Can an injection molding machine be (easily) converted into a filament extruder?

[seb3dge]

Hello everyone, this is my first post as I joined the forums just to ask this one question... Hopefully I'll end up staying here :)

So... I have been thinking about starting to produce filament for 3D printing, and recently I noticed an old, used BOY 15 injection molding machine for a hilariously low price, and was wondering how hard it could be to convert it to a (basic) filament extruder, given their similarities.

Right now I don't care about the diameter consistency, just if it's mechanically feasible to just extrude one long string with a modified injection molder.

Thank you in advance for your replies!

Cheers,
Seb

[JayDub]

Short answer: No.

Injection molding is a discrete process, extrusion is continuous, so unless you want to produce filament in 3” lengths it’s not really feasible. You could bolt a sort of extrusion die to the fixed platen and dismantle the moving platen etc., but the PLC is going to wait for specific input signals before it rotates the screw and the “Cycle Start” button isn’t going to do that for you. [Unless it’s a really old machine with no PLC and you’re really good at reverse engineering relay ladder logic]. Or you could put the press in ‘Manual’ mode and stand there with your thumb on the “Screw Rotate” button, but that might get boring after a few hours.

With a bit of patience you can probably find an old bench-top or lab extruder for about the same price. You will still need tooling and downstream equipment though.