Here are some shocking works of the Welding Martial Arts Emperor:
There are many required skills for hardware engineers, and circuit soldering is definitely one of the top required skills.
Contour welding is designed to correctly weld all kinds of electronic components to the corresponding positions on the PCB according to the circuit identification. shaped so that the components are fixed in their respective PCB positions.
As the integration level of a chip gets higher and higher, the corresponding package gets smaller and smaller, and the pin pitch gets smaller and smaller. The era of one soldering iron is gone forever. Having a good welding tool can make welding jobs more efficient.
The following shows the different tools used by the dispatcher boy, compare them with the tools in your hands:
1) T12 Soldering StationThis is the most commonly used tool. When choosing a soldering station, pay attention to choosing a soldering station that heats up and returns quickly. The T12 soldering station is a good choice, and it is also equipped with multiple soldering tips. Commonly used are sharp tips, knife tips, horseshoes. tips, etc., depending on the type of components to be soldered, replace with another soldering iron tip.
2) Heat gun
Required artifact for desoldering SMD components. The one in the video is the Quick 850A+ with a maximum air volume of 24L/min, 8 levels of continuous adjustment and stepless temperature control from 150 to 500 degrees.
3) Heating the soldering stationMainly used for preheat welding, aluminum substrate welding, manual reflow soldering, etc. The following CNC heating platform has an effective heating area of 15cm * 15cm, and the temperature is at room temperature - 450 constant temperature adjustable degrees, and the user experience is relatively good.
Then there is the MHP30 Mini Heating Platform. Some people may get confused here. Isn't there a CNC heating platform? Why do you need a mini heating platform? Of course, everyone has their own magic.
MHP30 mini heating platform, the effective heating area is 3cm*3cm, and the maximum heating temperature is 350 degrees. Only heat the part of the PCB that needs to be desoldered to prevent reheating of other parts. the screen has a very beautiful design. In addition to being a great tool, it is also a work of art.
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4) Auxiliary welding toolsHigh temperature sponges, tweezers, tin absorbent tape, tin absorbers, electronic magnifiers, circuit board holders, flux and, most importantly, solder.
Among them, flux can enhance the solderability of components and welding surfaces, and there are many types. You can choose according to your own welding objects. Rosin is the most commonly used.
Commonly used solder includes solder, tin paste, tin balls, tin rods, etc. Among them, solder and tin paste are most commonly used, while tin balls and tin rods are mostly not used. The choice of solder wire is mainly based on the wire diameter, tin content and melting point. Generally, three wire diameters are used: 0.5mm, 0.5mm and 0.8mm. Lead-free tin has better oxidation resistance and higher melting temperature.
The following are tips and precautions for real world welding:
1) ConnectorSet the temperature of the soldering station to 370 degrees, insert the component into the corresponding hole on the PCB, position the pin as far as possibleIf the component is perpendicular to the PCB pad, the soldering iron tip should be at a 45 degree angle to the pad. The board and soldering iron tip rest against the pins of the component Preheat the pad and then start feeding the solder wire When the solder wire melts, control the tin feed rate When the entire pad melts, stop and remove the tin wire. Finally, cut off the excess pins with diagonal pliers.
2) Welding of chip componentsSoldering SOP8 and SOP16 is relatively easy. Align the IC with the PCB pad, fix one pin first, make sure the other pins are also aligned with the corresponding pad, and then solder the rest of the pins one by one. . Contact welding is also possible.
As for soldering the LQFP48 package, it is impossible to solder the leads one at a time, and the efficiency is too low. You can align the chip with the PCB pins first, pin one pin first, and then pin the diagonal pin. After fixing is complete, apply an appropriate amount of flux to the surrounding pins. Then use the tip of a soldering iron to carry out the soldering by drawing. After completing the soldering by drawing, use an electronic magnifying glass to check the quality of the soldering and ensure that there is no lead solder.
If you use a QFN-24 soldering iron, it's more of a hassle. To solder this type of chip, you need to use a heat gun or a heating platform.
This video uses the MHP30 Mini Heating Platform. Since there is no stencil, solder paste can only be applied evenly by hand. After coating is completed, align the chip with the PCB pad, set the temperature, heat the pad to 190 degrees, align the position where the PCB should be soldered to the heating pad, and start heating. You can see that the solder paste is gradually melting. The process is very decompressed. After the solder paste is completely melted, slowly remove the circuit board and wait for it to cool naturally. Check the soldering quality with an electronic magnifier and find excess solder. and soldering is complete.
3) Special welding of printed circuit boardsFor students and friends, the ability to weld a universal board is very important in the competition. The quality of the weld can affect the progress of the competition and even the quality of the function. You can watch the above video about welding the universal board.
Finally, let's talk about special PCB soldering. We are talking about aluminum substrates. Aluminum substrates are copper-plated metal-based laminates with good heat dissipation functions. Generally, single-sided panels are composed of three-layer structures, which circuit layers (copper foil), insulating layer and metalallic base layer commonly found in LED lighting products. Due to the very good thermal conductivity of the aluminum substrate, it is difficult to solder it with an electric soldering iron. Usually, manual welding of an aluminum substrate requires the use of a hot bed to assist the soldering iron, or direct use of a heating table. for manual reflow soldering, and the soldering temperature should not be too high. Soldering time within 20 seconds.
Well, welding is often done with the brain and not with the hands, so I hope you take every opportunity in your regular studies, practice hard, practice makes perfect, and become a real "Welding Emperor" as soon as possible.