Metalworking fluid involves cutting and grinding fluids and must satisfy six basic requirements:
- Conduct heat away from the part and tool
- Wash away chips and swarf
- Prevent corrosion
- Reduce tool wear
- Improve surface finish and high reflective surface having no residue
- Increase productivity
NuSol™ Technologies are semi-synthetics that have become more popular because they deliver more lubricity and less sticky residues than traditional soluble oils with the bio-stability, minimal foam and maintenance free ability of synthetics. NuSol is the next step in semi-synthetic formulation technology. In conventional semi-synthetic formulations, typically only thin viscosity oils and esters can be incorporated to form a stable and homogenous mixture. We have made high viscosity, stable, pre-formed emulsion intermediates in which we blend to fine tune our formulations. This strategy increases the film strength to increase the hydrodynamic effect occurring with modern high-speed operations. Using pre-formed emulsions also better disperses dirt and maintains not only on the part but the entire machining operation.
Synthetics are products that contain no petroleum. This class contains functional additives and forms a single-phase true solution (no micelles) when mixed with water. As such, these products form a see-through, transparent mixture with water. With the addition of water these products need to be monitored but tend to require less maintenance than soluble oils since they reject tramp oil and fines, which are a large variable in consistent performance.
Semi-synthetics are essentially a hybrid of soluble oils and synthetics. They are defined as a product that generally >20% water and <50% petroleum oil in it. These products create a micro-emulsion having an average particle size <1 µm when diluted with water. They tend to form a “blue” or near translucent emulsion. The performance of the product depends on the formulation and the process and formulae may have to be optimized for conditions and processes.
Straight Oils are used “straight from the drum” and are not diluted. These products provide the greatest lubrication, but the poorest cooling. These products are composed of base petroleum oil and additives which may be combination of boundary additives (esters and/or fatty acids) and extreme pressure additives such as sulfur, phosphorous and chlorine.
Soluble Oils are basically straight oils with emulsifiers in them such that the oil can be emulsified in water. The oil in water (O/W) emulsion typically resembles milk and the benefits are a high lubricity with the added cooling capacity of water. The average particle size of the oil droplets in the water is >1 µm. With today’s modern high-speed machining processes, tooling can exceed 2,000°F at 200,000 PSI and requires the high heat capacity of water to keep tooling cool and the plated out oil well lubricated. With the addition of water these products should be monitored more closely since tramp oil, bacteria and fungi could thrive depending on conditions.