Messages

871

General Mach Discussion / Re: Problems threading on the lathe

« on: October 12, 2009, 10:20:38 AM »

btw,, Its Thanksgiving here in Canada, so Ill be hard to find most of the day. :-)

Happy Turkey-Day. ( for Canucks anyway..)

Art

872

General Mach Discussion / Re: Problems threading on the lathe

« on: October 12, 2009, 10:19:29 AM »

Hi Rich:

  Hmm.. .003 eh? Well, try this one, Im suspecting a 0.000 spread from expected. ( or close to it).

Art

873

General Mach Discussion / Re: Tool Changing problems on the lathe

« on: October 12, 2009, 10:15:07 AM »

Sounds liek a macro thing.. Whats the m6.m1s look like? It may have some code in it to set tool length offsets or something.

When the T0505 is encountered, the offset #5 is applied, so the dro may change to reflect current coordinate. this makes the next move different from what youd assume
depending on whats in offset#5. But if theres any code in the m6.m1s then anything is possible.

  Dont know about homing, the system wont change the motor tuning unless your swapping between metric and english.. I take it the machine is setup in the coordinate system
that you use in the code?

Art

874

General Mach Discussion / Re: Problems threading on the lathe

« on: October 11, 2009, 09:46:11 PM »

Rich:

  Hmm, sounds liek averaging should be on. The gradual tappering from pass to pass seems to indicate that its not locking in at all and its sensing a differing rpm as it goes.

We didnt see that before the averaging was turned off I dont think. The increase pitch seems proper, I added 1%, and it seems to lead by 1%. Can you restest just with averaging on,
do we then get a repeatable pitch of .01 over?  If so, Ill back off to 0 again.. I think I didnt help much on that one. I need to check the RPM gets properly locked, I think I may have screwed up..

Art

875

General Mach Discussion / Re: Problems threading on the lathe

« on: October 11, 2009, 07:40:03 PM »

Rich:

  Thx., Probably doesnt matter if on or off, in fact since you normally have it on and it varys , that shows its more stable with
the changes anyway. So in the end it probably doesnt matter. Might be better on in fact.. hard to say though. ( Am I dithering enough.? :-) )

Art

876

General Mach Discussion / Re: Problems threading on the lathe

« on: October 11, 2009, 06:21:32 PM »

Hi Rich:

  This one is an experiment. Same driver you just used.. But Im correcting by 1/2 the assumption of 1024ms per second. Seems to large a correction,
but Im interested in the resullt.

Art

877

General Mach Discussion / Re: Problems threading on the lathe

« on: October 11, 2009, 06:10:37 PM »

Hi Rich:

Do you know if SpindleAveraging was turned on or off? Id prefer it off.
Good sign if the RPM stays constant with averaging off though, that would
 mean the time nature of it is much more stable
than the old way, that may explain the better pitch.

  Im trying now to think what elese may be inaccurate. If we know RPM is now accurate,
( or we assume so due to stability ), then a couple things are possible..

Its possible the PCI clock is misreporting the number of clocks per second, which I base the RPM on.
Since compuiters tend to the binary.. a second can really mean 1024ms or 1.024 seconds. That would explain
another .24% of error. Im leading to the RPM being the trouble since its about the only thing that could explain
why higher rpm's are close to pitch than lower RPM's.

  SO I think Ill try a tweak that assumes the reported pci base clock is counts per 1024ms just in case the chip
designer had a prediliction to think in binary when describing a second.

Thx
Art

Back to you soon.



Art

878

General Mach Discussion / Re: Problems threading on the lathe

« on: October 11, 2009, 01:10:32 PM »

Rich:

  Sorry this one is harder to test. You need to run the enclosed Mach3SpindleTime.exe AND load the enclosed driver to test it. Turn off Advanced threading for this test,
it basically changes the spindle RPM under the old system to a time based measurement. I suspect youll find your reading slightly higher RPM's, and this will
lead to a slightly higher pitch, so its quite possible the lagged thread will be correct. That , at least woudl be one bug poisoned..

Thx, Good luck
Art

879

General Mach Discussion / Re: Problems threading on the lathe

« on: October 11, 2009, 12:23:31 PM »

Rich:

 Interesting that the 6th pass didnt trigger at the wrong time.. it appears to have a much greater pitch is all.. so almost as if the rpm locked in
at a higher rate than the previous ones locked in at. Higher rate of RPM caused the feedrate to be higher.. so the pitch increased..

Ill give this some though. Interesting too that the pitch still decreased by .006" , better than .008 .. but we may be seeing come correction
error since this uses toally different correction coding.


 I think Ill change the RPM to do time based on the old single pulse and see what the outcome is..

Thx
Art

PS: Love the document from previosu post. Says it all very well.

880

General Mach Discussion / Re: Problems threading on the lathe

« on: October 10, 2009, 09:13:18 PM »

Hi Rich:
 

   Yes, in theory the multislot works just as the single slot does in terms of correction, but though it will thread it isnt heavily tested.
Id be interested in the results, but dont be too disappointed if some other problem develops, I think your testing has shown what
the culprit is, the RPM varys too much when based on # of interrupts, but when based on the gigaclock counters, its much more
accurate and true, so in theory all I need to do is change the normal threading to gigaclock based counters and we should be able to prove a
perfectly working system can thread just fine, though thjose with varying systems may still see some aberations..

Let me know how it goes..

Art