One of the most important parts of the surface mount assembly process is the application of solder paste to the printed circuit board (PCB). The aim of this process is to accurately deposit the correct amount onto each of the pads to be soldered. This is achieved by screen-printing the solder paste through a stencil or foil but also can be applied by jet printing. It is widely believed that this part of the process, if not controlled correctly, accounts for the many assembly defects.