In the automotive sector an increasing number of components contain specifications for cleanliness in product drawings, which generates a requirement for a comprehensive particle analysis   Examples of automotive parts that may require filter analysis: Engine and powertrain components (valves, camshafts, crankshafts, gear, wheels etc.) Hydraulic components (ABS, ESP, power-steering etc.) Fuel supply components (valves, hoses, elements of hose pipes) Electronic assemblies

Methods used for evaluating cleanliness levels (extracting, analysing and expressing results) are covered by the standard ISO 16232.

When determing the contamination of components (i.e. after components have undergone their standard cleaning process) sample parts are selected and cleaned again in a defined and controlled manner.
The method of cleaning (e.g. ultrasonic bath, rinsing), the cleaning fluid (e.g. water, alcohol), the volume of cleaning fluid and other parameters are part of the production evaluation process and subject to strict specifications.

The cleaning fluid is then passed through a filter membrane which will entrap the residual particles.
In this stage the membrane type (Cellulose, Teflon, Polyester net) will have an influence on the number and size of captured particles.

After this process the filter is dried and one of the following methods is used to determine cleanliness.

Method of Determining Technical Cleanliness: