables are properly stored from the probing stage then they should remain so even after you restart Mach3.

If what Art said is true and Mach goes through the gcode until it gets to the start point then I guess it could wipe the variables clean again. What you could try is to make a copy of the gcode file after probing and delete the starting probe section altogether. Load the new gcode in Mach and then you can run from the start and go straight into milling.

I know in Mach you can check the variables in one of the menu options. If you check the variable/parameter 501, its value should be something other than zero.

Not sure if that helps or makes sense.

[booski]

Having used both Mach and LinuxCNC.

If you use what is essentially a 'start from here' in mach3, it'll simulate the entire code from the start up to the point where you've asked it to start from.

Whether it resets saved variables or not I don't know. It's to make sure the tool is in the right position before moving.

[Hessel Oosten]

Hi All,

A few things:

Editing:
a file in MACH3 means that it's loaded "new"again, so all variables lost. Starting from the beginning.

"Run from here"
is not possible with an AL generated file. When trying it (even 100000 lines away...) it always STOPS immediately during the simulation at the G92 line below:

G21 (millimeters)
G90 (absolute distance mode, not incremental)
(begin initial probe and set Z to 0)
G0 X-0.794 Y-0.791 Z0
G31 Z-10 F100
G92 Z0
So;
1. the simulation can never do a probing because simulations cannot probe ...
2. MACH is not even coming to the probe lines.

Just to make some confusing things more clear to myself.

Hessel