We have received complaints from customers recentlyPCBAThere are solder pads falling off, parts falling off, irregular pads, and annular rings falling off, seeminglyPCBDuring the production process of the board, the solder pads and annular rings were worn off by the machine in the etching section. Through line analysis experiments, it was found that it was not the etching machine that was jammed, becausePCBThere is a series of production processes, and each link is inspected. After etching and before soldering, it must be100 percentgo throughAOIScan to check and confirmOKAfter that, it can be sent for solder mask production. It needs to pass the continuity test after the shape. After passing the test, it can be sent to the next process for inspection, packaging and patching.
existPCBADuring the processing, you need to pay attention to the amount of flux (too much or too little), and then the purity and density of the flux.PCBAWhen welding, the purity of the tin wire or tin bar does not meet the requirements, which can also lead toPCBAThe phenomenon of solder pad falling off. When welding products, you need to carefully check whether the solder paste fully meets the customer's requirements. For example, the purity and lead content of the solder paste need to be checked clearly and confirmed before it can be used on the machine. The solder paste needs to be observed during use. Is there any abnormal change? If there is any abnormality, it is necessary to stop using it immediately and notify the process department for analysis and processing.
Through troubleshootingPCBAfter a series of problems that may occur during the plate and production process, the suspicious points were finally placed at the patch and post-welding repairs. By following the patch, the plug-in passes through the furnace and the furnace temperature is controlled. When the furnace temperature is normal, the preheated A period of temperature control at110degrees Celsius±2degrees Celsius, the temperature in the second stage of preheating is controlled at120degrees Celsius±2degrees Celsius, the temperature in the 3rd stage of preheating is controlled at130degrees Celsius±2degrees Celsius, the temperature in the 4th stage of preheating is controlled at260-270Between degrees Celsius. First stage speed of wave soldering26.5rice\/hours, the speed of the second stage of wave soldering is controlled at35rice\/No one was found within the hour range.PCBAThe phenomenon of solder pads falling off. At the same time, I followed other customers’ boards and found no such phenomenon.PCBAThe soldering pad phenomenon was removed, and then the repair parts were used to analyze the problem caused by the excessive temperature of the soldering iron.PCBAThe soldering pad falls off, the temperature of the soldering iron is too high and the soldering iron stays on the weldment for too long, which may lead toPCBAThe solder pad falls off. The soldering iron temperature reaches500Repair parts with temperatures above Celsius will appear to have solder pads. After analysis, adjust the soldering iron temperature to350-370The experiment was repeated at a temperature between degrees Celsius and the follow-up showed that there was no sign of pad loss.