First experiments with the heated chamber today. Optos still work in the semi darkness, lucky me. First off I tried the same wall component from yesterday. 50C air. 70C build plate (same low setting on the slow cooker goes higher with a higher ambient temperature. Yes, arduino and a thermistor soon enough)
Pleasingly the wall didn't curl off the build plate like it had been doing in air at room temperature, but it's no achievement given how close the plate was to PLA's glass transition temperature. Of course, the wall also started to sag heavily and the print head was pushing the semi molten plastic around. I also still have the new-perimeter adherence trouble.
Next I mean to print a series of experiments to get a better handle of how the different temperature variables affect the outcome. It is possible that for very tall, 'delicate' parts like the wall component above, sufficient heat cannot be conducted from the build plate, up through the relatively low cross-sectional-area to surface-area ratio of the part, in order to keep it from curling. This problem compounds the taller the part. There is also much less radiant heat reaching the upper layers from the build plate. This is where a heated build chamber will hopefully make a difference. In fact the build plate has a propensity for generating a distinct temperature gradient over the height of a tall part, increasing likelihood of curling. This might be a reason for printing with a heated chamber and not a heated build plate.
Woodsmoke
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