In this category, you will find answers about the most frequently asked questions dealing with coolants.

Many Oemeta products are equipped with specific lubricating additives reducing the friction between tool and workpiece and thus, contribute to a longer tool life. 

Normally, the pH values of cooling lubricants in use are above 9.0. Due to microbiology and/or low application concentrations, the pH value can drop below 9.0 deteriorating secondary characteristics such as corrosion protection. In this case, the emulsion can be stabilized by means of increase in concentration, adding of alkalizing biocides or alkalizing additives for corrosion protection.

Water and air are the input sources for microorganisms. For that reason, first of all the water quality has to be checked regularly in order to prevent pollution due to contaminated pipes and connections. Additionally, contamination of the cooling lubricant, for example with cigarette butts, waste, food leftovers, must be absolutely avoided. Keeping the cooling lubricant clean and complying with the recommended application concentrations are preconditions for low bacteria growth and a long machine life.

Copper is extracted from the workpiece and the chip and reacts with the amines of the cooling lubricant leading to a green colour. Thus, for the machining of copper alloys it is recommended to use cooling lubricants without amines or with specific amines combined with inhibitors, which prevent the extraction and discoloration of copper.

It is most important to first add water and then to add the concentrate. Even better is the use of mixing devices, which ensure a homogeneous cooling lubricant.
Please refer to info sheet Technical Information_New filling with water-miscible metalworking fluids.

Cooling lubricants can become discoloured due to all sorts of contamination. Mostly, metal ions such as copper (blue-green), cobalt (red-pink) and iron (brown) lead to discoloration. But also tramp oil (brown) or abrasion particles (grey) discolour emulsions. Ingredients of concentrates play an important role: Oil-free concentrates are clear to yellow; oily ones are yellow to brown. Some specific additives such as EP additives and biocides can darken the concentrates or make them appear reddish. As long as the storage period has not been exceeded, usually, these discolorations do not influence the performance characteristics of the cooling lubricant.

There are different groups of biocidal agents. Formaldehyde releasers are pure bactericides.
Fungicides can be based on iodine carbamate, sodium pyrithione or some isothiazolinones (OIT, BBIT). A widely used combination product against bacteria and fungi is CIT/MIT.

In case, pipework and especially ring networks, are clogged with lime soaps, they can be cleaned with compressed air. The use of dispersants, for example ADDI PROX LC, is only successful as long as some of the cooling lubricant can still pass through the pipe.

The protective layer of the skin consists of fatty acids, thus, tensides and alkaline substances attack this protective layer of the skin. For that reason, excessive skin contact should be avoided and skin protection should always be applied. Biocides, EP additives and specific inhibitors could additionally irritate the skin. All Oemeta products are tested regarding skin compatibility. On request, we will provide the respective reports. Further information is available in the safety data sheets of the cooling lubricants.

In order to fulfil all primary and secondary requirements of the cooling lubricant, a minimum concentration should be complied with. For example, longer tool life will not be achieved with a low application concentration also when using a high-performance cooling lubricant. As well, characteristics such as corrosion protection and stability have to be kept constant against external influence.