On Tuesday, February 22, 2022 12:58:05 PM EST Chris Albertson wrote: > On Tue, Feb 22, 2022 at 9:14 AM John Dammeyer <jo...@autoartisans.com> > > wrote: > > Thanks Martin, > > His question and the subsequent discussion on the MACH group has > > morphed in now discussions on whether to use closed loop steppers > > and ethercat.> > > Not sure why everyone is so fond of leadshine closed loop steppers > > but > > > > what do I know. I like my AC servos. > > The answer is price. A closed loop stepper is not really stepping. > The motor is run by an FOC controller and measured with a rotary > encoders. The step/direction interface is kept. So the system is as > easy to interface as a stepper but has performance characteristics > like your A/C servo but at about $100 per axis. The closed-loop > stepper's disadvantage is they come only in limited sized and power > > > A decade or more ago it was MACH3 and the ESS or USB smooth stepper > > or the EMC as it was then called. Now it seems there are a lot more > > CNC solutions around and the number of people even considering LCNC > > seems to have dropped. > > When the typical machinist sees an under $300 turn-key solution on > Amazon that has an LCD touch screen and is all wired up with software > and a place to connect the motors. Then he hears about LCNC where you > first need to locate an antique computer with a parallel port then > test it with a latency test then install a modified version of Linux, > and only then can he begin to edit config files. He goes for the > $300 turn-key system. > > Here is the "competition" > amazon.com/DDCSV3-1-Upgrade-Stand-alone-Controller... > <https://www.amazon.com/DDCSV3-1-Upgrade-Stand-alone-Controller-Engrave > r/dp/B07SR854D1/ref=pd_sbs_5/139-3455477-1339233?pd_rd_w=oXb8b&pf_rd_p= > dfec2022-428d-4b18-a6d4-8f791333a139&pf_rd_r=XC1A6X2PEV1N61AZWS5C&pd_rd > _r=62aa4f06-4bb7-45db-9de9-6bf67f0f4072&pd_rd_wg=sRlvK&pd_rd_i=B07SR854 > D1&psc=1> I think it should be clear why it is attractive. It is very > much the polar opposite of what LCNC is. >
I dunno. It doesn't say what it cannot do, and that scares me. With lcnc, I can do as many io's as I can scare up motors for, soon to have a V axis on my 6040, a if I can carry it on the flimsey X axis, maybe even a U axis, and a B is also it the planning and printing parts stage. Can it do rigid tapping with automatic backoff to keep the tap from bottoming in a blind hole and braking the tap? I can, I have a proof of concept working but lack the tool holder facility to make it work daily. Can this thing do that? My guess is a resounding no. But I can do that with LCNC, all it takes is me writing the hal code. > > I'm also surprised there isn't some sort of teaching module ready to > > go for LCNC although again, really, how many even want something > > like that. Maybe so, but I can write the code quicker than I could learn how to run a teaching program. > > Much as Brian Barker might want to create a module the ultimate issue > > isn't the starting point but support a year or so later. Without > > sales to support the work that only one client wanted that may leave > > him hi and dry. At least a DIY LCNC solution is always open source > > with more than one clever person ready to help. Which is its strongest testimony. How many other gone by dawn wanabeee's has LCNC outlasted now. > That is the big advantage of open source. But the problem is running > it on an antique computer using a modified OS and having to hand-wire > everything yourself scares off 99% of potential users. I think if you > could buy a packaged LCNC machine that came inside a closed box with > an LCD touchscreen and it booted up when you applied power and if you > could sell it at under $500 and offer tech support and warranty, then > LCNC would "take off". The box would still be "hackable" by the 1% who > wanted to mess with Linux and config files but for most uses that > would not even know there was a Linux PC inside. > > > And since there are versions of the MESA that close the loop for > > servo > > control on each axis I'd think that a training version with servos > > would be pretty easy. But again I may be simplifying all this. > > What is the total cost per axis for the motor size that is typically > used? This is what people look at. Closed loop steppers seem to the > be best and lowest cost solution for a certain range of power that is > needed for smaller CNC routers. Perhaps the bigger problem isn't the complexity of LCNC, but a lack of teachers willing to share their time. Andy is spread pretty thin at times. Take care and stay well everybody. 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
