Non-trivial kinematics is when moving one axis causes another axis to move. We call these "serial links"
For example, if you were to mount one rotary axis "B" cross-wise on another rotary axis "A" such that moving "A" redefines where "B" is pointing to. This is common with robots but uncommon with machine tools. But even with a complex robot arm that has a chain of 7 rotary joints, one connected to the next in a chain. You could still drive it with trivial kinematics. The coordinate space would be "joint angles". It would be really hard to program but could be done. My question? Why not do this on a lathe? If this is in wood, cut a tool with the thread profile on a bench grinder (or your mill) A good source of tool steel for custom prile shaper blades is paddle drills. They are cheap and come in different widths and you can turn a paddle drill into a custom shape pretty quickly. On Fri, Feb 25, 2022 at 7:19 AM gene heskett <ghesk...@shentel.net> wrote: > Greetings all; > > I am about to install this rebuilt rotary drive on my 6040 mill, aligned > to rotate stuff on the Y axis, which is the long axis on a 6040. > > Out of the alphabet of ABCUVW, which is the proper axis to call it? > > It will for the next job, be turning a 2"x2"x18" on center of its 2x2 > end, stick of hard maple, carving a 2 start buttress thread that 18" long > to make a screw for a leg vise paddle on my woodworking bench. > > And, does this change the kinematics module which is trivkins now? > > The intention is to turn the stick while advancing Y at 2x the pitch per > rev of this axis, rotate the stick 180 degrees and reverse it to come > back, carving the the 2nd start thread on the back stroke. Then advance > both Z in the profile of the thread, doing a forward stroke up this 2nd > start, back up the new axis by the 180 it was advanced to come back on > the 1st start path. Then advance the starting rotation position along > with a z to the next point in the profile, wash, rinse and repeat until > the full depth of the buttress thread has been carved. Done right, both > thread starts will get cuts from both directions of Y travel. Automatic > backlash comp, although this mill does not seem to have measureable > backlash. I used it to carve its own ER chuck wrenches from 1/2" alu > plate, and should have added another thou, they fit very tightly. > > I am assuming that I can drive this new axis from 30,000 degrees to > 30,180 and back to 30,000 at the back end turn around wihout the axis > doing any mod[360]'s on me. And while I've yet to start the g-code > itself, I'm thinking I should fix the y linear start and stop points, but > increment the rotational degrees to carve the threads profile by small > advances in Z vs rotation start. The dead center end of the stick could > then have threads clear to the end without an entry groove, it would just > run off the end of the stick. > > At the speed this rotary can move with its printed 50/1 harmonic drive, > this could easily be a 3 or more day job. With lots of vacuum cleanup. > I've obtained 20 SC, 1/16" ball nose cutters, some with 3/16" LOC, some > with 1//4" LOC. With that puny a cutter, I do expect to dull and break > some of them. > > Comments/guidance to keep me from doing something stupid would be much > appreciated. > > Thanks all. Take care and stay well. > > 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, 1940) > If we desire respect for the law, we must first make the law respectable. > - Louis D. Brandeis > Genes Web page <http://geneslinuxbox.net:6309/gene> > > > > > > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > -- Chris Albertson Redondo Beach, California _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
