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Author Topic: Old turret lathe  (Read 1658 times)

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Re: Old turret lathe
« Reply #10 on: September 10, 2018, 10:30:20 AM »
Chad,
That is exactly what I’m trying to do. The turret needs to rapid approx 4.5 inches then feed for approx 2 inches then rapid out. What would be “a nice to have” is something that I can enter numbers in that would plug into the axis movement. That way it isn’t locked into one particular job. I was thinking the two computers would give me that option. I could also monitor the turret via the dro on the second screen. I do understand your concerns but I’m not lua smart enough to make it work.

Offline Stuart

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Re: Old turret lathe
« Reply #11 on: September 10, 2018, 10:38:08 AM »
Why no look into using a arduino to generat the movement , the code could be triggered from an output from mach4

Have a look at nyccnc YT Chanel he as some examples of usining a arduino to drive a clear path servo

Just a rambling of a old git
Re: Old turret lathe
« Reply #12 on: September 10, 2018, 01:45:03 PM »
Art,
Like Stuart said, you could use an arduino.  Personally I never liked the idea of adding an arduino to a cnc machine, it never seemed like it would be robust to me, I add PLCs to our machines instead.  But that is my opinion.

I'm not sure about drilling while it is machining a profile, doesn't sound like a good idea to me.  But I also don't know your setup and it may be working just fine for you. 

If you use a servo in Mach4 you can write a macro to drill what you want using DROs on the screen to set start, end, and rest positions.   

Have DROs for:
Drill Start Position  (DSP)
Drill End Position   (DEP)
Drill Rest Position  (DRS)
Drill Feed Rate      (DFR)

Your macro can rapid to DSP DRO value then drill to DRE DRO Value at the DFR DRO Value rapid out to DRS DRO Value. 
If you use an OBO Axis you can still monitor axis position.  I figured out how to do that a few months ago.

The only thing you would need to figure out is how to do it while the machine is running your turning operations. 
Just spitballing here.
Write a function to do the drilling ops and call it from the PLC script.  That may allow it to run in the background.  This is just a theory and I don't have time to delve into it this week, we are heading to IMTS in the morning so I won't be able to test this. 
Maybe Craig or Steve can jump in here and see if this is a feasible idea.
Chad Byrd
Re: Old turret lathe
« Reply #13 on: September 10, 2018, 02:13:01 PM »
Chad,
This Warner & Swasey was built in 1940. My dad had been running these machines forever. I have to listen to him telling me that these wimpy cnc machines can’t remove material any faster than he could on this old clunker. Lol! That’s part of my motivation to drill at the same time as the turning op, I actually have been drilling using the old power feed for thr turret while the cnc is doing the turning op. The drilling op is shorter than the turning op and is out of the way when the facing in being finished. Dad would run this whole part turning handles manually, it is sometimes amazing how these types of parts were done before cnc machines were around.
Thanks
Art
Re: Old turret lathe
« Reply #14 on: September 10, 2018, 02:38:25 PM »
Art,
That's true.  We have a turret lathe here at the shop.  Pretty cool machines. 
To do these at the same time... I would look into a PLC function of some kind.  It may have to be broken into parts, but doable.
Chad Byrd
Re: Old turret lathe
« Reply #15 on: September 10, 2018, 03:07:43 PM »
Hi,
an Out-of-Band axis can do exactly as you require, the regular coordinated CNC axes move as normal and at the same time
turret can drill.

Craig
My wife left with my best friend...
     and I miss him!
Re: Old turret lathe
« Reply #16 on: September 10, 2018, 03:20:33 PM »
Hey Craig,
How do you think one would you move it to the desired positions while G Code is going?
I am going to have a call from the PLC to initiate movement for a tool carousel; but how would you make it move to 3 or 4 positions like Art is wanting. 
I was/am thinking having a function called from the PLC script from a macro in the G Code.  This could trigger the Turret to a rapid position, then that function could fire another function from the PLC that would be the drill cycle, then that would fire the retract function from the PLC.
Thoughts on that?
Chad Byrd
Re: Old turret lathe
« Reply #17 on: September 10, 2018, 04:42:01 PM »
Hi,
when a line of  Gcode is read, interpreted and the PVT data is sent to the motion controller the
call returns to read the next line while the current line is executing.
If the next Gcode line is a jog move to an OB axis it processes that and dispatches that to the
controller. Unlike a coordinated move it can start imediately, thus you have Gcode executing
and you can still issue OB axis moves at the same time.

Craig
My wife left with my best friend...
     and I miss him!
Re: Old turret lathe
« Reply #18 on: September 11, 2018, 08:53:27 AM »
Craig,
Next question is does the motion controller store any moves in a buffer of sorts? So let’s say we tell the turret g00 t0.1, then we tell x and z to start to do their thing can we then tell axis t to g01 t-2.5? How would that be handled if the rapid isn’t done, does it have to wait until the turret rapid move is complete? Would that pause the next x and z move until the rapid is done, load the next turret feed move then continue on with the next x and z move? I’ve never done anything like this so forgive my ignorance.
Thanks
Art
Re: Old turret lathe
« Reply #19 on: September 11, 2018, 09:02:33 AM »
The motion controller must use buffering to assure smooth uninterrupted motion.

It is up to the motion controller vendor to decide how much buffer. The motion
controller asks Mach4 for a packet of date and specifies the update rate and how
much data to provide. Mach4 does not send complete G code type motions to
the motion controller. Motion is broken down into many many small segments
typically only a few milliseconds long each. Thus it is Mach4 that determines
if two motions can proceed at the same time, and to provide that motion as
simultaneous small segments.
Steve Stallings
www.PMDX.com
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