I put a piece of red painter tape on the axis (at the bottom near the motor) and ran this command :

G1 Z25.4 F40

and I counted the turn ... 14 and ~ 1/5 turns !!!! not 18 as you said.
So there is definitely something wrong here.
Rodolphe

Did you by chance measure the z movement in this case?  If you have a 5/16-18 zrod then 14 turns wouldn't get you 1 inch of movement.

In regards to voltage, there is a separate trimmer pot on the board for each of the motors that adjusts the voltage for that line.  The wiki has instructions and reference voltages you should see for each motor.

G1 Z25.4 F40

and I counted the turn ... 14 and ~ 1/5 turns !!!! not 18 as you said.
So there is definitely something wrong here.
Rodolphe

Thanks for your help on this.
Regards, Rodolphe

I did another test with a 2mm profile, Slic3r did 100 slices as expected... en result is ~ 1.6cm high

Rodolphe

I think the extruder and slicing software are wild goose chases.  Neither would give you anything like what you're seeing.  Instead, just try controlling the bed manually with RH or Pronterface or even raw gcode commands.  Watch what the z-rod does and see whether it's correct and repeatable.  For instance:

1) tell it to move, say, 50mm and measure exactly how far it goes. If it's wrong, the problem is in your hardware or firmware settings.

2) Go back and forth to see if it's repeatable. 

3) Put a piece of tape on the z-rod so you can see it's rotational position.  The stepper motor moves digitally so it should go back to the exact same rotational position if you move it a distance then move it back. If not, the driver voltage may be off adjustment and the motor is skipping steps. 

4) If the angle is correct but the bed movement is incorrect, then something may be slipping somewhere around the z-axis nut, though I'm not sure how this could be.

5) You can also use a gcode command turn down the maximum rotation speed.  This might help the problem or at least help you see it happen.  For instance, if you tell the bed to move up or down 25.4mm, count exactly how many rotations the rod goes around.  It should of course rotate *exactly* 18 times.  If not, the step value is off (but you said it was 2268, which is correct), or again the motor is not getting enough voltage and is skipping steps.

Rodolphe

Rodolphe

Thanks, Rodolphe
PS : I've attached all the config file I'm using at this point.

it extruded 13.3 cm instead of 10 so I guess I need to adjust the extrude step per mm with the M92 command. My current value is 138, so 138/13.6*10 = 101.4576so I'll try with 101.46 and will redo the extrusion test and a print.

Regards, Rodolphe

; layer_height = 0.300
; perimeters = 1
; top_solid_layers = 0
; bottom_solid_layers = 3
; fill_density = 0
; perimeter_speed = 60
; infill_speed = 60
; travel_speed = 75
; nozzle_diameter = 0.4
; filament_diameter = 1.75
; extrusion_multiplier = 1
; perimeters extrusion width = 0.42mm
; infill extrusion width = 0.42mm
; solid infill extrusion width = 0.42mm
; top infill extrusion width = 0.42mm
; first layer extrusion width = 0.42mm

Thanks,
Rodolphe

Thanks, Rodolphe

Thanks for all your help.
Rodolphe

Thanks again for your help
Rodolphe