Industrial Lubricants are always a vast and interesting subject to discuss and share. Broadly Industrial Lubricants can be discussed in two verticals – one is of course Factory, Plant & Machinery [ FPM ] products like Hydraulics, Gear Oils, Compressor Oils, etc. Another is Lubricants used in processing. In the later segment, one of the most sensitive portfolios is water extendable cutting coolants used in metal processing industries. Many technical publications and in-depth experiences are shared for the maintenance of cutting coolants. However, today's effort is to address the basics of maintenance of Soluble cutting coolants either mineral based conventional high oil content products or new generation semi-synthetic products.
Before going into maintenance practices let us have a quick look at the composition and chemistry of Cutting coolants. New generation cutting oils are a complex combination of Lubricity components blended with Emulsifiers, Co-emulsifiers, Corrosion Inhibitors, Special Anti-wear chemistry to enhance tool life and Biocides to prevent microbial manifestations in the coolant. So it's a power-packed chemistry made stable by the formulator intended to be used as an Oil in Water Emulsion, typically in the range of 4 to 8% concentration depending on application type.
Now if we recall the maintenance issues, typically those are associated with Component Finish, Corrosion, pH drop, Bacterial Growth, etc. Let's talk about the right maintenance practices in these contexts.
Its starts with water quality. For water extendable products on an average 95% in water content in the coolant. So the quality of water in coolant has paramount importance and we often forget this as we focus on product attributes.
Water used for making and top-up in coolant must have few basics:-
- Hardness below 50 ppm [ too soft water leads to foaming ].
- Chlorides and Sulphates should be below 20 ppm. These ions are primary reasons of corrosion on metal parts.
- Should not have a bacterial load more than 102 CFU. Higher level of bacterial load in water will make the emulsion prone to the accelerated growth of micro-organism in case of contamination or abuse during the use.
- Last but never the least coolant to be made with proper mixing facilities where Oil to be added slowly into water [ never the other way round ] to have a uniform dispersion of oil in water.
Once water parameters are ensured, it would be critical to maintaining in-process controls during use.
Following are the salient points for good control of coolant and extended sump life:-
- Most important parameter of in-process control is Concentration which can be easily checked by a handheld refractometer. The right concentration would maintain the right alkalinity ie. pH of the coolant. The right level of pH [ above 8.5 ] ensures there is the right level of corrosion protection and it would also ensure that Microbiological manifestations do not take place in the coolant. A lower pH environment is conducive for the growth of Bacteria or Fungi. So just by maintaining the right concentration level recommended by Oil manufacturer, the user not only achieves the machining properties of lubrication, but it also ensures the health of emulsion for an extended period of use.
- Apart from concentration, tramp oil is another critical factor. The key to keeping the sump healthy is the timely and periodic removal of tramp oil floating on the surface of the emulsion. A skimmer or manual removal is important so that the aeration of coolant in circulation is not hindered by the floating tramp oil layer. Else it cuts off the air to go into coolant which results in anaerobic growth of Bacteria. Machine shop identifies this growth as bad odor coming from coolant, typically after a shutdown day which is called “Monday morning smell”. To prevent this, it's important to keep the coolant free from floating tram oil typically comes from hydraulic or sideway lubricants, and keep the circulation on to avoid stagnation of liquid.
These are some of the basics of coolant control and trust you could find these simple practices useful. I look forward to hearing about your experience and please share your thoughts to enrich our learning curve.
Author Bio
Prasenjit
Ray
Chief
Executive Officer
Email : prasenjit@goldoilcorporation.com
GOC
Petrochemicals Pvt Ltd
Website
: www.goldoilcorporation.com
Plot
No.5, Sr.No.207/5,Umerkui, Silvassa, Dadra Nagar Haveli -396230
Manufacturer of Automotive & Industrial
Lubricants, MWF, Grease, Rubber Process Oils, White
Oils, Transformer Oils, Synthetic Lubricants, Light Liquid Paraffin &
Petroleum Jelly
Brief self-introduction: " A post-graduate in Chemistry with 27 years of
experience in the Lubricant business. He has worked in various Technical and
Operations roles in Gulf Oil, Houghton, Shell, and Gulf Petroleum before
joining GOC Petrochemicals to lead as CEO in 2018. Apart from mainstream
Automotive and Industrial Lubricants, his area of expertise is Metal Working
Fluids."
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