In the process and maintenance of SMT, chip components are one of the materials that contact more. In SMT processing, it is often necessary to replace chip components. It seems easy to replace chip components, but there are still many tips. If you don't pay attention, the operation is still troublesome. In order to ensure product quality, we need to replace chip components in strict accordance with relevant requirements. Today, let's take a look at the method of replacing chip components with Xiaobian.
Before replacing chip components in SMT processing and maintenance, we need to prepare an electric soldering iron with ground wire and temperature control. The width of the welding head should be consistent with the size of the metal end face of the plate, and the soldering iron should be heated to 320℃. In addition to the electric soldering iron, you need to prepare basic tools such as tweezers, tin bars, fine low-temperature rosin and welding wire.
When replacing chip components, the heated welding head can be directly placed on the upper surface of the damaged component. After the solder on both sides of the chip component and the adhesive under the component are melted at high temperature, the damaged component can be directly taken out with tweezers. After the damaged components are removed, it is necessary to absorb the residual tin on the circuit board with a tin remover, and then clean the adhesive and other stains on the original pad with alcohol.
When processing PCBA, usually only a proper amount of solder is ironed on one side of the pad on the circuit board; Then put the component on the mat with tweezers. In order to quickly heat the tin on the pad, it is necessary to place the molten tin contact element on the metal end, but another point needs special attention. Do not let welding head directly touch the components.
Usually, as long as one end of a newly replaced sheet element is fixed, the other end can be welded. It is necessary to heat the pads on the circuit board and add proper amount of solder to form a bright cambered surface between the pads and the end faces of the components. It should be noted that the amount of solder should not be too much, otherwise the molten solder will flow under the component, resulting in short circuit of the pad. Just like the other end of welding, the other end can only let molten tin soak into the metal end face of the component, and welding head can't touch the component, thus completing the whole replacement process.
