Replicator 2X Fan Duct by jmcskixc

Last crawled date: 4 years ago

ATTN: Work-In-Progress!! I'm still working out some details in the model. Also this design may not blow enough air to be very effective. Tubeaxial fans can move a lot of air (CFM) but they aren't very good at generating pressure (as in through a nozzle). I'm working on a second design using a blower-style fan which generates about 6x the pressure, which may work better.
This thing allows you to add the third cooling fan to a Replicator 2X. The third fan cools the freshly extruded plastic, which is critical for successful PLA printing.
It cools only the right-side nozzle. If you want to cool the left side, just mirror the part before printing. I may add a mirrored version soon.
This part requires no modifications to the Replicator itself. However, you will need to snip off one of the mounting ears on each of the fan grilles or the screws may not be long enough to thread into the stepper motors.
I added a wire to the unused fan output on the factory board and ran it up and around to the extruder. I bought a 24v fan on Digikey (the Rep's fans are all 24v fans) as well as the plug-in connectors for the wiring. This way you can unplug the fan as needed, and the wire simply plugs in to the Replicator's board.
Wiring:
You'll need to solder two of the crimp connectors to one end of your 2-conductor wire. Trim the fan leads down to about 2 inches long and solder two crimp connectors to the fan as well. Insert the crimp fittings into the plastic housings to make a plug. Plug this end of the wire into the fan output on the board and run the wire up and over to the extruder. I zip-tied it in place along the existing wiring harness. Then cut the wire to rough length and solder on the female connector that receives the fan's plug (this connector already has the pins in it). Watch your polarities here, you don’t want the fan to run in reverse. You may choose to add some very small heat shrink tubing on these solder joints, but it’s not critical depending on how you have things arranged.
Mechanical assembly:
Remove the middle two long screws that go through the fans, through the extruder, and back into the stepper motors. Use wire cutters and snip off the mounting ears for the fan grilles in these two locations. Don't worry, one screw is more than sturdy enough to keep each grille in place (or just get rid of the grilles altogether). The tension in the assembly should keep the plastic spacers in place between the fans and the heatsinks. Insert the screws in the middle holes of the duct. Insert the screws back where they go and push the whole assembly back together. The thickness of the duct replaces the space previously occupied by the grille mounting ears. Tighten the screws snugly but not too tight.
(If the spacers fall out, you may need to remove the other two screws and slide everything together first, then install the whole deal onto the heater block. You can also just tack the spacers to the fans with a little CA glue.)
Mount the fan to the duct in the remaining holes. I used some small #6 screws and nuts, commonly available at any hardware store, Lowes, Home Depot, McMaster-Carr, etc. Plug the fan into the plug on the wire you installed earlier and that's it.
With the combination of stock firmware and Makerbot Desktop, the cooling fan is controlled manually with the on-board menu on the Replicator 2X. I just wait until the first layer or two is down, then manually turn the fan on and leave it on. I'm sure there's a more sophisticated way to handle the fan control, but up to this point I was more concerned with getting it wired and mounted. Comments are suggestions are welcome.
Part Numbers:
Fan:
Digi-Key Part Number P15610-ND Manufacturer Part Number
1606KL-05W-B30-L00
Connectors:
Digi-Key Part Number 455-2266-ND Manufacturer Part Number
XHP-2
Digi-Key Part Number 455-2879-ND Manufacturer Part Number
B2B-XH-A-M(LF)(SN)
Digi-Key Part Number 455-2261-1-ND Manufacturer Part Number
SXH-002T-P0.6
Wire:
I used some leftover fine 2-conductor wire I had laying around. Other good choices are the cord from an old mouse, or fan wires from the inside of an old PC. Just use something thin enough to be flexible and fir the application appropriately. These fans don't draw much current, esp at 24 volts.