We know that science and technology is a double-edged sword. As electronic products are becoming increasingly "lightweight, thin and small", the difficulty of quality control has also increased. Testing is an important part of ensuring the reliability of SMT. SMT testing technology mainly includes testability design, incoming raw material testing, process testing, assembly component testing, etc. The following is a brief introduction about SMT patch detection technology from Sanjing.

With the development of SMT technology and the improvement of SMT assembly density, circuit pattern wiring is getting finer and thinner, and the spacing of surface mount devices is getting smaller and smaller, which brings many new technologies to SMT product quality control and corresponding detection technology. problem. At the same time, the use of appropriate testability design methods and detection methods has also become an indispensable task in the SMT process.

The testability design is mainly the PCB circuit testability design carried out in the chip processing circuit design stage, which includes test circuits, test pads, test point distribution, testability design of test instruments, etc.

The incoming raw material inspection includes the inspection of PCB and components, as well as the inspection of all SMT assembly process materials such as solder paste and flux.

The process inspection includes the process quality inspection of printing, patching, welding, cleaning and other processes. Component inspection includes component appearance inspection, solder joint inspection, component performance testing and functional testing.

In each step of SMT processing, it is very important to prevent various defects and unqualified hazards from flowing into the next process through effective inspection methods. Therefore, inspection is an indispensable important method in the process of process control. The inspection methods of SMT patch processing mainly include: incoming material inspection, process inspection and surface assembly board inspection. Anti-static gloves and PU coated gloves are required for inspection.

In process inspection, it is found that quality problems can be improved through rework. In incoming material inspection, pre-soldering inspection and inspection after solder paste printing, if unqualified products are found, the rework cost is lower and the reliability of electronic products is also relatively small. . However, rework after soldering is more troublesome, because after soldering, it needs to be re-soldered after unsoldering, which not only consumes time and labor for consumables, but also easily damages circuit boards and components.

Surface mount board inspection. Nowadays, market competition is fierce. Product qualification and reliability are the key to gaining customers’ trust. Whether a product is qualified and reliable depends on product inspection. Surface mount board inspection items include appearance inspection, component location, model, polarity inspection, and welding. Point testing, electrical performance and reliability testing, etc.

Since some components are irreversible, such as Flip chips that require underfilling, and BGA and CSP that need to be re-balled after rework, it is more difficult to repair products such as embedded technology and multi-chip stacking, so rework after soldering If the loss is large, you need to wear anti-static gloves and PU coated gloves. It can be seen that in process inspection, especially the first few processes, defect analysis can be used to prevent quality hazards from the source as early as possible, which can not only reduce the defect rate and scrap rate, but also reduce the cost of rework and repair.

Well, today Sanjing will introduce you here, I hope it can be helpful to everyone!