BGA Rework Not SMT Rework

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BGA rework repair is commonly used on circuit boards that have chipsets soldered to the board using tiny solder balls. These tiny solder balls are underneath the chipset package and are therefore not within the reach of a typical soldering iron. SMT rework machines are commonly used to perform BGA rework repair but these machines lack the amount of power to complete such tasks properly. A typical SMT rework machine ranges from 200 to 500 watts. The BGA rework machine start at 1200 and go as high as 4000 watts or more.

Aside from wattage, BGA rework machines use larger heaters in order to properly heat the package and the board evenly. Through the use of profiles, the board is brought to an appropriate temperature to prevent board flex and thermal shock when the solder balls on the BGA package are taken to a liquidous temperature. Profiles are basically a set of instructions created by the technician sent from SSR controllers inside the machine telling the heaters how to heat and for how long.

There are a few SMT components that utilize the same process and procedure found in BGA rework. QFN and DFN packages are a couple of those, these are not to be confused with QFP, LQFP, and TQFP which have leads that extend out and onto solder pads and are accessible with a soldering iron. The similarity of QFN/ DFN to BGA packages is that the solder is directly underneath the package while this allows for thinner packages that take less room it does pose a problem for those without proper reworking equipment. These SMT packages can be reworked with a smaller, portable station that consist of a top and bottom heater. Typically the bottom uses IR and the top uses hot air. While BGA stations are not necessary for SMT packages they can be used, and have the benefit of performing BGA reworking as well.

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