CR-10 X-belt straightener with motor shaft support

thingiverse

<h3>Merging Two Designs</h3> This integration adds motor-shaft support to the x-axis and incorporates an additional tension idler to straighten the lower part of the drive belt, combining the concepts of https://www.thingiverse.com/thing:3140464 and https://www.thingiverse.com/thing:3288949. <h3>Opting for a Slimmer Bearing</h3> Space is tight due to the endstop microswitch. The use of a S685-2RS bearing (5x11x5) that happens to be available could be improved by a slimmer MR85-2RS (5x8x2), which will fit much easier. <h3>Reversing Endstop Microswitch Screws and Nuts</h3> In either case, it's a good idea to reverse the screws and nuts that secure the microswitch board to the OEM cover plate. The nuts and protruding ends of these screws are clashing or too close to the new bearing. Flip them over so that the screw heads are on the circuit board side and the nuts (and protruding screw ends) are exposed on the outside of the black cover. <h3>Using GT2-16T Pulley-Bearing as in Cornely Cool's Belt Straightener</h3> The design uses one with a 3mm bore, held in place by an M3-26 screw with a tapered head, no nut required. <h3>OEM X-Belt is Long Enough but Very Tension Sensitive</h3> The belt path is barely longer and adjusting tension is enough to accommodate this increase. Also, the OEM smooth pulleys on the tensioning side are actually keeping the lower part of the belt straight, although adding cornely_cool's x-belt straightener-tensioner can be useful. The 16T pulley needs a fair bit of tension to remain securely engaged with the belt. However, too much tension can produce very pronounced x-axis ripples (interestingly mirror the belt pitch). In some cases, the ripples were severe enough to be felt easily by touch! Too little tension tends to cause the belt to skip the 16T pulleys (more ripples and layer shifts) and it is a very narrow sweet spot on my printer. In the end, I eventually opted for the OEM smooth pulleys instead of a tensioner mod which always caused some x-ripples, something I rarely experienced before. With more toothed pulleys, increased noise seems unavoidable which means more belt vibrations and risk of severe ripples. (Belt path in this version is unsatisfactory, will need radical redesign) The small washer is there to avoid the need for supports when printing the top plate. A spacing bump would have been preferable. <h3>Potential X-Axis Recalibration Need</h3> After this modification, multiple prints of a 2-line 20mm cube shell (no top or bottom) showed consistently wider walls in the x direction, by approximately 4-5%. Did Creality compensate for the lower belt angle albeit that it is causing non-constant movement deviations?