Z axis won't home

Hello everybody, I am a new user and have finished building a Prusa i3 printer. I have been able to home the X and Y axis but when ever I attempt to auto home the Z axis there's a loud squealing, the motors only turn about one rotation, then stop. I am not sure what I'm doing wrong.

Here's my setup

Arduino Mego 2560 with ramps 1.4 board

Marlin firmware (newest version)

Arduino software being used to upload Marlin (newest version of Arduino IDE)

Repetier Host being used to control manual movement and homing of machine.

I will put my configuration.h file in another post

Thank you so much for your help!

What is your stepper current for each stepper driver.

Can you easily move the Z_Axis with your fingers by turning the Z_Axis lead-screws or couplers.

configuration.h would be helpful.

max feed rate on Z is to high reduce it to 2 or 3.

Sorry for the delay, but here is my configuration.h

My Z feedrate is at 2 right now

also

I can move the Z_axis easy by turning the Z_axis couplers

Hello;

Just some suggestions
#define Z_MIN_PROBE_ENDSTOP_INVERTING true // set to same logic as "Z_MIN_ENDSTOP_INVERTING".

You must have a probe to enable this line
#define Z_MIN_PROBE_USES_Z_MIN_ENDSTOP_PIN
So this must be enabled for the above to work correctly
#define FIX_MOUNTED_PROBE

Edited 1 time(s). Last edit at 04/18/2018 08:27PM by Roberts_Clif.

Sorry for the delay, but here is my configuration.h

My Z feedrate is at 2 right now

also

I can move the Z_axis easy by turning the Z_axis couplers

Did you remember to fit the 3 jumpers under the Z driver ?

Quote
Wrestler99
Sorry for the delay, but here is my configuration.h

My Z feedrate is at 2 right now

also

I can move the Z_axis easy by turning the Z_axis couplers

How are you moving the Z axis? Is it with 5mm threaded rod, or T8 leadscrew or M8 threaded rod? On my printer I tried to use T8 leadscrew and got a lot of issues with friction between the nut and the leadscrew, I gave up and used 8mm threaded rod instead.

Also what stepper driver are you using for the Z axis and what voltage have you set? I've just built my i3 clone and set 0.8v on my Z driver.

You could also try turning down your default_max_acceleration, can't remember what mine is but I would have thought if your stepper motors are lacking in torque then slowing their workrate down might help, between this and a decent amount of voltage at the driver, it may help your issue? I'm only new to this myself though

was reseting micro swich on z axis home stop and some reason my z well go up but not down