Welding process specification for electronic components

Manual welding tool requirements

1, solder wire selection requirements

1) The diameter of 1.0mm solder wire is used for welding copper jack, solder sheet and PCB board, and welding of some larger components.

2) The diameter of 0.8mm solder wire is used for welding of common electronic components.

3) The diameter of the solder wire is 0.6mm, which is used for the welding of SMT and smaller electronic components.

2, electric iron power selection requirements

1) When welding conventional electronic components and other components vulnerable to heat, consider using 35W internal heat type electric soldering iron.

2) When welding wires, copper jacks, soldering pads and tin plating on PCB boards, 60W internal heat electric soldering iron should be selected.

3) When disassembling some electronic components and heat shrinkable tubes for heat shrinkable, consider choosing hot air gun.

3, electric iron use matters needing attention

1) new iron before use must first give it a layer of tin dipped in (to the soldering iron electricity, then the iron when heated to a certain article tin near the welding head), use for a long time of soldering iron to make the rough soldering iron head light, and electric heating to heat up, and the welding head dipped in rosin, burning with rosin in the tin, make on the surface of the welding head first plating a layer of tin.

2) after the electric iron is energized, it should be put on the iron frame when it is not used, but the power should be cut off when it is not used for a long time to prevent the high temperature from "burning" the iron head (being oxidized). To prevent the electric iron from burning other components, especially the power cord, if the insulation layer is burned by the iron and do not pay attention to it, it is easy to cause safety accidents.

3) do not put the electric iron forcefully beat, so as not to shock the electric wire or lead inside the soldering iron and produce failure.

4) after using the electric iron for a period of time, there may be tin dirt on the head of the iron. Under the condition of heating the iron, we can use a wet cloth to wipe it lightly. If there are pits or oxide blocks, apply a fine line file to repair or directly replace the iron head

Installation of electronic components

1. Basic requirements for component pin bending and shaping

Manual bending pins can be used with tweezers or a small screwdriver on the pin shaping. All pins of the components shall not be bent from the root, generally more than 1.5mm should be left; Resistors, diodes, and similar components are mounted by bending the pins perpendicular to the component.

2. Component insertion requirements

1) The insertion of electronic components shall be neat, beautiful and stable, and the components shall be inserted in place without obvious tilt or deformation. At the same time, it should be convenient for welding and conducive to heat dissipation of components during welding.

2) The resistor, diode and similar components should be parallel to the circuit board, and the component surface with characters should be placed in a position where it is easy to observe.

3) Capacitors, audions, inductors, SCR and similar components shall be installed vertically, and the components shall be perpendicular to the circuit board.

4) When installing plug-ins in integrated circuits and integrated circuit sockets, note that the pin sequence cannot be inserted in reverse and the installation should be in place. The components should be parallel to the circuit board.

5) Polar components should pay attention to the polarity when installing, can not be reversed polarity.

6) The same components should be highly unified when they are installed. Manual insert welding should follow the principle of first low and then high, first small and then big.

7) During the installation process, hands can only hold the edge of the circuit board where there are no electronic components. Hands should not touch the pins of electronic components to prevent the damage of components caused by electrostatic release.

Welding Requirements for Components

1, before the electric iron is energized, check whether the electric leakage, to ensure the integrity of the preheating power. The electric iron reaches the specified temperature in the welding. If the welding is sensitive to electrostatic release devices, the soldering iron should be well grounded.

2. First, check whether the PCB panel meets the design requirements according to the design drawings: the surface of the PCB panel is required to be smooth and there is no scratch or fracture; PCB panel is required to be flat without deformation.

3. Check whether the surface of the electronic components is oxidized before installing the plug-in to ensure that the electronic components installed on the circuit board are not oxidized; Strictly check the models and parameters of electronic components to ensure that they meet the design requirements.

4, welding to grasp the welding time, general components in 2 to 3 seconds of time, the larger welding joint in 3 to 4 seconds of time. When the first welding is not completed, wait for a period of time after the element cooling and then conduct a second welding.

5, the solder joint is required to be smooth and bright, and the size is uniform and conical. Can not appear false welding, false welding, leakage welding, wrong welding, welding, welding, surfacing, drawing phenomenon.

6. The surface of oxidized components or circuit boards should be clear and clean before welding, and soldered after tin treatment. The surface of the wire should be tin treated when welding.

7, flux can not be used too much, the welding surface should be clean, there can be no residue.

8, PCB board welding is not allowed to have the phenomenon of copper foil warping fracture, short wiring welding to do a good job of insulation treatment. Prevent short circuit phenomenon. When welding the pin plug with the wire, the heat shrinkable tube should be covered.

9, welding integrated circuit should wear a good anti-static bracelet, so as not to damage the device.

10, welding must be certified and checked to ensure that the welding is correct.

11. Desktop tools, components and circuit boards shall be placed in an orderly manner, and no disorderly arrangement shall be allowed.

12, pay attention to personal safety and device safety. Be careful to be scalded or scratched by the iron, be careful of the short circuit caused by the iron iron, or the line leakage beware of electric shock.