Printer fails at remembering Z position: prints in air

[optimizer]

After a failed print where the printerhead dislodged itself, it seems the printer is having trouble keeping track of its own Z position.

Everytime I start a new print it starts printing a lot higher than the previous one, making it print completely in the air.

When I make the motor go all the way up untill it refuses to move further, and then start the print from that position it seems to be better, but still not great, forcing me to do both this and level the bed after every print, which is of course extremely tiresome.

Any idea about what could cause and fix this would be greatly appreciated.

[bkjones]

What do you mean by the printer head dislodged itself? I would start by checking the Z axis stop switch and make sure it hasn’t been bumped. The next thing would be to manually turn the Z axis to the top and make sure both sides are even. Engage the stepper motors and then check again at 100 mm or so. After that make sure the X axis and Z axis are square. I think you will find the problem by doing the above steps. If not let me know and I will see if there is something else I can think of.

[Inventreneur]

I also had the same problem and found that the stl file is corrupt. Try printing another file that worked previously.

[horsj]

I would concur with bkjones analysis and approach, which should be your first steps, but would add that I had similar problems; constantly having to re-level the bed. After spending some time trying to work out was happening, I changed the Z axis microswitch for a higher quality Omron switch and have since had no problems. I found these work really well for aligning the Z axis: Wanhao Duplicator i3 Z-Axis Alignment Posts by zolan - Thingiverse

[BrimstoneE]

My printer had this issue which could only be resolved by unplugging the printer power cable and USB cables. This seamed to reset everything. I have a Wanhao DS5 Mini.

[optimizer]

Manually screwing it all the way to the top seems to have done the trick, as bkjones suggested. I unfortunately only tried it with the motor before.

And with dislodging I meant that the printer actually pushed one of the horizontal bars out with the pressure of the PLA.

Anyway, thanks a lot for all your input, you guys are awesome.

[Stephen_Jones]

you can manually reset the hiegth by including an auto ref stop check in the g code at say 100 and then disengaging the screws and manually adjusting to q00mm, but if unsure you can force dropout by screwing to the top. if you have altered the bottom ref limit switch don’t forget to include in your calculation.

[Stephen_Jones]

you can check for lamination abnormalities this way as well, if you work backwards you can find the area that is delaminating and check things like srew claelyness, ball race freeness, etc at that location. first look for the source code call online for the operation you want to do and supply a numerical distance. simple, g-code is, its been around well before the 8086. StevetheBuddistXXX