Soldering plays a vital role in PCB production. So, what should we pay attention to when welding?
Before welding, it should be observed whether each solder joint (copper skin) is smooth and oxidized. The sequence of component assembly and welding is as follows: resistors, capacitors, diodes, triodes, integrated circuits, and high-power tubes.
When soldering items, be careful of the soldering point to avoid short circuit caused by poor soldering of the circuit. Both the chip and the base are oriented. When soldering, strictly follow the direction pointed by the notch on the PCB, so that the chip, the base and the notches on the PCB all correspond.
If the pins of the integrated circuit are gold-plated, do not scratch with a knife, just use a clean eraser to clean it. For CMOS integrated circuits, if the pins have been short-circuited first, do not remove the short-circuit line before welding. It is advisable to use low melting point flux, and the temperature should generally not be higher than 150 degrees Celsius.
Choose an internal heating type 20-35W or temperature-adjustable electric soldering iron. The shape of the soldering iron tip should be conical according to the size of the printed circuit board pad. When heating, the temperature of the soldering iron tip should be adjusted to no more than 300 degrees Celsius.
When heating, try to avoid letting the soldering iron tip stay in one place for a long time, so as not to cause local overheating and damage copper foil or components.
Do not use the method of rubbing the soldering iron tip to increase the wettability of the solder when soldering, but use the method of surface cleaning and pre-tinning.
When soldering metallized holes, the solder should wet and fill the entire hole, not just the surface pad.
After welding, check the solder joints with a magnifying glass to check whether there is any false welding and short circuit.
When there is a connecting wire, be careful not to make the connecting wire too deep, so that it will be rotated on the rubber skin of the wire, and the circuit will be broken.
After the circuit is connected, it is best to clean the surface of the circuit with a cleaning agent to prevent the iron filings attached to the surface of the circuit board from short-circuiting the circuit.
Many problems can be found in the aging process; the connection must be connected tightly, and the screws must be tightened. After repeated plugging and unplugging for many times, pay attention to whether the connection connector is damaged.