Add a screw in the extruder

We are saleing filaments, we have 1000kg in stocks every month that we can have much low price for resalers, but it is not easy to get low price on small quantity.
There are no 100% perfect products include the reprap machine, some time, very accidentally , 1% our products occur this problem, block the 1.7 nozzle.
I want to analyze this problem, I am plastic engineer, we always process extruding plastic with screw extruder, we wander why this 3D printer no screw but process plastic, the printing rate is so slow.And the plastic in the nozzle is not well melting and shear thinning,once there is very little imputies , the 1.7mm nozzle will be blocked.

If add a screw in the extruder, the block problem will likely be solved.And extrude process with plastic pellets will come true, the filaments price is high for the process rate is slow.

We have a laboratory equipment to text the melt flow index of plastic , drop the pellets into the barrel and heat, push 2.16 or 5kg force, the pellets coming out as filaments .

We sale filaments, we also care about the reprap machine, some day if pellets take place of filaments, we also would do some works before that day.Maybe we can sale the 3D printer , supply the tiny screw extruder, some one will be interested?

I think many people would be interested in a screw driven extruder for plastic pellets. Then our feed stock would be far cheaper and it would be easier to experiment with various plastics.

Some people have been working on that very idea, though I don't know that anyone has found a practical solution yet. Problems include keeping the screw from heating up and melting the plastic too far up the extruder, as well as maintaining constant pressure so the extruded filament has a constant cross section.

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the problem is that pellets come in heavy 10 - 25 kg bags (sometimes cheap bags that can puncture easily) and people all over the world would be spilling them everywhere. not as bad for PLA because it's just going to degrade in the wild, but still filament printing is very easy and much more contained, just swap out the filament.

Also this is speculation but we are all used to printing with plastic that has been processed once already, making it slightly stiffer which would give nicer prints. PLA filament has such low viscocity already i can imagine pelletss would be even lower, you'de probably have to add something to give it more viscosity. (maybe you guys are already doing that for the filaments i don't know)

I would be only be interested in the screw extruder if i had access to a granulator. You would still need to buy virgin pellets of whatever i'm granulating but if your producing objects that are 80% recycled PET for instance that would make up for the mess that processing pellets make.

There is also a scale issue, pellets tend to have a minimum size, this affects how small the feed unit and screw can be, given the current size and power of the machine, an extrusion unit based on screw principles may be too big for a typical Mendel design.

Would love to see one though if it is feasible.

How about a screw extruder for pellets to make 3 mm or 1.75 mm filaments that feeds into a 3D printer? In other words, just put the pellet extruder before the printer.

Great idea ! Can you share designs on your proposed extruder or the existing one that you in the lab. Using pellets with reduce cost
of materials and open up other materials for use.

The problem is that screw extruders don't control the volume well. If they did then the filament you are making would not be inconsistent. But the reality is that even you guys with hundreds of thousands of dollars worth of equipment can't extrude consistent diameter filament. So putting an extruder on a RepRap that does not produce consistent extrusions is going backwards.

How about you guys figure out how to extrude perfect diameter filament and then maybe we will want your filament or extruder. But until then quit pushing garbage on us.

P.s. The only review I have seen of your filament made me NOT buy from you. Your quality is far below what is available in Canada and the U.S..

Please read [www.villageplastics.com] to see the quality control we are used to.

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