ABSTRACT
Defining and maintaining the surface preparation at "proper" levels is the key to good surface finish. However defining a "proper" level of surface cleanliness is, at best, subjective. For consistent results, it is important to define "how clean is clean". Often the inadequacy of surface preparation processes is not discovered until problems, such as poor adhesion, occur downstream resulting in nonconformance due to poor surface cleanliness. To assure consistent quality of surface cleanliness, it is important to: understand the types of contaminants to be monitored; most common cleanliness monitoring techniques and their strengths and limitations; factors that affect the choice of cleanliness monitoring technique^); select an appropriate cleanliness monitoring method; specify a desirable
level of surface cleanliness; and monitor the surface cleanliness to an established level on an on-going basis.
