Machine Development…….Extrusion

Please use this Sub category for all posts & information regarding the Extruder Machine Development. Thanks 🙂

first of all, Dave, congratulations on the awesome new site and very detailed materials. Thank you very much
You saved us from having to buy the extruder infinite screw 🙂

– a quick question about the bandheaters: what power do you suggest? 300W ?

– any specific model or other details about them?

also, we wanted to build the machines on sturdy wheels that have a break so that we can move them around easily. Do you see any inconvenience for that?

– what about building the extrusion machine without the base, so that it can rest on top of any table? Do you see any inconvenience with that too?

I’ve noticed that besides the intro video the plastic and building videos don’t have translations. I’d like to contribute with those translations (into spanish and maybe other languages). Are you aware if somebody is already working on that so that I don’t duplicate or that we can share the task?

looking forward to your answers

@princy Hello and welcome to Precious Plastic. I am a machine builder from India and you can contact me if you need any help.

Is it necessary to have extrusion screw L:D ratio equal to or greater than 20:1 if I am using it just for transportation of already molten material.

@dustintweir Do you have by chance the source files for the STL file you posted here ? I have a hard time to re-construct this in Fusion-360 (to make the CAM operations). Thanks

@davehakkens @dustintweir @lyricalpolymath @paulfreed

Like we said, we have troubles finding a right motor for the extruder screw (it’s not that difficult, but we have a lack of time and budget) and we came up with this idea. I would like to have your comments on wether this could work or not.

The extruder’s screw is from a normal (or maybe bigger) drill. We want to buy a drill, put the screw in it, and attach it firmly to the barrel holder. The mayor benefits could be that you can just find a second hand drill. And the biggest win could be that you can adjust the speed very easy in a drill, so you could bypass the screw in the nozzle. Knowing that this is what makes the extruder the most difficult machine to make (in our point of view). Correct me if I’m wrrong, but now we could just mount the drill, adjust the speed, hence we can use very easily the nozzles with the plumbing sizes.

Any reflexions? Is this tried out already? Or is the idea ridiculous? 🙂

@paulfreed @dustintweir We are building the extruder in Belgium. We also have our doubts about the power of 2 kW for the extruder. The only thing it should do, is push the plastic further. We are thinking of using a motor of only 800W. A lot easier to find. We’ll try it, and post our results. Is anybody building their machines close to Belgium?

What are the specifications of the motor used for extrusion?

Hi Dave/Community members,

I’m Ferdin from India, I’m working on a Thermocol (EPS) machine which is on similar lines as “precious plastic” project.

Has anyone tried to use Dave’s (or Dave have you?) design for shredding and extruding/compressing EPS before?

Since EPS is a form of plastic, I’m looking to integrate both plastic and EPS recycling into a single machine. The temperature and a few other things will have to be changed.

Also what happens to plastic if its dirty, wet, muddy; shredded and extruded out of the machine. Do you anticipate any blocks or jams? Has anyone encountered or experimented with dirty plastic?
Reason I’m asking is because during my EPS recycling ground work and waste conditions, I realized the machine will have to be able to handle dirty EPS as well.

The modular structure is an awesome touch, hope to work together with you guys to make it even more versatile.

Warm Regards,

Are there too many variables for us mortals to roughly calculate the torque (Nm) needed to turn the screw? …And ultimately the minimum size motor needed.

@keesdeligt thanks!
Do you know how many watts the 3ph motor was?

Interesting, thanks. I don’t suppose you’d know how much current the 24v wiper motor drew under load?


well euhm…
We experimented a lot ;).

With the drill we used Drill the RPM was around 30 to get a decent stream.

The cheapest solution, was a scrapyard setup. A 24V windowwiper motor from a Truck.
Powered by 2 Computer powersupplies. wired to get 24V out of the 12 V supply.
Power/Speed regulated with a simple DC dimmer like regulator.
Worked well…

We found out for making filament you want a very stable rpm. So we used a 3 phsed motor with a 220V 1 phase to 380 3Fase frequency inverter…

Regards Kees

Yes please, I’d like to know this too. More specifically, the torque required to turn the screw. I’m guessing it’s in the region of 10Nm (considerably less than the shredder) but I might be way off.


Hi Guys,

I was unsuccessful finding your motor & worm gear specs. I’m sure you went through allot of trial and error before deciding on the gear and motor that you used in V2.
That is why I’d like to use what you used – do you have the specs for us?

If you have posted these already – sorry (I did look).

Greetings from Durban,

We have been investigate about this process, but we can’t find how the 3D printers can identify this material and can work with it, so, is it necessary a special 3D printer that can work to this material? or it need a special additives or something like that? or maybe is it the extrusion procces the key?.

I would really appreciate if you help me with my research, thank you.

Thought of using a Chinese manufacturer.
Quick turn around and cheap

This has got me thinking, It wouldn’t be too hard to construct such a grinding machine, and you wouldn’t actually need an original screw to copy. Since the pitch of the screw doesn’t change, you only need to couple the linear motion of the grinder to the rotation of the screw being ground at the right ratio (could be varied for different size screws). And for the minor diameter of the screw a simple 2D template could be followed by the grinder.

Impressive. This is always been high on our to do list! A custom screw. Do you think its possible to make them yourself or somewhere local? And what would it cost if you made them?


Thanks for the excellent information! About the compression ratio too, I was wondering about that.