changing milling head orientation while toolchange

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12 Dec 2010 08:49 #5979 by nursum
Hello, I'am working on a big milling center project, a 4 axes machine with turnable milling head from vertical to horizontal orientation (hydraulic driven), now my question: When the orientation of the head is vertical and I want to make a toolchange, the machine have to go up to a save z-position and then check out if the head is vertically or horizontally orientated, if it is verticaly a custom module is foreseen to manage the hydraulics to change to vertically orientation. After that the machine goes to the toolchange position and the toolchange procedure itself should happen (40 toolholders chain and a lot of hydraulics). How can I manage the question if the head is horizontally or vertically while the toolchange process? I have the toolchange prepare place and the toolchange place and between I need the milling head orientation module implementation....

Which strategy is useful?

Thanks a lot for tipps! Ingo (from Germany)

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12 Dec 2010 17:30 #5992 by skunkworks
My spindle requires a orient before the tool change can happen. I have a custom comp that orients the spindle (it is part of the gear change comp that I wrote). The tool change loop (iocontrol.0.tool-change, iocontrol.0.tool-changed) goes though the lock comp - then goes on to the ladder that actually does the tool change.

so - iocontrol.0.tool-change -> Spindle orient comp -> Ladder logic -> iocontrol.0.tool-changed

Somthing like that..


I am sure there is about 100 ways to do it.

sam

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12 Dec 2010 20:49 #5996 by robh
if i understand this right

you have a Z axes that also has a C axes ontop of it, correct?

so, you can tilt the head left or right over the machines X and Y table. but you need the spindle head to be vertical for the tool change arm to work and change tools.

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12 Dec 2010 22:51 #5998 by nursum
Hi Sam,
I have also to orient my spindle, but that is not the problem, I will explain the problematic more detailed. My milling head can turn from the vertical to the horizontal orientation, but for that turning the machine position is not the tool change position! In the tool changing position a head turn crashes the machine! So the normal procedure looks like this: If the head is in horizontal position the machine can go directly to the tool change position, but when the head is in vertikal position the machine have to go up in z direction about 1200mm ( it is a 12 ton milling centre!) then the head has to turn in horizontal direction and after that the machine can go to the tool change position. I have to insert a Ladder logic after the machine goes up in Z position and before it goes to the tool change position... how can I manage that?

Ingo (Germany)

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12 Dec 2010 22:56 #5999 by nursum
Hi robh,

it is not a real C axis it is a hydraulic driven head which has only two positions horizontal and vertical and the tool changing works only in the horizontal direction. I explained the procedure one reply above to Sam.. so if you have an idea... Ingo

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14 Dec 2010 13:14 #6027 by andypugh
You are likely to need a Classic Ladder setup to run the toolchange anyway, so adding a head orient stage to that should not be too hard.

Alternatively you could write a HAL component (userspace or realtime) that would fit in the same "slot" as the hal_manualtoolchange component.
it needs to respond to the tool change request pin going high, then set the change-completed pin when it finishes. There is almost no limit to the number of ways this can be achieved.
If you are comfortable with ladder-logic then use Classic Ladder, if you are happy with C then write a HAL component.. There is a tool called "comp" that makes writing HAL components fairly simple.

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14 Dec 2010 13:46 #6031 by nursum
Hello Andy, the toolchange and to orient the head is not the problem, the problem is that, that the head has to be orientated between the movements. The machine goes up to the changing position and the tool change request pin is set, but the machine are not allowed to go to the toolchange position without turning the head! If the head turns before movement it will crash the tool. So the machine have to go to a safety Z position, then turn the head and then go to the tool change position...

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14 Dec 2010 14:05 #6032 by andypugh
I think you will have to not use any of the "built in" toolchange position options, and handle it all in the toolchange sequence control.

However, you might be able to wangle something.

The full set of options is here:

linuxcnc.org/docs/html/config_ini_config...:%5BEMCIO%5D-Section

I believe that they are not mutually exclusive, so if you select quill-up and G30 modes it does them in sequence (experimenting in a sim machine might be needed to work out _what_ sequence)

Personally I would probably use a couple of hal modules linked together, a "head up" module which responds to the tool-change-request pin by starting a head tilt operation, then sets an output pin true when it detects that the head is up (or was already up). That output pin would then connect to your tool-change sequencer in the same way as the tool-change request would normally do.

It is possible that you can simply set the halui.joint.2.home pin to put the head in the right place for a toolchange as part of your sequence.

I think there is a way to issue MDI movement commands inside a script or HAL component, but if there is I don't know it.

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14 Dec 2010 14:08 #6033 by skunkworks
well - what about doing a MDI move?

I have a pallet stations on the machine - when I do a pallet change - I use ladder to command movements with the halui and ini.

linuxcnc.org/docs/2.4/html/gui_halui.html#sub:MDI

So for you - maybe
Tool change pin goes high.
G53Zsafe
Wait for in position
rotate head
G53xyz <actual tool change postion.
Wait for in positoin
Swap tools.

maybe?

sam

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14 Dec 2010 14:36 #6035 by andypugh
I have never been entirely sure that MDI_COMMANDS work during toolchange as they are inhibited in Auto mode. It is an easy experiment I have never bothered to perform.
Can you confirm that it works, ie that you can run a line of G-code on the basis of the tool-change-request pin going high?

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