Tool change routine

[rnc]

Hello dear folks,

first time poster here. I've successfully converted my trusty "old" router to an acorn board (perviously running LinuxCNC).
Took a while but I finally got everything neatly running. Now its time to set everything up for a nice workflow.
Im running ab ER20 collet with fixed tool length sensor, so my goal is to set following tool change routine:
on M6, move to specified tool change position, change tool manually, move to TT Probe, probe and be done

Reading though the manual and this forum i figured there are more than one way to achive this:

- Specify TT Probe location with G28 and set Parameter 17 accordingly. What i haven't figured out: if i can also set Tool change position in Parameters (as G30 perhaps?)

alternatively:

- write a custom M6 Macro, or use Swissi's much recommended Probe App.

So my question is, is there a preferred method, am i missing something, how would you go about this? I feel reluctant writing a custom Macro, as i find the samples (i found on here) rather confusing and un-intuitive... coding is not my forté.
Swisis App seems to be the way of least resistance but most features I'll never really need - an i want to compensate for the whole product, not just the parts i need.

Looking for some advice how to do this properly.
Thanks a lot guys & girls!

All the best,

Raph.

[ShawnM]

What you want to do is very easy and has been documented very thoroughly in this topic. There are several examples of m6 macros in this topic.

https://centroidcncforum.com/viewtopic.php?p=9150#p9150

I started with one of these and modified it to be a lot simpler and faster without all the moves and questions. My old machine had a movable and a fixed tool touch off to help set everything up for fast tool changes.

[rnc]

Tried it and It worked! Thanks for the hint.

Raph.

[ShawnM]

So glad one of those worked for you. It will speed up your "semi-automatic" tool changes for sure. When you are more comfortable with macros you can refine it even further if you desire. I had mine setup so that after the M6 was started I only had to press "enter" or "cycle start" one time and it would measure the new tool and go right back to work.

[rnc]

Aye, you can really find all the answers on here, just have to know where to look! So thanks for the pointer Mr. Shawn!

Writing the macro was not as difficult as i thought. I modified one of the examples which looked promising initially
BUT! I just tried to mill my first operation, simple 2d surfacing - The WCS Z0 was totally off.
I loaded T1 (my touch off tool), touched it off, found and set Z0 on my stock, then loaded my Programm wich prompted me to use another tool, touched it off again and went to work - only the Tool went waaaay to deep. Had my hands on the estop luckily, so nothing broke.
I did the same operation again, only i set my Z0 on the part with the same tool that i had planned for the milling operation and it worked out fine...
I cant really wrap my head around it... I found it awkward when fiddling with my M6 macro that it never got saved to the tool table. My best guess is that im missing some key element that does exactly that: Save my tool length to the tool table.

Tomorrow ill try a operation with a tool change in between and see where that goes.

Seems im not quite there yet, so any guesses would be appreciated!

Cheers and all the best,

Raph.

[ShawnM]

You can’t use your tool table with a manual tool change as the tool will be a different length every time you insert it into the collet. Do you have a movable AND a fixed tool touch sensor? The first procedure you did is not correct for the type of system you have or the macro you downloaded. You do not need a touch off tool to measure against.

The macro is setup for tool changes like your second attempt, You have to start with the first tool for your job, set Z0 on your material with the first tool and then have it touch off on the fixed and measure the offset and it stores that value in a parameter in the system. It does not store anything in your tool table, that’s for ATC systems.

[rnc]

Sure, tool lengths vary after each change... my thoughts would be that it cloud just override after each touch off. At least thats how it worked on my previous setup running LinuxCNC.

Now back to square 1.5...
I only have a fixed sensor. I usually setup my XYZ 0s is with an analoge probe similar to a Haimer 3D(The one im using: https://www.tschorn-gmbh.de/de/produkte ... lusV2.html). When touching off the tool length I a have a little 3D printed contraption that locks the Z0 on the Haimer-like probe. (As both the probe and my touch off sensor have some travel).
I could just find Z0 on my stock with the same tool for the first op, but that would leave some accuracy to be desired.
Not the most elegant way - granted im quite the noob still, so theres probably some clumsiness in everything i do.

So before jumping in and adding another piece to the equation (e.g. a movable sensor?) i wonder if there is any other solution...
I guess I could include my probing tool into the Gcode as T1... but that seems a little unrefined.
any other guesses highly appreciated!

Cheers,

Raph.

[ShawnM]

I'm sure it's quite possible to store the tool length in the tool database but to do that but it would require another custom macro. My question is why? As soon as you manually change the tool the stored tool length is useless. I'm not even sure what you need it for anyway, how would you use that value again? The macro you have does not use the tool length rather a stored offset value from Z zero and the height of your fixed tool touch off.

I can maybe see setting X and Y zero with your analog probe but it's a router so I don't think you'll even get that much precision out of it anyway. And how often do you start precisely at the edge of your material with a router?

The macro you have works by you setting Z zero with the first tool for the job and then touch off on the fixed tool height sensor. CNC12 then stores that offset value in parameter 71. When you change to the next tool in the job it touches off again to basically find the difference between the new tool and the offset value stored in parameter 71. It doesn't look at your tool library for anything.

There are numerous ways to set Z0 with the first tool on the workpiece (or spoil board) and most are very accurate despite what you may have read on the internet. Of course the movable touch plate is probably the most accurate but many still use the paper method or just by visually jogging the Z axis until it just touches the work piece.

[rnc]

Okay, my initial post was more detailed but i forgot to save the draft and got logged out, so here is the light version:

You are absolutely right: my macro is still not set up correctly.

instead of
G92 Z[0+[#9071]] ;Set Z position to 0 + detector height stored in parameter 71 - material thickness

it should be something like:

G10 H2 R [[ Z-Ref. Position] - [actual, absolut Z Position (Machine Coordinate)] (might be other way round )

(for this to work we need to set all tools to refer to H2 in the tool-library, which doesn't matter anyways, as the tool lengths vary each time)

Questions are: how to refer to the "z ref. position" (which is set in the Tool-Offset-Library) and the absolute Z-machine-coordinate (where we are right at that moment) in our macro? (Is Z ref pos. stored as H0?)

Workflow would look like this:
-insert analoge probe
-"Set Z Reference" in tool-offset-library
-manually set work-piece-origin
-start program which asks for the first tool
-machine touches off the new tool, compares new tool length to analoge probe length and saves the difference to H2
-machine continues utilizing H2 as tool-offset

Hope this makes sense and someone can share another piece of this puzzle, or maybe there's a different way i haven't though about?... did't think it would be that hard.
Man i just want to see chips fly...

anyways have a great weekend!

Cheers,

Raph.

[ShawnM]

Hi Raph, what you want to do requires a new macro or heavily modifying the ones available on the forum. The one I modified and use does exactly what you want to do with many fewer steps and does not use a reference tool or the tool library. It's highly accurate as I use my router to cut aluminum aircraft instrument panels.

My workflow looks like this:
-insert first tool
-manually set work-piece-origin for X and Y
-start program which then asks me to set Z0 on my workpiece
-machine then touches off first tool and stores that offset vale in parameter 71
-machine then starts making chips

-at the next tool change for T2 the machine moves to my "tool change position" set in G28 and I manually change the tool
-press cycle start and the machine quickly touches off T2 (sets new Z0) and goes right back to making chips

I don't think I could make it any easier for a machine that requires a manual tool change. I press one button during a tool change. If I could get the machine to read my mind then it would be even easier.

I wish you luck in your macro programming. Have a look at the macro manual if you need more help.