Now more and more circuit board use the surface to stick outfit component, enclose photograph comparing traditionally together, it can reduce the area of circuit board, easily big batch treatment, wiring density is high. The down-lead inductance that sticks a resistor and capacitance decreases greatly, very big advantage is had in high frequency circuit. It is disadvantageous that the surface sticks the no-go office that holds component solder at handiwork. For this, the article encloses chip to be with common PQFP exemple, those who introduce the surface to stick outfit component is basic solder method. One, the copperhead small iron that requires tool and material welder provide need to have 25 W, can use temperature conditionally to be able to mediate the solder stand that takes ESD protection, notice iron needle wants fine, the width of coping cannot be more than １ ｍ ｍ . Forceps of a cusp can use shift and fixed chip and examination circuit. Prepare even fine welding wire and aid alcohol of propyl of welding flux, different to wait. Using the end that aids welding flux basically is the liquidity that adds soldering tin, such soldering tin can use iron drawing, the wrap up of action light slippery ground that relies on exterior tension is bringing foot and solder dish on. Keep clear of with alcohol after solder board the welding flux that go up. 2, solder methodological １ . Before soldering preexistence solder dish go up Tu Shangzhu welding flux, handle with iron, lest solder dish tin-plating undesirable or be oxidized, cause bad solder, chip does not need to handle commonly. 2. Put PQFP chip carefully PCB with forceps board on, the attention does not want attaint to cite a base. Make its and solder dish right neat, the placement that should assure chip way is right. Move the temperature of iron to 300 much Celsius, touch soldering-iron head needle a few soldering tin, press the chip that already aimed the place downward with the tool, in two diagonally positions bring add on the foot a few welding flux, still press chip downward, solder two diagonal locally cite a base, make chip is secured and cannot move. Be over in solder whether is the place that chip checks afresh after diagonal aimed. If be necessary,can undertake adjustment or be demolished and be in newly again PCB board on alignment position. 3. Begin all bringing to solder when the foot, answer to add soldering tin on iron needle, make the welding flux on all besmear that cite a base bring a foot to keep wet. With iron needle osculatory chip brings crural fag end every, until see soldering tin is flowed into cite a base. Iron should maintain when soldering the needle is as collateral as the foot that be brought by solder, because soldering tin excessive happens,prevent to build receive. 4. Solder is over all bringing after the foot, soak all bringing with welding flux so that the foot cleans soldering tin. Surplus soldering tin is sucked in the place of need, with eliminating any short circuit are mixed build receive. Whether is there empty solder with forceps examination finally, after the examination is finished, from circuit board go up cleared welding flux, brush bristle the alcohol on dip to be wiped carefully along the direction that cite a base, disappear till welding flux till. 5. It is relatively easy to stick a block to contain element solder a few, can preexistence the stannum on the dot on dot of a solder, a when put component next, clip component with forceps, on solder one later, look to whether be put again; If already was put, again on solder additionally one. Should master truly solder the practice with skill many need. CNC Milling
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