Disassembly Technique Of Flake Components On PCB

 The sheet components on the printed circuit board (PCB) are new micro components without lead or short lead. They are directly mounted on the printed circuit board and are special devices for surface assembly technology.The flake components have the advantages of small size, light weight, high installation density, high reliability, strong vibration resistance, good high frequency characteristic, strong anti-interference ability and so on.At present, it has been widely used in computer equipment, mobile communication equipment, video integrated machine, color TV high frequency head VCD and other products, rapid development.

           The commonly used flake components are: (1)flake resistor (2)chip capacitor (3)Sheet inductor (4)chip diode (5)Flake triode (6)Small chip integrated circuit etc.

           These flaky components are very small in size, fear of heat and touch, and some lead feet are too many to disassemble, which brings great difficulties to maintenance. Therefore, scientific disassembly method is very important.

           1.Tin absorption copper net method

           Tin-absorbing copper mesh is woven from fine copper wire mesh belt can also be used as cable metal shielding wire or multi-strand soft wire replacement.When using, the mesh wire is covered on multiple pins, coated with rosin alcohol flux, heated with soldering iron, and pulled by wire, and the solder on each foot is adsorbed by the wire.Cut off the wire attached to the solder and repeat it several times, gradually reducing the amount of solder on the pin until the pin is separated from the printed board.

           2.Tin melting cleaning method

          When the multipod element is heated by antistatic soldering iron, solder can be cleaned with toothbrush or oil brush, paint brush and so on, and the components can be removed quickly.After removal of components, PCB should be cleaned in time to prevent short circuit of other parts caused by residual tin.

           3.Lead pulling method

          This method is suitable for disassembling chip integrated circuits.With a lacquer wire of appropriate thickness and a certain strength, piercing through the inner gap of the pin of the integrated circuit, one end of the enamelled wire is fixed in a suitable position, the other end is held by hand, and when the solder dissolves,Pull enamel wire "cut" solder joint, integrated circuit pin and printed board separation.

          4.Dismounting method for tin - sucking device

         Tin absorbers have ordinary tin absorbers and tin soldering iron two kinds.When the ordinary tin absorber is used, the piston rod of the tin absorber is pressed down. When the soldering joint of the disassembled piece is melted by the electric soldering iron, the suction nozzle of the tin absorber is pressed against the melting point and the release button of the tin absorber is pressed, and the tin melt is sucked away while the piston rod of the tin absorber is bouncing back.Repeated several times, can be separated from the PCB.Tin soldering iron is a special tin absorbing tool which assembles the ordinary tin absorber and the electric soldering iron, and its usage is the same as that of the ordinary tin absorber.Attention should be paid to the anti-static during local heating, the power of the soldering iron and the size of the iron head should be appropriate.