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Those giant vases next to it look pretty cool. How does the thing work with warping? And how does it feed plastic?

They print with PLA pellets, so no real warp issues. Pellets are fed in with a screw.

Saw it printing tonight at our Maker meeting at SeeMeCNC...
2 mm layers & 6 mm wide extrusion, crazy!

Since it uses an auger screw to extrude and it has a huge nozzle, aren't there huge blobs? Seems like that kind of setup would be limited to continuous rate extrusion with no retracts. And how do they get it to extrude at a constant rate with pellets?

Generic Default wrote:Since it uses an auger screw to extrude and it has a huge nozzle, aren't there huge blobs? Seems like that kind of setup would be limited to continuous rate extrusion with no retracts. And how do they get it to extrude at a constant rate with pellets?

No retracts, but you should be able to get consistent flow with a long enough extruder screw feeding the material. If you can do it with a filastruder, no reason why not here. Also, I imagine you need a pretty high pressure to keep the flow going, so if you were to have a servo controlled screw, you could do reasonably clean stops.

Actually, if your feed system "pump" was positive-displacement, you could get a little suck-back/retract by reversing the drive. We do something like that on a filling line at work - you're putting hot cream cheese (roughly the consistency of pudding) in a cup with a servo-driven piston. If I need an 85mm stroke to fill a cup, I'll do an 85mm stroke, then suck back 1mm. No drip.

The eyes on he factory sign are backwards.

no matter which side, the eyes point toward the building, so on one side they are "backwards".... but on the other side they are correct...

Guanu

That huge printer is an interesting design challenge. There are some mods I can think of.

One change would be to melt the nurdles in an external tank (like they do with wax in candle factories), route the melted plastic through heated PTFE hosing down to the hot end (it would need to be pumped to meet the volume demanded), and then re-heat it to the perfect temperature for extrusion.

You could also do the above, but instead of a heated hose, you run the melted plastic through a Peltier block to cool it down to perhaps 50-100C. The output would be fat filament, maybe 5-10mm thick. This would be simple to route through PTFE tubing down to the effector, where a standard extruder (albeit with really big hobbed gears) would drive it and retract as necessary. The hot end wouldn't have to work quite as hard as usual, as the plastic would already be well above room temperature before it gets there.

Another idea would be to keep the Archimedes screw drive, but mount a piston to the side of the hot end's melting chamber and drive it with a linear stepper. Drive the piston out and it creates vacuum, and the vacuum causes a retract. Drive it in and the filament is pushed back out to the nozzle tip. To prevent plastic from creeping around the piston, it might be possible to find some tough high-temp rubber, fit that to a hole in the melt chamber, and let the piston control the pressure or vacuum behind the rubber.

You could also do something like a needle valve for retracts. At this scale, maybe a tiny spatula swiveled in place to block the nozzle.

I want to buy some of their remnants!

[img]http://i.imgur.com/eQTkWw5.png[/img]

I think someone needs to make a midnight trip to that sign and change it to "Revenant Sale".

g.

Is this the PartDaddy I see on this MakerCon video?
http://makezine.com/2014/09/18/how-the- ... with-nasa/

Yep.

g.

Part Daddy Awesomeness

[youtube]http://www.youtube.com/watch?v=FtQG733dC1s[/youtube]

This thing is everywhere I look!

Just browsing the Wikipedia 3D printing page...
BAM!
http://en.wikipedia.org/wiki/3D_printing#Large_3D_printers