In the beginning…
One of the oldest and best-known methods of coating is the dip process. In the manual dip operation, operators immerse the PCB in a tank of coating.Components on the PCB that cannot be exposed to coating must first be masked(Figure 1). Tape or boot masking (boot masking is typically used for spray applications and are not “water-tight” enough for submersion) is manually applied prior to coating. The masking is then removed after the board is cured. Masking
is labor intensive and involves consumables,making the process inherently wasteful.Some dip systems automatically move the board in and out of the tank, allowing for better repeatability. Although dip systems are simple and involve a low capital investment, the variation in coating thickness, contamination issues, viscosity variations, manual masking,
cleanliness and operator comfort and exposure make this a crude process with little control.