@Andre_Frazatto What magnitude of error are you seeing? An average printer will have a tolerance of about +/- 0.1mm. If you print a series of lines say 10 mm apart do they get closer or further apart or stay the same in relation to each other as you move further away from the home location? If you measure from the home position to each incremental line do you get an error stacking up? This will tell you if there is a mechanical imprecision in your machine through a stack up of step setting inaccuracies from a small scale measurement.
At 10mm with an error of 0.01mm you might call that good enough. However at 200 mm with the same amount of error you are now off 0.5mm. The ratio stays the same.
You need to be certain first that your printer moves exactly the distance you tell it to. This is not determined by printing calibration cubes at this point.
For example if you print a small cube that is supposed to be 10x10x10 and lets say the X and Y are both off by the some error factor so you change your steps to compensate you are likely adjusting your mechanical steps based on the thermal expansion or shrinkage properties of your filament for a small mass object. When you scale it up you will see an error related to that shrinkage rate multiplied and the error stack up in the steps is more apparent.
If the error factors are the same ratio wise in all directions then your steps are also the correct ratios to each other. If you know that your travel distance is correct then any refinement of actual measurement left is thermal calibration.
In the end it might be from cheap Chinese stuff. Just trying to help rule out other possible causes.
I set the steps for all the motors on my machines with a measurement and a mathematical calculation. My X and Y steps/mm always come out the same for 1/16 stepping on my drivers. I never adjust them from there. Movement in any direction is pretty close to exact what I tell it to move. Mechanically the printer is precise to within less than .075mm (about 3 thousands of an inch) at any distance.
Filament is the big variable. The first thing I do with a new roll of filament is print a set of thermal calibration “C” clips. I determine the proper melt temperature with a coiled rope (cobra) extrusion test about 35mm above the bed. Then I determine the true thermal diameter by printing the clips and testing the fit. Once calibrated to an easy but snug fit I write the melt temp and the thermal diameter on the spool and those are the settings I use in my slicer.
If I want to test the thermal stability of the filament I will print an accuracy block and measure the error ratio based on increasing mass. Typically not necessary but it does give me additional insight into the behavior of the filament I’m using if i want to go that far.