Hi, I own a K8400 printer for a few weeks now, and it’s been a bumpy road with failures and success.
From my point of view the Vertex assembly instructions concerning alignment and belt tension are not adequate. Not only can they lead to bad performance, it can even cause damage or fast wear of the printer’s components.
So here are my two cents ‘golden’ tips:
- without belts the extruder carriage should move easy and with equal resistance. If that’s not the case, play around a bit with how far the XY rods sit inside the linear bearing clamps
- the manual states to frimly bolt down the belt clamps, basically not leaving any room for adjustment of the tension. The k8400 printer is a great piece of kit, however the mechanical components are not industrial grade. The initial tension on the belts are way too high, causes too much movement resistance forcing the stepper motors beyond their limits, causing layer shifts, hard noises when missing steps, and overall fast wear. [color=#008000]Use these belt tensionners instead:http://www.thingiverse.com/thing:691419. They work great![/color] I also found out that fairly low (half than original) belt tension does not have a negative affect on printing quality. On the contrary: detailed prints without any problem with the original settings and speed on 150%. And when you move the extruder carriage by hand, you immediately feel how easy the movement is; your printer will last much longer.
- with just a caliper it’s close to impossible to get the XY alignement spot on. After initial assembly with alignement not perfect, [color=#408040]print the calibration parts from thingiverse.com/thing:606083[/color], and re-align your printer perfect now.