Chip components are small and micro components without leads or short leads, which are directly installed on PCB and are special devices for surface assembly technology. Chip components have the advantages of small size, light weight, high installation density, high reliability, strong seismic resistance, good high frequency characteristics, strong anti-interference ability, but also because of their very small volume, fear of heat, fear of touch, some lead pins are many, it is difficult to disassemble, which brings great difficulties to maintenance.
Common disassembly techniques are as follows. It is important to note that: in the local heating process, we should prevent static electricity, and the power of the electric iron and the size of the iron head should be appropriate.
I. Sin-absorbing copper mesh method
Suction copper net is made of fine copper wire woven into a reticulated belt, can be replaced by the metal shielding line of the cable or more strands of soft wire. When in use, cover the cable on the multi-pin and apply rosin alcohol flux. Heat with a soldering iron, and pull the wire, the solder on the feet is adsorbed by the wire. Cut off the wire with the solder and repeat several times to absorb the solder. The solder on the pin gradually decreases until the pin of the component is separated from the printed board.
II. Special iron head disassembly method to choose and buy special “N” shaped iron head, the end of the notch width (W) and length (L) can be determined according to the size of the disassembled parts. Special iron head can make the solder of the lead pins on both sides of the dismantled parts melt at the same time, so as to facilitate the removal of the dismantled components. The self-made method of the iron head is to choose a red copper tube with an inner diameter matching the outside of the iron head, clamp one end with a vice (or hammer) and drill a small hole, as shown in Figure 1 (a). Then two copper plates (or copper tubes are lengthwise cut and flattened) are used to process them to the same size as the dismantled parts, and holes are drilled, as shown in Figure 1 (b). The end face of the copper plate was filed flat, polished clean, and finally assembled into the shape as shown in Figure 1 (c) with bolts, which were put on the soldering head. The soldering head can be used by heating and dipping tin. For rectangular flake components with two solder spots, as long as the soldering iron head is knocked into a flat shape, so that the width of the end face is equal to the length of the component, the two solder spots can be heated and melted simultaneously, and the flake components can be removed.
III. The solder cleaning method
When the solder is heated with the antistatic soldering iron, the solder is cleaned with a toothbrush (or an oil brush, a paint brush, etc.), and the components can also be quickly removed. After the components are removed, the printed board should be cleaned in time to prevent short circuit of other parts caused by tin residue.
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Post time: Jun-17-2021