November 24, 2020
In SMT processing and repair, chip components are one of the materials with more contact. In SMT processing, chip components need to be replaced from time to time. It seems very simple to replace chip components, but there are still many tricks in it. If you don't pay attention, it is still very troublesome to operate. In order to ensure product quality, we need to replace chip components in strict accordance with relevant requirements.
Before the replacement of chip components in SMT processing and repair, we need to prepare an electric soldering iron that is connected to the ground and the temperature can be controlled. The width of the soldering iron tip must match the size of the metal end face of the chip component, and the soldering iron needs to be heated to 320 degrees Celsius. In addition to the electric soldering iron, you also need to prepare basic tools such as tweezers, tin strips, fine low-temperature rosin, and welding wire.
When replacing chip components, you can directly put the heated soldering iron tip on the upper surface of the damaged component, and then wait until the solder on both sides of the chip component and the adhesive under the component are melted by high temperature, you can use tweezers directly Removed the damaged Mrs. component. After removing the damaged component, you need to use a de-tin strip to suck up the remaining tin on the circuit board, and then use alcohol to wipe off the adhesive and other stains on the original pad.
When PCBA is processed, usually only a proper amount of solder is applied to one pad on the circuit board; then use tweezers to place the component on the pad. In order to quickly heat the tin on the pad, the molten tin contact chip component needs to be placed on the metal end , But there is another point that needs special attention, do not let the soldering iron tip directly touch the component.
Generally, only one end of the newly replaced chip component can be soldered after the other end is fixed. It is necessary to heat the pad on the circuit board and add an appropriate amount of solder to make the pad and the component end surface form a bright arc. It should be noted that the amount of solder can not be put too much, otherwise the molten solder will flow under the component and cause the pad to short-circuit. Just like the other end of soldering, the remaining end can only allow the molten tin to dip into the metal end of the component. Let the soldering iron tip touch the component to complete the entire replacement process.