PCB Golden Finger is the gold-plated columns that you see along the connecting edges of printed circuit boards (PCBs). The purpose of gold fingers is to connect a secondary PCB to the motherboard of a computer. PCB gold fingers are also used in various other devices that communicate via digital signals, such as smartphones and smartwatches. Gold is used for the connecting points along a PCB because of the alloy’s superior conductivity.
Types of Golden Fingers PCBA
In the current market, there are two main types of gold plating for gold fingers. These are:
1. Electroless Nickel Immersion Gold (ENIG): ENIG is cheaper to acquire and more comfortable to solder than hard gold. However, it is softer, and it cannot withstand constant plugging and unplug without wearing out. It is recommendable for experimentations and prototypes. ENIG is not a good option for commercial usage.
2. Hard plated Gold over Nickel: Hard plated gold over nickel is harder and thicker than ENIG. It is most suitable for commercial applications.
In recent applications, most manufacturers use a combination of two types of gold plating technology to strike a balance between the efficiency of electronic equipment and lower production costs.
Design Specifications for PCB Golden Finger
- The inner PCB layers towards the PCB edges must be Copper-free, to prevent exposure at the time of Beveling.
- It is not advisable to include the plated through holes (PTH) within 1 mm of Gold Fingers.
- Maintain at least 0.5 mm of the distance between the gold fingers and the board outline.
- Any compromise with the standard spacing values can lead to weak and malfunctioned PCB board.
- No solder mask or screen printing should be performed near the Gold Fingers.
- Place a gold finger on the PCB center-out.
Quality Measures for Golden Fingers PCBA
The Association Connecting Electronics Industries (IPC) has prescribed some standards for the production of PCB Gold Fingers. The IPC standards are as follows:
- Chemical composition: To achieve maximum rigidity along the edges of PCB Gold Fingers, the gold plating should consist of between 5 to 10% Cobalt.
- Thickness: The plating thickness should be in the range of 2 to 50 microinches. The standard thicknesses by size are 0.031 inches, 0.062 inches, 0.093 inches, and 0.125 inches.
- Visual test: Visual inspection with a magnifying glass. The contact edges should be smooth, have a clean surface and also be free from excess plating like Nickel.
- Tape test: Check the adhesion of gold plating and contacts. In this test, fix it with a piece of tape on the contact edge and remove it. In the next step, check the tape for plating traces. If any gold is visible on the tape, it may be that the plating is not sufficient for continuous injection and ejection.
|Min Hole Size||0.15mm|
|Min Line Width||4mil|
|Min. Line Spacing||4mil|
|Surface Finishing||HASL, HASL Lead Free, Immersion Gold, Immersion Tin, Immersion Silver|
1. Is it ok if I want some free samples?
Yes, we can supply you with free samples if you have mass production order.
2. What is the minimum order quantity if I want to order PCB?
We don’t have MOQ. We accept any quantity even one piece.
3. If I want to get a quotation from Aluminum PCB, Metal Core PCB, LED PCB, what should I do?
You can kindly send us the Gerber file, specifications of your requirement, we will quote immediately for you.
4. If I have special requirements for PCB material, how to deal with it?
We can make many kinds of special material PCB, for more details, please contact our sales.
5. Could you offer a custom layer stack up?
Yes, we do, in order to guarantee your PCB work well, we can offer it to you.
6. Do you supply a plastic case for our product?
We supply customized plastic or metal housing/enclosure for your PCBA products.
7. Could you do BGA assembly and X-RAY testing?
All of BGA pitch distance smaller than 0.4mm will have to go through X-RAY testing.
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To make a PCB, please provide Gerber file, If you need PCBs to be assembled, you should also provide us a BOM list and Pick & place file.
9. How many days for making PCB? How long does it take for a PCBA order?
Usually 2-4 working days for PCB samples, 10-15 working days for bulk order. PCBA depends on the project, from PCB making to components purchasing till assembly work, it usually costs 2-4 weeks.
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