To answer Ken's question... N. Christopher Perry
> On May 16, 2017, at 2:00 PM, Gene Heskett <[email protected]> wrote: > > On Tuesday 16 May 2017 11:56:40 Ken Strauss wrote: > >>> -----Original Message----- >>> From: N. Christopher Perry [mailto:[email protected]] >>> Sent: Tuesday, May 16, 2017 10:07 AM >>> To: Enhanced Machine Controller (EMC) >>> Subject: Re: [Emc-users] new thread inspired by Christophers >>> question >> >> about >> >>> 3d printer sliceing SW. >>> >>> Gene, >>> >>> Turns out that printing with a heavy machine like a mill presents >>> some problems, as the inertia is orders of magnitude higher than on >>> 3D >> >> printers. >> >>> 3D printers are designed to have as low an inertia as possible to >>> simplify >> >> the >> >>> filament control dynamics. With a larger/heavier machine those >>> control dynamics get pretty complex as I understand it. Plus, your >>> prints would >> >> take an >> >>> eternity. >>> >>> N. Christopher Perry >> >> I certainly understand that a heavy mill may not be able to move as >> fast as a very lightweight 3d printhead and printing may take a long >> time. However, why would "filament control dynamics" be a problem? As I understand it on, at least small hobby scale printers, the extruders don't exactly behave in linear manor during changes in their extrusion rate (your basically pushing a 'rope' into the extrusion chamber, and the rope isn't perfectly consistent in geometry or density). They compensate for this with a variety of parameter like retraction on stop, etc. When inertia of the system is small the start/stop transients are short enough that the filament controller can just about ignore small changes in the differential nozzle speed, reducing it to a nearly on/off control. With slow accelerations you can't ignore the nonlinearities in the extruder and need a much broader range of control. >> With the mill the table would be moving and the filament stationary >> which should, if anything, make the problem simpler. What am I not >> understanding? Or are you concerned about the movement of the object >> being printed? >> >> I have not experience with 3d printing. How fast do the typical >> inexpensive 3d printers move? >> > Pretty fast, Ken, when you can't see it move 4" in a u-tube movie. Its > there, and in the next frame is a blur, and its there in the 3rd frame. > > Even if my G0704 could do the Russian step dance, its still 10x slower > than that. :( >> >> ---------------------------------------------------------------------- >> -------- Check out the vibrant tech community on one of the world's >> most engaging tech sites, Slashdot.org! http://sdm.link/slashdot >> _______________________________________________ >> Emc-users mailing list >> [email protected] >> https://lists.sourceforge.net/lists/listinfo/emc-users > > > 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> > > ------------------------------------------------------------------------------ > Check out the vibrant tech community on one of the world's most > engaging tech sites, Slashdot.org! http://sdm.link/slashdot > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
