Engineer experience: 78% of hardware failures are caused by welding problems

Have you spent a long time on failure analysis of circuit boards? Have you spent a lot of energy on sample debugging? Have you ever doubted your original correct design?

Perhaps many hardware engineers have had similar psychological conversations. Data shows that 78% of hardware failures are caused by poor welding and incorrect material placement. This causes engineers to spend a lot of time and energy on sample debugging and analysis, delaying the project progress. If the cause of the failure cannot be found for a while, the engineer will doubt his original correct design, causing himself to go astray in the incorrect direction of thinking. When actually debugging the hardware, engineers often consider many profound potential causes, but are reluctant to doubt whether the welding is reliable enough, but often "the safest place is the most dangerous place." Engineers will habitually think that something as simple as welding will not cause many seemingly complex problems. Once such a problem occurs, they will also habitually consider the robustness of the software and the rationality of the hardware circuit design. For example,

Case 1: Due to a poor solder joint in a certain signal of the DDR high-speed signal part, the system seemed to work normally when transmitting a small amount of data. However, when performing a burst operation with a large amount of data, such as playing a high-definition movie or loading an operating system, errors would often be reported. This was often mistakenly believed to be a software problem, and the software engineer spent a long time checking the code to no avail.

Case 2: Due to improper time and temperature control during welding, the plastic structure inside connectors such as LCD and USB melted and deformed due to high temperature, causing a certain signal to be accidentally disconnected, resulting in no LCD display and no USB communication, which was mistakenly believed to be a software driver problem.

Case 3: There are a lot of decoupling capacitors densely distributed next to the CPU power supply . Due to the excess solder during the welding process, one of the capacitors short-circuited, resulting in the hardware engineer spending a lot of time to check the cause of the short circuit one by one.

Case 4: High-speed signal interface connector. Due to a signal solder joint failure, the system can work at a lower bus frequency. Once the bus speed is increased, the system immediately reports an error. The cause of this problem is basically difficult to locate.

Case 5: Due to poor welding of the inductor , the PWM dimming function of the LED failed. Engineers spent a lot of time to confirm whether it was a software or hardware problem.

Welding, seemingly simple, is also made up of many work details and steps, and these links are closely linked to each other. Any mistake in any link will lead to the final problem. The China Southern Electronics Industry Association, in collaboration with Massembly Technology, established a service organization specializing in sample patch welding in Shenzhen Nanshan High-tech Park, aiming to provide effective and reliable sample patch services for the majority of R&D electronic technology companies, and improve the speed of R&D and product launch. It has creatively added its own 3Q quality inspection links in the overall patch workflow, such as material selection, marking, printing, patch, and furnace passing, which effectively reduces the possibility of hardware failure.

Therefore, during the hardware debugging process, it is recommended that engineers first observe the welding quality of your prototype: 1. Is the material correct? 2. Is the pin position correct? 3. Is there any solder joint, empty solder joint, or cold solder joint? 4. Is the solder paste full and reflective after passing through the furnace? 5. Is the PCB board browned? 6. Does the structural part of the connector melt under high temperature? 7. Does the chip position correspond to the silk screen?

After checking the “simple” items above, focus your energy on those “advanced” issues!