Tangential grinding force and grinding power can be minimized and generated heat reduced by reducing friction using a cooling lubricant with a strong lubricating effect [Howes 1990, Brinks — meier 1991a]. Successful cooling leads to quick heat dissipation keeping the active partners below a critical temperature. However, the shear resistance of the workpiece material is increased through the cooling of the active zone, again causing an increase in the process forces [Brinksmeier 1991a]. Depending on its cooling and lubricating performance, the cooling lubricant has a significant influence on the achievable material removal rate, grinding forces, grinding temperature, and on grinding wheel wear. Beyond the influence on process parameters, achievable surface quality and subsurface characteristics crucially depend on the cooling lubricant used. It has also been reported that clogging of the grinding wheel depends on the type of cooling lubricant [Khudobin 1969, Tawakoli 1990]. Against this background, a specific selection and adaptation of the cooling lubricant is necessary for a particular machining task.
Increasing public awareness toward environmental protection, new ecological legal conditions as well as increasing disposal costs have led to new approaches in manufacturing for grinding fluids. It has been recognized that inappropriate disposal and landfilling of cooling lubricants represent a serious hazard since deposition has a significant impact on the air, soil, and ground water. Moreover, dioxins are emitted to the environment. The “Act of Closed Substance Cycle Waste Management and Ensuring Environmentally Compatible Waste Disposal,” which became effective in 1996 in Germany, focuses on the protection of natural resources through the avoidance and recycling of waste. Production is required by law to take place with a minimum input and first of all with a minimum consumption of resources emitting a minimum of harmful substances [Brinksmeier 1993]. Hence the entire cooling lubricant system represents a key starting point for an ecoefficient design of the grinding process. Grinding fluid is fed in large amounts to the grinding machine and large quantities of abrasive slurry are generated in the fluid supply system.
Ecological and health aspects are resulting in a more frequent application of dry machining or of so-called “Minimum Quantity Lubrication” systems. Increasing demands for improved product quality and economic grinding of parts, and a minimum amount of grinding fluid, represent contradictory requirements [Klocke and Gerschwiler 1996, Heinzel 1999, Weinert 1999].