After completing the process in the plating
bath, the work is emersed in the first water
bath, where most of the residuals from the plating
bath are removed. Because these residuals
simply dissolve in the rinse water, they are
present on the surface of the rinsed work in
proportion to their concentration in the rinse
water. Therefore, it is necessary to rinse the
work in a cleaner bath after the first rinse, and
so on, until the work is sufficiently clean. Each
time an object is removed from an emersion
tank, it brings a certain amount of the bath
solution (dragout) with it. Dragout contaminates
the next emersion solution or rinsewater
bath. Use of air squeegees and/or longer drip
times can minimize dragout. Figure 4-2 shows
a typical rinsing sequence for an electroplating
process.
It is common to have three rinse tanks in
series and advisable to have them set up
such that fresh makeup water is added to the
final rinse tank, ensuring a concentration
of “impurities” sufficiently low that the rinsed