During the entire process of PCBA circuit board welding, due to the hazards of welding materials, processing technology, personnel, and other factors, PCBA circuit board welding will be weaker.

① Excessive residual PCBA circuit board
Excessive residue on the board may be due to heating before welding or low heating temperature, resulting in insufficient temperature in the tin furnace; The speed of the circuit board is too fast, and antioxidants and antioxidant oil are added to the antioxidants; Excessive application of welding flux; The component support legs and orifice plates are inversely proportional (with high porosity), resulting in accumulated flux. During the application of the auxiliary solution, it is not easy to add paint thinner for a long time.

② Etching, emerald green ingredients, blackened pads
Mainly due to insufficient heating, there are many residual welding flux and excessive harmful substances; Apply the welding flux to be cleaned, but do not clean it after welding. PCBA circuit board manufacturers have relatively high assembly density, small electronic device size, and light weight. The volume and net weight of SMT components can only be about 1/10 of traditional plug-in components. Generally, after using SMT, the volume of electronic devices decreases by 40% to 60%, and the net weight is reduced by 60% to 80%.

③ Virtual junction
Virtual welding is a common drawback that poses a great threat to circuit boards. PCBA circuit board manufacturers have relatively high assembly density, small electronic device size, and light weight. The volume and net weight of SMT components can only be about 1/10 of traditional plug-in components. Generally, after using SMT, the volume of electronic devices decreases by 40% to 60%, and the net weight is reduced by 60% to 80%. The relative density of PCBA assembly is high, the size of electronic devices is small, and the weight is relatively light. The volume and net weight of SMT components can only be about 1/10 of traditional plug-in components. Generally, after using SMT, the volume of electronic devices is reduced by 40% to 60%, and the net weight is reduced by 60% to 80%. The coating amount of flux is mainly small or uneven.

Some welding layers or legs may be severely oxidized by air; PCBA circuit board wiring is not scientific; The foam plastic pipe is blocked, and the polyurethane foam is uneven, resulting in the uneven coating of the welding fluid; Poor practical operation of hand tin immersion; Unscientific chain franchise trends.

④ Cold welding
The surface of spot welding is made by the method of water tofu. The key is that due to the insufficient temperature of the soldering iron or the welding material being welded before drying, the compressive strength of spot welding is not high, and the conductivity is weak, which can easily cause the components to turn on the power circuit due to external forces

⑤ Spot welding whitening
Strong and deep. The relative density of PCBA circuit board assembly is high, the size of electronic devices is small, and the weight is relatively light. The volume and net weight of SMT components can only be about 1/10 of traditional plug-in components. Generally, after using SMT, the volume of electronic devices decreases by 40% to 60%, and the net weight is reduced by 60% to 80%. It is generally caused by the high temperature or prolonged heating time of the electric soldering iron. The disadvantage is that the compressive strength of spot welding is not enough, and it is very easy to cause the ineffectiveness of components due to external forces.

⑥ Detachment of cushion
The key reason is that the pad detaches from the printed circuit board after being subjected to high temperature, and defective spot welding can easily cause component damage.

⑦ Tin bead
Processing technology: The heating temperature is low (the organic solvent in the auxiliary solution is not completely evaporated), the plate speed is fast, and the actual heating effect cannot be achieved. The angle of the transmission chain is not good, and there are bubbles between the tin liquid and the PCB. After the bubbles crack, they cause tin beads; Poor practical operation; A damp and cold office environment; Difficulties with PCBA circuit boards: The surface is damp and cold with moisture, and the design of holes in the operation of PCBA circuit boards is unscientific, resulting in gas between the PCBA circuit board and the tin liquid; The PCB design scheme is not scientific, and the components are too clustered to cause gas. There are many reasons for poor welding of PCBA circuit boards, and it is necessary to strictly control each processing technology to reduce the post hazards of previous processing processes.