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Author Topic: Problems threading on the lathe  (Read 332037 times)

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Re: Problems threading on the lathe
« Reply #710 on: November 26, 2009, 11:49:38 AM »
Last message should read status is same as messages 704 and 706. The RPM indication is working correctly but spindle start problem remains.

Peter

Offline ART

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Re: Problems threading on the lathe
« Reply #711 on: November 26, 2009, 12:06:21 PM »
thx peter. Ill check it out.

Art
Re: Problems threading on the lathe
« Reply #712 on: November 27, 2009, 01:44:37 PM »
Peter,
    Did you check to see if if threading now works or if it hangs looking for an index pulse? - Terry
Re: Problems threading on the lathe
« Reply #713 on: November 27, 2009, 03:23:34 PM »
I didn't get a chance so far due to work commitments, but I will try it tomorrow and post findings here.

Peter
Re: Problems threading on the lathe
« Reply #714 on: November 28, 2009, 10:29:24 AM »
I tested threading today with the special version of .32 attatched to Art's post number 703, using the simple threading wizard.

At first the spindle would not run at the speed programmed in the wizard and I was getting an error message "Scripter Compile Error. In: Spindle Speed.mis" Could not resolve this, so reloaded version 042.020 and ran threading wizard succesfully.

Reloaded special version of .32 and tried threading wizard again. This time spindle speed was as programmed with no error messages.

Threading program ran OK but the pitch was incorrect. Further investigation showed that the pitch varied with spindle speed. Testing with a pitch of 1 mm the following feed rates were noted:

RPM 600,  Feed 0.31 mm/rev
RPM 200,  Feed 0.72 mm/rev
RPM 100,  Feed 0.98 mm/rev

Z axis velocity is set at 1000mm/min

At 100 RPM the feed rate was unstable and the Z axis motor could be heard to be continuously hunting.

During testing, the programmed spindle speed, indicated spindle speed and measured spindle speed (tacho) were all within 2 to 3 RPM.

During threading the tool engaged correctly during each pass (although at the wrong pitch) except at 100 RPM where the fluctuating feedrate destroyed the thread.

Peter

Offline ART

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Re: Problems threading on the lathe
« Reply #715 on: November 28, 2009, 12:54:42 PM »
Hi Peter:

  Hmm. Ill check this out. What was the G76 line you used. That pitch seems strange.. cant figure what its related to.

Better yet, can you try 600rpm again, and then p[ost whats in the lasterrors.txt file.. Itll tell us why the pitch was wrong..


Art

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Re: Problems threading on the lathe
« Reply #716 on: November 28, 2009, 01:37:11 PM »
Peter:

 My appologies, I think I may have found the problem, I had forgotten your machien was the fast one that overwrote the neg bit in the timer.
I found the correction had to be fixed up for that as well. It may explain the pitch error. Try this version and let us know what happens.

Thx
Art
Re: Problems threading on the lathe
« Reply #717 on: November 29, 2009, 06:17:12 AM »
Art

It looks good.

I cut 4 threads today as follows:

1.75mm pitch at 600 RPM
1.25mm pitch at 200 RPM
1.0mm pitch at 400 RPM
0.5mm pitch at 100 RPM

Spindle RPM and pitches were correct as programmed and were stable. 1.75mm pitch was gauge perfect, the others fitted nuts well (no gauges available) Threads look good, everything ran smoothly.

Thanks for your help on this.

Peter

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Re: Problems threading on the lathe
« Reply #718 on: November 29, 2009, 07:51:22 AM »
Peter,
 Save me some reading. Can you post your XML so i can see your configuration?

ART,
I assume that this fix doesn't affect threading when setting the rpm manualy?

RICH
Re: Problems threading on the lathe
« Reply #719 on: November 29, 2009, 10:48:28 AM »
Rich

XML attatched as requested.

Peter