Hi
I have been making and modifying a Mendel at the school where I work and have managed to get it to print well, the problem that I have not been able to resolve involved zeroing the z axis. The z axis stepper motors work well when raising the print head, the problem is when you ask it to return to the z zero position, the stepper motors just buzz unless you press the limit switch then they bring the head down about 10mm and stop. Because of this is it the head stops in any position above the bead I have to keep pressing the z home button and flick the home limit switch to get it to move. I have checked the switch and it functions ok so I have just put up with it but I do wish I could solve the problem. Help
(enthusiastic amateur)

Did you mean to post in this forum? This forum is for the Ormerod printer. Try this forum [forums.reprap.org] or this one [forums.reprap.org]

Dave

Sorry :-(