The following explains the conversion of my Ender 5+ to a dual independent extruder printer (idex). The stl and dxf files are available on THINGIVERSE.
These changes can be done on almost any cube frame printer and aren't very specific to the Ender 5+. The only requirement for the cube is that 2 parallel top rails need to have a full length of extrusion running along them. That is, at the front and the back you need to have an extrusion that reaches to both edges of the printer. To test this (and because the use of aluminum parts makes a very high quality printer), I have performed the same mod to convert an existing custom printer to the same setup.
The use of the second carriage and second extruder is also entirely optional. On the second conversion, I ended up only doing a single extruder printer because I needed the larger volume more than I needed a second idex printer. As such, this also is just a nice upgrade for a cube based printer.
As part of the process, you will need to upgrade the control board and need to be comfortable doing lots of wiring. I used a Duet 3 Mini 5+ with a 3HC expansion board connected to the CAN bus. Whatever you choose, you will need 8 stepper drivers. I'm planning on also performing on designing a bed upgrade to convert the bed into a kinematic (3 drive, auto leveling) design. You may want to make sure that you have 9 stepper drivers to accommodate that in the future. I am going to be adding in a 2 stepper mini expansion board which will leave 1 free stepper.
The steps in this conversion are:
Prepare the frame and relocate the bed
X axis build
X carriage build
Firmware configuration
Slicer configuration