Perfect Calibration of Cheap 3D Printers ...

At the beginnig of 2016 I bought a very cheap 3D Printer, with an easy calibration instruction:

Turn the screws until only a paper fits between printhead and printbed ...

But what does it mean ? In my case I was able to turn the screws one turn and the paper fits between both of them ... And in my first month of printing I had very big problems with warping and misprints ...

So I searched for a solution ...

I created an 3D object with 4 rings which fits to my printbed, with the height of the first layer (0.3 mm) and a wall thickness of 0.6 mm and then I printed it ...

In pic 1 you can see the result of a non well calibrated printbed:

- top right you can see that the printhead touches the printbed ...

- on the left side the rings are very thin and have a shadow, so the distance between printhead and is printbed is "very high"

( the fifth ring is the skirt from Cura )

- after fine calibration the 3 inner rings have the same broadness, this means that the distance (printhead <-> printbed ) is similiar in all areas ...

- the rings are thick and a little bit transparent, this means that the distance is very small, this is good for a high grip ...

- in combination with buildtak print surfaces I have no problems with my prints, sometimes I need tools to remove the print objects ...

- the fourth ring is not so perfect, but this ring has the biggest angle dependency, with a second calibration run you can change it ...