Circuit board maintenance often need to carry out Electronic Componentss welding and disassembly, instrumentation workers must master the circuit board Electronic Componentss welding and demolition techniques, in order to improve the quality of instrument maintenance. Electrician learning network Xiaobian in this article to share instrumentation circuit board Electronic Componentss welding and demolition techniques and experience.
1, welding Electronic Componentss of the skills
It is important to choose flux
Instrument repair welding can be used rosin flux. Soldering rosin and solder to be added to the solder joints, do not use hot soldering head to dipped rosin; use rosin alcohol solution more convenient.
② attention to the component pin cleaning work
Electronic Componentss of the metal pins often oxide, oxide conductivity is poor, and it is difficult on the tin, welding before welding the metal surface to be polished with an eraser. In order to make the Electronic Componentss pin easy to weld, the components are manufactured through the surface treatment. For severely oxidized components, the oxide layer on the component pins can be removed with a knife or sandpaper. After the oxide layer is removed, tin is plated on the bright element leads, so that the leads are evenly plated with a thin layer of tin. Only after careful cleaning and tinning after the Electronic Componentss of the pin, after welding will not appear "Weld" problem.
③ welding operation points
When welding components should use low melting point rosin solder wire. When welding with tweezers to clamp the components of the pin, one can fix the components do not move, one can heat to protect the components. When welding the tip of the temperature should be appropriate, welding components and soldering iron contact time should be appropriate, welding time is too short will cause Weld, but the welding time is too long will be hot components. General parts of the welding time to 2-3s is appropriate. Solder joints are not solidified before welding, can not shake the components or lead, otherwise it will cause Weld. Welding parts in the process of not to move the tip, otherwise it will affect the quality of solder joints. Welding of special devices should be carried out according to component requirements, such as CMOS devices require electric iron metal shell is not charged and should be grounded. When the conditions are best to use anti-static welding station, there is no conditions, you can first heating the soldering iron, to be welded when the electric iron from the power outlet unplugged, the use of waste heat for welding. After the welding is completed, use residual alcohol to clean the residual flux on the circuit board.
Welding technology is a basic workmanship must master the instrument, but also to ensure reliable operation of the instrument an important part of the instrument workers to fight for more welding, more operations in order to continuously improve the welding technology in practice.
2, remove the circuit board components of the skills
As long as the repair of the circuit board of the people, have experience, the circuit board welding on the easy, difficult to remove. The key to removing components from the circuit board is tin and heat dissipation. Only the components of the pin to remove the tin on the components to remove the components; have good heat conditions will not burn the circuit board copper foil and components, when using the replacement method to check the components, not hot components is particularly important.
Usually remove the components with tweezers to pinch the element lead root, to be welded when the solder, quickly pull the pin from the solder joints, tweezers both clamping and cooling effect, pull away when the iron can be used with iron and other movements. In order to facilitate the disassembly, solder joints can be added to promote the melting of tin. Disassembly components used in the soldering iron can be selected than the welding when the large 5-10W, iron power is also a large heat, melting tin time to remove the component time is short, if the soldering iron power is too small, melting tin long enough to burn element.
The following methods can also be used to remove components:
① hollow needle separation method
Select one of the injection needles, when the component pin soldering solder, with the needle needle ramps the component pin and insert the circuit board hole a little rotation, the component pin and the circuit board separated.
② melting tin cleaning or blowing method
When the component pins are melted, use a small brush to clean the solder, leaving the component pins out of the board. Or choose a ball-point pen, with the mouth of the pen with the bulk of the head, the hole at the device pin solder melting point, blowing breath, while removing the soldering iron, tin will be the majority of electric iron will be taken away, Repeat the operation can be, the shortcomings of this law is to run around the waste tin to be cleaned to avoid short circuit between the solder joints.
③ wire in addition to tin method
With a section of the stripping of the multi-stranded wire or shielded wire of the metal shield, covering the component feet, coated with rosin alcohol solution, with electric iron heating and wire to move, the component pin on the wire was wire adsorption. Repeated several times, the component pins are separated from the circuit board. Multi-strand wire more thin line, the more the number of shares, in addition to the better tin effect.
④ wire drawing method
Used to disassemble patch components. With a thick and appropriate, there is a certain strength of the enameled wire from the inside of the chip components through the gap, enameled wire ends welded on the circuit board for the appropriate location for the other end with the left hand to hold. When the solder melts, pull the enameled wire to cut off the solder joint, and the component pins are removed from the circuit board.
⑤ assembly block removal method
The disassembly of the manifold can be made with a special tip, which is a variety of sizes to accommodate different manifolds. The special tip can melt the solder at each pin of the manifold so that the manifold can be easily removed. Have hands-on ability, the special tip can also be made with copper plate.
⑥ with the increase in solder melting to disassemble
The method used properly when the effect is very good, the specific operation is to be removed in the manifold block on the pin and then add some solder, so that each column of the solder joints are connected, when disassembling with 75-100W electric iron, through the effective transmission Heat to disassemble; for each row of a heater, use a pointed tweezers to pry a pry, turn on the two rows of turns, until it is removed.
In addition, you can also use a tin soldering iron or tin sucker to melt the molten tin, the assembly block pin and circuit board separation. Suction tin can also be self-made, put in a medical syringe with a moderate elastic strength, the size of the appropriate size of the spring and cut the needle to form a simple tin suction device.
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