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What is a gold finger PCB?

A gold finger PCB has conductive contacts along a board edge that mate with a connector. The useful specification is the complete mating interface: board thickness, contact positions, keying, insertion depth, bevel and the contact finish. Gold colour alone does not identify coating thickness, hardness, wear resistance or the connector system鈥檚 durability.

Start with the connector manufacturer鈥檚 approved card drawing. Then identify the required nickel and gold system, finish boundaries and inspection evidence for those contacts. Selective hard gold may suit a repeated sliding interface; an immersion-gold soldering finish should not be treated as an equivalent simply because both appear gold. The correct choice follows the actual connection and its qualification requirements.

This page helps with contact-edge geometry and a manufacturing brief. For the wider coating decision, use the PCB gold-plating process guide. For a board needing conductive sidewalls instead of mating fingers, review PCB edge plating. These features can coexist, but they require separate drawing details.

Define the mating edge from a common datum

Place the first contact, key slot and board outline against a shared mechanical origin. Equal pitch does not guarantee that the connector touches the intended area: the whole pattern can be shifted relative to the insertion stop. Include the board鈥檚 finished thickness tolerance, because the connector must accept the complete interval after the relevant finishes and processing.

The contact drawing should distinguish the wipe region from the full plated length. A connector spring moves across a specific track during insertion. Mask, legend, exposed glass, machining damage and unintended steps must stay outside the agreed functional region. Staggered contact lengths may implement sequencing, but they must come from the interface specification rather than a cosmetic layout preference.

Check pattern width and symmetric bevel geometry

The worksheet checks a simple equally spaced contact array. It reports the pattern span, remaining width after two end allowances, nominal contact area and the run of a symmetric bevel. It starts blank; the example is deliberately labelled as illustrative. For staggered lengths or unequal widths, split the pattern into defined groups or send the complete drawing for review.

The bevel model measures angle from the PCB face. With a 1.6 mm board, a 0.8 mm remaining tip and a 30-degree angle, the calculated run is about 0.693 mm on each face. This demonstrates the convention, not a recommended connector geometry. A negative edge allowance exposes a dimensional conflict; a positive value does not prove correct mating or adequate end clearance.

Keep the downloaded result with its drawing basis. The tool does not model spring deflection, contact force, insertion life, electrical rating or the effects of contamination. Do not use the contact-area result as the complete plated area for a purchase order: process buses, masking boundaries and other plated features can change the actual scope.

Specify the bevel, contact setback and tip together

鈥淏evel the edge鈥� is incomplete. State the angle convention, remaining flat tip, permitted board-edge position and the relation between the bevel and each contact. A long chamfer may remove useful contact area; a sharp or poorly controlled edge can interfere with insertion. Different connectors can require different entry geometry, so a familiar angle is not automatically transferable.

Agree which dimensions refer to the finished board after beveling. Review key slots and local cutouts near the mating edge, including the way the board is held during machining. Thin sections and closely spaced contacts may need additional support. If the bevel is asymmetric, the symmetric worksheet does not apply; provide a section drawing with separate top and bottom dimensions.

For a prototype, include a mating check using the actual connector and the intended assembly position. That check can reveal a gross alignment issue, but it does not replace dimensional inspection or durability qualification. Keep any change to card thickness, finish or bevel under revision control so that the next build reproduces the same interface.

For a dedicated drawing and quotation review, use the PCB edge connector beveling guide. It makes the angle reference explicit, checks symmetric setback geometry and separates the machining allowance from contact-plating cost. Keep the exact mating connector drawing with the final edge specification.

Separate contact durability from solderability

The mating contact and the component solder pad serve different tasks. A selective finish plan can preserve a connector contact system while using an appropriate solderable finish elsewhere. On the drawing, identify the boundary and the surface treatment on each side of it. Do not leave a supplier to infer the required coating from a photograph or the phrase 鈥済old PCB.鈥�

Discuss the nickel underlayer, gold system, thickness requirement, measurement locations and applicable test method. A quoted average does not answer a local minimum requirement. If a specification is expressed in microinches, retain the original unit and show any conversion explicitly; one microinch equals 0.0254 micrometres. Avoid mixing a gold requirement with the much thicker nickel requirement in a single unlabeled number.

Connector suppliers describe contact finishes in the context of their own products. is useful background on the role of contact plating, but its connector specifications are not a universal PCB-finger standard. Use the selected connector鈥檚 application documents and the agreed board finish specification for your order.

Plan selective plating and panel release early

The fabricator needs an electrical and mechanical route for processing the specified contact region. Discuss plating connections, selective masking, pattern geometry, beveling and removal from the manufacturing panel. A plating lead that helps production may become an unwanted electrical feature if its removal is not defined. Likewise, a panel support tab can damage a functional edge when it is removed in the wrong place.

Review the final condition after separation, not only the panel before routing. Confirm the permitted conductor termination at the edge, exposed substrate condition and any burr or edge-quality requirements. Where fingers have different lengths, ask how each contact receives the required finish and how temporary process connections are eliminated. The answer belongs in the agreed route, not in an assumption that all selective patterns are equally simple.

Use PCB DFM review for the combined artwork, mechanical and fabrication questions. This is particularly useful when the board also includes fine-pitch assembly, unusual materials or tight mechanical mounting constraints. Process changes that solve the contact edge must not silently alter another critical interface.

Ask for evidence that matches the risk

Inspection should address the features that control mating. Dimensional checks cover thickness, contact location, outline, keying and bevel. Finish verification addresses the specified coating and the agreed measurement method. Visual inspection can reveal obvious damage or contamination, but it cannot by itself establish gold thickness or predict a given number of mating cycles.

Product-level qualification may include the actual connector, contact resistance under defined conditions, repeated insertion and the intended environmental exposure. The product owner should define this plan with the connector supplier and manufacturing team. A board vendor鈥檚 attractive sample is not evidence that a different contact system will pass the same duty cycle.

Use the to identify the applicable board and acceptance documents with their revisions. State the contracted requirements explicitly. 鈥淚PC compliant鈥� without a document, class, revision and applicable drawing requirements leaves too much room for disagreement, especially around special contact finishes and mechanical features.

What changes the cost of gold finger PCBs?

Cost follows the specified interface and its process route. Contact area and finish thickness affect coating scope, but they are only part of the quote. Selective masking, plating connections, bevel setup, unusual contact patterns, panel utilization, dimensional control and inspection can matter as much as the visible gold area. Quantity changes how one-time engineering and setup allowances are allocated.

Compare quotations against the same finished drawing. A lower price based on a different gold system, omitted bevel, wider board-thickness interval or reduced verification scope is not the same offer. Identify whether the quotation covers the full bare board or only the incremental finger process. Assembly, freight, tax and connector qualification should be named separately when excluded.

This brief uses only allowances you enter from a dated source. With all costs blank it becomes a technical enquiry brief. It does not contain current gold prices or a calibrated market-rate model, and changing the scope clears previously entered allowances. For an exact review, send the contact drawing and fabrication files directly; using the worksheet is optional.

A useful first enquiry is more than a Gerber archive

Include fabrication outputs, drill data, stackup, board outline, connector part and revision, contact-detail drawing, finish callout, bevel section and requested quantity. Mark open items clearly. If the design is early, a preliminary connector drawing and a marked contact region are useful starting points; do not invent a finish requirement merely to complete a form.

Ask which dimensions or process details need adjustment before production. A practical response should identify the affected feature, proposed change and consequence for the mating interface. Keep approvals attached to the design revision. For the rest of the board build, the PCB manufacturing overview explains the broader fabrication path without replacing this contact-specific review.

Gold-finger questions before release