PCBA Tech - PCBA disassembly and welding skills

In the SMT chip processing of PCBA manufacturer, the main disassembly suggestion for high needle density components is the hot air gun. SMT technicians clamp the components with tweezers and blow the PCBA back and forth with the hot air gun. When melting, the components are lifted. If the parts need to be disassembled, the hot air gun shall not blow to the center of the parts, and the time shall be controlled as short as possible. After the parts are removed, clean the gasket with a soldering iron for manual treatment.

1. For SMT components with a small number of pins, such as resistance, capacitance, bipolar and triode, SMT technicians will first tin a pad on PCBA, and then clamp the components in the installation position with SMT patch tweezers with their left hand and fix them on the circuit board. With their right hand, solder the pin on the pad to the sold pad, and the tweezers with their left hand can be loosened, The remaining feet can be welded with tin wire instead. This part is also easy to disassemble. As long as both ends of the part are heated with the soldering iron at the same time, it can be disassembled by gently lifting it after melting tin.

2. Chip components with a large number of pins and wide spacing adopt similar methods. First, tin is plated on the pad. The SMT patch processing operator of PCB Factory will continue to clamp the components on the left with tweezers and weld one foot, and then weld the other foot with tin wire. It is usually better to disassemble these parts with a hot-air gun. On the other hand, hold a hot-air gun to melt the solder. On the other hand, when the solder melts, Remove parts with clamps such as tweezers.

3. For parts with high sales density, the welding technology is similar. First, weld the feet and weld the remaining feet with lines. The number of feet is large and dense. The alignment of nails and pads is very important. Usually, the pad on the corner is plated with a small amount of tin, the parts are aligned with the pad with tweezers or hands, and the edges of the sales are aligned. These parts are pressed slightly on the PCB printed circuit board, The pins on the pad are welded with a soldering iron.

What are the processes of SMT chip processing quality inspection, so as to interconnect the quality policy of one-time compliance rate and high reliability of SMT chip processing, it is necessary to operate the scheme design of printed circuit board, electronic devices, materials, processing technology, machinery and equipment, management system, etc, The process management of the processing plant based on prevention is particularly important in the patch processing and manufacturing industry. In each step of the whole process of patch processing, production and manufacturing, it is necessary to prevent all kinds of shortcomings and potential safety hazards according to effective detection methods before moving to the next process flow.

The quality inspection of patch processing includes quality inspection, processing technology inspection and surface assembly board inspection. The product quality problems found in the whole process can be corrected according to the repair status. The repair cost of unqualified products found in quality inspection, welding paste packaging and printing and grinding before welding is relatively low, The harm to the credibility of electronic equipment is relatively small.

The surface of PCBA repaired products of unqualified products after PCBA welding is completely different. Since the post welding maintenance needs to be disassembled and welded from the beginning, in addition to the working hours and raw materials, electronic devices and circuit boards will also be damaged. According to the defect analysis, the whole process of quality inspection of SMT patch processing can reduce the unqualified rate and reduce the repair and maintenance cost, Prevent serious quality damage from the root.