When I try to print something, it’s almost half as high as it should be. I’ve noticed that when I move the Z-axis up manually, it’s not at the same height as it says on the computer e.g. I move the Z-axis up 20mm and when I measure the height from the print bed to the extruder it only moved up 10mm. Is this normal? Or can that be the problem why my prints are thinner then they should be? If so, what can I do to fix it?
If the Y and X dimensions are OK, it isn’t a scaling problem ! You have just the Z axis to fix.
- Check the connections of the Z axis Motor, maybe the wires are on the wrong place. ( the controller have only a half of the step motor informations ?)
- Check the Z driver voltage is more than 0.425 Volt. (0.55v max)
Hi Maria74,
you wrote about problems with your Z motor before. Did you get it to work correctly inbetween or has your printer since then been in this “Z axis has problems”-state?
In Repetier Host, can you access your printer’s firmware EEPROM settings (menu “Configuration”)? What values are set in the first line (steps per mm)?
Cheers,
kuraasu
Do you mean the first layer height?
Hi Maria74,
no, “First layer height” is a setting for Slic3r. Repetier Host itself has a menu bar on top (at least it should - do you use the Windows or the Mac version?) which also contains a menu “Config”, and inside that menu, one of the items is “Firmware EEPROM Configuration”. In the Windows version, pressing “Alt+E” is the shortcut for the EEPROM dialog. The printer must be connected to RH, otherwise that dialog is disabled.
Cheers,
kuraasu
Hi Kuraasu,
I found it and for the Z-axis it says 2560.00 steps per mm.
Hi Maria74,
that’s the correct value for the original M8x1.25 rod.
Then I only have one suggestion left for “easy” testing: in the manual control tab, you can send commands to the printer, either with the arrow buttons or “by hand” using the box with the “Send” button next to it. Use those to move the Z axis and watch the rod carefully, examining the angle it actually turned. Do this at first with everything mounted as if being ready to print. Secondly (this is the complicated part), disconnect the Z motor from the rod so that it can run freely, mark the shaft with a pen or a piece of adhesive tape, and try again.
When you move the z axis up (or down) with the arrow, you’ll have 1 mm steps, so that should be a 4/5th turn or 288°. Or four full turns after moving 5 mm, of course …
When using the custom command input, you can issue a “G1 Z1.25 F100”, which would be (starting at 0 mm / home) 1.25 mm upwards or one full turn. Next move up would have to be “G1 Z2.5” for another full turn, then to Z3.75 and so on (absolute positioning). F100 sets the speed at which the movement happens (in mm/min!), so feel free to change it if you think it moves too slow or too fast. You only need to specify the F value once in the beginning, and after that only if you want to change the speed.
So, does the Z motor do full (or 4/5th) turns like it’s supposed to? In both cases, mounted and disconnected from the rod?
Cheers,
kuraasu
Hi Kuraasu,
We’ve tested the Z-axis and it doesn’t turn 288 degrees. It turns appr. 152 degrees but it always changes. One time it turns 148, the other time 160. We’ve tested it mounted and disconnected from the rod and there’s no difference mounted or disconnected.
Hi Maria74,
that’s a real mystery. Somehow, your motor seems to loose steps even when used without any load. But at least the mechanical part of the Z axis seems to be fine so far.
Ok, next step: can you test the Z output of the controller board with another motor, like the one in the extruder or X or Y axis?
Keep in mind that there’s a factor of approx. 40 between the steps per mm for Z axis and X and Y axis, so if you hit “move 1 mm” (for Z), and the X or Y motor is connected, it would move ca. 40 mm and will not be stopped by its own endstop, since the controller thinks it’s moving another axis. Perhaps the extruder motor (with filament unloaded, so the bolt can move freely) would be safest, but with propper precaution, X and Y motor are just as good. For the E motor, the stock steps per mm is 600, so for “calibration” whether it turns correctly, 5.33 mm equals one full turn.
All three axes, X, Y, and E, are moving without errors, right?
It’s again the angle that’s interesting. Does another motor also turn only by those “wrong” 140 - 160°? This should make it clear whether the Z motor is broken or not.
When the motor is fine (i.e. another motor, that otherwise runs fine, shows the same error when driven by the Z output), this leads to the motor driver and/or controller board. Again, switching the component in question (this time the Z pololu) with another one, that is known to work, and examining the reaction is the way to go.
Please remind me, since you had previous issues with the controller board: did you have any components replaced by Velleman already? Or is there any other “old” problem which disappeared in the meantime, but could be related to this?
Cheers,
kuraasu
Hi Kuraasu,
Sorry for the late reply but I think we found the problem. A few days ago the Z-axis wouldn’t move anymore. Turns out that the stepper driver is defect. We switched it with a different one and now the height is correct when we move the Z-axis manually.