On Thu, Aug 19, 2010 at 2:12 PM, Speaker To-Dirt <[email protected]> wrote: >> >> For the 4th axis, I have a Troyke CNC rotary table that I >> bought on >> eBay for $149: >> >> http://igor.chudov.com/projects/Bridgeport-Series-II-Interact-2-CNC-Mill/24-Troyke-Rotary-Table-U12PNC/ >> > > Wow, that looks like a really great deal! I was worried about backlash in a > rotary table with an acme screw. Or does that tale come with a ball nut and a > ground screw? >
I figured that Troyke made it for CNC and they knew what they were doing. So one way or another, I hope that backlash will turn out to be acceptable. >> The only minor complication with this table is that it uses >> a resolver >> instead of an encoder. >> > > I assume you mean the motor has a resolver? Either way, you can use a > microcontroller with a decent A/D (10 bit or better) and turn that resolver > into an encoder. > Yes, I already bought a converter from Jon. >> I heard that most people who want a 4th axis, buy a manual >> rotary >> table and add a position controlled motor to it. > > That was my orig idea myself. Right up until I started playing with my > manual rotary table and noted the backlash. I was also thinking that the high > gear ratios will limit overall speed to extremely slow speeds. I think that at least some rotary tables, have some kind of a backlash adjustment. As for speeds, I do not really care for a rotary table to be zipping and flipping at extreme speeds. Mine turns at about 5-10 RPM (IIRC) at 70v, and I am completely cool with that. At 70v, the motor RPM is approximately 1,000. I hope that I am not misremembering. If it takes 3-5 seconds to flip a part upside down, I am satisfied. On troyke tables that I sold in the past, there was not much backlash. > >> So, the bottom line, please share what you find. > > I will thanks! > > Andrew > > > > > > ------------------------------------------------------------------------------ > This SF.net email is sponsored by > > Make an app they can't live without > Enter the BlackBerry Developer Challenge > http://p.sf.net/sfu/RIM-dev2dev > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > ------------------------------------------------------------------------------ This SF.net email is sponsored by Make an app they can't live without Enter the BlackBerry Developer Challenge http://p.sf.net/sfu/RIM-dev2dev _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
