EMI — Etched EMI/RFI Shielding Cans: Vents, Fold Lines and Logos in a Single Pass

The shield is usually the last part designed and the first part to hold up a build. The board respins, components move, the vent pattern shifts — and the can no longer fits. Etched shields don't have that problem, because the shield is a drawing before it's anything else.

Shielding is one of the four product lines Metching is built around. From our Dongguan plant, etching electronics and semiconductor components since 2005, we make shielding cans, covers, lids and board-level shields in stainless steel, titanium, copper, brass and nickel, 0.05 to 2.5 mm thick. Parts come off the line burr-free and flat, from digital artwork. No hard tooling.

The working specs

• Materials: stainless steel (304, 316L), titanium, copper, brass and nickel

• Thickness: 0.05–2.5 mm

• Smallest features: vent holes, slots and apertures at least roughly the material thickness (≈0.8–1.2×)

• Edges: burr-free, no heat-affected zone — nothing raised to cut a gasket, a cable or a glove

• Fold lines: half-etched into the blank in-house, so a flat blank folds into a can on simple fixtures; forming itself runs through our partner network

• Finishes: plating for solderability or corrosion protection via qualified partner finishers — nickel, tin, silver, gold and others on request

• Tolerance: Tolerances are evaluated based on material thickness, drawings and processing requirements. Metching does not apply a single fixed tolerance to every project.

The artwork carries the detail

On a stamped or machined shield, every feature is an operation. A dense vent field costs die complexity. A logo costs a marking step. A pick-up tab costs a redesign of the tool.

On an etched blank, all of it is just drawing. Two hundred vent holes cost the same tooling as twenty: nothing. Part numbers and logos etch through, or half-etch as surface marks, in the same pass as the outline. The detail budget on an etched shield is effectively zero, which changes how freely a designer can spec the part.

Edges behave around electronics, too. A stamping burr can slice insulation, shed particles inside the enclosure, or hold a lid off its fence so the seam leaks RF. Etched parts arrive clean on both faces. No deburring step, no burr-related surprises at assembly.

And when the board respins — it will — the shield follows in days. New artwork, new blanks, done. The shield stops being the long-lead item on the BOM.

Two-piece sets suit the process well, incidentally. A soldered fence and a removable cover are two flat etched parts; the fence's contact fingers and the cover's vent field are both just artwork, and the cover can come off for rework without desoldering anything. If your service engineers open the shield more than once, design it that way from the start.

Honest limits

Deep-drawn one-piece enclosures, thick milled RF housings and waveguide structures are drawing or machining work, not etching. We cover the thin, flat and fold-formed shielding layer. We also don't etch aluminium, so aluminium shields need another process.

Questions we get

Can you supply a finished can, or only the blank?

Both routes exist. Etching produces the blank — fold lines, vents and tabs in one pass. Take flat blanks and fold them in your own assembly, or take formed cans, with forming done via our partner network. Say which at quotation; plenty of customers fold in-house.

How small can the vent holes go?

Same rule as every etched feature: about the material thickness and up. A 0.15 mm cover supports vent holes around 0.15 mm — finer and denser than punching manages economically at that gauge.

Can you etch our logo and part number into the cover?

Yes. Text, logos and part numbers are artwork, not operations — etched through or half-etched as surface marks in the same pass as the outline, at no tooling cost. It also kills a separate marking step downstream, and the mark can't rub off in service the way ink does.

Does the material change the shielding?

Copper solders readily and suits soldered, lower-frequency applications. Stainless is stiffer, shrugs off corrosion, and is the usual pick for clip-on covers. Both etch in the same process; if the design calls for a plated finish, note it on the drawing and we arrange it through our finishers.

CTA: Send the blank or can drawing to info@metching.com or call +1 (630) 474-4019 — Metching, Dongguan · since 2005 · metching.com