The concept of a “vanishing” or “evaporative” lubricant is pretty simple. The product is designed to “vanish” or “evaporate” during the processing of the part—or shortly thereafter.
Conventional “vanishing” lubricants are based on solvents that volatize at certain temperatures. Some solvents can be more volatile than others—this is where the stamping process temperature comes into play. When the lubricant is applied to the blank or coil as it enters the die, the metal is comparatively cool. Once the part is stamped, heat generated by friction between the tooling and the substrate provides the additional heat necessary to volatize the fluid. If there are “non-volatile” additives used to provide more lubricity or extreme pressure performance in the fluid—these additives will stay behind on the part surface.
Water-based “evaporative” lubricants function very much the same way conventional water-based stamping fluids do—additives provide protection for tooling and stamped parts, while the water provides a “carrier” for the additives, but also provides cooling for tooling and parts. Much the same way people sweat to cool themselves—evaporative loss of water from these stamping fluids help cool metal surfaces. Water-based, oil-free stamping fluids tend to leave behind drier residues on parts than do oil-based or solvent-based “vanishing” lubricants fortified for higher performance.
In reality—the water-based “evaporative” lubricants are very similar to conventional , water-based stamping fluids, but they differ in the level of actives. Think of it like concentrated laundry or dish detergent—the chemistry may be the same, but there are “super-concentrates” for tougher applications or newer, higher efficiency equipment. Substituting very dilute solutions of water-based stamping fluids for solvent-based, “vanishing” lubricants is not new—it has been practiced for decades. Success depends upon balancing the concentration of the stamping fluid and the method of application to control residues on parts. In most instances—one will be hard pressed to find any appreciable residue on finished parts.