September 7th, 2013

 I mounted the extruders, turned on the heaters and attempted to run some filament through them, only to find that the barrels were getting hot enough to melt the filament causing it to clog. A little research revealed that this is a common problem with the QU-BD extruders. This lead me to make the following mods...

• Replace the QU-BD delrin feed block with the spring-bearing tensioner (I printed one set, then mirrored the STL and printed another) (http://www.punchtec.com/download-page/) [ext_Armv4 and extruder_spring_block]

• Knurl the extruder gear groves to give better traction on the filament (here is an example of what I did http://www.youtube.com/watch?feature=player_embedded&v=Hl4Gf5R4YJg).

• Fit the barrels for PTFE tubing sleeve (http://www.buildlog.net/forum/viewtopic.php?f=27&t=1977).

After all of this work, I was extruding filament accurately!

September 8th, 2013

 I set the appropriate settings in Slic3r (Repetier-Host integrated version) for my dual extruders (# of extruders and X & y offsets).

I covered the glass with blue painter's tape and pre-heated the unit.

I loaded and sliced the 20mm calibration cube and hit print.

Here is a video clip of that first run... http://youtu.be/hiNy9-SiaEo

As you can see, I need to do some calibration, but it's not bad for the first run.

I went on to complete 3 more prints, adjusting settings (software and hardware) each time.

These are the results…