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Author Topic: G76 threading issues - any thougts?  (Read 15944 times)

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Offline Chaoticone

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Re: G76 threading issues - any thougts?
« Reply #20 on: April 01, 2013, 09:56:23 AM »
I have notifications on for this thread and notes of this being a potential bug.  The more we know, the more likely we can get it sorted. 

Brett
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Re: G76 threading issues - any thougts?
« Reply #21 on: April 01, 2013, 10:25:14 AM »
Hi all,
Simon0362 in your video the Speed DRO is at zero rpm.
Maybe I am wrong, but I think you have to code a speed for threading
( S230) in your case.

just a thought

Alex


Offline Hood

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Re: G76 threading issues - any thougts?
« Reply #22 on: April 01, 2013, 10:49:49 AM »
As Alex says unless you have told Mach the spindle is running then things will not work correctly. Doesnt matter if the spindle is running as in your video as you have not told Mach the spindle is running with a M3/M4.
Hood
Re: G76 threading issues - any thougts?
« Reply #23 on: April 01, 2013, 01:17:21 PM »
Guys,
Thanks for the observation but I do tell Mach that the spindle is running - in the short gcode program, there is a M3 almost at the start. I also force a M3 manually as well at times, in fact I think the G32 will not run at all if there is no M3.
However I agree that I have not instructed a speed but I understood that this was not necessary since Mach is only concerned with index pulses for threading and derives the spindle speed from that.

Nonetheless I will give it a try later on tonight.

Simon

Offline Hood

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Re: G76 threading issues - any thougts?
« Reply #24 on: April 01, 2013, 01:21:45 PM »
I didnt see a  M3 in that code you had on the screen and if there had been the spindle speed should have been in the DRO. If you had told Mach the spindle was running then there is a problem somewhere as you are not getting the RPM showing.
Hood

Offline Hood

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Re: G76 threading issues - any thougts?
« Reply #25 on: April 01, 2013, 01:33:14 PM »
My apologies, I just looked at your xml again and used the standard lathe screen and I see the Spindle true DRO is above where I thought the spindle RPM should be. Like you I dont like the standard screen so never use it. I see your spindle rpm was indeed showing there, again apologies.
Hood
Re: G76 threading issues - any thougts?
« Reply #26 on: April 01, 2013, 01:50:39 PM »
No problems -this is the first time I have used the standard screens and had to hunt each item down as well, nothing was where I was expecting it to be!
Re: G76 threading issues - any thougts?
« Reply #27 on: April 01, 2013, 05:19:43 PM »
Confirmed that including the S parameter to define the speed is not needed - I added  S230 to the M3 in the program and it failed first time!

I have also run the driver tests - and almost thought I had found the problem since the initial message as it started was 'pulsing too fast' ...however this almost instantly cleared and I had a stead almost completely clean line with an occasional short spike. The program f_inished successfully, so I ran it a second time to see if I could see anything on the data appearing on the screen that was of any significance - and couldn't see anything. The 2nd pass was fine too.

I looked closely at the gcode(which was edited from the original 'extended, verbose' G76 file) and remarked out a G49 that seems to have no meaning(odd....).

I then reran the video - well my iPhone - for another hopefully less crappy run. http://youtu.be/xcP9VJCs--M
This shows the standard fail again, on the MSM screens which I find easier to view and use.

It also shows another issue which I have only seen twice before I think. The usual problem happens but the Z continues to advance at a g l a c i a l pace - the feedrate shows flashes of 5-10mm/min (when it should be 350) and eventually reaches the end point after which, all of the other movements are at a similar pace - I timed one cycle and it took about 16 mins rather than the normal 16 or so seconds.
I checked the index and it is still there happily pulsing away!

This was the point I ran the driver test to see if there was some weird clock instability.

Brett, good to know that someone is looking at the issue, let me know if there is anything else that I can look at or test to help clarify - I think I am at the limit of checking my own systems though - and most of this system also drives my mill and has run multi thousand line programs lasting for up to around 2 hours without any problems (apart from operator induced ones!).

Simon

Offline Hood

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Re: G76 threading issues - any thougts?
« Reply #28 on: April 01, 2013, 05:34:17 PM »
Did you try in Dia mode?

Offline Hood

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Re: G76 threading issues - any thougts?
« Reply #29 on: April 01, 2013, 05:35:46 PM »
Also G49, dont think I have ever seen the wizard produce that in the threading code, will have to go and have a look.
Hood