Hi,
I'm quite new at this 3D printers world but I'm starting a project where I'll try to develop my won 3D printer arduino based.
I've been doing lots of research, reading articles and watching lots of videos, but most of the information refers to already-built printers, kits or upgrades for commercial printers so I actually miss some details abot how it works. Anyway I'm now specially centered on hot ends and extrusion and there are some base questions to which I can't find an answer, let's see:
As far as I know a hot end is the device that heats the filament until it's melted. So, the filament is pushed by a stepper motor, it melts down in the hot end and it goes out through a nozzle. My questions are:
- I can see everywhere "hot end temperatures" (like 240 C for ABS), can I assume that is the temperature on the inside surface of the hot end? or even further, if I were using nichrome wire around a barrel, could I assume for the calculations that 240 is the temperature I should get on the nichrome wire?
And related to this, where should I set the temperature sensor? Does it go inside the hot end or does it measure the barrel temperature?
- About extrusion: the way to extrude the plastic is simply melting it and letting it fall through the nozzle hole? I mean, I'm wondering if the hole through which the filament goes inside of the hot end was so tight that the movement of the filament generated pressure inside and that madethe melted plastic go out. Maybe this guess is just a fool idea but as I said I couldn't find this info anywhere
- A bit to do with the previous one, how do you prevent the reflux of the melted plastic, i mean, how do you get the melted plastic not going up through the conduction where the filament comes in?
Just to make it clear, I'm not trying to make you work for me, I think these are basic questions and probably some of you won't answer because of that, but I couldn't find an aswer anywhere and I think you guys know a lot about this. I'm so excited with this 3D printing world and its enormous potential.
Thank you all in advance
Toalla