print with pellets not filament  

RE: print with pellets not filament

Basically the only advantage is material cost, and you can get that advantage without the disadvantages in complexity, convenience, quality, flexibility, etc by extruding the pellets into filament.

RE: print with pellets not filament

The main issue from what I understand is extrusion consistency. Those options in the hobbyist market that exist and are feasible in this market are not managing the level of extrusion consistency that filament based printers routinely achieve.

I'd say that pellet based printers start to make sense on printers at least as large as the XL, rather larger. That is why giant 3D printers are usually pellet based. If your printed objects weigh often 5 kg or more filaments get really expensive, not to forget that refilling a pellet tank is much less of an issue than changing filament. 

I think for hobbyists, pellet based printing is a nice DIY project bu not really something Prusa has to get into. There are more important things the company should address IMHO.

RE: print with pellets not filament

Basically the only advantage is material cost

We'll that is a huge advantage is it not? 

Also, I've certainly have had prints fail because the filament got twisted and locked up coming off the spool, so that's another thing as well. 

RE: print with pellets not filament

refilling a pellet tank is much less of an issue than changing filament

The pellet hopper is actually a pretty significant issue. A tiny little thing on the print head is going to obviate any of the benefits with large scale printing, you're going to be constantly monitoring and refilling the thing. And there's other impacts on performance...a gravity fed setup from a hopper positioned above with a flexible tube is going to add a lot of resistance and inertia as well as potential for jamming, and of course the hopper has to be up on top. The XL is already pretty tall.

And then that tool's dedicated to what's in the hopper until you can empty and clean it all out. That's not just no mid-print material swaps, but significant printer downtime for doing so.

RE: print with pellets not filament

We'll that is a huge advantage is it not? 

No, it's a pretty small advantage. Look at what you'd need to print to have material costs reach just half of your total cost...it's about a quarter of a metric ton for my XL. It's really only relevant if you're not just printing constantly, but on printers designed and tuned to crank out big prints as quickly as possible, and then you're asking for something a bit different from "a printer that prints with pellets".

And again, you can get that same advantage by extruding the pellets into filament.

Also, I've certainly have had prints fail because the filament got twisted and locked up coming off the spool, so that's another thing as well. 

You think you're not going to have pellets jam? Or have the extruder get clogged due to some random bit of debris or stray pellet of higher-melting plastic that got into the hopper?

RE: print with pellets not filament

For a consumer product, I don't ever see this as being a big selling point.  I switch filaments constantly (and I'm not even talking about changing filaments in the middle of a print) and switching whole hoppers (and the delivery tubes and hot-end) of plastic sounds like a lot more work.  Not to mention what happens when a random spider or fly ends up trying to go through with the pellets and the issue of getting a consistent flow.  Look at the complexity of an actual pellet to filament process, it's fairly complex and finicky (there are many YouTube videos talking about it).  There's also the humidity issue that's much easier to control with filament drybox than an open hopper of pellets.  I could go on.

If you're printing constantly 24/7 with the same material then it might be worth the savings and the hassle.  If not, it seems unlikely to ever pay for itself.  If you do it, I want pictures though!

RE: print with pellets not filament

Look at the complexity of an actual pellet to filament process, it's fairly complex and finicky

And that's producing a relatively thick, uninterrupted extrusion, with a disruption meaning some meters of lost filament instead of hours of lost print time.

There's also the humidity issue that's much easier to control with filament drybox than an open hopper of pellets.

Ouch. Imagine a mishap while trying to use silica gel to manage this issue...a packet of silica gel gets into the auger, or some beads get spilled into a box of pellets. Could have a couple hundred dollars of plastic become unusable. Similarly, if you spill some, good luck getting all the contamination out. Most likely, those pellets are scrap.

If you're printing constantly 24/7 with the same material then it might be worth the savings and the hassle.

Notice that Prusa actually does just this, and they even make their own filament from pellets in the same facility. They still print from filament.

This is the kind of thing that makes sense if you're printing furniture or architectural components on some system with a 3 mm nozzle depositing 1.5 mm thick layers, laying down 2 kg of plastic in an hour (like this). I don't think it makes sense for anything close to XL-scale or below.

RE: print with pellets not filament

Wow, now I want one of those giant printers.  Imagine, a benchy you could actually sail...

RE: print with pellets not filament

I would love a Greenboy3D extruder, but not for pellets, but for shreds.

I would love to recycle failed prints and stuff like Supports by shredding and reusing the material. I could live with less quality in these cases.

RE: print with pellets not filament

Get a grinder and use it to grind broken prints etc as an infill for epoxy.