Orb wrote:One thing to consider on the 12v vs 120v debate is that in at least one case (the ExtrusionBot) the unit extrudes much faster than a Filastruder. In order to keep up with the thermal demand of melting that much plastic, you need to be able to make sure the heater can keep up. Sure, you could do it with a high current 12v supply, but when you start playing with that much current, I don't know if it's any different where possibilities of fire are concerned. Wall outlets are free, but high current 12v supplies aren't.
Barely any of the heat goes into melting the plastic.
ABS has a heat capacity of around 1300J/kg-k. We need to raise it around 180K, so that's 234kJ/kg. Even at 1m/min, that's 5 hours/kg (which calls into question some of ExtrusionBot's marketing, but moving on...).
234kJ is 65watt-hours. You have 5 hours to put that energy in. That's 13 watts. So: ExtrusionBot needs 13 watts of heat into the ABS to melt it. On the other hand, the Filastruder runs at about half that speed so you need 6.5 watts of heat into the ABS.
Typically, the Filastruder runs a 40w heater at 80% duty cycle to extrude ABS, depending on ambient temperature and how the insulation is positioned. Moving to 100% would make up the remaining 6.5w needed.
It is possible I made a math error as this is all back of the envelope, but the fact remains: You don't need a massive heater. Most of the heat is lost to atmosphere. I'd guess about 10w off the nozzle face, 10w off the pipe, 5w through the insulation, and the remaining wattage into the polymer.
There is no need for big heaters unless you're in pursuit of higher temperature plastics.
Orb wrote:The Filastruder is quite safe in use. I accidentally left the heater on and went to bed. Smelled some hot plastic the next morning, but no smoke or flames. On the bright side, it was ready to make filament after removing the wad at the end and pushing out the overcooked stuff. I'll make sure I don't do that again 
. But after that incident, I am happy that it is as safe as it is.
I'm glad everything was okay, but please be careful in the future! I put mine on a timer that shuts off at midnight every night in case I ever forget.
Orb wrote:I won't lie and say that I haven't considered putting a bigger heater and a faster motor on the unit though, just to see how far it can be pushed while still making quality filament.
Feel free to try a bigger motor, or the upgraded motor in the store + active cooling + 15-18v. I've done it before and it seems to work well and push another 50% or so in speed.
... he's happy with what he produces (and so am I, both with what he made and what I'm making for myself now!)
