[slabity]

> But you can definitely get printers to dump a blob of filament out without worrying about cooling problems

Yes, but we're not talking about dumping a blob of filament. We're talking about injecting filament into a well-insulated channel where it's physically impossible for it to receive any active cooling whatsoever.

That's not a situation where you can just ignore cooling.

[Aurornis]

> We're talking about injecting filament into a well-insulated channel where it's physically impossible for it to receive any active cooling whatsoever.

Look up the thermal conductivity of air.

Then look up the thermal conductivity of 3D printing filaments which form those channels that are being injected into.

The filament will be cooling faster in the channel than in free air.

This cannot work unless the part is heated to a temperature where the filament flows.

[slabity]

You cannot compare the raw thermal conductivity of a fluid like air (that pulls heat via convection) to a solid material like plastic (that pulls heat via conduction). Especially when the fluid is being actively moved with the intention of cooling down the plastic.

On top of that, the lattice structure of the infill will mean that heat will not conduct away from the channels well regardless of the material used.

[amluto]

I can imagine it working with a needle shaped nozzle that inserts into a hole and extrudes filament as it withdraws back out. This is probably much more than a software change, though.