Ender 3 V1 CoreXZ

CoreXZ (CoreXY but for X and Z on a beltslinger printer) allows for rapid z movement while moving the weight of the stepper motors to the bottom of the frame.  There are several other projects out there that modify an Ender 3 to be CoreXY, but many only work for a particular version of it due to differences in the way the Z carriages are shaped and attach to the X axis extrusion that they hold up.  This project is for the original Ender 3 (which are available as returned items resold as-is for cheap) and has not been tested on any other version.

Some things seen in the pictures such as the x carriage and the Y axis are not part of this mod - this mod was designed as part of a larger project on 4 and 5 axis 3d printing.

Print in the default orientation. Only the motor mounts need supports, and only around the 2 horizontal holes used for mounting to the vertical extrusions.

The left side pulley mounts have mounting holes for the X and Z endstops.  Mounting the Z endstop on the Left Upper Pulley Mount is optional but will allow for homing away from the build plate, which is just as fast and will never cause crashing the hot end into the build surface.  Use the self taping m3 screws it came with to mount it in the recess in the part, using the through holes to reach with the mini screw driver the Ender 3 comes with.  Do this before mounting the part to the frame.  The X endstop mounts to the Left Z Carriage Pulley Mount and can be added before or after mounting.

All parts attach to 2020 extrusion using button headed M4x8mm screws and matching T nuts.  It is important to use button head screws especially on the underside of the Z carriage parts as the belt paths pass by very close.  The Left Z Carriage Pulley Mount also has 2 through holes for M3 screws that line up with through holes on the aluminum z carriage they rest on.  Use M3x10 screws and nuts to clamp the two together.

The belts ride on paired F695 ball bearings. For each of the upper pulley mounts assemble on an M5x25 screw one washer, then two bearings with flanges facing away from each other, then another washer, another pair of bearings and another washer. Screw the assembly into the hole in the plastic until there is no side to side play in the bearings.  For the Z carriage parts use M5x16 screws with a washer on each side of a pair of bearings.  The lower screw on the Right Z Carriage Pulley mount needs an additional 2 washers next to the screw head, else it will bottom out against the aluminum z carriage.

Use standard Nema 17 stepper motors with D shafts and 20 tooth gt2 timing belt pulleys attached with set screws.  Any steppers that come with the Ender 3 with press fit belt pulleys will not work, as you cannot adjust how far down the shaft the pulley rests.  Cut your gt2 belts at 158cm.

No custom X carriage is included in this conversion.  The belt paths run beneath the x axis extrusion at about the same height as the original x belt.  If you are using the original x carriage, the slot for attaching the single x belt is too shallow to fit two belts, so i recommend deepening the slot with a hacksaw and deburring with sandpaper. 

Again, this is all for the original Ender 3.  Check out these other similar conversions if this one is not right for your machine:

https://www.printables.com/model/492543-ender-3-s1-corexz-v21

By Marvin Smith for the Ender 3 S1 (and not compatible with the original Ender 3)

https://github.com/boubounokefalos/Ender_SW

The Enderwire is a full Ender 3 conversion to a Voron Switchwire, with CoreXZ motion with linear rails as one of many upgrades involved.

https://www.thingiverse.com/thing:4783263

B1XZ mod by MSA for the Biqu B1, but replaces virtually everything including the Z carriages with printed parts, so may be broadly applicable to Ender 3 style printers.

Created as part of a larger project on 4 and 5 axis 3D printing, to be shared later.