Helical Help

I am trying to machine some wavy grooves around a cylinder (see Fanuc 21i operation manual on G07.1 for a pretty close example). From all my
testing I have determined that the C axis is not in sync with the Z axis during cutting moves. It appears that the C axis delays movement at the start of a move by about 1 degree for a 45 degree ZC move.
It then tracks OK at this 1 degree lag. Then when a line of code comes in which there is no C move (C axis stationary) the C axis kind of jumps to where it should be. Thus, suddenly making up that 1 degree lag at the end of its move.
Any ideas?
Thanks in advance Daveb
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DaveB wrote:

Oh come on, what are you complaining about. At least it catches up...<G>
ca
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lol Daveb
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DaveB wrote:

Have you looked at how you are commanding the feed rates?
--

John R. Carroll
www.machiningsolution.com
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On Wed, 23 Apr 2008 19:24:42 -0700, "John R. Carroll"

I dont have the code yet (customers) I will post it when I do.
Thanks John Daveb
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wrote:

Make sure and pay attention as to where and exactly how the code activates any C axis angular offset (and/or any transitional calls machine to local sys)....better yet, suggest always endeavor to keep ANY rotary axis offset set at zero unless you have some pre-existing feature in the part needs to be hard tooled/ and physically tWeeKed KnocKed HammErd bAngeD into pOsition.
--




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Could be a backlash issue or a backlash parameter set improperly as well.
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Dan

CNC Videos - <http://tinyurl.com/yzdt6d
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lol Daveb
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