The parameter for a cleanliness inspection are selected by the test laboratory based on previous test cycles. The component is cleaned for a timespan "t" with the solvent volume "V". Recording of the extraction curve shows under which conditions more than 90% of the contaminants were detached from the component.
The elaboration of the extraction curve is done via repetition of the cleaning process for 6 times under identical conditions (6x time "t" and 6x volume "V"). After each cleaning step the detached contamination mass is related to the overall detached contamination mass - meaning that die detached mass in cleaning cycle 4 is compared to the total mass of cycles 1, 2 and 3.
The graphical illustration of the results is called extraction curve.
Several factory standards specify the elaboration of an extraction curve as mandatory.