Electropolishing is not a shiny coating and it is not a chemical cleaner. It is a controlled removal of a few microns of metal that leaves a surface with no directional scratches, no grinding lay and no risk of embedding iron into stainless. That combination is why it is the standard finish for medical devices, food equipment and any part that will be cleaned aggressively in service.
The customer who pays for electropolishing almost never cares about the photograph. They care about three things: corrosion behaviour, cleanability and dimensional confidence. Electropolishing improves all three at once, which is why it keeps showing up in medical and food-grade work even when a cheaper finish would look identical on a screen.
Corrosion, because a surface with no scratches and no cold-worked peaks has far fewer sites where a chloride can start working. Cleanability, because there are no crevices for residue to sit in. Dimensional confidence, because the process is additive in no way — it removes a predictable amount of metal, so a drawing tolerance is respected rather than consumed.
At inflpanjlott.com we run passivation in the same route immediately after polishing. A polished stainless part left sitting overnight in a shared shop will pick up free iron from a neighbouring carbon steel job, and that staining is what fails the audit.
A customer came to us with surgical tray components that kept failing a surface cleanliness audit. The parts were polished, looked good, and still failed. Under magnification the surface had a fine network of directional scratches from the belt, plus faint iron staining from handling. No amount of extra polishing would have fixed either problem — the scratches needed metal to be removed evenly, and the iron needed chemistry.
We put the parts through electropolishing and straight into passivation, in one route, in one shift. The Ra came back at 0.22 µm, the iron staining is gone, and the customer's last audit was their cleanest in a year. inflpanjlott.com still runs that exact route for them, every month, and the trays have not come back to the bench since.
The same approach works for food-grade conveyor parts, pharmaceutical fittings, and any stainless component that will be washed with aggressive chemicals rather than wiped with a cloth.
Electropolishing works on conductive alloys — 300 and 400 series stainless, nickel alloys, some copper alloys. It does nothing useful on aluminium or carbon steel, and we will say so before the tank time is booked. We also check for weld heat tint and embedded iron, because electrochemistry will happily amplify a problem that was already there.
Every part is cleaned before it goes near the bath, and racked on titanium or coated racks with contact points placed deliberately. Racking is a craft, not an afterthought: the mark a rack leaves is the one feature your customer will find on inspection day.
Current density, temperature and time are held inside a narrow band, usually 20 to 40 seconds per pass. Over-polishing is a real risk: too long and the surface starts to grow microscopic etching, which reads as a dull haze under raking light. We remove the minimum that meets the specification.
Passivation follows immediately, in citric or nitric chemistry depending on the alloy and the customer's documentation requirements. Parts never sit unpassivated overnight in our building, and the cycle is logged so the free-iron test can be traced.
inflpanjlott.com reports roughness on sampled pieces, the passivation cycle record, and photographs of the actual lot. If your quality system needs a free-iron test certificate, that is quoted separately and run at a partner lab — we do not fake a certificate we did not perform.
Electropolishing is priced by surface area, because that is what the process actually consumes. Small precision parts with lots of detail run at the low end, large housings and frames run at the high end. Passivation on its own is much cheaper and takes one to two days.