Saturday, October 30, 2010
Today I spend most of my time making my extruder work. I must have assembled and disassembled it about 100 times. But its working now. I changed the place of the thermistor a few times, but that didn't help. I think it is just reading too low values. At room temperature it reads 13°C, which is also too low. So now I just set the temperature to 265°C and the ABS comes out. It isn't bubbling or brown, so I assume its just an incorrect value that is being read. I don't have any accurate thermometers that go that high, so I can't see if my assumption is correct.
I tried printing a few lines without a heated bed, but of course that didn't work. I got some extra nichrome wire to add under the bed and I can isolate it with kapton tape. I hope that will work and I don't get myself electrocuted. As my PSU is really old, I think it will just blow up when I attach the heated bed to it. So I was thinking about using a single long nichrome wire with a resistance of about 160 ohm. That way I'll have 330W of power. My nichrome wire has a resistance of 19 ohm per meter, so I'll need 8.5m of it. That will also make sure everything is heated evenly.
I also have an old thermostat from an oven. That will be more reliable than the one I tried to make myself.
The only thing I'm not sure about is whether kapton can isolate the nichrome wire enough if 230V is going through it and it is being heated. But as it is being used in airplanes, it won't be that bad.