After machining plastic implants, what is the recommendation for an in process cleaning using a small ultrasonic tank?
The recommendation would be to use 1% Liquinox (a mild alkaline, emulsifying and dispersing cleaner) at a temperature well within the temperature tolerance of the plastic. Warm solutions clean faster than ambient temperature ones, so if some heat is an option, use it. Liquinox would not harm plastics other than possibly stressed polycarbonate where there is potential for stress cracking. Stressed polycarbonate in the presence of heat and low surface tension solution (like a solvent or a detergent) will undergo stress cracking (fogging or crazing). Very dilute (0.25%) solutions of Liquinox used without heat can usually safely clean even stressed polycarbonate without problems - of course hopefully the polycarbonate is not that dirty because of course a 0.25% solution does not clean as well as the typical 1% solution.