Z Axis starts print too high

HI all,

I've recently replaced my Melzi board in my printer with the 2.3 model.

Whilst the z axis can be manually set up fine, after slicing with crusa it decides to start too high. This is a part of the g-code:

;Generated with Cura_SteamEngine 14.12
; Default start code
G28 ; Home extruder
G1 Z15 F100
M107 ; Turn off fan
G90 ; Absolute positioning
M82 ; Extruder in absolute mode
M190 S50
; Activate all used extruder
M104 T0 S210
G92 E0 ; Reset extruder position
; Wait for all used extruders to reach temperature
M109 T0 S210
;Layer count: 179
;LAYER:0
M107
G0 F9000 X41.851 Y75.877 Z0.300
;TYPEKIRT
G1 F1800 X54.809 Y75.859 E0.64648
G1 X55.766 Y75.859 E0.69422
G1 X64.109 Y75.855 E1.11046
G1 X66.290 Y75.851 E1.21927
G1 X69.712 Y75.851 E1.38999
G1 X74.456 Y75.863 E1.62667

If I set the bolded and underlined z axis to 0, its fine, but subsequent layers revert back to being too high

Does anyone know how to fix this for good?

Thanks in advance...

That isn't a problem . . . the first layer can't be at zero, since the nozzle would be blocked by the bed. The first layer is typically at 1x the layer height, or at the 1st layer height set in the slicer (typically higher) since there needs to be a space for the first layer to extrude into. If the nozzle is too high for your first layer, your Z axis calibration is wrong.

- Tim

Thanks Tim,

The nozzle is now touching the bed, can't get it any lower. Height on start up is just set up way too high. Any ideas on where or how to change it?

Thanks

Have you checked your steps/mm calibration? If you are running a typical .4 mm nozzle, .3 mm first layer height is pretty much exactly where you want to be, but you can change it in your slicer . . .

If your microstepping is notsetup correctly, that will cause you to be too high also . . . this really looks like a mechanical or setup problem, not bad gcode . . .

- Tim

Hi Tim,

Do you think it could be the firmware?

I only started to have the problem when I replaced the board.

If you loaded the exact same firmware image to the new board as was on the old one, then questionable that it's a firmware issue. If you didn't take the jumpers (if this board uses them) to set microstepping from the old to the new board, or one is bad or misseated, then that could do it as well.

Microstep at 8 instead of 16, and you will be at 2x the height, and so forth . . .

- Tim

Have you checked you z-offset? Probably not it, but worth a check!

I am currently having the same issue , did you figure out what it was ?

Quote
widespreaddeadhead
Have you checked you z-offset? Probably not it, but worth a check!

After the issues I have atm, that would also be my guess

But you should see that when you manually move to Z=0 as well, no?

- Tim

Nope, not offset, and still having issues. I'm pretty sure it's the firmware, as it was working fine until I replaced the board.

As the firmware was already installed, what's the best way of checking it and the settings?

I can't say that I know that specific board, but you might try the typical gcode commands for showing config values. M115, M503, etc.

Again, this board may be different in it's firmware support, but myself, I won't run anything I don't know the contents of and that I didn't load myself . . .

- Tim

Edited 1 time(s). Last edit at 06/24/2015 02:11PM by tadawson.

Thanks Tim, will look at it over the weekend.

josh