D - Drying

Question/problem:
Why is drying of parts so important in ensuring critical cleaning?

Solution:
This addresses the eighth variable "DRYING" in Alconox's acronym BATHCARD, factors that contribute to successful cleaning. Click here to learn more.

DRYING
Drying can be done by physically removal of rinse water or by evaporation. Physically removal by wiping, blowing, centrifuging, drying fluids, absorption, or other physical techniques will eliminate the rinse water before it has a chance to evaporate.

Such methods prevent precipitating out of any salts or impurities that could form water spots. Water removing drying methods also minimize the risk of corrosion occurring during drying.

Evaporation methods such as air drying, heat drying, and vacuum drying can deposit nonvolatile impurities present in the rinse water and cause water spots. Although vacuum drying does evaporate water and can lead to deposits, in many cases the deposits themselves evaporate under vacuum drying conditions. Drying can affect residues and corrosion because impurities from rinse water can be deposited during evaporation.

Water, particularly high-purity rinse water, can be corrosive to metal substrates during heated and air drying. Physical removal of rinse water, various drying techniques and the addition of corrosion inhibitors (with tolerance for inhibitor residue), to the rinse water, can help minimize such corrosion.

By choosing an appropriate cleaning agitation method, using the right rinsing and drying process, then varying the cleaner, concentration, heat, and time, an optimized aqueous-cleaning system can be achieved. To sustain successful cleaning, control before, and after, cleaning are important considerations. If you think about the variables in BATHCARD (before, agitation, time, heat, chemistry, after, rinse, dry) while evaluating your cleaning process, you will be more successful at diagnosing problems and optimizing your process. Click here for the pdf.