Some quick background: Part 4 was V1 of the printer. A V2 was released shortly after to improve the Z leadscrew nut mounting scheme, making the gantry more stable. This then is the V3 update.
Improvements from previous versions:
- Rotated the ‘front’ of the printer 90 degrees. Now the front looks at the extruder nozzle assembly and has much better access.
- Flipped the gantry 180 degrees, with the XY extrusion now on top. This frees up around 50mm of Z travel, and also improves print quality, as it moves the nozzle closer to the Y rail slides (in Z height).
- Standardized on four Z leadscrews, which are also now directly driven. This removes the extra step and parts of Z belts. For firmware without four Z leveling (Marlin as of this writing), the leadscrews can be manually turned to level the gantry (with the printer off), much like bed leveling nuts. This actually works quite well, as they are 1 Start/2mm leadscrews with anti-backlash nuts, so they don’t lose position even with the steppers unpowered. Duet has four motor leveling, and it is development for Marlin.
- Moved to E3D Hemera as the default extruder. This extruder can easily be firmly mounted to the ExoSlides, which also improves print quality.
- Machined the XY belt carrier. This allows higher belt tension, and improved print quality (this must be a theme!)
- Moved to a magnetic bed with spring steel PEI sheet. Easy print removal.
The current ExoCube kit for sale is V3 with all these changes incorporated.
A couple more notes: The printer was initially developed using all 500mm extrusion to keep it simple. Based on feedback from builders, they are commonly building bigger sizes. As such, the standardized version will be 400mm build volume cube (600 x 600 x 520 outside extrusions).
And how do all these changes stack up? The printer has excellent print quality. The layer lines are perfect with no Z wobble, and the duct design is evenly cooling both sides of the print.
What is next for the ExoCube? Well, lots actually. Keen observers may have picked up on the production looking electrical box and wiring harness, both which will be available soon. An XL version is also in the works by popular demand, and will be based on 3030 extrusion and have an 800mm to 1m cube build volume!
Posted by Giles Medlicott on Jul 17, 2020