Stainless steel is the default etched metal — until the part has to carry current, move heat, or solder cleanly. Then the drawing usually changes to copper or brass, and engineers ask what else changes with it. Xinketching is a precision photochemical etching manufacturer in Dongguan, China, producing flat etched metal parts since 2005. We etch copper and brass from 0.05 to 2.5 mm thick, burr-free and stress-free, with a standard etch tolerance of ±10% of material thickness and no hard tooling. H62 brass (UNS C27200) is the copper alloy we hold as standard; other copper grades are sourced to the grade specified on your drawing — we do not substitute materials silently.
Answer capsule: copper, brass, or stainless?
- Copper — choose it when the part’s job is electrical or thermal: lead frames, bus and contact elements, heat spreaders and etched cold-plate layers. Copper’s conductivity is the reason it is specified; etching keeps thin copper flat and burr-free, which is what sealing faces and fine lead patterns need.
- Brass (H62 / UNS C27200 standard) — choose it when the part needs copper-alloy conductivity plus easier forming and a lower material cost than pure copper: terminals, contacts, decorative-precision mesh and lead-frame work where the drawing calls for brass. State the grade on the drawing; other grades are sourced per order.
- Stainless steel (304 / 316L) — choose it when stiffness, corrosion resistance or spring performance matter more than conductivity. If the part does not carry current or heat, stainless is usually the cheaper, stronger answer.
The process rules do not change with the metal: tolerance, minimum feature size and half-etch depth are set by thickness, not by alloy.
Specifications (same rules as stainless)
- Thickness range: 0.05–2.5 mm — gauges 0.05, 0.08, 0.1, 0.12, 0.15, 0.2, 0.25, 0.3, 0.4 and 0.5 mm are stocked; above 0.5 mm up to 2.5 mm is sourced per order
- Dimensional tolerance: ±10% of material thickness (e.g. ±0.02 mm on 0.2 mm stock, ±0.03 mm on 0.3 mm stock); raw-stock thickness tolerance ±0.02 mm
- Minimum through-feature: holes and slots at least roughly the material thickness (design rule ≈ 0.8–1.2× thickness)
- Half-etching: partial-depth features (channels, fold lines, surface marks) at ≈50–75% of thickness, depth control ±0.05 mm
- Format: flat sheets only, no coil/reel-to-reel; maximum single sheet 600 × 14,500 mm for material 0.5 mm and above; encoder discs up to Ø600 mm
- Finishing: passivation in-house where applicable; plating (all types, via qualified partners) and bending/forming via qualified partners — plating is commonly specified on copper and brass for solderability and contact resistance, so note the finish on the drawing
- Lead times and order terms: samples 3–5 days, production 7–10 days; no minimum order quantity, minimum order charge US$100; FOB
- Quality documents: material test certificate with per-run material batch traceability; PPAP Level 3 supported; IMDS data available; NDAs on request
Why does copper behave differently in service, not in the etch?
Etching is photochemical, not mechanical: the pattern is exposed photographically and dissolved, so a soft metal is not pushed, punched or heated out of shape. That is why thin copper — which stamps with burrs and oil-cans easily — comes off an etch line flat, with clean edges on fine leads and channel walls. What copper changes is the finished part’s behaviour: it conducts heat and current far better than stainless, it solders readily, and it is softer, so a copper part that must also act as a stiff spring or a wear surface is usually the wrong specification. Surface finish matters more, too: bare copper and brass oxidise in air, so drawings commonly call for a plated finish (nickel, tin, silver, gold and others are available through our finishing partners) or a defined packing/storage condition — raise it at quotation, not after delivery.
Where does brass earn its place?
Brass is a copper-zinc alloy, and H62 is the standard grade we work to. It keeps much of copper’s conductivity and solderability, machines and forms readily after etching (forming is a partner process), and typically costs less than pure copper at the same gauge. Typical etched brass work: terminals and contact elements, precision mesh and grille work where the alloy is specified, and lead-frame or connector parts whose drawings name brass rather than a high-conductivity copper grade. The trade-off is the same one the alloy itself makes: if the design’s current or thermal budget was calculated on pure copper, brass is not a silent substitute — which is why we quote to the grade on the drawing and confirm any grade change with you first.
Does switching from stainless to copper change tolerances or feature sizes?
No. The governing rules are thickness-driven and identical across the metals we etch: tolerance is ±10% of material thickness, through-holes and slots start at roughly the material thickness (≈0.8–1.2×), and half-etch depth is controlled to ±0.05 mm. A 0.2 mm copper lead frame and a 0.2 mm stainless shim are designed to the same feature rules. What changes when you switch is service behaviour (conductivity, stiffness, corrosion and oxidation) and material price — and, because there is no hard tooling, switching grades between prototype and production costs a redraw, not a new die.
When are copper and brass the wrong choice?
When the part needs stainless-level stiffness or spring force in the same gauge, when the environment will attack copper alloys and no plated finish is planned, or when the part is not flat thin sheet at all — etching covers 0.05–2.5 mm flat parts only. We also do not etch aluminium, the other common “light conductor” engineers ask about; a design that truly needs aluminium belongs to a different process, and we will say so at drawing review.
FAQ
Which copper grade should our drawing call out?
The grade your electrical or thermal design requires. H62 brass (UNS C27200) is the copper alloy we hold as standard; other copper grades are sourced per order to match the drawing, so naming the grade at enquiry stage lets us include material lead time in the quote.
Can an etched copper part be plated for solderability?
Yes. Plating is arranged through qualified partner finishers, with nickel, tin, silver, gold and other finishes available on request. Note the finish and any thickness requirement on the drawing so it is quoted with the part.
Do copper and brass etch to the same tolerance as stainless steel?
Yes — ±10% of material thickness, with the same minimum-feature rule (≈0.8–1.2× thickness) and the same half-etch depth control (±0.05 mm). Tolerance is set by gauge, not alloy.
Can we prototype in stainless and produce in copper?
Yes, if the geometry stays within the same thickness rules — there is no hard tooling to remake. Tell us the switch is planned, because material price, oxidation protection and any plating belong in the production quote, not the prototype quote.
What do you need for a quotation?
A drawing or DXF, the exact grade, thickness, quantity, and any plating or finish callout. State any critical dimension on the drawing and we will confirm it at quotation.
CTA: Send your drawing to sales@xinketching.com — Xinketching, Dongguan · since 2005 · xinketching.com
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