SMD Soldering Equipment

At some point you will need to solder a surface-mount device (SMD) package. While it may seem intimidating at first, SMD soldering is easier than you may think, and you probably already have the necessary equipment, like a soldering station.

Your soldering equipment should be able to reach at least 350°C (660°F). Although most of the time you will be soldering with a temperature between 330 and 340°C, there are times when it is beneficial to use a higher temperature. Be sure you don’t get a soldering station with too much power, because you will sometimes want to use a lower temperature, say 270°C.

You might already own a soldering station, but you should consider upgrading if your station doesn’t have temperature control and read-out functionality. Always keep a wet soldering sponge nearby when soldering SMDs.

Use the smallest soldering iron tip you can. Ensure that the tip is clean and smooth — steel wool may be sufficient, but if your soldering iron tip is especially dirty, you may need to replace it. Tin the soldering iron tip before using it for the first time.

Tweezers are critical when soldering SMDs. Look for higher quality tweezers with small points. Having several different tweezers on-hand is often helpful.

If you use large-diameter solder, you will likely get solder bridges, so opt for small-diameter solder (28 AWG/.38 mm) to make the soldering process much easier.

When soldering SMDs, flux is particularly important. Since it comes in pens, applying the flux is easy. The lower the flux’s number is, the more active it is. Soldering is easier and solder bridges are less likely to form as the flux’s activity increases. However, if the flux’s activity is too high you must clean the flux off the circuit board or the flux will eat through it.

Desoldering braid, or solder wick, allows you to clean solder off old pads, remove any excess solder from solder joints, and remove solder bridges. Small solder wick is great for SMD parts because it heats up rapidly and contains some flux to help keep everything clean, but keep in mind that small solder wick won’t be very good for through-hole parts.

George

George Leger has a Masters in Electrical Engineering from Stanford University, worked in private industry pioneering surface-mount technology and in government research labs for twenty years, published several papers on surface-mount technology, co-authored papers published in national symposiums on accelerator technology, was past president of SMTA and an adjunct professor at the community college level, holds a patent, and is a certified microchip design partner, serving as a consultant to many companies developing electronic circuits.

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