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Author Topic: Special code for threading?  (Read 9478 times)

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Offline dresda

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Special code for threading?
« on: January 21, 2013, 09:58:46 PM »
Using DSPMC, is there a special G code to sink the spindle and feed before threading or do I just leave it in g95, Rufi at at Vital systems with the DSPMC said you have to trigger an LED with a G code when threading then turn it off when finished...
ray.

Offline Hood

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Re: Special code for threading?
« Reply #1 on: January 22, 2013, 03:35:11 AM »
What are you meaning by threading? Single point lathe threading or rigid tapping?
Either way the control itslef needs to do the actual motion.
Hood

Offline RICH

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Re: Special code for threading?
« Reply #2 on: January 22, 2013, 06:54:27 AM »
For lathe threading see the lathe manual for G32 defnition. Also have a look at G94 & G95.
RICH

Offline dresda

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Re: Special code for threading?
« Reply #3 on: January 22, 2013, 02:29:29 PM »
Sorry, lets start again. I know all about threading single point on the the lathe like using g76 etc and not having to turn led's on and off, don't know what Rufi is on about, that's the problem with trying to marry two systems together, it's a pain. This is what his manual says:

Mach3 Threading Bug Workaround:
DSPMC plugin uses LED 1370 to workaround threading logic problem with mach3.
In your G-Code program, turn on LED 1370 right before the threading g-code command and turn it off after the threading cycle is done. This will cause the programmed RPM +20% to be sent to Mach3 instead of true RPM during the threading cycle. This makes sure mach3 will generate correct feedrate for Z axis. Once this LED is off, true RPM will be shown on mach3 spindle rpm DRO.

Also he telsl me I can't run 2 hanwheels at the same time and to wait for Mach4 to out, don't if that's the capability of DSPMC or Mach?
ray.

Offline Hood

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Re: Special code for threading?
« Reply #4 on: January 22, 2013, 03:44:46 PM »
Sounds weird, shouldnt be a problem with threading at all as other controllers manage it no problem without having to set rpm to some imaginary value.
 Also regarding the MPG, that is a DSMPC plugin  restriction I would think as although I have never used 2 MPGs there are people using the parallel port that do. It may be that the plugin interface cant do it.

Hood

Offline RICH

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Re: Special code for threading?
« Reply #5 on: January 22, 2013, 05:15:57 PM »
Use two mpg's here via the PP and have no problem's at all with them.

Mach allows for adjustment of the feedrate depending on what the true rpm reading was so it can fix the thread if required
due to spindle slow down but will not address spindle speed up. You don't want some arbitrary value screwing up the next cycle.
That's what was meant by the vfd fighting Mach and thus setting the spindle rpm manualy and letting the rpm settle  before threading.

If you so desire  you can have a read of page 4 in the Threading on the Lathe write up as it explains the cycle in detail.
As you read that break down each step and consider how the rpm and also the Z axis move, or any other part of the system can and will affect the threading cycle. You threading will only be accurate as your lathe SYSTEM.

RICH

Offline Hood

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Re: Special code for threading?
« Reply #6 on: January 22, 2013, 05:18:51 PM »
Rich, think the latest driver for the PP can handle speed up as well, or at least I think thats what Art said on Yahoo. Dont use the driver myself so not certain.
Hood

Offline RICH

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Re: Special code for threading?
« Reply #7 on: January 22, 2013, 05:23:47 PM »
Hood, would't know as i don't follow Yahoo anymore and still use a rather old version of Mach .....works too well for me to change. ;)
RICH

Offline Hood

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Re: Special code for threading?
« Reply #8 on: January 22, 2013, 05:34:05 PM »
It was a while ago but seem to remember something about it anyway. As you say if its working then leave alone :)
All this is no importance to dreda anyway as he doesnt use the pp. Not sure why the DSPMC has to do that with the LED and spindle RPM.
Hood

Offline RICH

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Re: Special code for threading?
« Reply #9 on: January 22, 2013, 06:19:39 PM »
My bad...didn't realise that he is using an external motion device.
Need to stop speed reading which i can't do anyway.  ???  :D
RICH