Why are filament spools so expensive compared to pellets?

Maybe something like an electric pressure cooker with a hole in the bottom of the bowl and a brass tube underneath. The pressure and gravity of the plastic should force it down as it attempts to equalize pressure? Does anyone make brass curly straws?

Does anyone have the spec and an estimate of total (global) abs consumption per year used in 3d printing?

the drill auger method will actually work and quite suprisingly the amount of force a 6mm auger can generate especially with the end ground properly is incredible,

my observations so far:

the one assumption anyone attempting to build one of these things should get out of their heads straight away is the idea that pressure , tortional load on the auger and what comes out the nozzles don't in any way correlate

ideally the size of the granule going into the auger should be 1/4 of the diameter of the auger at a maximum, so some kind of system to shread and reduce existing granule or scrap abs down the right size is very critical,

ideally the difference in diameter between the bore and the auger diameter should be kept to as small as possible < .25mm otherwise you will find the smaller finer pieces of granule (powder) will get between the auger and the walls and put a large amount of resistance on the auger, this can stop the flow of granules making their way to the tip,

ideally the tip of the auger should be ground to an angle less than that of the auger "thread" to create a ramping action on tip

ideally you don't want the tip in the meltzone, you want it pushing on the "packed" granules,

This year I am printing personalized Christmas gifts. I use Faberdashery plastic, which is probably the most expensive available, but it comes in a wide range of colours - perfect for making gifts. Even with the very high plastic cost it will end up saving me money overall compared to time and money going around the shops week after week struggling to find things.

In fact I estimate my machine will pay for itself just doing that.

Andy

Order from New Image Plastics. Their prices are very reasonable.

Less economics, more engineering, please? Or if it is about economics, at least make it about how 'we' can do it better. If people are selling it with markup, well maybe that is funding some reprap development, maybe not. The problem with it is that it might be fickle, or an unspoken thing that people do to be able to live making repraps. Also, each person wanting to do things full time making their own store seems inefficient. But i dont see how to do it otherwise, perhaps more ideas on that are needed.

There are wiki pages Granule extruding. That wiki page last updated nov 2011, new information would be good. Makibox worked on a piston driven extruder.(reddit post but found that less clear) There is also the Web4Deb extruder.

Aw, i didnt meant to kill it. Did i at least get someone reading/thinking along other lines?

dunno, one of the ideas i know that is floating around is the idea of using a "slug" extruder type arrangement where instead of using filament or granule,you would use say a 16mmX50mm slug of round plastic, getting 1000 slugs made up in china would cost around 0.05cents a piece, and work out way way cheaper than filament,

the bonus there is that recycling becomes an easier option as well simply because it's much easier to build an injection moulding machine that it is to build an extruder,

Got a link? Cant really search with what you've given me. Nor do i quite understand what you mean.

Tbh i suspect that using pellets directly is the best solution. Makibox' approach seems good. If you use relatively much i suppose you'd filament stuff yourself.

But many probably dont? I really wonder if those 'industrial prices' mentioned in this thread are reasonable. I doubt it, but i also worry about consistency of one of those smaller scale methods. Lets do some math:

If you get pellets @3$/kg and incur a constant cost of ~60$/day running the machines, and expect a demand d you the absolute minimum is price is 60$/day /d + 3$/k with d=100kg/day 3.6$/kg; if d=10kg/day; 9$, in you can ask<30$/kg and be ahead of current sources as far as i can (easily)see.

Of course you need some number of machines, conservatively assume 4h/day up time for each, extruding @~1mm/s one produces 14m/day, with 3mm diameter that is ~10mm^2 ~ 0.13L that would not cut it. Even the 10kg/day scenario would imply 100 machines.. You need at least 1cm/s, preferably more in a company.(Of course initiating a company for it makes it even more and you then basically need to expect customers..) (edit: also from this: smaller diameter is more expensive)

edit2: stupid question; dont even know the throughput of filament now.

Edited 2 time(s). Last edit at 12/18/2012 06:31PM by Jasper1984.

I've developed an extruder that converts pellets to 1.75mm filament:

[www.soliforum.com]

The basics:

$175 total parts cost
Tolerance is +/-0.05mm, usually +/-0.02mm
Extrudes 0.05kg/hour at 40 watts average power consumption

Pretty cool. At 1kg/day Looks like the extrusion rate i estimated is pretty close.(0.13L/day was at a 4 hour day, i was generally being conservative on the negative side) I made yet another filament production page. The issue with forums is that everything gets so diluted. In wikis perhaps every subject should distinguish between the ideas/principles and particular implementations. (the thread you linked to is listed there)

One thing i found was a design with BOM, etcetera. Fairly elaborate. I think he is being a bit too 'loud' with the all-caps and trying to name the principle after himself but ah well. Also imo yours looks better.

If it works on ABS, would it also work on PLA? My naive intuition says yes.

I suspect it would work fine with PLA. Unfortunately, I don't have a source for PLA pellets. Do you?

wow was hoping to just find out the cost of pallets from all the above - was that in there somewhere
like $x/kg as opposed to $60/kg for filament that i pay (in AUD).

---

Prusa 'Explorer' (3dStuffMaker), GEN6, J-head Mk III-B, Bowden Extruder, Marlin 1.0.0 RC2, Repitier-Host V0.84 and Slic3r 0.9.8, PLA. Live at Victoria, Australia.

I get ABS pellets for about $2.50/lb ($6.00/kg) including shipping. (US dollars)

thanks - great

---

Prusa 'Explorer' (3dStuffMaker), GEN6, J-head Mk III-B, Bowden Extruder, Marlin 1.0.0 RC2, Repitier-Host V0.84 and Slic3r 0.9.8, PLA. Live at Victoria, Australia.

Price really depends on the specific resin - SABIC Cycolac resins ran me over $5/lb. at special sample pricing. Normally, they would have been over $30/lb. for a minimum 55lb. order!

---

[haveblue.org]

thanks have_blue,
i don;t know my plastics very well (except for PLA ).
i am making a product and know how much it costs to make in PLA but want a rough idea how much it would cost
in production (just plastic that is) ie. need to work out if it will be $1 or $10 a part. (moulds are usually made in china but extrusion is done locally).
the attached photo shows the type of plastic i want - the long thing is used to place steel starter or shear bars into a concrete slab - that is the type of plastic i want.
the flat thing is a non-compressible plastic packer or shim which we place under pre-cast concrete walls (to level up).
my device would have wall thicknesses similar to the shear bar thing ie.2-3mm. but would need to be make of non-compressible plastic (i think the shear bar thing looks pretty non-compressible anyway!).
do you know what plastic that would be - a common one i would think. do you know the production vol price of this plastic - would be looking at per ton ie. 30000+ units PA.

roger

---

Prusa 'Explorer' (3dStuffMaker), GEN6, J-head Mk III-B, Bowden Extruder, Marlin 1.0.0 RC2, Repitier-Host V0.84 and Slic3r 0.9.8, PLA. Live at Victoria, Australia.