Tuesday, February 06, 2007
Forensics on the 2 amp low thermal intertia extruder barrel
Sure enough the heating coil failed while I was extruding ABS.
This morning I stripped the barrel and discovered that the heater coil was not partially delaminated from the barrel but completely delaminated. The insulation had completely disappeared from the nichome in places. While I didn't not look closely for the break I suspect that the coil shorted and overheated at a contact point causing the break.
This time around I am going to follow Adrian's suggestion and use about 7 inches of nichrome 80 instead of two lengths of 14 in parallel like I did last time. I am also going to space the wire out a bit on the lower end of the barrel instead of wrapping it tightly. This will be more like what I did with the first test barrel that I build.
I am also going to give it 8 coats of BBQ paint before laying down the wire and another 8 coats to tack it down this time. As well, I plan to secure the two ends of the coil to the barrel with copper filament before I paint it.
Links to this post: