QU-BD Revolution XL Review Part 1

I have had my eye on QU-BD ever since their successful Kickstarter campaign last year.  When I visited their booth at last year's Makerfair, I was impressed with the engineering and build quality of their RPM mill/3D printer.  So when they offered their Revolution and Revolution XL printers to customers willing to beta test and willing to wait in exchange for a great price ($800 for the RXL) and for what might be a truly revolutionary new 3D printer, I signed up.  That was in January, 2013.  There were of course delays and I watched over the following months as the impatient beta customers and I slowly transformed into an angry mob.  So it happened yesterday that I was rummaging through my closet looking for my pitchfork and torch when my dog announced with his usual oratory flair that a package had arrived.

The promise of the RXL's revolutionary leap beyond the current landscape of affordable FDM printers was in its speed.  Most reprap 3D printers use an extruder mounted on the X carriage.  This limits their speed.  Other printers, like Ultimaker, speed things up by removing the extruder from the carriage and using a Bowden extruder.  The downside to that approach is that anti-ooze retraction, used to prevent stringing, does not work well with a Bowden extruder.  The RXL was to have the best of all worlds -- a super-light (<6oz) extruder (they call X-truder) combined with 2 X motors and 2 Y motors.  In an early youtube video, they demonstrated 900mm/second travel speeds.  Later, after they tweaked things, QU-BD was able to demo 500+mm/second ABS printing.  For a reprapper like me used to speeds 1/10th of that, it was indeed a great promise.

The first thing I successfully printed with the RXL was a vase for which QU-BD included tweaked gcode to demonstrate the RXL's speed.  That went well.  I then moved on to printing a Filastruder hopper at conservative speeds:

After some success, I became more ambitious and set out to print an over-sized Eiffel Tower at 400mm/sec:

Check out the speed:

It seemed to be working great for a while but something seemed to "slip" somehow on my Y axis, causing the print to fail.  I will investigate and figure out what caused this failure:

Stay tuned as I continue to put this machine through it's paces.