Printed cap for vitamin pulleys on a Prusa Simplified Mendel

thingiverse

The Z pulley's lineage can be traced back to the first parametric file established for the Mendel, specifically focusing on this part. If we lived in an ideal world, such a component wouldn't be necessary. Its primary purpose is to address the aftermath of motor mount flexing due to belt tension, notably affecting the Simplified Prusa Mendel's X axis. This flexion results in the loss of parallelism between axes, causing the belt to stray from the pulley and misalign with the carriage. The issue arises because the plastic-saving design has produced overly thin pieces for their intended function. A simple solution would be to reinstate plastic where structural reinforcement is required, thus saving time and zip ties. Designers, it's time to acknowledge that some reductions in plastic use have gone too far, particularly in stiffening the Y and X motor mounts (I will attempt to assist with design modifications, albeit it may take time). Interestingly, the Selis Mendel featured a massive 17.5 mm thick Y bracket. Meanwhile, as an interim fix, the pulley cap (alongside substandard zip ties) helps keep the belt in line. To install, print, add two M3 nuts and two M3x8 bolts, then slip on the 8-toothed pulley. Some adjustments might be necessary based on your printer settings. Note that the picture quality of the pulley cap is not up to par due to changes made in E reversal settings to combat residual blobbing and strings.