Sunday, July 17, 2016

3D Printing Redux

It's been quite some time since my last post! Shortly after my last 3D printer update, I completed the machine and began testing and tweaking. The machine worked, but overall performance wasn't up to my standards. I spent some time revisiting the design, and ultimately decided to tear it down and begin anew with higher quality components.

I designed a new printer, also a cubic foot H-bot, using OpenBuild's V-slot aluminum extrusion. The extrusion and accessories are fairly low cost, easy to work with, and high performing. Additionally, I decided to complete an overhaul of the electronics. I switched out the Printrboard for a Duet 0.8.5. This controller provides significantly more features than the Printrboard, such as native dual nozzle support, network control (similar to OctoPrint), and 24v power. Also, the DC powered 12" silicone heater was replaced with an AC version and a heatsinked solid state relay.

Additional electronic changes included use of the E3D PT100 temp sensor+board for the hotend, and the differential IR sensor for auto bed leveling. There were some hardships in getting the PT100 sensor functioning, since the E3D amplifier boards were designed for 5v electronics. To make things even more difficult, the Duet 0.8.5 did not have any software support for PT100 sensors (DC42 has since added some functionality).

At the time of writing this post, I completed the project about 9 months previously. There's still some work to be done on the printer for getting the second nozzle operating and watercooling the hotend. For now, enjoy some pictures of the build process!

Frame nearly finished at this stage. The black panels are a textured 1/4" HDPE called StarBoard. Cheap and robust!

Solid state relay and matching heatsink. Absolutely critical for keeping the relay functioning.

Electronics are in a compartment underneath the print area. Includes SSR and 24v power supply on the left with the Duet and 12v+5v power supply on the right.

The first powered test with all critical to function pieces wired. It works!

A 1/4" polycarbonate shell forms covers all sides but the front to limit temperature fluctuations in the build area. Eventually the enclosure will seal to prevent warping; but the hotend will need to be watercooled.

I printed a calibration cube before this to check basic functionality, then threw the iconic octopus on it. Finished it like a champ!

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