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Author Topic: Mach 3 Threading Hangs  (Read 633 times)

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Mach 3 Threading Hangs
« on: March 30, 2019, 03:22:37 PM »
Hi,

I just retrofit an Emco PC Turn 50 lathe under Mach 3 with a UB1/UC300ETH interface.  I'm using the original index pulse circuit from Emco and I get a very clean square wave about 6ms long at 500 rpm.  The index light lights up on the diagnostics screen when I turn the spindle by hand (the lathe diagnostic plugin appears to be incompatible with the UB1).  When the spindle is running, the index pulse light comes on erratically but a scope on the signal shows the pulses to be very regular.  I can see accurate actual spindle speed and can run feed-per-revolution moves just fine.  When I enter a G32 threading command, though, that block of code just hangs with no axis movement.

I've tried setting the debounce time from zero to the default of 100x40us and it doesn't seem to matter.  Also, have tried spindle speed averaging both on and off with no change.

Any ideas about where to look for the problem?

Thanks,

Mark
Re: Mach 3 Threading Hangs
« Reply #1 on: March 30, 2019, 04:27:52 PM »
p.s. When I run the G32, I can see the waiting for trigger light come on and then go out but there's no axis motion...
Re: Mach 3 Threading Hangs
« Reply #2 on: March 30, 2019, 04:32:49 PM »
Hi,
I have no experience with threading so cannot offer a solution.

I do now however that the LED on the diagnostics screen will never be able to keep pace with the index signal.
It sounds like you have made considerable effort to ensure a clean index signal and that the index LED operates
as it should when turned by hand. Even more, when running that the spindle speed should be accurately displayed
and feed per turn work correctly all suggest that the index signal is good notwithstanding the intermittent operation
of the LED.

Craig
« Last Edit: March 30, 2019, 04:43:02 PM by joeaverage »
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Re: Mach 3 Threading Hangs
« Reply #3 on: March 30, 2019, 06:46:13 PM »
Hi,

I just retrofit an Emco PC Turn 50 lathe under Mach 3 with a UB1/UC300ETH interface.  I'm using the original index pulse circuit from Emco and I get a very clean square wave about 6ms long at 500 rpm.  The index light lights up on the diagnostics screen when I turn the spindle by hand (the lathe diagnostic plugin appears to be incompatible with the UB1).  When the spindle is running, the index pulse light comes on erratically but a scope on the signal shows the pulses to be very regular.  I can see accurate actual spindle speed and can run feed-per-revolution moves just fine.  When I enter a G32 threading command, though, that block of code just hangs with no axis movement.

I've tried setting the debounce time from zero to the default of 100x40us and it doesn't seem to matter.  Also, have tried spindle speed averaging both on and off with no change.

Any ideas about where to look for the problem?

Thanks,

Mark

Since threading was written for the parallel port, could it STILL be expecting a slow pulse signal of only "1 pulse/rev"?
Art Fenerty said:
"when you consider Mach3 was designed for the printer port, and its
architecture is derived from the treacherous territory of Windows kernel mode, then it
will be understood more easily, why the design architecture, which has evolved over
time, must reflect the original printer port operation in terms of its internal limitations.
This means that the simple fact you are using an external engine does not mean you
will not necessarily have a limitation enforced by the original specifications of the
software."

So I would try to use simple pulse of 1 pulse/rev.
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Re: Mach 3 Threading Hangs
« Reply #4 on: March 30, 2019, 08:29:54 PM »
Hi,
I'm pretty sure that the UC300 supports lathe threading but are you sure it supports G32?
Could it be that the UC300 is expecting G76?

Do you have any documentation from CNCDrive as to exactly what is supported and how?

Craig
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Re: Mach 3 Threading Hangs
« Reply #5 on: March 30, 2019, 10:48:10 PM »
UCCNC (unlike MACH3) does use G76 (instead of G32) for Thread Cutting.

But listen to the horse's mouth...
"Post by cncdrive ยป Wed Jun 06, 2018 9:28 pm
We advice to not to use the UCCNC on lathes, because several lathe functions are missing for comfortable lathe usage.
With Mach3 the syncronous thread cutting is working, but there are a few bugs in Mach3 about the thread cutting which can cause issues with some type of thread cutting codes. (I can't remember at the moment which are the cases.)
With Mach4 the UC controllers can't cut threads. We have tried to implement thread cutting some time ago, but found out that it did not work at all on the Mach4 side, so we gave up on it.
Later it was reported to be fixed, but we could not find the time yet to make another try.
With the UCCNC the syncronous thread cutting works perfectly, but again there are missing lathe functions..."
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Re: Mach 3 Threading Hangs
« Reply #6 on: March 31, 2019, 02:55:12 AM »
I think "cncdrive" was taking about some types of "Metric screw threads" used in Europe & elsewhere, that MACH3 doesn't support.
Mach3 should have no issues threading all Imperial Threads (based on TPI) and most common metric threads.
Correct me if I am wrong.
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Re: Mach 3 Threading Hangs
« Reply #7 on: March 31, 2019, 04:10:23 AM »
Do you have a legitimate licence for Mach? If not threading doesn't work in demo mode.
Re: Mach 3 Threading Hangs
« Reply #8 on: March 31, 2019, 03:01:58 PM »
...
So I would try to use simple pulse of 1 pulse/rev.
...

Yes, I'm using a 1p signal about 6ms long at 500 rpm.  The pulse is a clean square wave.
Re: Mach 3 Threading Hangs
« Reply #9 on: March 31, 2019, 03:03:50 PM »
...
Do you have a legitimate licence for Mach? If not threading doesn't work in demo mode.
...

Yes, I am using a licensed copy of Mach 3.  Your comment makes me wonder is threading is something that can be "turned on," though.