Overview

An etched connector contact is a precision contact finger or spring beam cut from thin metal by photochemical machining instead of stamping. The resist pattern defines the contact profile, and the surrounding metal is dissolved away chemically, so the finger is formed without the burrs, roll-over and stress concentrations that a punch leaves on a contact edge. This gives the contact a clean, uniform geometry and a stable spring rate, which are what determine insertion force, retention and electrical performance.

The controlling properties are spring force, fatigue life and contact resistance. Materials are chosen for their elastic and electrical behavior — beryllium copper for high conductivity with strength, phosphor bronze for economy and fatigue, and stainless steel for corrosion resistance. Foil runs from 0.05 mm to 0.5 mm thick, and because the profile is artwork-driven, an etched connector contact can be revised or re-pitched without cutting a new die, making it ideal for fine-pitch, high-density connectors where stamping is too coarse.

Parameter Window

• Available Materials: beryllium copper (C17200), phosphor bronze (C5191), stainless steel 301/304
• Material Thickness Range: 0.05–0.5 mm
• Tolerance: profile ±0.025 mm, finger width ±0.02 mm
• Minimum Feature: finger width and gap down to 0.1 mm
• Surface Options: nickel underplating, gold, tin or silver plating, passivation
• Compliance: ISO 9001 process control, RoHS/REACH material traceability

Manufacturing Process / Workflow (8 Steps)

1. Contact Design Review — Convert the connector layout to vector artwork and confirm finger width, pitch and spring deflection targets.
2. Material Selection — Choose beryllium copper, phosphor bronze or stainless for the required force, fatigue and conductivity.
3. Cleaning & Lamination — Degrease the strip and laminate dry film resist, ensuring bubble-free coverage over the fine fingers.
4. UV Exposure — Expose the contact profile through film with registration to the strip edge for repeat pitch.
5. Development — Wash out unexposed resist and inspect finger edges for residue or under-development.
6. Etching — Etch with chemistry matched to the alloy, controlling undercut to hold finger width and edge quality.
7. Stripping & Plating — Strip resist, neutralize, then apply nickel underplate and gold, tin or silver finish.
8. Inspection & Packaging — Measure finger width, pitch and plating thickness, test spring force on samples, then pack in trays or on reel.

Core Advantages

1. Burr-free contact edges: Chemical removal leaves no stamping burr, so mating is smooth and plating adheres evenly.
2. Stable spring force: Uniform cross-section and edge quality give a repeatable insertion and retention force.
3. Fine pitch capability: Fingers and gaps down to 0.1 mm suit high-density connectors that stamping cannot reach.
4. No tooling: A new contact layout is a new film, so prototypes and re-pitches cost nothing to re-tool.
5. Fatigue-resistant materials: Beryllium copper and phosphor bronze are processed without work-hardening the spring zone.
6. Controlled contact resistance: Clean geometry plus a uniform nickel and gold finish keep resistance low and stable.

Typical Applications

• Board-to-board connectors: Fine-pitch contact fingers for high-density mating.
• Battery and spring contacts: Etched contact beams for cell and module connection.
• SIM and card connectors: Precision fingers for card detection and contact.
• Test and pogo connectors: Contact elements with controlled force and deflection.
• Automotive connectors: Vibration-tolerant contact fingers in stainless or beryllium copper.
• Shield and ground contacts: Conductive fingers for grounding clips and shielding.

Design Notes & Process Considerations

1. Finger width versus thickness: Keep finger width near 1× thickness or greater so the beam flexes predictably without twisting.
2. Spring deflection: Specify the working deflection and target force so the beam length and width can be sized.
3. Material selection: Beryllium copper for force and conductivity, phosphor bronze for cost, stainless for corrosion.
4. Plating stack: Name the underplate and finish — nickel plus gold for low contact resistance — with thickness per layer.
5. Pitch and gap: Confirm minimum gap is at least 1× thickness so fingers do not short during etch.
6. Fatigue life: State the expected mating cycles so the material and heat treatment are matched to the requirement.