Alfawise U20 Wrong Part Z Axis bug fix

thingiverse

Human: Warning: after installing the workaround adjusting the Z axis and X axis can be extremely complicated, do it only if you have a lot of time and only if you have experience with mounting 3D printers. The problem that I found printing some test pieces in the Alfawise U20 is that it detects a linear protrusion that appeared systematically at a certain height (Z axis) around the perimeter of the piece (see pictures below). After thoroughly reviewing the settings (8 hours), I discovered where the problem was, it is the three-bearing system that supports the Z-axis, specifically the lower bearing of the Z-axis. This bearing should use on both sides two small aluminum tubes of 9mm width (8.5mm outer diameter and 1.5mm thickness), well the separator tube located on the right of the bearing if it was 9mm, but the separator tube the left one was much shorter (see pictures below), that is, the left separator is the wrong piece. This caused the lower end of the chassis holding the extruder to touch the chassis that holds the servo motor that moves the Z axis, causing distortion in the print. As Workaround place three washers so that the bearing was centered with the channel of the aluminum profile and in this way the chassis will no longer rub. The printing is now perfect as you can see in the pictures below. Also as workaround you can print the 9mm spacer piece, but it has to be 100% filler and with a hard material like the ASA, since when tightening the nut it will be subjected to a lot of pressure. The final solution would be to replace the piece with the original aluminum.