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Author Topic: A-axis rotary lathe question for Mach 3  (Read 8069 times)

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A-axis rotary lathe question for Mach 3
« on: November 03, 2017, 12:21:42 AM »
Hi,  This is a Mach3 question. I purchased a Rotary lathe for A-axis.  Set it up and got it to turn.  Now my situation is that I need the rotary axis to turn at on speed and then I need to have the y axis move the spindle forward so that it "trues" the wooden dowel.  I have the spindle speed in manual so I can adjust that independent of the other factors.  So can someone help me understand how to set up codes in MDi so that while the a-axis lathe is turning at one speed, while the y-axis moves forward (y- in my case) at another speed? Right now, the rotary turns but none of the other axis will move.  For instance if the A-axis rotary is turning and  then I go to the jog-screen, none of the keys that would normally get the x or y axis to move will work.  Pressing the shift-arrow keys for instance have no effect.  All help appreciated.

Offline RICH

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Re: A-axis rotary lathe question for Mach 3
« Reply #1 on: November 03, 2017, 04:16:41 AM »
Post the xml file that you are using.
You will find the file in the directory where Mach is installed.
Someone will look at the profile  to see how you have Mach3 configured.

RICH
Re: A-axis rotary lathe question for Mach 3
« Reply #2 on: November 03, 2017, 01:12:49 PM »
ok, let me go look for the file and see how to post it back to you.  Thank you for responding... bob
Re: A-axis rotary lathe question for Mach 3
« Reply #3 on: November 03, 2017, 02:55:49 PM »
ok lets see if this works ,  bobmill attached
Re: A-axis rotary lathe question for Mach 3
« Reply #4 on: November 03, 2017, 06:24:29 PM »
Hi Halfmill,
if you wish your rotary axis just to turn at a constant speed then its not really an 'axis' but rather a spindle. An axis as far as CNC is concerned is a drive/motor
that can be driven in angular synchronicity with other axes. The most obvious example is threading, one axis turns whereas the other axis advances a precise
(pitch of the thread) distance per revolution.

An axis can be indexing....that is to say that you can drive to a particular and precise angle but not be able to synchronise motion with another axis. An example
of that sort of thing is a dividing head for making gears, you can advance 2.345 degrees say, and then have the mill cut the next tooth. This kind of axis is
called indexing-out of band.

The sort of motion you require is just a spindle, rotation but not synchronised to any other axes nor does it stop so indexing makes no sense either.

Could you not disconnect your regular spindle and use Step/Dir signals for a spindle but hook it to your 'A spindle' instead?

Craig
My wife left with my best friend...
     and I miss him!
Re: A-axis rotary lathe question for Mach 3
« Reply #5 on: November 03, 2017, 09:52:18 PM »
Let me look into what your suggesting and see what I learn.  I am new to all of this.  I need the rotary to do several functions... like cutting the curve on  classical guitar bridges.   I have been a hand builder of classical guitars for many years.  I decided to build and use a cnc for making parts more accurately.  So let me take your suggestions and work with them a bit... bob   thanks again...
Re: A-axis rotary lathe question for Mach 3
« Reply #6 on: November 03, 2017, 10:24:09 PM »
Hi Bob,
sounds like a great hobby or is it a lively hood?

As a lad I lived in a small town and next door for about six months a year lived a middle aged couple who lived in Hong Kong for the remainder of the
year, they were very wealthy. Us kids always considered Mrs Buyers to be mad and treated her as such and no-one wanted to be caught alone by her husband.
No evidence mind, its just what us kids knew.

He died and she rather lost it. I was a few years older then and had been dragooned by my mother and other neighbours to help her with a few chores
and also company, it turns out she wasn't mad after all, but lonely, eccentric and old. Amongst the things I learned was that her husband was a true
craftsman in wood and would hand make violins form timber gleaned from old pianos and other sources. The noises that my brother, sister and I had heard
were not him strangling his wife but tuning and testing the violins he made.

All those years I had shunned him and yet had I known he might have been a friend and a marvellously skilled teacher.

Craig
My wife left with my best friend...
     and I miss him!
Re: A-axis rotary lathe question for Mach 3
« Reply #7 on: November 04, 2017, 12:55:51 AM »
great story of how wisdom is often hidden...
Re: A-axis rotary lathe question for Mach 3
« Reply #8 on: November 04, 2017, 02:06:34 AM »
Hi,
the curve on the bridge of my guitar (steel acoustic) is curved but slightly. If I were making it I wouldn't bother with a rotary axis.
Mach can quite comfortably mill around a curve like that. Do you have a sketch or a pic of what you want to do?

Craig
My wife left with my best friend...
     and I miss him!
Re: A-axis rotary lathe question for Mach 3
« Reply #9 on: November 04, 2017, 03:27:06 AM »
I would love to talk about making a classical guitar bridge without a rotary.  I have attached 3 photos.  Two photos are of one of my handmade instruments, shows the bridge on one from top view. The last is of an image I got off google that illustrates something that drove me to 4th axis...notice where I drew the arrow... that part that rises up to hold the strings is 90 degrees from the top of the curve of the "wings" on each side.  But please explain what you know.  bob