| "The team identified three factors limiting a printer’s speed: how fast a printer can move its printhead, how much force a printhead can apply to a material to push it through the nozzle, and how quickly the printhead can transfer heat to melt a material and make it flow." None of these are the actual limiting factor on print speed. Many 3D printers are capable of traveling at 300 mm/s, and extruding at more than 100 mm/s, yet in practice the fastest parts of a print are usually done at 60 - 80 mm/s. This is because the faster you try to go, the worse the print quality is. The outer shells of a print, where quality is most important, are usually done at 30 mm/s. Quality 3D printing is all about maintaining a delicate thermal balance. You want the plastic to cool to below it's melting point (if it has one) as soon as it leaves the nozzle so that it hardens and maintains it's shape. However you also want to keep it warmer than it's glass transition temperature in order to combat the effects of thermal contraction. As you try to go faster the soft plastic will get dragged around harder and will have less time to cool. The layer below will be softer when the layer above is being deposited on top of it. This causes sharp corners to get rounded off and overhangs to curl upwards. The article does not have any close up shots of the objects printed on this machine, but I expect that they are pretty rough. As QAPereo pointed out, the article mentions that they ran into this problem. This does not mean that this is a bad idea, though. Products like E3D Volcano and the Lulzbot Moarstruder have proven that there is a niche in the 3D printing marked for fast sloppy printing. Another thing that they don't talk about is how this extruder deals with retraction. One nice thing about gear driven extruders is they give you very precise control over how much plastic is being put out. You can also quickly retract the filament a bit to drop the chamber pressure and minimize plastic leaking from the nozzle as it travels from one part of the print to another. I'd like to know how well the auger is able to do this. |
I think you bring up a good point about the lack of precision at high speed. I think the next big thing in this industry is going to be diving into the factors behind the 'sloppyness' you mention.
> I'd like to know how well the auger is able to do this.
I can answer this one! it's actually more like a nut on a bolt, instead of an auger, meaning it can reverse just fine.