Terawatt Industries 00str00der Follow-up review

After running the Terawatt Industries 00str00der for a few weeks, I had a few initial impressions:

• belt drive extruders seem to be far superior to geared extruders - no backlash, smooth operation, and no wear. 
• The 00str00der design didn't seem to be optimum, at least for my installation on a MendelMax 1.5 printer:
• The mounting orientation perpendicular to the X-slides causes considerable flexing of the slide rods during prints, causing the nozzle to move in the "y" direction and thus adding print inaccuracies



Photo showing stepper motor hanging over front edge of X-slide rods

• Extruder design doesn't tie stepper mount to structure surrounding hobbed bolt, possibly allowing flex
• Use of rubber discs for springs vs. wound steel springs does not create as much clamping force between the idler bearing and the hobbed bolt, causing filament feed problems
• The slots that provide for belt tensioning don't have enough travel, making installation of the belt difficult.

Since I'm trying to slowly increase the print quality and precision of the printer, I decided to re-design the printer to try and address the problems I noticed. I couldn't find Solidworks files of either the 00str00der or any of the Greg's Wade style extruders, I started this design from scratch, using a few of the existing components. (Idler being one)

Main features of this new extruder:

• orients all components directly over X-slide rods to minimize twisting
• long slots for belt tension adjustment and easy belt installation
• super-beefy construction to minimize flex within part during prints

I've uploaded the .stl files and solidworks models to thingiverse, located here. 

Belt Drive Extruder, assembled

Extruder, Mounted

Note stepper mount is directly attached to extruder body, no gaps

So far is seems to work well. I did switch the rubber elastomer pucks in the idler tension mechanism for some coil springs. The pucks wouldn't supply consistent pressure on the idler wheel.