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ATC using stepper motor on A axis
« on: December 11, 2007, 09:41:40 PM »
I figured out how to cram a stepper motor in my CHNC in place of the air motor which originally rotated the turret but I need to know if I can drive it.  I would like to wire the stepper into a Gecko drive and control it as an auxiliary axis, that way I can tell the turret to rotate a certain number of steps to go to the proper tool, etc.  Is it possible to write a tool change macro or use brains to control an axis in this way?  I've been looking it over and I understand how to control a simple output like a solenoid or something, but I don't see how to use it for step/dir output (if it can).  Can it?

-Ryan

Offline Chaoticone

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Re: ATC using stepper motor on A axis
« Reply #1 on: December 11, 2007, 10:05:29 PM »
Yes, you most certainly can. I'm no VB GURU like some of the guys here but will try to think of where I saw an example. If I forget, please remind me. I have had a more than full plate latley.

Brett
;D If you could see the things I have in my head, you would be laughing too. ;D

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Re: ATC using stepper motor on A axis
« Reply #2 on: December 12, 2007, 06:56:19 AM »
Ryan,Brett,
Try this link from poppabear,
http://www.machsupport.com/forum/index.php/topic,4191.0.html
I think this is what you were looking for.

Regards,
Cutmore
Re: ATC using stepper motor on A axis
« Reply #3 on: December 12, 2007, 07:52:36 PM »
Thanks guys, at least I know I can go ahead with the hardware end of things.  I did see that post from poppabear but I can't figure out what part of the code is actually doing the step/direction output.  Time to do more digging...where can I find a listing and description of what all the command words mean?

-Ryan

Offline N4NV

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Re: ATC using stepper motor on A axis
« Reply #4 on: January 06, 2008, 09:11:43 PM »
My CHNC is missing the air motor.  Can you provide more information on the type of stepper you got to fit?  Any other information would be usefull, like what type of worm screw you used.

Thanks

Vince
Re: ATC using stepper motor on A axis
« Reply #5 on: January 30, 2008, 10:53:41 AM »
Vince,

Sorry, I didn't notice your post before. 

I'll have to take some pics of the setup to show you what I did exactly but I'll tell you quick anyway.  I couldn't find a stepper to fit directly where the airmotor was so I mounted one on the steel plate at the end of the carriage (the plate the wires pass through) and ran a driveshaft out to the worm.  Actually, I used parts from the old airmotor to mount the driveshaft in the casting.  The only downside is that you need to put a 1/2" spacer between the rear cover and the carriage to clear the stepper...not a bad compromise I figured though.

I'll try to get some pictures for you when I get a chance.

I don't know much about the worm as far as part numbers go...I just used the one that was in the machine originally.

-Ryan

Offline jimpinder

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Re: ATC using stepper motor on A axis
« Reply #6 on: January 30, 2008, 01:14:51 PM »
I think the easiest way to drive the thing woud be to  alter the steps per unit configuration, so that for a unit of "one" the stepper motor moved enough to move your turret one position. You could then move it backwards or forwards as though it were a rotary axis using G Code.

Once you have got to this, a simple Vis Basic program (which writes GCode anyway) would suffice, picking up your tool number from the DRO and moving the turret to a suitable position.

Jim
Not me driving the engine - I'm better looking.

Offline N4NV

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Re: ATC using stepper motor on A axis
« Reply #7 on: January 30, 2008, 11:50:31 PM »
Once you have got to this, a simple Vis Basic program (which writes GCode anyway) would suffice, picking up your tool number from the DRO and moving the turret to a suitable position.

Jim

Once I get the servo/stepper installed, can I plan on your help with the simple Vis Basic program?

Thanks

Vince

Offline jimpinder

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Re: ATC using stepper motor on A axis
« Reply #8 on: January 31, 2008, 09:39:08 AM »
Yes - no problem - (you don't need a guarantee it will work, do you ???)

I will open my big mouth.

Seriously - I think it is a quite simple program - I don't know how many tool positions there are, but what I had in mind was one that responded to the tool number, and rotated in the quickest direction to get there. I think the only caveat on that would be that the tools would have to be 1 to 6 or whatever - and these would have to be left blank in the tool table.
Not me driving the engine - I'm better looking.

Offline Graham Waterworth

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Re: ATC using stepper motor on A axis
« Reply #9 on: January 31, 2008, 11:49:44 AM »
Here is one I did for Chris (guynamedbathgate) it is a lock to pawl type changer but the code will work with a few mods.

Graham.
Never give up, time will pass, the cloud will clear, the sun will shine once more.