13 common test methods used in PCB manufacturing, how many have you mastered?

Printed circuit boards (PCBs) are widely used in a variety of electronic devices; whether it's a cell phone, a computer, or a complex machine, you can find circuit boards. If a PCB is defective or has manufacturing issues, it can lead to malfunctions and inconvenience in the final product.probe test system In these cases, manufacturers will have to recall these devices and spend more time and resources to fix the fault.

Therefore, PCB testing has become an integral part of the circuit board manufacturing process, which identifies problems in a timely manner, assists staff to deal with them quickly, and ensures the high quality of PCBs.

Here we come to understand the PCB commonly used 13 kinds of test methods.

1. In-Circuit Testing (ICT)

ICT, that is, automatic in-line test, is a modern PCB manufacturers must test equipment, very powerful.RF probes It is mainly through the test probe contact PCB layout out of the test point to detect the PCBA line open circuit, short circuit, all parts of the fault situation, and clearly inform the staff.

ICT use a wide range of measurement accuracy, high, clear instructions on the problems detected, even if the general standard of electronic technology workers to deal with problematic PCBA is also very easy. The use of ICT can greatly improve production efficiency and reduce production costs.

2. flying probe test

Flying probe testing and in-circuit testing (ICT) are both highly recognized forms of effective testing, both can be effective in detecting production quality problems, but flying probe testing has proved to be a particularly cost-effective way to raise the standard of circuit boards.

In contrast to traditional test methods that fix test probes in a fixed position, flying probe testing uses two or more independent probes that operate without a fixed test point. These probes are electromechanically controlled and move according to specific software instructions. As a result, the initial cost of flying probe testing is low, and it can be accomplished by modifying the software without changing the fixed structure. ICT, by contrast, has a higher initial fixture cost, making flying probe testing cheaper for small orders, but ICT is faster and less error-prone than flying probe testing, making it more cost-effective for larger orders.

3. Functional Testing

Functional system testing uses special test equipment in the middle and end of the production line to conduct comprehensive testing of the functional modules of the board to confirm the quality of the board. There are two main types of functional tests: Final Product Test and Hot Mock-up.

Instead of providing in-depth data (e.g., pin locations and component-level diagnostics) to improve the process, functional testing usually requires specialized equipment and specially designed test programs. Writing a functional test program is very complex and therefore not applicable to most board production lines.

4. Automated Optical Inspection (AOI)

AOI uses a single 2D camera or two 3D cameras to take a picture of the PCB and then compares the picture of the board to a detailed schematic. If the board does not match the schematic to some degree, the board mismatch is flagged for inspection by a technician,probe card and AOI can detect failure problems in a timely manner.

However, AOI inspection does not power up the board to detect 100% of all component problems, so AOI is typically used in conjunction with other test methods, and a common test combination is:

AOI and flying probe

AOI and In-Circuit Testing (ICT)

AOI and functional test

5. X-ray test

X-ray test, i.e. X-ray inspection, which uses low-energy X-rays to quickly detect circuit board open circuits, short circuits, empty solder, leakage of solder and other problems.

X-ray is mainly used to detect defective circuit boards with ultra-fine pitch and ultra-high density, as well as defects such as bridges, missing chips, and misalignments from the assembly process. It can also be used to detect internal defects in IC chips using tomography. This is the only way to test the quality of ball grid arrays and solder ball bonding. The main advantage is that BGA solder quality and embedded components can be inspected without the expense of a fixture.

6. Laser Inspection

This is the latest development in pcb testing technology. It scans the printed board with a laser beam, collects all measurements and compares the actual measurements with preset acceptance limits. The technique has been proven on bare boards and is being considered for assembled board testing. This speed is sufficient for mass production lines. Fast output, no fixturing, and smooth visualization are the main advantages; high initial cost and maintenance and usage issues are the main disadvantages.

7. Aging Test

Aging test refers to the process of simulating the aging of a product by various factors involved in real-life usage conditions and conducting experiments to strengthen the conditions accordingly. The purpose is to detect the stability and reliability of the product in a specific environment.

According to the design requirements, the product will be placed in a specific temperature, humidity conditions, continuous simulation of the work of 72 hours ~ 7 days, record the performance data, the inverse of the production process to improve, in order to ensure that its performance to meet market demand. Aging test usually refers to the electrical performance test, similar tests are drop test, vibration test, salt spray test, etc..