Anaerobic bacteria and aerobic bacteria
Aerobic bacteria are generated where oxygen exists, as it’s said aerobic. Although it depends on the condition of tanks and inside machines when changing cutting oil, propagation starts a few days or a few weeks after changing generally. If it’s used under the appropriate condition, it’s possible to inhibit a certain level of bacteria generation, since water-soluble cutting oil contains bactericide which inhibits generation of microorganisms. However, it’s devilishly difficult to inhibit generation yet, since there is a series of bad conditions such as oily material, machining swarf which comes out when cutting, hydraulic oil and lubricating oil leaks out when operating machines in processing operation actually
The aerobic bacteria generated first eats cutting oil and releases water and carbon dioxide as by-products which have a negligible effect.
However, power among bacteria changes, then aerobic bacteria die out and anaerobic bacteria increase in power, under the condition that oxygen is not provided due to oil film on the surface by hydraulic oil. Most bacteria in a tank turn out to anaerobic bacteria at the time, and generate hydrogen sulfide (Rotten-egg smell - peculiar smell when eggs are rotten which is the odor of the principal component in hydrogen sulfide) as a by-product of anaerobic bacteria which is serious status with stain inside machines, paint deterioration, and effects on the human body such as pain in the eyes. What is most important is to inhibit generation of these anaerobic bacteria
Status of cutting oil
- Measure pH level of water-soluble cutting oil periodically and maintain it at the standard value.
- Clean oil on the surface of cutting oil in a tank such as hydraulic oil and lubricating oil frequently.
- Remove machining swarf
- Control concentration
Generation of bacteria can be inhibited to the minimum with the maintenance above. This unit supports where daily maintenance cannot cover.
- It doesn’t create oil film even if you forget to clean lubricating oil (Oil dissipates in four directions).
- It kills anaerobic bacteria with pumping air.
- Bactericidal action is accelerated by “oligodynamic metal action” of silver and copper.
[Oligodynamic metal action]
Metal such as copper and silver has an effect called oligodynamic metal action. It exerts astonishing antibacterial action with a small amount. It means that a trace of metal ion eluted into water inhibits bacteria activity, and the similar effect has been found on gold and metal. In 1893, Karl Wilhelm von Nägeli, a botanist in Switzerland, found that the water with only a small amount of copper ion which was difficult to be analyzed at that time kills spirogyra, a kind of algae. He also noticed that the water with other metal such as silver or mercury has the similar effect. Thus, the mechanism that the liquid which has very low concentration with metal ion eluted kills microorganisms and algae was called oligodynamia at that time. Now it’s called “oligodynamic metal action” generally. Although the full details of the mechanism has not been known, more than the acceptable amount of copper ion stored in bacteria or microorganisms seem to disturb the activity of the enzymes which is similar that humans and animals develop symptoms of poisoning. Other than this phenomenon, the bactericidal effect on the environmental surface of copper has become paid attention recently. This kills MRSA (methicillin-resistant Staphylococcus aureus) or MDRP (multidrug resistant Pseudomonas aeruginosa) which cause hospital infection with contacting copper directly.
Cited from Japan Copper Development Association