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mach3 turn threading issue
« on: September 08, 2019, 02:22:07 PM »
hi everyone
i have just started to turn a thread with my mach3 turn lathe . i have an issue . the rev counter works so i guess mach is receiving the signal ok.

when i started the program using either g32 or g76  . it moves in to position to cut the thread but just sits and waits doing nothing.
i would guess its waiting for the rpm signal . i presume i dont have some of the settings configured properly
can anyone help

cheers

Offline Graham Waterworth

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Re: mach3 turn threading issue
« Reply #1 on: September 08, 2019, 07:59:49 PM »
if you turn the spindle slowly by hand and watch the index LED on the diagnostic screen do you see a pulse?
Without engineers the world stops
Re: mach3 turn threading issue
« Reply #2 on: September 09, 2019, 02:30:44 AM »
yes

Offline RICH

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Re: mach3 turn threading issue
« Reply #3 on: September 09, 2019, 06:56:50 AM »
chessie,

Mach is monitoring the spindle rpm, and will allow the Z axis to start the thread path, once Mach is satisfied that an amount of  index signals received are appropriate.

Adjust the Index Debounce  in General Logic Configuration. See Figure 7.1.4 in Threading On the Lathe write up.

RICH
Re: mach3 turn threading issue
« Reply #4 on: September 09, 2019, 07:19:49 AM »
hi rich

the index debounce is already set to 10 , i tried 1  and no difference.

the feed per rev  (1.5) was flashing 1.5 /off

when looking at diagnostics  the  index flashes if i turn it by hand  ,its intermittent at high revs

the true spindle speed registers ok

i have a npn  proximity switch  picking up a bolt head on a disc on the spindle
will this provide a good consistent signal

cheers

Offline RICH

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Re: mach3 turn threading issue
« Reply #5 on: September 09, 2019, 07:36:19 AM »
Try a higher number for the debounce.  I use 10, some can use a lower number, yet others have needed to increase it.
Just depends on the signal. If the rpm is fluctuating too much Mach will sit there a long time waiting to get a consistent rpm.

At higher rpm's the DRO can't update fast enough to shows the rpm for each time an index is sensed.

You rpm should be within say 1 rpm under no load at spindle. I use a Halls affect sensor along with small magnet and works a treat.

Try this......... dry run with  a few different rpms settings for threading and leave the index setting at 10. Say 50/100/200 etc and see if the thread path will start. Some sensors are  not good at higher spindle rpm,s .

As to quality of signal one can view with an O'scope but most don't have one.

RICH

Offline RICH

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Re: mach3 turn threading issue
« Reply #6 on: September 09, 2019, 08:28:28 AM »
chessie,

Found my notes on index debounce and will post some info for your use ( I just don't keep all this stuff in the cloud
above my head anymore ). ;)

RICH

Offline RICH

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Re: mach3 turn threading issue
« Reply #7 on: September 09, 2019, 09:05:45 AM »
chessie,

Info on debounce see attached file

RICH
Re: mach3 turn threading issue
« Reply #8 on: September 15, 2019, 11:10:49 AM »
hi   i still have the same issue .i changed the sensor to a hall effect and the index light flashes on diagnostics page. rev counter  works ok and i can calibrate spindle rpm.

(THREAD1)
N28 M6T0707
N29 G54
N30 G95
N31 G97 S500 M3
N32 G0 X45.4 Z5.
N33 G0 Z7.5
N34 X23.6
N35 G32 Z-24.8 F1.5
N36 X24. Z-25. F1.5
N37 G0 X45.4
N38 Z7.5

it just sits waiting on the g32 line.
is there some tick in the box im missing .i only have input for index , left timing unabled or is itsomething wrong with the code

forgot to add i use a UC400ETH Motion Controller

thanks
« Last Edit: September 15, 2019, 11:16:40 AM by chessie »

Offline BR549

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Re: mach3 turn threading issue
« Reply #9 on: September 15, 2019, 05:58:24 PM »
The UC400eth uses an encoder for threading ABI signals required.

Just a thought , (;-) TP