How do you test a PCBA?
One, what is pcba test
The process flow of PCBA patch processing is very complicated, including many important processes such as PCB board manufacturing process, electronic components procurement and inspection, Surface-Mount (SMT) &BGA Assembly, DIP plug-in, PCBA test and so on. Among them, PCBA testing is the most critical quality control link in the entire PCBA processing process, which determines the final use performance of the product. So what are the PCBA test formats?
PCBA testing mainly includes five forms: ICT test, FCT test, aging test, fatigue test, and test under harsh environment.
1. ICT test mainly includes circuit on-off, voltage and current value, fluctuation curve, amplitude, noise, etc.
2. FCT test requires IC program firing, simulation test of the entire PCBA board function, discovery of problems in hardware and software, and equipped with necessary patch processing production jigs and test racks.
3. The fatigue test is mainly to sample the PCBA board, and perform high-frequency and long-term operation of the function, observe whether there is failure, and judge the probability of failure in the test, so as to feedback the working performance of the PCBA board in the electronic product.
4. The test in harsh environments is mainly to expose the PCBA board to extreme temperature, humidity, drop, splashing, and vibration, and obtain the test results of random samples, so as to infer the reliability of the entire PCBA board batch product.
5. The aging test is mainly to energize the PCBA board and electronic products for a long time, keep them working and observe whether there are any failures. After the aging test, the electronic products can be sold in batches.
The PCBA process is complicated. During the production and processing, various problems may occur due to improper equipment or operation, and there is no guarantee that the products produced are qualified. Therefore, PCB testing is required to ensure that each product does not have quality problems. .
Two, how to test pcba
Common methods of PCBA testing mainly include the following:
1. Manual test
Manual testing is to directly rely on vision to test and confirm SMT chip processing on the PCB through vision and comparison. This technique is widely used. However, the large number and small electronic components make this method less and less applicable. And there are some functional flaws that are not easy to detect, and data is not easy to collect. In this way, more professional testing methods are needed.
2. Automatic optical inspection (AOI)
Automatic optical inspection is also called automatic visual inspection, which is carried out by a special inspection instrument. It is used before and after reflow, which has a better effect on the polarity inspection of components. It is easy to follow the diagnosis, which is a relatively common method, but this method is poor in identifying short circuits.
3. Flying probe test machine
Due to advances in mechanical accuracy, speed, and reliability, needle testing has gained widespread popularity in the past few years. In addition, the current requirements for prototype (Prototype) custom pcb fabrication manufacturing and low-volume manufacturing require a test system with fast conversion and no fixture capabilities, making flying probe testing the best choice.
4. Functional test
This is a test method for a specific PCB or a specific unit, which is done by special equipment. Functional testing mainly includes final product test (Final Product Test) and the latest entity model (Hot Mock-up).
5. Manufacturing defect analyzer (MDA)
The main advantages of this test method are low initial cost, high output, easy follow-up diagnosis and fast and complete short-circuit and open-circuit tests. The disadvantage is that functional testing cannot be performed, there is usually no test coverage indication, fixtures must be used, and the test cost is high.
