Mega Kossel Upgrade: Direct Drive Effector with Titan Aero

Titan Aero Heat Sink

     Happy New Year! Over December 2018 I was experimenting with flexible filament, 90A TPE specifically, and ran into issues with running it on the Mega Kossel, so I decided to upgrade the extruder to full direct drive to correct the issue. I've had an old Titan clone in my parts bin since 2016, so the logical route to go was upgrading to the E3D Titan Aero with a pancake stepper motor.

Motor and Titan body mounted to modified Ultibots effector

     While I was waiting for the parts to arrive I started looking for an effector design to mount it on. The Ultibots D300 series design files turned out to have what I needed, but it was meant for some specialized type of rod-arm joint. Pulling the source files into Fusion 360 made it easy to customize both the effector and part-cooling duct. The remixed files are on Thingiverse (thing:3321195).

Titan Aero Volcano 90% installed

    Once the effector was sorted out, it was simply a matter of following the Titan assembly instructions to get it mounted and mostly assembled. Getting the drive gear in is probably the hardest part, it kind of has to be slid in sideways before the motor is installed, I ended up using the screw that connects the motor and extruder body to hold the body in place during that step. The idler arm is the other tricky bit, you need to slide it into its slot before installing the motor, otherwise it's a pain to mount, I ended up sliding it in at an angle and snapping it over the end of the motor shaft, not the best way to mount that bit.

Cooling fans installed, Noctua 4010 on the left, 40x40 radial on the right

    With the mechanical side of stuff assembled, it was time to mount the fans and sort out the electrical side of things. For the main heat-sink fan, I decided to get one of the much vaunted Noctua fans to see what all the fuss was about. The difference going from a 3010 axial fan for the heat-sink to the Noctua is instantly noticeable on initial power up, the 30mm fan was loud enough that I could always tell if the printer was on when in the workshop, the Noctua is completely silent by comparison, I can't even hear it unless I'm right next to the effector to clean the nozzle, so I'm probably going to replace all my constant on fans with them over time. Installing the part fan is slightly odd, there is one short screw to connect the fan duct to the effector that goes in first, then the fan gets slotted in and bolted down, the top hole needs a longer screw since it doubles as the second connector to the effector.

Wiring nest under the print-bed

    The last bit of installation was figuring out why the pancake NEMA17 wasn't working. Plugging in the working wire from the old extruder just resulted in the motor sitting there and making noise, so I thought one of the coils might be connected backwards or something. Digging into the documentation, it turns out that 25mm NEMA 17 motors have the coil pinouts reversed relative to longer models, so I had to use some jumper lines to build a cross-over cable to fix the issue, it's the black/grey/yellow/orange set of wires in the picture above.

Mega Kossel ready to print