The amount of cutting oil which is used in different production processes, but particularly in the machine tool industry, remains very high. However, these can cause health risks for the operator, have a negative impact on the environment and can often lead to considerable storage, maintenance, disposal and other costs.
To fulfil the essential functions of a cutting fluid (lubrication, cooling, chip removal and protection from corrosion) in this type of industry, and at the same time satisfy a society which is concerned about health issues and which is increasingly committed to protecting the environment and to efficiency, alternatives are now being considered in the search for low-impact formulations:
- Dry machining or with a minimum amount of lubricant, employing more environmentally friendly formulations or using refrigerant gases.
- Use of base oils of vegetable or synthetic origin, biodegradable and with low impact as opposed to mineral oil formulations with more negative environmental impacts.
- Reducing the level of aromatics, because of their relationship with skin cancer.
- The trend in the use of additives which lead to low levels of oxygen demand for degradation.
- Removal of chlorinated hydrocarbons from the formulations. These are generally used as extreme pressure additives and are highly polluting.
- Reduction in the use of sodium nitrite as a corrosion inhibitor due to its combination with amines to form highly carcinogenic nitrosamines.
- Study and reduction in the use of biocides, because they are environmentally polluting and appear to be directly related to dermatitis. The upward trend in the use of highly biodegradable compounds in the formulations and the reduction of additives of a biocidal nature creates a serious problem of bacterial overgrowth.
- Elimination of the use of heavy metals (Zn, Cu) in the formulations, because of the problems associated with their subsequent elimination.
- Limitation in the formulations of compounds contributing to bacterial growth, such as nutrient compounds of N and P or elimination of the sulphur that the additives contain.
- Reduction in the use of water miscible lubricants when technically feasible, and evolution towards multifunctional and biodegradable compounds immiscible in water.
