IDEX mod for Geeetech i3 Aluminum

thingiverse

IDEX mod for Geeetech i3 Aluminum TLDR: Build a mirror image X axis on the other side of the backplate. Works on the Geeetech i3 Al, likely to work on similar Geeetech machines, possibly even on the Prusa originals. An extension to the Y axis is likely needed to give the secondary extruder access to the entire bed. I had long wanted to make a dual extruder/multimaterial setup on my printer but the Geeetech i3 Al is limited in this regard in that its frame size is quite small compared to other 200x200 printers. A normal idex or dual extruder setup using the same x axis would take too much space on the x axis. The logical way to go is to build a mirror image X axis on the back side of the vertical plate. So I took this Z carriage design: https://www.thingiverse.com/thing:2477413 and merged the motor side and idler side. A spacer is added in between so the part will straddle across the backplate. Also added are fixtures for additional hardware. Print 2 sets in PETG as stepper motors can get hot enough to soften PLA. There are some built-in supports that need to be cut away. M3 hardware is needed to assemble the Z carriage. A second set of Z smooth rods are also needed on the backside to keep the carriage stable. Thus a second set of motor mounts and Z rod mounts are added to the back side. You can keep the original parts and bolt through the new ones, or print two sets and make it symmetric. I anticipated the need for a second set of Z leadscrew and motors but it seems that two Z motors are enough for the job, although the Z carriage is so heavy that sometimes it slips down a bit when the motors are disabled. Of course you will need to find a new home for your control board and PSU as they can't sit on the backplate anymore. And all the cables going into the extruder carriage needs to come out the front so they will not run into the other extruder. If your two extruders are identical you can skip this, but I had a MZ76 extruder on and a Titan Aero lying around from previous upgrades. So I also designed a height adjustable X carriage for the Titan Aero so the two extruders can be tuned to the same height. The extruder can slide up and down a rail and is secured by a pair of screws pushing against it on both ends. This also helps if you swap around between a Volcano hotend and a normal one. Print in PETG as it gets hot there, and this mount needs M4x20 screws and nuts and one M4x25 for one of the screws that goes into the X carriage. Use socket head screws; some pan heads may be too big. The Y offset between the two X carriages is 109.7mm, so most likely the Y axis needs to be extended to give the second extruder access to the entire print bed. For the Geeetech i3 this can be accomplished by using a longer set of M8 smooth rods and M10 threaded rods for the Y axis. I used a set of 500mm rods. On my printer the Y endstop is on the rear Y motor plate so the print bed cannot go past it. Also provided is a mount for the Y endstop that sits on the threaded rod and secured by a pair of M10 nuts. It extends out to the back so the print bed can go past the rear plate, giving it more travel. Control wise, I had a GT2560 board and the Sanguinololu board. I connected both to a Raspberry Pi and ran Klipper which enables multiple MCUs to work together, giving me enough output between the two boards to run all the hardware. Note: flashing Sanguinololu is kind of Voodoo so Klipper is likely to fail. I had to copy the klipper.elf.hex file and manually flash through the SPI pins. See here for instructions: https://atlantisq.wordpress.com/2021/05/30/flashing-klipper-to-sanguinololu/ Feel free to comment for additional instructions or design files!