Extraction Curve
ISO 16232 and VDA 19 as well as several factory standards specify the qualification of the testing procedure for cleanliness inspections. But what does this mean in detail?
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.