The main recommendation for disassembly of high-pin density components in SMT pcb online china patch processing is to use a hot air gun, clamp the components with tweezers, blow all the pins back and forth with the hot air gun, and lift the components when they are melted. If you need to disassemble the parts, do not blow to the center of the parts, and the time should be as short as possible. After removing the parts, clean the gasket with a soldering iron. 1. For SMT components with a small number of pins, such as resistors, capacitors, bipolars and triodes, first tin plating on a pad on the PCB board, and then use tweezers to clamp the components in the mounting position with your left hand and fix them On the circuit board, use the right hand to solder the pins on the pads to the pads sold. The tweezers in the left hand can be loosened, and the remaining feet can be soldered with tin wires. This kind of part is also easy to disassemble, as long as both ends of the part and the soldering iron are heated at the same time, and the tin is melted and lifted slightly to disassemble. 2. A similar method is used for chip components with a large number of needles and wide spacing. First, tin plating on the pad, then use tweezers to clamp the component on the left to solder one foot, and then solder the other foot with tin wire. It is usually better to disassemble these parts with a heat gun. On the other hand, the solder is melted by holding a hot air gun. On the other hand, when the solder is melted, parts are removed with a jig such as tweezers. 3. For the parts with high sales density, the welding technology is similar. First, solder the legs and use the wire to weld the remaining legs. The number of feet is large and dense, and the alignment of nails and mats is important. Usually, the pads on the corners are plated with a small amount of tin, and the parts are aligned with the pads with tweezers or hands. The edges of the sale are aligned. These parts are pressed slightly harder on the printed circuit board, and the pins on the pads are soldered with a soldering iron. The above content is about the relevant content of the desoldering skills in SMT patch processing. If you want to know more about SMT PCB Assembly Manufacturing patch processing, please contact POE online customer service, we will be happy to serve you .

In PCB proofing, how to reduce or eliminate the deformation caused by different material characteristics or processing has become one of the most complicated problems faced by PCB manufacturers. Next, let the engineer share with you: What are the causes of pcba manufacturer board deformation? 1. The weight of the circuit board itself will cause the board to dent and deform Generally, the reflow furnace uses a chain to drive the circuit board forward in the reflow furnace. If there are heavy parts on the board or the size of the board is too large, it will appear concave in the middle due to its own weight, resulting in the board. bend. 2. The depth of the V-Cut and the connecting strip will affect the deformation of the jigsaw V-Cut is to cut grooves in the original large sheet, so the place where V-Cut appears is prone to deformation. 3. Deformation caused during PCB processing The reason for the deformation of PCB board processing is very complicated, which can be divided into two kinds of stress: thermal stress and mechanical stress. Among them, the thermal stress is mainly generated during the pressing process, and the mechanical stress is mainly generated during the stacking, handling and baking of the plates. The following is a brief discussion in the order of the process. Incoming copper clad laminate: the size of the copper clad laminate press is large, and there are temperature differences in different areas of the hot plate, which will cause slight differences in the curing speed and degree of the resin in different areas during the pressing process, and will also generate local stress, which will be gradually released in future processing. Deformed. Pressing: The PCB pressing process is the main process that generates thermal stress, which is released in subsequent processes such as drilling, shape or grilling, resulting in deformation of the board. Baking process of solder mask, characters, etc.: Since solder mask inks cannot be stacked on each other when they are cured, PCB boards will be placed in a rack to cure the boards, and the boards are easily deformed under the action of their own weight or the strong wind of the oven. Hot-air solder leveling: The entire hot-air solder leveling process is a sudden heating and cooling process, and thermal stress will inevitably appear, leading to microscopic strain and overall deformation and warping zone. Storage: The storage of turnkey PCB assembly at the stage of semi-finished products is generally firmly inserted in the shelf, and the tightness of the shelf is not adjusted properly, or the stacking of the boards during the storage process will cause mechanical deformation of the boards. In addition to the above factors, there are many factors that affect the deformation of the PCB board. I won't list them all here.

Why is it not easy to tin on some china pcb assembly board pads? Here, Shenzhen PCBA processing factory POE Technology will give you an analysis of the possible reasons. The first reason is: we need to consider whether it is a customer design problem, and we need to check whether there is a connection between the pad and the copper skin, which will cause the pad to be insufficiently heated. The second reason is: whether there are customer operational problems. If the welding method is wrong, it will affect the heating power, the temperature is not enough, and the contact time is not enough. The third reason is: the problem of improper storage. ①Under normal circumstances, the tin spray surface will be completely oxidized in about a week or even shorter ②OSP surface treatment process can be stored for about 3 months ③Long-term preservation of immersion gold plate The fourth reason is: the problem of flux. ①Insufficient activity, unable to completely remove the oxide material on the PCB pad or SMD soldering position ②The amount of solder paste at the solder joint is not enough, and the wetting performance of the flux in the solder paste is not good ③The tin on some solder joints is not full, and the flux and tin powder may not be fully fused before using; The fifth reason is: the problem handled by the board factory. There is oily substance on the pad that has not been removed, and the pad surface has not been oxidized before leaving the factory. The sixth reason is: the problem of Flexible PCB reflow soldering. If the preheating time is too long or the preheating temperature is too high, the activation of the flux will be invalid; the temperature is too low or the speed is too fast, and the tin does not melt.