In PCB assembly manufacturers, circuit board soldering usually includes reflow soldering, wave soldering and electric soldering iron soldering. Reflow soldering and wave soldering are SMT patches, which are less affected by human factors. Electric soldering iron soldering is manual soldering, which is affected by human factors. relatively large impact. Ucreatepcb provides intelligent manufacturing services such as PCB copy board, PCB processing, SMT placement, circuit board welding and PCBA OEM. It is always necessary to pay attention to various matters during the soldering process of circuit boards, otherwise it is easy to cause damage to printed circuit boards or components. During the circuit board welding process, the process and component welding will always bring some problems that cannot be simulated, which will affect the electrical performance. The following editor will explain the precautions that need to be known during the circuit board welding process?

1. For the bare printed circuit board, first conduct a visual inspection to see if there are short circuits, open circuits, etc. Then familiarize yourself with the PCB file of the circuit board, compare the PCB file with the PCB screen printing layer, and avoid the discrepancy between the PCB file and the PCB board.

2. After all the materials required for circuit board welding are prepared, the components must be classified. All components can be divided into several categories according to their size, which is convenient for subsequent welding. A complete bill of materials needs to be printed. During the welding process, if there is an item that is not welded, the corresponding option will be crossed out with a pen to facilitate subsequent welding operations.

3. Before soldering the circuit board, anti-static measures such as wearing a wrist strap should be taken to avoid damage to components by static electricity. After the equipment required for welding is ready, the welding head should be kept clean and tidy. A flat soldering iron is recommended for initial soldering. When soldering components such as 0603 packages, the soldering iron can better contact the pads for easy soldering. Of course, for masters, this is not a problem.

4. When selecting circuit board soldering processing components, soldering should be performed in the order from low to high and small to large. Thereby avoiding the inconvenience of welding smaller parts caused by welding larger parts. Priority soldering of integrated circuit chips

5. Before soldering the integrated circuit chip, make sure that the chip is placed in the correct direction. For the silkscreen layer of the chip, usually a rectangular pad represents the start pin. When soldering, one pin of the chip should be fixed first, and then the diagonal pin of the chip should be fixed after fine-tuning the position of the component, so that the component can be accurately connected to the position before welding.

6. For crystal oscillators, passive crystal oscillators usually have only two pins, which are not positive or negative. Active crystal oscillators generally have four pins, pay attention to the definition of each pin to avoid welding errors

7. For the soldering of plug-in components, such as components related to power modules, the pins of the components can be modified before the circuit board is soldered. After the components are placed and fixed, the solder is usually melted with a soldering iron on the back, and then integrated from the pad to the front. You don't need to put too much solder, but stabilize the components first.

In addition to following the essentials of soldering, the soldering process of circuit boards also needs to pay special attention to the selection of the temperature of the soldering iron and the selection of the shape of the soldering iron tip . should. When heating the component pins, try to make the tip of the soldering iron contact the copper foil on the printed circuit board at the same time. When soldering a larger pad, the tip of the soldering iron can be moved around the pad to avoid localized soldering caused by heating a certain pad for a long time. overheat. After the circuit board is welded and processed, it is necessary to cut off the redundant pins of the components on the pad, check whether the solder joints of all components on the printed circuit board are good, and perform welding repairs in time.

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