Anet A8 Dual Bowden Conversion

In an effort to gain more accuracy out of my printer, and gain the ability to print in dual colors, I've come up with this design.

I also felt that I would be able to gain some printing speed by decreasing the moving mass on the print head.

I've tried to keep the hot ends as close together as possible, so as not to lose build space. Both nozzles have access to the entire build plate.

Also, the auto level servo mount was designed to not lose space or interfere with the side of the machine. You MUST route your heating and thermistor wires carefully so that they don't hit the frame when homing the X axis or on the far side of the build plate.

This design, like several others, deflects hot end cooling air out the sides of the mount, keeping it away from the build plate.

I also have found that most small servos have quite a bit of slop in the gear train. Most of the servo arm designs I've seen have the button on the switch offset from the center line of the servo shaft. When the switch hits the build plate, the force causes the arm rotate slightly (taking up the slop), thereby changing the actual reading each time it hits the plate. By keeping the switch button of the switch in line with the shaft of the servo, forces are applied more to the shaft bearing surfaces and not to the gear train. You get less deflection/movement during auto level operations (this one change made a HUGE difference in my auto level / printing). I've included 2 servo arms. The arm with holes was designed around MY switch. I urge you to print the arm WITHOUT holes and use your switch as a template to drill mounting holes.

IMPORTANT!!
During assembly I found that the servo mount was hitting the X drive belt. I had to insert washers between the back of the carriage and the servo mount to clear the belt. I am working on a new design to fix this.

MISC NOTES:

I printed everything in PLA. I have not seen any melting issues with the mounts yet, but I run the hot end fans all the time.
When running dual extruders, the RAMPS board does not have a way to turn on / throttle the work piece cooling fan. You need an extender board. I have one on order, but right now I have my cooling fan tied to voltage through a switch.... I have to manually turn it on when needed, and it only runs at full speed. I'm only printing in PLA, so after the first layer, I turn it on.