Hi Guys; I did notice yesterday while cutting that 4mmx0.7 thread, which btw came out real nice, that the spindle speed you start at should not be changed during the run as it will widen the cut thread, leaving a distorted profile at the root of the thread. I had started it at an S200 and had run it up to 300 with the spindle override for a couple of loops as I was touching off to the final size. Slowing the spindle back down to 200 put it back on track and it cleaned it up nicely. As for cutting, with that fine a thread, I could have cut it at 600+ rpms, z was not speed challenged.
My guess is that there is a get up to speed lag in the z accel after seeing the index before z is actually phase locked to the spindle. I have always started a thread well off the end of it in air, and I'm thinking this phenom could be backlash related. To that end, would it be possible to incorporate in the retrace motion of G76, and extra 2 thousandths of an inch to the right of its park & wait for index, which is then brought back to the z starting position with a 2 thou move to do nothing but take up the backlash while it is waiting for the index. This 'turn around' move would then take up the backlash, hopefully preventing this spindle speed related slippage between the spindle and Z. If the index arrives while the backlash move is in progress, skip it and wait for the next index of course. Am I making any sense here? Cheers, Gene -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) My web page: <http://coyoteden.dyndns-free.com:85/gene> "I am ecstatic that some moron re-invented a 1995 windows fuckup." -- Alan Cox ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
