Ender 3 v2 X & Y Gantry GT2 Holder for Increased Accuracy

thingiverse

Update 18 Apr 2022: The Y-axis mod suffered significant deformation probably due to heat from its close proximity to the heated bed even with insulation. Suggest to have this printed only in ABS at this point of time. Update 7 Apr 2022: Included Y axis belt holders which eliminates 1.75mm height each side. Installing this however is much harder to do than the X axis holders and involves removing the heated bed. Included also some pictures on how to install it for reference. I did not notice as much improvement with this Y axis mod (from +/-0.09 to +/-0.05mm over 20mm travel) and would attribute it to being able to tighten the belts more with the mod. Still, even if this particular mod does not help with improving the accuracy, there is still the benefit of the pulling tension on the belt not being concentrated in one area. Note that you should re-calibrate your X/Y steppers after installing or changing the belt tension. Summary: The original Ender 3 v2 gantry consist of a belt and pulley system which is slightly off the plane of travel. For the Creality Ender 3 v2 and others like it, the X gantry belt is roughly 5mm vertically off-axis between where it rolls off the pulleys and where the GT2 belts are held on the X gantry. Because of this, when the gantry moves at the edges of X axis, it requires more rotation of the stepper motors to equal 1mm of distance compared to when it is at the middle of the X axis. This causes inaccuracies when printing in the middle vs at the edge of the printer (i.e. parts would be smaller at the edges of the print area compared to the middle of the bed - assuming you have calibrated the travel distance to the middle of the print bed). Refer to the forth picture for the theory, assumptions and calculations from which this is based upon. Solution: To reduce the inaccuracies when traveling, the off-axis deflection has to be reduced or eliminated for this purpose. This mod seeks to accomplish that; by reducing the off-axis deflection to as close to zero. With this mod I am able to achieve within +/-0.01mm difference between instructed and actual travel distance of the X gantry when the gantry is in the middle vs at the edges. I used the dial gauge method to measure the actual travel distance per [Teaching Tech's ](https://www.youtube.com/watch?v=2v7EGDp55n4) video. Previous experience saw up to +/-0.05mm or more difference between requested (e.g. G0 X12) and the actual traveled distance in the same setting. Additional benefit to using this mod is that it removes the sharp angle in which the GT2 belts are held in the X gantry. It is now held in place across a bigger surface area where it was held only in 1 spot. However the unfortunate thing about this mod however is that you might lose 7mm of print area because it sticks out slightly. This is however dependent on the type of hotend assemble being used. Included is a 7mm offset to be attached on the Ender 3 v2 X gantry plate so that the X end stop switch can be triggered. If you plan to use this mode, I kindly request your help to put in the comments your "before" and "after" improvements in accuracy. When I first made this mod I unfortunately forgot to before measurements and the values indicated here are from memory. Many thanks.