On Friday 11 April 2014 16:25:14 John Kasunich did opine: > On Fri, Apr 11, 2014, at 12:11 PM, Jon Elson wrote: > > On 04/11/2014 12:41 AM, Gene Heskett wrote: > > > And I haven't checked (I have to think about this stuff & > > > then go back & check) as to whether the soft limits move > > > with the touchoff or not. > > > > The soft limits are in machine coordinates. They > > should be established when you home the machine, > > and should not be altered by touchoff, G92 or anthing > > else that affects WORK offsets only. > > > > Now, unless somebody worked on it with this in mind, I > > could easily see how you could have a threading cycle that > > would exceed a machine limit (I guess that would be +Z) > > that might not be detected by the trajectory planner. > > The T.P. can't know how long the spindle will coast when > > powered off, so it could end up coasting backwards beyond > > the machine limit, if the start of the thread was just barely > > below the +Z limit. > > I'm pretty sure that Gene doesn't "touch off" in the way > we think of it. If I've followed past conversations correctly, > he actually homes the machine using contact between > tool and work (or tool and a widget that gives him a > reference point).
The "widgit". If there is nothing in the chuck, it works well, but if I need to rehome, and something is in the chuck, preventing the widget from backing up to the chuck, then yes, limits will move. What I think I need to do is make a dummy tool I can't chip by running a workpiece into it, take a stick out measurement when I start making 4 copies of the next big thing, so that when the part is finished and cut off, I can put that tool back in, loosen the chuck and slide the work until it strikes the tool set with Z at the stickout point. Re-center the workpiece and repeat, which would be far better than just re-homing to the stick out. > Normally, you'd home the machine once and be done > with it, and the limits would be set to protect the machine > while allowing you to get your work done. Then use > "touch off" and G5x coordinate systems and/or tool > offsets to deal with tool and part specifics. Sounds like a headache reduction procedure to me, thanks. > > Since Gene uses home to deal with tool and part specifics, > he has the side effect of limits moving around. Yes. 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) Genes Web page <http://geneslinuxbox.net:6309/gene> US V Castleman, SCOTUS, Mar 2014 is grounds for Impeaching SCOTUS ------------------------------------------------------------------------------ Put Bad Developers to Shame Dominate Development with Jenkins Continuous Integration Continuously Automate Build, Test & Deployment Start a new project now. Try Jenkins in the cloud. http://p.sf.net/sfu/13600_Cloudbees _______________________________________________ Emc-developers mailing list Emc-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-developers
