Product reliability test is a common test method in PCB manufacturing

Date：2022-09-02 16:27:45Views：869

PCB has become the most important and key part of electronic information products. Its quality and reliability level determine the quality and reliability of the whole equipment. If the PCB has defects or manufacturing problems, the final product may fail and cause inconvenience. In these cases, manufacturers will have to recall these devices and spend more time and resources to repair the faults. PCB testing has become an indispensable part of the circuit board manufacturing process. It finds problems in time, assists staff to deal with them quickly, and ensures the high quality of PCB.

PCBA testing is a necessary process. If properly completed, it can prevent the product from being damaged by quality problems when it is launched. Let's learn about several common test methods for PCB.

1. Online test (ICT)

ICT, that is, automatic online testing, is a necessary test equipment for modern PCB manufacturers, which is very powerful. It mainly detects the open circuit, short circuit and faults of all parts of PCBA by contacting the test points out of PCB layout with the test probe, and clearly informs the staff.

ICT has a wide range of uses, high measurement accuracy, and clear instructions for the detected problems. Even workers with ordinary electronic skills can easily handle PCBA with problems. Using ICT can greatly improve production efficiency and reduce production costs.

2. Flying needle test

Flying pin test and on-line test (ICT) are both recognized and effective test forms. Both can effectively find production quality problems, but flying pin test has proved to be a particularly cost-effective method to improve circuit board standards.

Contrary to the traditional test method of fixing the test probe in position, the flying probe test uses two or more independent probes and runs without a fixed test point. These probes are electromechanical controlled and move according to specific software instructions. Therefore, the initial cost of flying needle test is low, and it can be completed by modifying the software without changing the fixed structure. In contrast, the initial fixture cost of ICT is higher, so for small batch orders, flying pin testing is cheaper, but ICT is faster and less prone to errors than flying pin testing, so for large batch orders, ICT is still more cost-effective.

3. Function test

Functional system test uses special test equipment at the middle and end of the production line to comprehensively test the functional modules of the circuit board to confirm the quality of the circuit board. Functional tests mainly include final product test and hot mock up.

Functional testing usually does not provide in-depth data (such as pin position and component level diagnosis) to improve the process, but requires special equipment and specially designed test procedures. Writing function test program is very complex, so it is not suitable for most circuit board production lines.

4. Automatic optical inspection (AOI)

AOI uses a single 2D camera or two 3D cameras to take photos of the PCB, and then compares the photos of the circuit board with the detailed schematic diagram. If the circuit board does not match the schematic diagram to a certain extent, the mismatch of the circuit board will be marked for inspection by technicians, and AOI can detect the fault in time.

However, AOI testing will not supply power to the circuit board, and can not 100% detect the problems of all components. Therefore, AOI will generally be used in combination with other testing methods. The common test combinations are:

AOI and flying needle

AOI and online testing (ICT)

AOI and functional test

5. X-ray test

X-ray testing, that is, X-ray testing, uses low-energy X-rays to quickly detect open circuit, short circuit, empty soldering, missing soldering and other problems of circuit boards.

X-ray is mainly used to detect defective circuit boards with ultra-fine spacing and ultra-high density, as well as defects such as bridging, chip missing and dislocation during assembly. It can also use tomography to detect internal defects in IC chips. This is the only way to test the bonding quality of ball grid array and solder ball. The main advantage is that BGA Solder quality and embedded components can be checked without the cost of fixing devices.

6. Laser detection

This is the latest development of PCB testing technology. It scans the printed board with a laser beam, collects all measurement data, and compares the actual measurement value with the preset acceptance limit. This technology has been verified on bare boards and is being considered for assembly board testing. This speed is enough for the mass production line. Fast output, no fixture and smooth vision are its main advantages; Its main disadvantages are high initial cost and maintenance and use problems.

7. Aging test

Aging test refers to the process of simulating various factors involved in the actual use conditions of products to carry out corresponding condition strengthening experiments on the aging of products. The purpose is to test the stability and reliability of the product in a specific environment.

According to the design requirements, the product is placed under specific temperature and humidity conditions, and the simulation work lasts for 72 hours to 7 days. The performance data is recorded, and the production process is improved to ensure that its performance meets the market demand. Aging test usually refers to electrical performance test, and similar tests include drop test, vibration test, salt spray test, etc.

In addition to the above seven tests, based on product requirements, other test methods will be used to further ensure PCB quality. For example:

Solderability test: ensure the surface is firm and increase the chance of forming reliable solder joints

PCB contamination test: detect a large number of ions that may contaminate the circuit board, cause corrosion and other problems

Microsection analysis: investigate defects, open circuits, short circuits and other faults

Time domain reflectometer (TDR): fault of high frequency board is found

Peel test: find out the strength measurement required to peel the laminate from the board

Floating solder test: determine the thermal stress level that PCB holes can resist

The above is the relevant content of the treatment and analysis of common failure problems of PCB compiled by Chuangxin detection. I hope it will be helpful to you. Chuangxin testing is a professional testing institution for electronic components. At present, it mainly provides testing services for integrated circuits such as capacitors, resistors, connectors, MCU, CPLD, FPGA and DSP. Specializing in functional testing of electronic components, appearance testing of incoming electronic components, anatomy testing of electronic components, acetone testing, X-ray scanning testing of electronic components, ROHS composition analysis testing. Welcome to call, we will serve you wholeheartedly!