Goldfinger circuit board

　　Goldfinger circuit board is a circuit board with special conductive contacts on the edge of PCB. It is named because its contact surface is usually gold-plated and shaped like fingers. These gold-plated contacts are the key to achieving electrical connection between circuit board and external devices (such as connectors and slots), and play an important role in electronic devices.

　　Structure and characteristics of goldfinger circuit board

　　Core structure: Goldfinger is mainly composed of substrate, conductive layer and gold-plated layer. The substrate usually uses materials such as FR-4 with good insulation performance; the conductive layer is copper foil, and a contact line of a specific shape is formed by etching; the gold-plated layer covers the surface of the copper foil, and the thickness is generally 0.1-0.5 microns. Some high-reliability scenarios will use thicker gold plating process.

　　Significant features: The gold-plated layer has excellent conductivity, wear resistance and oxidation resistance, which can ensure that the goldfinger maintains a stable electrical connection during multiple plug-in and unplug processes and prolongs its service life. At the same time, the arrangement density and spacing of the goldfinger can be designed according to demand, from the early large spacing to today's high-density fine lines, to meet the connection needs of different devices.

　　Gold finger production process

　　Substrate pretreatment: Clean and polish the PCB substrate to ensure that the surface is flat, free of oil and impurities, laying the foundation for subsequent copper foil lamination.

　　Copper foil etching: After laminating the copper foil on the substrate surface, the pattern of the gold finger is transferred to the copper foil through photolithography technology, and then the excess copper foil is removed with etching liquid to form the conductive circuit prototype of the gold finger.

　　Gold plating: Gold is plated on the surface of the copper foil contact using electroplating technology. The copper foil needs to be activated before electroplating to ensure that the gold layer and the copper layer are firmly combined. During the gold plating process, the current, temperature and time are strictly controlled to ensure that the thickness of the gold layer is uniform and dense.

　　Molding and testing: The circuit board is processed in shape and the gold finger part is accurately cut and formed. After that, the quality of the gold finger is ensured through appearance inspection (check whether the gold-plated layer has scratches, exposed copper and other defects), conduction test (verify whether the connection between the gold finger and the internal circuit is good) and other links.

　　Application scenarios of gold finger circuit boards

　　Computer field: In graphics cards, sound cards, memory sticks and other boards, gold fingers are the core components to achieve the connection between the board and the motherboard slot. Through the plugging and unplugging of gold fingers, data transmission and power supply are completed.

　　Consumer electronics: The expansion dock interface of laptops, the charging and data transmission interface of mobile phones (partly using gold finger design), etc., use the high conductivity and wear resistance of gold fingers to ensure stable connection under frequent plugging and unplugging.

　　Industrial equipment: Various modules in the field of industrial control (such as PLC modules, sensor modules) are often connected to the motherboard through gold fingers to meet the high requirements for reliability and anti-interference in industrial environments.

　　Automotive electronics: In the on-board computer, navigation module and other components of the car, the gold finger circuit board is used to achieve fast connection and data interaction between modules. Its temperature resistance and vibration resistance meet the strict standards of automotive electronics.

　　Precautions for gold finger circuit boards in PCB Assembly Online

　　In the online PCB assembly (PCB Assembly Online) service, special attention should be paid to the following points when handling gold finger circuit boards:

　　Design review: After the online platform receives the gold finger circuit board design file, the engineer will focus on reviewing whether the parameters such as the size, spacing, and gold plating thickness of the gold finger meet the manufacturability requirements, and whether it is compatible with the matching connector, to avoid design problems that lead to failure to use normally after assembly.

　　Production control: The gold finger gold plating process has extremely high requirements for environmental cleanliness and process parameters. Online assembly service providers must have professional gold plating production lines and quality control capabilities to ensure the quality of the gold layer. At the same time, in the SMT patch, plug-in and other links, it is necessary to avoid contamination or scratches on the gold finger surface.

　　Test verification: In addition to the conventional PCBA test, special plug-in test and contact resistance test are required for the gold finger to simulate the actual use scenario to ensure that the gold finger can still maintain good electrical performance after multiple plug-ins.

　　Packaging protection: When packaging the gold finger circuit board, a special anti-static protective cover or tray should be used to prevent the gold finger from being damaged by friction with other objects, especially during transportation, anti-vibration and moisture-proof measures should be taken.

　　It is very important to choose an online PCB assembly service provider with experience in gold finger circuit board processing. Such service providers are familiar with the special process requirements of gold fingers and can provide full process support from design optimization to production testing to ensure the quality and reliability of gold finger circuit boards and meet the needs of different application scenarios.