Choose the grade for the part, then plan the cut
316L is the default for instruments and body-contact parts because its low carbon content keeps its corrosion resistance through welding and heat. 17-4 PH is chosen when the part needs strength: it is precipitation-hardened after machining, reaching roughly twice the yield strength of 316L. Free-machining 303 is the easiest of the three to cut, and the sulphur that makes it so costs corrosion resistance, which is why it rarely appears on a drawing for a part that touches a patient.
Work hardening sets a floor on the cut
Every pass that rubs instead of cutting leaves a harder skin for the next pass. So the chip load has to stay above the edge radius of the tool, and a finishing pass has to take a real chip rather than skim. At micro scale the edge radius is a larger fraction of the cut, which makes the floor easier to fall below.
17-4 PH: machine it, then age it
17-4 PH is usually machined in the solution-treated condition and aged afterwards. Aging hardens it and moves it very slightly, and the movement is small but real at micron tolerances. Whether the final dimensions are taken before or after aging, and whether a finishing pass follows it, is decided before the first cut.
Burrs are part of the design at this scale
Stainless steel is ductile and forms burrs rather than breaking cleanly, and on a micro part a burr can be a large fraction of the feature. Deburring by hand does not scale down. The toolpath, the exit direction of the cutter and the edge breaks on the drawing are where burrs are controlled — a note on the print saying “remove all burrs” is a wish, not a method.
Passivation is a separate step, and worth specifying
Machining can leave free iron on a stainless surface, and passivation removes it so the protective oxide can form evenly. It is a chemical process step, normally called out on the drawing to a standard such as ASTM A967, and it should be specified rather than assumed — including who performs it and how it will be verified.