Overview

Custom terminal etching produces flat electrical terminals, contact fingers, busbar tabs and connector contacts by photochemical machining instead of progressive stamping. The terminal outline, including lead-in chamfers, contact beams, locating tabs and solder pads, is imaged on resist and etched from copper, brass or bronze strip, so an entire connector family can be produced from one sheet with no die and no blanking burr on the contact face. Stock runs from 0.1 mm to 1.5 mm, with slot widths down to 0.15 mm and contact pitch held by the artwork rather than by punch clearance.

Current carrying capacity and contact resistance both scale with the cross-section and the cleanliness of the mating surface, which is why the etch route suits terminals that must be plated afterwards. Etched edges are smooth and free of the roll-over and burr that plating cannot cover, so a nickel underplate followed by gold or reflowed tin covers the full edge rather than bridging a void. Multi-beam contacts, compliant pins and mezzanine pads can all be laid out on one panel, and the plating current distribution stays even because the parts share a common carrier.

Parameter Window

• Available Materials: copper C11000, brass C26000, phosphor bronze C51000, beryllium copper C17200, nickel silver
• Material Thickness Range: 0.1–1.5 mm, half-hard to full-hard temper
• Tolerance: ±0.05 mm on profile and slot, ±0.02 mm on contact beam width
• Minimum Feature: 0.15 mm slot, 0.3 mm minimum contact pad, pitch from 0.5 mm
• Surface Options: selective gold over nickel, reflowed tin, silver flash, anti-tarnish, solder-mask-free finish
• Compliance: ISO 9001 process control, RoHS/REACH material traceability

Manufacturing Process / Workflow (8 Steps)

1. Terminal Review — Check beam width against current, verify that the contact pitch and lead-in geometry can be etched at the specified thickness, and flag any pad smaller than the minimum.
2. Alloy Selection — Copper for conductivity, brass for strength and cost, phosphor bronze for spring contact force, beryllium copper where both conductivity and fatigue life are needed.
3. Stress Relief — Relief the strip before coating so tab co-planarity holds after etching, especially on half-hard material.
4. Lamination — Apply dry film to both faces and keep it thin, since film thickness variation becomes beam width variation at fine pitch.
5. Exposure & Development — Expose both sides in registration, develop, and check beam width and slot opening on a coupon before etching the panel.
6. Etching — Etch from both faces at matched rates, controlling over-etch so the beam keeps a rectangular section and the pitch does not drift.
7. Plating — Strip resist, activate, then plate nickel plus gold or reflow tin; selective masking keeps plating off areas that must stay solderable or bondable.
8. Inspection & Reel Pack — Check pitch, beam width, plating thickness and co-planarity, then pack in trays or tape-and-reel for the assembly line.

Core Advantages

1. No die cost per family: Every new terminal position is a new film, so a connector series with twenty variants needs one process rather than twenty dies.
2. Burr-free contact faces: The mating surface leaves the bath smooth, so plating covers the edge completely and contact resistance stays stable.
3. Tight pitch at low force: Fine slots and narrow beams are formed chemically, allowing high pin counts without the punch clearance limits of stamping.
4. Even plating: Parts stay on a common carrier through plating, so current distribution is uniform and gold thickness does not vary across the panel.
5. Flat, co-planar tabs: No blanking shock means solder tabs sit in one plane, which matters for surface-mount connectors.
6. Fast qualification: Changing a contact beam to trim normal force takes one film revision. Custom terminal etching therefore shortens connector qualification cycles.

Typical Applications

• Board-to-board contacts: Fine-pitch beams on phosphor bronze for mezzanine connectors in handheld electronics.
• Solder tabs and lugs: Flat tinned tabs on brass for wire-to-board termination in appliances and controllers.
• Busbar and ground tabs: Copper links with multiple legs etched from one sheet for inverter and power modules.
• Battery contacts: Spring contacts on beryllium copper for cell holders that must survive repeated insertion.
• Test probe contacts: Fine beams for probe cards and test sockets where pitch is below stamping capability.
• Sensor and antenna terminals: Small copper contacts with controlled impedance geometry for RF modules.

Design Notes & Process Considerations

1. Beam width versus current: Size the beam for the temperature rise allowed, remembering that etched edges taper slightly and the effective section is smaller than the drawn width.
2. Pitch and slot: Keep the slot between contacts at least equal to material thickness; below that, over-etch closes the gap and pitch drifts.
3. Lead-in geometry: Specify chamfers and radii at the entry so a mating pin does not stub on a square edge; etched chamfers are reproducible at 0.2 mm.
4. Plating callout: Name underplate and top plate thickness separately, and mark any area that must remain unplated for soldering or wire bonding.
5. Carrier design: Keep a carrier rail on two sides for handling and plating, and define where the rail is cut after plating.
6. Normal force check: Confirm contact force on real parts after plating. Custom terminal etching controls geometry, but normal force also depends on temper and formed angle.