Universal extruder for 3D printers

The kickstarter project: Open Source Universal 3D Printer Extruder | DUAL EXTRUSION | by Chelsea Thompson — Kickstarter

Maybe helpful for the various 3D printer projects going on.

[quote]The QU-BD (pronounced “cubed”) project on Kickstarter seeks to make 3D printing cheaper and more precise, at least for the tech-savvy. Aimed squarely at those who are already familiar with 3D printers, QU-BD is an open-source mission to improve the individual components of 3D extruders, buy raw materials in bulk to produce those components inexpensively, and sell the parts piecemeal.

"Essentially what we did is take Makerbot’s open-source design and improve reliability by replacing the hobbed gear with a 20 tooth spur gear (ala Makergear) with a groove machined into it which centers the filament along the axis of movement; this majorly cuts down on any slipping or stripping.

We also changed the ‘plunger’ to allow for much smoother engagement and precision during adjustment. The extruder is also ready to go for dual-extrusion for those that want to experiment, you would just need to get two of them instead of one! All the parts of the extruder are CNC machined in house at our mini machine shop."

I’ve been eyeing this since they fired up the kickstarter… Overall it looks like good stuff but there are a couple bits that make me twitch. One is that they call it a universal extruder but, well, I don’t see how I’d mount one on my Ultimaker. Or the new RepRap Tantillus. Or any other bowden-extruder machine… Another is that they seem fond of no printed or wooden parts but printed parts mean you can print fixes/improvements and wood is plenty strong for this application and is very light - they’re both good materials for this application and are things you can fab at home more easily than metal.

The whole dual-extrusion thing is more marketing than reality right now. The software really isn’t there yet and the workflow to get a dual-color print to actually print is clunky and, IMO, a real hack. A better solution would be to mix colors (ala RepRap: Blog: Colour mixing) anyway, instead of limiting yourself to 2 colors. You could use the 2nd extruder for support material - PVA is getting popular - but it’s tricky to get right, both configuring and getting both printheads exactly planar with build platform: when you’re printing layers that are less than 0.1mm tall, you really don’t want either head to smack into the object.

Not saying it’s bad, just that it’s not a slam dunk…