7. Aqueous degreasing process controls

In addition to controlling physical parameters such as temperature, agitation and immersion time, which play an important role in treatment quality, degreasing baths require regular monitoring of changes in their composition. Experience has shown that a decrease in bath concentration alters the degreasing power of the bath, whereas an increase in bath concentration does not lead to any malfunction other than the entrainment of a more concentrated solution, resulting in greater losses. Maintaining the bath in optimum operating condition, and consequently its concentrations, is therefore essential for subsequent treatments to run smoothly.

Bath depletion results from the chemical saponification reaction and entrainment losses. It is difficult to assess the contribution of the chemical reaction for two main reasons:

• experience...