The next step in assembling the printer was fabricating the printhead. The printhead attaches to the X/Y carriage via three alignment pins. These ensure a perfect alignment and make it easy to switch out multiple types of printheads quickly and easily. The initial printhead I've fabricated is a dual extruder direct drive configuration. I also have designs for a single extruder, dual and quad bowden extruders, and others.
The 3D printed version of the base plate that connects the pins and the motor was sufficiently rigid to use for actual run-time testing of the printhead. On the other hand the plate that holds the hotends to the motors had to be CNC machined to ensure a proper alignment. This was the first time I was able to use my new Automatic Tool Changer and Tool Height touch-off. It worked out very well once I figured out the process.
The current printer prototype hands the motors below the XY carriage. However in the second prototype I plan on flipping this to have the motors on top. Thus the printhead plates and brackets are designed to be reversible for either configuration:
And since this is the configuration I'm really aiming for I wanted to make sure there was enough clearance for the hotends to pass through the carriage block. Everything looked good. Obviously the plastic version of the carriage block is only temporary, but even that should be sufficient for some initial testing:
And here's the assembled printhead attached to the carriage in the printer:
I have a few more odds-and-ends to work on and it should be ready for the first test print.