Assessment of Alternatives to CFCs for Cleaning Electrical and Electronic Components

A recent EC directive has banned the use of CFCs in cleaning processes because of potential damage to the ozone layer.

Therefore, new cleaning schedules are having to be introduced for sensitive electrical and electronic components, such as switch or relay contacts.

This report surveys the effects of a number of permitted cleaning solutions.

A range of mainly electrical assemblies, cleaned in a variety of solutions were collected together.

Mounted in batches on scanning electron microscope (SEM) stubs, so that the whole batch could be examined and analyzed under the same operating conditions, the samples were inserted into a SEM and photographed at low and high magnification.

While in the SEM, the samples were also analyzed using an energy dispersive X-ray (EDX).

The results were assessed and presented in three ways: the efficiency of each solvent in dealing with particulates; the solvents used for each type of surface in terms of the general finish and of any observed staining; and, finally, the surfaces cleaned with each solvent in terms of the general finish and of any observed staining.

The findings are tabulated, and the cleaning schedules are compared. The method is a useful tool in deciding which solvent, or combination of solvents, to use for particular types of surface.

Useful conclusions are drawn. Although the samples were mainly electrical, the method is equally applicable to electronic components.

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