Friday, November 5, 2010

Oct 19, 2010 heated bed. done.


I have built a heated bed for my catalyst repstrap. In testing it gets up to a PLA heat as quick as the extruder, about 2 minutes. But I did notice that it slowed as it reached 55C, the target temperature. I'm still using my fork of the generation 2 firmware, I added in code for a heated bed. I couldn't find that anyone else has added heated bed support to the generation 2 firmware... looks like everybody moved on to other things.

The bed it's self I made from a road sign I found in my parent's basement. Probably from my brother's ill spent youth... or mine. I thought it quite appropriate that it says fire lane on the build platform. Between the rat's nest wiring and too many things heating from a janky power supply, this will probably catch fire soon. I'm not sure if it will work with ABS, and I'm inclined to not find out. On the back of the metal base are lines of nichrome wire which I liberated from an old fish tank heater. The nichrome is held on with kapton tape, and that is covered with a small amount of ceramic tape. To complete the sandwich I have the original crappy plexiglas build platform that came with the machine. The ceramic tape, I hope, is just enough insulation that there aren't any points of high heat that might melt the plexiglas. The binder clips are there in case the plexiglas does deform... more.

I haven't tried printing on this yet, I still have ABS in the machine from the last time I printed. I want to test some PLA I got from Ultimachine, maybe make a wade extruder to reduce the mess. Two things; 1. I'm not sure if anything will stick to the fire lane graphic and 2. If I use ABS I don't know if I can get the platform up to a high enough heat. Let alone what may fail at that high heat.

some references:
http://wiki.makerbot.com/heated-build-platforms
http://ultimachine.com/content/printing-circuit-boards-mendel
http://www.brokentoaster.com/blog/?p=358
http://reprap.org/wiki/Mendel_heated_bed

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