Identification, processing and maintenance of surface mount components

Identification, processing and maintenance of surface mount components
In modern science and technology, miniaturization and simplified SMT processing technology have been realized. The components that need to be used are becoming smaller and smaller, and the commonly used processing resistors, inductors and capacitors have become difficult to distinguish from the outside world How to quickly distinguish common patch components?
The difference between them is that SMT machining facet inductance and facet capacitance;
Color (Black) - Common black is a chip inductor. On precision instruments, only tantalum capacitors are black, while other common chip capacitors are basically not black.
The chip inductance should start from l, and the chip capacitor should start from c. The preliminary judgment of circle should be inductance. If the resistance at both ends exceeds 0 Ω, the inductance shall be measured.

The chip inductor usually has low resistance, and the multimeter pointer will not move back and forth due to "charging and discharging". Charging and discharging of chip capacitors.
If you view a component, such as an internal structure, you can cut the component and view the internal structure. Chip inductor with coil structure.
According to different shapes, the inductance is polygonal and the resistance is basically rectangular. The shape of the component to be identified is usually considered inductance, especially in the case of polygons (especially circles).
The resistance of the inductor used to measure the resistance value is small, while the resistance of the resistor is relatively large.
The difference between smt processed chip capacitors and chip resistors is that the color of chip capacitors is usually gray, blue gray and yellow, and in the case of hard copies, these colors are generally slightly brighter than yellow. Some chip capacitors are mainly sintered at high temperature and cannot be printed on the surface.
SMT patch processing and maintenance skills
The processing and maintenance skills for manual welding of SMT patches should follow the principle of "small first, then repair", "large first, low first, then high", welding in batches and classifications, solder resistors, chip capacitors, first transistors, and then welding small integrated circuit devices and large integrated circuits Equipment, and finally weld the insertion part When welding wafer components, the width of the selected soldering head shall be the same as that of the component If it is too small, it is difficult to locate during assembly and welding When welding SOP, QFP, PLCC and other devices with pins at both ends or four sides, SMT chip processing shall first weld several locating points on both sides or four sides After carefully checking and confirming that each pin is consistent with the corresponding gasket, drag the welding to complete the welding of the remaining pins When dragging, the speed should not be too fast, just drag a solder joint in about 1 second After welding, you can use 4-6 times magnifying glass to check whether there is bridge between the welding points Where there is a bridge, you can dip a little flux in the brush and drag it again The same part shall not be welded more than twice, if not welded once Wait for cooling before welding When welding IC equipment, apply a layer of flux paste evenly on the pad, which can not only penetrate and assist the solder joints, but also greatly facilitate SMT patch processing and maintenance work and improve the repair speed The two most critical processes for successful rework are preheating before welding and cooling after welding

The above is the explanation given by the editor of PCB circuit board company.
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