Xinketching is a precision photochemical etching manufacturer in Dongguan, China, etching flat metal components since 2005. For hydrogen programmes we etch metallic bipolar plates, flow-field plates and separator plates in stainless steel and titanium — the standard metallic bipolar-plate materials — from 0.05 to 2.5 mm thick, with copper used for electrolyser and current-collection plates. Etching puts the flow channels, ports and sealing features into thin metal from digital artwork — no stamping die — which makes it the practical process for stack development, prototype builds and design iterations, where the flow field is still being optimised.

Specifications

  • Materials: stainless steel (304, 316L), titanium and copper — bipolar plates are most commonly stainless steel or titanium (brass and nickel are also etched; see our full materials range)
  • Thickness range: 0.05–2.5 mm (metallic bipolar plates typically use the thinner end)
  • Channel design rule: channel widths and land widths should be at least roughly the material thickness (design rule ≈ 0.8–1.2× thickness); channels can be etched single-side or both sides — as half-etched features their depths typically run 50–75% of plate thickness, with depth controlled to ±0.05 mm
  • Edge and channel condition: burr-free — no raised burr to puncture a membrane or damage a gas diffusion layer; no heat-affected zone
  • Plate size: etched from flat sheets up to 600 × 14,500 mm for material 0.5 mm and thicker; thinner gauges are run in smaller formats to prevent distortion
  • Coatings and surface treatment: plates are supplied bare (uncoated) — coatings are not offered; if your coating strategy requires one, it is applied downstream by your own coating supplier
  • Dimensional tolerance: ±10% of material thickness (e.g. ±0.01 mm on 0.1 mm stock, ±0.02 mm on 0.2 mm stock)

Typical parts & applications

  • Metallic bipolar plates for PEM fuel cell stacks
  • Flow-field plates (serpentine, parallel, pin and custom patterns)
  • Electrolyser separator and flow plates for hydrogen production
  • Single-cell test and short-stack development plates
  • Current-collector plates, meshes and screens for cells
  • Coolant and distribution plates for stack assemblies

Why etching for this part

The flow field is still a drawing — keep it that way. Stack performance lives in the flow-field geometry, and development teams revise channel layouts repeatedly. Etching turns each revision into new artwork, not a new stamping die, so fluid-flow testing can drive the design instead of tooling cost freezing it early.

Burr-free channels protect the membrane. A single raised burr in a flow field can puncture a membrane electrode assembly and kill a cell. Etching removes metal chemically, leaving channel edges clean — a decisive point for a part whose neighbour is a thin polymer film.

Both faces in one process. Cooling channels on one side and reactant flow fields on the other can be etched into the same thin plate, keeping plate weight and stack volume down versus assembled constructions.

Flat plates for stack sealing. Etching adds no mechanical stress and no heat distortion, so thin plates stay flat — which is what gaskets and stack compression need to seal evenly across the active area.

When etching is not the best fit

Graphite and moulded-composite plates are a different material route entirely, and once a metallic plate design is frozen for very high automotive volumes, stamping usually wins on unit cost. Etching carries the programme through development and lower volumes, and proves the geometry a production die will later copy. One more material boundary: we do not etch aluminium plates.

FAQ

How fine can flow channels be?

Channels and lands follow the etch design rule: at least roughly the plate thickness (≈0.8–1.2×). On a 0.1–0.2 mm plate that means sub-millimetre serpentine channels are realistic work. Send the flow-field drawing and we will verify every channel and land width before quoting.

Can you etch different patterns on the two faces?

Yes — different patterns can be etched on the two faces of the same plate. Double-sided features are dimensioned like half-etched features and controlled to the same standard as single-sided etching (±10% of material thickness). Many stack designs pair a reactant field on one face with a coolant field on the other; flag the requirement at quotation so the construction is confirmed before artwork is made.

Which material should a bipolar plate be?

316L stainless steel is the common choice for corrosion resistance in the cell environment; titanium is used where the corrosion environment is harsher or weight is critical; copper suits some electrolyser and current-collection parts. Final selection depends on your coating strategy and cell chemistry — plates are supplied bare and coatings are not offered, so any coating is applied downstream on your side — and we etch to the material your design specifies within our stainless steel, titanium and copper range.

How do etched plates support stack development timelines?

Because there is no die, a revised flow field only needs new artwork — samples typically ship in 3–5 days. Development teams typically order several pattern variants together and down-select on test results.

What do you need from us to quote?

A drawing or DXF of the plate with material, thickness, channel pattern and port positions, plus quantity. If coating is part of your specification, include it — and tell us if plates are for single-cell testing or a short stack, as that affects panel layout and cost.

CTA: Send your drawing to sales@xinketching.com — Xinketching, Dongguan · since 2005 · xinketching.com