-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 6/11/2013 3:26 PM, Viesturs Lācis wrote: > > No homing _and_ touch-off? What if the stepper motor is turned, > when power is off, how does it recover from this lost position?
<snip> > But I still do not understand, how do these stepper-driven 3D > printers do without homing or at least touch-off. Stepper motors > tend to move a up to a full step back or forth, when the power is > applied, so there would be some position error acumulated over > time. Some printers are set with home and/or limit switches and the software will automatically home. My printer was supposed to have these, but I've been too busy to actually install them (and I'm far from the only one). When the printer is powered on, the controller assumes it's at [ 0, 0, 0, ]. X and Y are easy to home...their position isn't amazingly critical, so I just slide the bed (Y) and extruder (X) to their approximate origin (about 5 mm off the mechanical travel limit) and that's good enough. Z is more important, and is a gantry axis on my printer (two motors, one on each side driving actual lead-screws). I try to leave Z in a known position (typically at +10 mm) and home with "G92 Z10" at power-on, but I almost always manually check Z before starting a print. At Z=0, I like to be able to have the extruder "capture" a sheet of paper placed between it and the bed, which should move more or less freely at Z=0.1mm. Any errors between the two gantry axis on Z is either ignored or fixed manually (I put marks on the lead screws when I initially got the Z axis aligned). Like I said, the 3D printer world (at least the "maker/RepRap part I'm familiar with) is quite a bit different from "real" machining, and I hope to be able to smooth over some of the rough spots and present LinuxCNC in a good light. ...and thanks for the link to the manuals! I've been crawling through the integrator and HAL docs, but I somehow forgot about the users guide! - -- Charles Steinkuehler char...@steinkuehler.net -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (MingW32) Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iEYEARECAAYFAlG3kdcACgkQLywbqEHdNFwDLQCgpKTvOVtb1Oxar06fnhpW7jPe 3fUAn3qBNsPg8IZzLLRNiKQS/q7wskHq =Iebk -----END PGP SIGNATURE----- ------------------------------------------------------------------------------ This SF.net email is sponsored by Windows: Build for Windows Store. http://p.sf.net/sfu/windows-dev2dev _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
