10.8.1 Introduction
The design of a supply system and the selection of the feed parameters must meet the specific technological demands of the grinding process. Since the cooling of the grinding process primarily depends on cooling lubricant supply to the contact zone, secondary cooling effects play only a minor role, hence the percentage of the cooling lubricant amount acting in the contact zone has to be set to a technologically required minimum.
10.8.2 Alternative Cooling Lubricant Systems
The amount of cooling lubricant required can be reduced by the use of alternative cooling lubricants. It has been shown that good grinding results can be achieved by using liquid nitrogen linked to minimum lubrication. Compared to grinding with oil, surface qualities are slightly poorer, but wear of the grinding wheel is much lower. The lubrication of the grinding process with solid graphite is a further possibility. In this case, machining forces are similar to those in grinding with a grinding fluid. If solid graphite lubrication is linked to dry machining, considerably lower process forces were found, first of all, in the case of increased feed rates.
Besides the design of the supply system, the use of alternative cooling lubricants, and the reduction of the cooling lubricant quantity, there is a further potential for optimization of the entire cooling system, including the whole life cycle of the cooling lubricant. Since cooling lubricants are designed for a particular machining task, the complex process of downstream cleaning and processing is not considered. Only cleaning of the filter system is included in the design. In this case, slurry in the filter system can be processed and a large part of the substances it contains can be recycled [Brinskmeier 1991a].
It is possible that the entire process will be integrated within the grinding machine in the future. After start-up, the grinding machine will be able to process a large part of the used cooling lubricant and refeed it to the process. Furthermore, residual material derived from the chip particles and abrasive residuals can be refed to the production process.