Topic: Fan installation
I've got a pretty nice fan installation based on Ian's fan duct over in the STL part of the forum:
http://www.soliforum.com/topic/182/nozzle-fan-duct/
I managed to put the previously unused 12V and ground pins from my Panelolu installation to use to power the fan.
Installation Steps
First step is to organise the following components:
- small switch
- 1m of red wire
- 1m black wire
- 40mm fan
- 2x connectors with pins to crimp
Crimp connectors onto the fan wires and one end of the red and black wires.
Close to the electronics end of the Panelolu ribbon cable, cut pin 1 (red stripe) and peel each side of the wire an inch or so.
Now add a little bit of extra wire to each end and crimp a connector onto the wires. Orientate the black and red as shown.
Undo the four hex bolts holding the stepper motor to the extruder.
Push one end of the 1m black and red wires through the black loom so that it goes from near the extruder to out the back of the machine. I wrapped tape around the wires, spiked in a wooden skewer and used this to push the wires through. Make sure the connector for the fan matches the connector near it on the red and black wires. Cut the wires to a good length and crimp a connector onto the other end once it's through.
Previously in the Panelolu ribbon cable, pins 1 and 2 were unused and simply tape to insulate them. Open up the Panelolu case and find these wires. Solder pin 1 (red stripe) to the center switch pin and pin 2 to one of the other switch pins. Heat shrink will keep everything neat.
An updated Panelolu front and back case have been uploaded to Thingiverse here:
http://www.thingiverse.com/thing:30049
Download and print the new cases pieces. In the corner of the front case panel, there is a blank section where a hole can be drilled to mount the switch. Drill this hole, poke the switch head through and do up the nut to hold the switch in place.
From the front it should look like this:
Print the either Ian's original file linked to at the start or my modified version from here:
http://www.thingiverse.com/thing:30828/
My modifications include simplifying of the fan duct, modifying the mount to use 1/4 x 1/4inch magnets (derived from Ian's dial indicator mount), and adding an adjustment screw which can be turned to push against the extruder and change the angle of the fan duct to get it square. My derivative with everything in place is shown below:
Setup and Printing
Place the duct in place and plug in the connectors at the fan and ribbon cable ends. Home the z-axis and turn the leveling screw in the fan duct to get it sitting parallel to the bed.
Printing performance is vastly improved on tricky parts. Previously, printing anything with small, angled, pointy edges would make them curl up and distort from the uneven heating and cooling. The image below depicts such a part mid print with the layers cooling and staying flat.
A before and after of the finished piece shows the dramatic improvement.
Bridging is also massively improved with the fan on. I know technically this is not what is called bridging, but you can see the trouble I had been having without the fan.
Print Settings
I had already switched to printing at 200 degrees C, and this seems to work well with the fan. I have had no layer separation issues like Ian mentioned, and bridging performance is improved too. I usually switch on the fan as the first layer is finishing its fill, just to help it stick. I also run the first layer bed temp at 95, and then 90 for the rest of the print.
Fine stringing has now started to happen, but no doubt this can be fixed with some Silc3r retraction settings.
Big thanks to Ian for designing the original part so that my process would be so smooth and successful in his foot steps.