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