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[clough42]

Here are some photos of the first prototype print of the block.

2014-10-24 07.46.17.jpg2014-10-24 07.46.44.jpg2014-10-24 07.48.54.jpg2014-10-24 07.49.45.jpg

[Roxy]

Very cool! I only have a PrintrBoard so I don't have an extra axis. But this could make it worth while to get a Ramps setup!

[AbuMaia]

Very nice clough42! I assume there will also be a printable "shelf" part to hold the two hotends, as well as a slot-mount plate? I'm looking forward to this being released.

edit: looking at the pictures again, would not both motors be in danger of colliding with the Z screw on either side? I see they hang off the sides of the X carriage about as far as the bed leveling servo sticks out, but they'll be high enough to risk colliding with the Z nut holders.

[clough42]

That's the idea.

I need to get the motors in hand and fit it all up, but I think I will need to move the whole assembly about 2mm forward for it to clear the Z nut traps.

[dacb]

Outstanding! Fantastic work, clough42!

[AbuMaia]

It may be quicker to find a NEMA 14 model on thingiverse and print out a couple to test with, then buy the actual equipment once it's near-finalized.

[clough42]

The real issues are around bearing fit, belt length, spring tension, bolt traction, feed channel friction, etc. I'm not really worried about the motors.

[gmay3]

Here are some photos of the first prototype print of the block.

Wow this looks awesome clough42! Thanks for the comparison shot with the greg's extruder. Your new design is much smaller than I would have thought! Can't wait to see it in action.

[clough42]

Wow this looks awesome clough42! Thanks for the comparison shot with the greg's extruder. Your new design is much smaller than I would have thought! Can't wait to see it in action.

I spent most of the weekend working on this. Here's how the whole X axis assembly is shaping up. I'm incorporating the double groove mount, X-axis platform, hexagon cooling, servo Z-probe and a print cooling fan. The back plate shown in these photos is the MakerFarm original, so you can get a sense of the scale.

HexagonFan.jpgRightFront.jpgTop.jpgBack.jpg

Keep in mind, this is all still a work in progress.

The drive system has proven itself in the Itty Bitty Belted Extruder (single) but this design has some new concepts. The filament path is longer and it's slightly curved. I don't think friction will be a problem, but that remains to be proven. I'm gambling that I can cool two hexagons with the same 25mm fan if I constrain the air input path tightly around the heat sinks. If I can get the overall input cross section similar to the single shroud, then I can harness the air that bypasses the single hexagon to cool two. I'm making the same bet for the print cooling. The tension springs on the idler blocks are also a gamble. I'm betting I can adjust tension by cutting and bending loops and that the lever arms will be sufficient to get good bolt traction. My suspicion is that most extruders are running with more tension than they need. The MakerFarm bolts are sharp and we only need enough traction to transfer available torque. As long as the motor skips first, there's enough tension.

[TopJimmyCooks]

Ordering 2 more nema 14's in preparation for this.

If the tension springs don't work, you could adapt the idler blocks with through holes for a pair of socket cap screws with compression springs ( like a typical Greg's setup) coming through each idler block and have them meet in the center in a hex coupling nut. if you ran two of these, it would be easy to print a barbell looking thing to connect the two hex couplers, fitting between the two filaments, to keep each coupler from turning when you don't want it to.

A brief search reveals that m3 coupling nuts aren't common. Hmm.