Flexible PCB Electrical Test

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Electrical test

During the production process of flexible circuit PCBs, external circuits can cause short circuits, open circuits, and electric leakage. As PCBs continue to evolve towards high density, fine pitch, and multi-level, screening for defective boards promptly is crucial to avoid cost waste. Improving testing can help PCB manufacturers reduce scrap rates and improve product quality, in addition to enhancing process control.

In the production process of electronic products, the cost loss caused by defects varies at each stage. It is more cost-effective to detect and remedy defects earlier in the process.

The "Rule of 10" is commonly used to assess PCB defects found in different process stages. For example, if an open circuit in the board is detected after it is completed, it can be easily fixed. However, if it is not detected and the board is shipped, the downstream assembly industry may ask the manufacturer to compensate for the cost of parts, inspection fees, and more. The cost of remedy increases as the defect is discovered later in the process, even after parts installation, furnace tin, and IR remelting.

To prevent such losses, it is essential to test PCBs for soft line function defects at each stage of production. This includes testing after the inner and outer layers are etched and the finished product. Each stage requires 2-3 tests with a 100% screening rate. The test station is an excellent source of data collection for analyzing process problems. Statistical results can provide insights into the percentage of open circuit, short circuit, and other insulation problems, which can then be used to identify and solve the root cause of the problem using quality control methods.

Flexible PCB Electrical Test

The methods and equipment used for electrical measurement include Dedicated, Universal Grid, Flying Probe, E-Beam, Conductive Cloth, and Capacitive tests. The most commonly used equipment includes three types: special test machine, universal test machine, and flying probe test machine. To better understand the functions of these devices, let's compare the characteristics of the three main types.

1. Dedicated test: This type is special because it uses a fixture that is only applicable to a specific material number, making it impossible to test or recycle boards with different material numbers. It can test a single panel at 10,240 points and both sides within 8,192 points. The thickness of the probe head is suitable for boards with a pitch above.

2. Universal Grid test: This test is based on the layout of the PCB line of the flexible circuit designed according to the Grid. The fixture is easy to manufacture, fast, and the probes are reusable. The universal type test has a standard Grid fixed large dial with many measuring points. The universal test machine can perform Open/Short electrical tests on the board using a high-voltage multi-measurement point, ensuring the smoothness of the completed PCB board line system. The general-purpose test points usually exceed 10,000 points and can reach QFP.

3. Flying Probe test: The principle of this test is simple, requiring only two probes to move the x, y, and z to test the two end points of each line one by one, making it unnecessary to use expensive jigs. However, the test speed is slow (around 10-40 points/sec), making it more suitable for sample and small quantity testing. The flying probe test can be applied to high-density boards such as MCM.

Why Choose China PCBA Supplier KSPCBA as Your Flexible PCB Electrical Test Manufacturer?

– Experienced and skilled team

– State-of-the-art equipment

– Strict quality control

– Excellent customer service

– Competitive price