Sodium Hydroxide Ultrasound Bath
PLA will decay-ie break into smaller pieces, in an ultrasound bath of fairly concentrated Sodium Hydroxide, sometimes sold as Lye, a powder or a liquid.
This is nasty, poisonous, dangerous stuff, much more so than Acetone. So, lets make our own ultrasound bath, using Piezo-electric sensors or rather the crystals in them, to break down PLA that is used as a support filament for ABS prints!
We need a corrosion proof container to mix NaOH (nomenclature for Sodium Hydroxide), as powder, bought from your local chemist. This is an exothermic reaction, lots of heat will be given off, so only make small batches at a time, and use plenty of water.
Search for vinland, youtube video makergear.
We can use Piezo-electric cystals to create vibration in the bath, instead of forking out money on an ultrasound bath like that made by Merck. The problem is that the metals they are made with may well corrode, and any such electronics must be kept dry.
Nylon plastic bag material ((is /is not suggested to)) contain piezo electric crystals that cover the base of your bath, these are connected to an Arduino Nano clone with wires that are kept out of contact with the NaOH solution, this Nano is programmed to stimulate the piezo electric crystals with small pulses of electricity that will cause them to vibrate, thus simulating, hopefully effectively, an expensive ultrasound bath. As PLA breaks down, it will be stimulated to 'flake off' leaving other non-PLA plastics intact, in theory.
Sample electronic circuit, based on an Arduino Uno, its suggested software acts as a drum player, to record, rather than play the crystals stimulation. Author: Ryo Kasaka, posted on instructables.com.
You would need to reprogram the Arduino Uno to play rather than record the piezo crystals.
Scratchbuilt Piezo Printhead
Underbed Piezo-electric sensors a big one, the size of the bath!
Automated Circuitry Making the spirit of reprap!
Text (not image) license: DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE v2, December 2004 (or later version)