Most people know that a microwave works by exciting water molecules, but I’m not interested in the dangers of the high voltage/current of a magnetron. I wonder what might be possible with scrap consumer drivers such as a piezo, speaker drivers, or ultrasonic inducers, preferably at a frequency outside of the core human audible spectrum.
- Would an induced vibration in an around 60°C, lightly convective environment, likely significantly increase the evaporation rate of water moisture absorbed within the filament of a spool of consumer grade 3d printing filament such as PLA, PETG, PC, TPU, or Aramid?
- Would certain frequencies likely alter performance?
There are medical applications where ultrasound is used to ablate small areas of tissue (see High Intensity Focused Ultrasound). It only works if you focus all the energy in a very small area, though. Sound is not an efficient way to heat a large mass. I would be impressed if you could warm a kilogram of plastic more than a few degrees above ambient. The waste heat coming off of your driving electronics (the amplifier, and the speaker/transducer itself) would dwarf whatever heat is generated by the sound waves hitting a target.
I am leaning this way too, but what I do not fully understand is the mechanics of moisture absorption and mobility at the molecular level along with the phase state transition of water. My intuition wants to picture little droplets moving around inside the filament. This infers that thermal contact with other molecules is a factor in transmitting heat energy into the droplets. So perhaps vibrationally moving the droplets around would promote mobility that reduces the total thermal contact and accelerates evaporation somehow.