Water for Metal Machining

A water-based, recyclable metalworking fluid comprises a polyalkylene glycol, an alkanolamine, a polyglycol surfactant, a polyol surfactant, a biocide and a corrosion inhibitor. The biocide may comprise a mixture of biocidal compounds effective against bacterial and fungal organisms. The material may also include an isoalkoxy amine oxide and a glycol ether. The composition may also include ancillary ingredients such as viscosity controlling agents, defoamers, coloring agents and the like. It is a notable feature of the composition of the present invention that it is free of hazardous materials and fatty acids. Also disclosed is a method for using the composition in a metal-shaping operation. But the most important factor is the quality of water.

Water quality should be a major concern in water-based metalworking. In fact most of metal shops that neglected the importance of water in working with metals has suffered some deficiency upon the result. When developing metalworking processes involving the application of a water-soluble fluid, it is critical to understand all of the variables that can affect the process, including the water used for both charging and replenishing the system.

Here are some of the recommendations from the expert for shops seeking to prevent problems and improve productivity by optimizing their use of coolants and other fluids:

• Be very careful with the pureness of water,which means working meticulously is a factor. Recognize the significance of water quality and appreciate its complexity.

• Learn about water quality and its effect on a fluid's performance. Water is rarely pure H2O. Other materials in the water affect its chemical and physical properties. Ultimately, all have an effect on the fluid's effectiveness.

• Set up and maintain the proper water treatment program to ensure that water of the right quality is available in sufficient quantities for charging and replenishing as needed.

• Keep tracking records in water quality all the time to maintain the stability of the system.

• Stay on top of developments in water treatment as well as formulations of metalworking fluid concentrates.

The goal of a water treatment program is to supply good water quality for the proper performance, stability and sump life of metalworking fluids.

Developing a water treatment program requires a balanced approach. In many cases, tap water can be used for charging a system, while treated water (preferably treated by deionization or reverse osmosis) must be used for regular make-up to compensate for evaporation.

Here are constant critical parameters for water quality and the values that should be achieved regularly.

• Appearance- clear and water-white, free of all debris.
• Odor- none
• PH- 7.0 to 8.5
• Hardness- 125 to 200 ppm
• Alkalinity- 25 to 100 ppm
• Turbidity- 5 ntu
• Bacteria- none
• Fungi- none
• Chlorides- 20 ppm
• Sulfates- 40 ppm
• Phosphates- 40 ppm