On Saturday 07 May 2016 08:18:48 Andy Pugh wrote: > I am trying to figure out where to put the limit/home target on the Z > axis of my lathe. The saddle can get all the way to the headstock if I > am using the collet chuck, though it doesn't need to. If I put on a > face-plate then the carriage will eventually hit that. The same is > true for each of the chucks. In different places. I can't figure out a > way to have useful soft _or_ hard limits, or a way to guarantee that > the carriage is parked the right side of the home switch. > I have the same problem Andy, so the first thing I do is jog to the right an inch or so, before I hit the home all button. My toy used to have a backsplash, but it left to make room for the crossfeed motor on the rear.
I placed a $0.50 microswitch about an inch from the chuck so a cap screw holding the gib strip operates it. It can't quite get past it with that 5" chuck mounted, so the error I get isn't running the wrong direction, but "can't home when a shared switch is already closed" > I do have an idea of a way to make the z-axis have absolute feedback. > This is looking like a good plan for homing but doesn't really help > with limits. I set SW limits about a millimeter from running into the right Z screw bearing, and leave about 20mm more travel to the left from the home switch triggered point. I can remove the QC tool holder, and with little concern over what might be mounted in the chuck, do a home-all. X backs away, trips its switch about .1mm from the hard stop, and gets parked about 5mm in from there, so its well out of the way for z to head left at a good clip looking for its switch. > I need an rfid tag in each chuck to change the soft limits on the fly, > clearly. Thats a neat idea, but how would that be carved up in the .hal file? I wasn't aware that was even accessible to hal. Not that I have anything in the way of chuck changing that could even be called slow change, it bolts on, and the nuts are very difficult to access when restarting the nuts onto the other chucks studs. Major PIMA. Dropped nuts of coarse are subject to Murphy's Law about where they wind up, always with the least accessible location imaginable as a target. OTOH, that PIMA is a huge advantage in that I'll never have to worry about unscrewing the chuck while doing the reversals a rigid tap pecking routine can do. In my case, its broken/stripped drive parts as the treadmill motor has no problem putting out the power to do the damage. BTDT. Added a limit3 to the pid.s command path to gentle the reversals. Yet to be done is to do a couple air cuts and record the turn-around overshoot it will do at that rpm, and use that as the final stop point modifier so I can let the gcode do the calcs so that the final 2 or 3 pecks will hit the zero rpm point at exactly the desired depth. Something along the same line as the 'spring' cuts at the end of a g76. Fun and games for this summer if my back doesn't put me completely out of commission. Old age is hell, put it off as long as you can... Cheers, Gene Heskett -- "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> ------------------------------------------------------------------------------ Find and fix application performance issues faster with Applications Manager Applications Manager provides deep performance insights into multiple tiers of your business applications. It resolves application problems quickly and reduces your MTTR. Get your free trial! https://ad.doubleclick.net/ddm/clk/302982198;130105516;z _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
