Mechanical separation of soils (oils and grease). One of today's manufacturing goals is that of source reduction. Source reduction is the better use of materials and the energy and labor required to convert those materials, as well as a reduction in the waste generated by each manufacturing operation. Source reduction equates to process cost reduction and, for that reason, its focus is altering most operational practices.

Until now, one of two principles of mechanical separation has been commonly used, namely adhesion techniques (such as an oil wheel/disk, hose or belt skimmer) or by skimming (weir skimmers, tank overflow to drain). There is always advantage in simplicity, although there are built-in disadvantages to using either of these methods in the aqueous cleaning process.

Due to skimmer construction features, users can either allow a thick layer to accumulate and skim oil only, which means a constant surface layer of oil. Or they can overflow or skim off a top layer, which removes significant amounts of cleaner from the bath. In skimming off a top layer that contains both oil and cleaner and putting it in the drain, users lose the composition of their cleaner.

With adhesion techniques, a floating layer of oil will always be on the surface of the cleaning bath. Because of the presence of surfactants, which prevent the oil from adhering to the oliophilic surfaces of the wheel or belt, the subsequent cleaning process will be compromised by uncollected oil being re-introduced to the work piece. This becomes more apparent in volume production where the low separation/removal capacity of oliophilic devices results in oil accumulation in the cleaner reservoir.

New approach to mechanical separation. A new concept in mechanical separation of oil and dirt is a continuous, in-line precision oil control technology. The genesis of this technology was in petroleum production and refining, a manufacturing process that requires continuous, high-efficiency oil/water separation. This thin-film separation technology provides the high efficiency required to remove the oil and dirt without affecting the composition of the aqueous cleaner.

Exploiting the differential between the specific gravity of two liquids, the "wing-shaped" module collects and concentrates the floating oil. This allows efficient removal of the contaminants.

One manufacturer who had switched to using non-soluble stamping oils and non-emulsifying cleaners found that instead of dumping its washer tanks every one-and-a-half days, it was able to extend the life of the aqueous cleaner to 60 days, according to the plant manager. This was its regular schedule for routine emptying of the washer for cleaning and maintenance.

The manufacturer independently analyzed the quality of the oil recovered by the thin-film oil control technology. They found that none of the aqueous cleaner surfactants was present in the recovered hydrocarbon. As well as extending the useful life of the aqueous cleaner, this finding also allowed for the immediate re-use of the stamping oil.