I’m machining 316L and PEEK in an ISO 7 cell and need a cutting fluid and coating combo that won’t complicate biocompatibility or leave residues before citric passivation and ultrasonic DI wash (40 kHz). Anyone had good luck with non‑sulfurized synthetics and uncoated carbide, or is there a TiAlN option that clears extractables while staying sharp on 0.020 in features?