Messages

1031

General Mach Discussion / Re: Problems threading on the lathe

« on: April 13, 2009, 08:50:06 AM »

Hi:

  Yes, I have been thinking the same thing. And I will be adding a selection to turn off compensation as well as a diagnostic for those vfd's that self coorect. In fact with self correction internal correction may not be
necessary at all. But I have some corrections to implement first to try to stabalise the readings a bit more. Might as well make it as tight as it can be before modifying the methodology used..
I may try to get an enocder to work yet.. I suspect it can be done but I'm still looking into it..

Thx
Art

1032

General Mach Discussion / Re: Problems threading on the lathe

« on: April 12, 2009, 11:58:51 PM »

Hi Rich:

 Thx, seems some PIT interval timers arent at the sam eport as mine..

More tests soon of an enhancment to pulse timing that I found while working..
Shoudl make it up to 5us more stable for most people I think..

Art

1033

General Mach Discussion / Re: Problems threading on the lathe

« on: April 12, 2009, 02:31:55 PM »

Hi Guys:

  Here is a driver and drivertest.exe, Id really liek to see a coupel screenshots form anyone willing to test it. A shot of the drivertest.exe runnign as per normal install, and then this one with the enclosed driver. I need to see the "Longest int" value, shoudl be -1 or -2 on most systems, and how the stability looks after lettig it run fro a few seconds to settle. The new drivertest uses the PIT timer on your motherboard. I need to know why Chip is 1000 times too high, and some of you get 0RPM .. This test may tell me that.

  Keep a copy of your old exe and sys file to copy them back and reinstall your normal driver after testing..

Thx
Art

1034

LazyTurn / Re: LazyTurn

« on: April 12, 2009, 02:28:59 PM »

Thanks for the video.. I love that.

 I have solved many issues with LTurn for the next version, but it'll be a little hwile yet, Im pulled off to soem MAch3 work for a few days..

Thx
Art

1035

General Mach Discussion / Re: Problems threading on the lathe

« on: April 12, 2009, 09:39:30 AM »

Chip:

  SO does that mean your getting a reading of spindle speed of 321.87xx over time, Is it really varying only .00xx as RPM?
I see its 1000 times greater than it shoudl be.. but other than that is it really that low a variation? Is that with averaging off?

And why does the pulse frequency read 8 thousand or so on the diags screen yu posted??

Thx
Art

1036

General Mach Discussion / Re: Problems threading on the lathe

« on: April 10, 2009, 10:27:56 PM »

Guys:

 Still trying to figure out why I have RPM, but you dont.. Can sopmeone put a DRO#72 on the screen and see
what it says while its turing..

Thx
ARt

1037

General Mach Discussion / Re: Problems threading on the lathe

« on: April 10, 2009, 10:26:37 PM »

Hi Chip:

 Is it varying? Rich: Can you try a ratio of .001 as well as a test.. Im researchign why that may be so..

thx

Art

1038

General Mach Discussion / Re: Problems threading on the lathe

« on: April 10, 2009, 03:00:13 PM »

Hi Guys:

  This test is for experienced testers with PP test only. What Ive done is hook into the main 1,193,181Hz timing clock, and am measuring spindle RPM
with it. This clock should never vary no matter what, so Im interested in RPM readings only. Does this stabalise rpmp readings on your system , OR make
them more accurate. Test with averaging off to see if its stable and correct to your known speed. This method should read to a very high max frequency..

  YOu need to install this driver... and copy this new MAch3.exe into your folder.. save your old .exe and driver to get back to normal..

Thx
Art

1039

General Mach Discussion / Re: Problems threading on the lathe

« on: April 10, 2009, 10:57:46 AM »

Hi Guys:

 >>My revs are rock steady in Mach,they dont even jump one digit and I am not using averaging

 Im of the opinion that THIS is the key to all of it. If the speed doesnt jump in non-averaged spindle, then it means
that computer is ROCK steady in cpu clock speed. In the old days they all were, but latest generations over past couple
years of CPU's vary the clock speed almost randomly even if your not power saving..

  I suspect this shows the real problem, random variance of the clock is slowly adding to an error that ccumulates over time.
Its why when I turn off correction, Johns machien actually looks liek a good thread..albeit it off flank cuts during the thread
on various passes, this coule be due to several different spindle speeds locking in as each pass changes the no-load RPM slightly
beofre taking off on its pass. The code assumes non-loaded is accurate prior to the pass and shoudl be the same pass to pass,
tru e on hoods, varying 1-2 on others, 5-6 on others.. Im coming to the conclusiogn this is the real culprit and explains why hoods is so
good.
   Im researching to see if I can take advantage of the system clock chip to better define "time" instead of using cpu clocks.. trouble is there
are technical challenges in such a thing.. but Im investigating. Keep up the good work, the testing is proving alow really, the linearity cal seems
unimportant and can be deleted, a new one can be made as a plugin to allow for better fine tuning for those that need it in future.

So it seems...
 The thread wandering over time is an accumulation of pass to pass errors caused by the divergence of "time" , and that length shows it best.
 Spindle RPM has an effect as the time variation affects the thread in a formula based on steps/pitch x lenth of pitch in some way, again, I suspect
this is accumulating error. Higher the RPM, the higher the variable speed sensed, and this affects them as you go up in speed..

   If I can hook into the timing chip in any meaningfull way this may solidify the rpm reading and we'll see what that gives. It'll take me a few days
to see how I may be able to do this..

  In truth though, the SS should be imune to this, Greg can read the actual RPM as exactly as it can be done. Rich: , how much fluctuation in speed reading do
YOU get?

Thanks
Art

1040

General Mach Discussion / Re: Problems threading on the lathe

« on: April 09, 2009, 11:48:53 AM »

Hi John:

    BTW: the end of the thread will always be ragged with thin crests, the distance of that will be equal to the deceleration of the Z axis, upping your accel for the Z axis will minimize the effect,
Id expect the last few turns to go thin if the accel isnt high enough, if your lathe can handle it, Id raise the accel up as high as possibel as long as you dont lose steps.

Thx
Art