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Metal Cutting Fluids Why do we need them? • Cooling • Lubrication Also provides:• Swarf Flushing • Corrosion Protection Metalworking Fluids Basic Principles of Metal CuttingFluids ; What they are & how to use them correctly What are neat cutting oils? The performance of a neat cutting oil is influenced by 3 factors:- » Viscosity » Additives » Levels of additives Viscosity Viscosity (at specific temperature) Measured in centistokes (cSt @ 40c) Range from 5 to 40 cSt Water = 1cSt Hydraulic = 32cSt Effects of viscosity Cooling & Swarf Flushing Lubricity Viscosity Viscosity Lubricity additives • Base Mineral Oils Highly refined oils of high, medium or low viscosity • Esters Natural fats Vegetable oils Synthetic esters Lubricity additives • Anti-wear additives Typically phosphorous compounds or ZDDP • E.P. (extreme pressure ) additives Chlorinated paraffins Sulphur Usually sulphurised esters or polysulphides Neat Oils vs Soluble Coolants Cooling Neat Oils Soluble Coolants Lubrication What are coolants? Lubricity Additives Add to water Emulsifiers & detergents Corrosion Inhibitors BioProtection HOCUT ? Metalworking coolant or emulsion Oil in water emulsion Coolant jargon • • • • • Conventional soluble oil Semi-synthetic Synthetic Extreme pressure Biostable Factors affecting Coolant life Micro-Organisms Tramp oil Water Quality System Design People Micro-Organisms ( typically bacteria / fungi) Results in:Bad smells Coolant separation Corrosion Increased disposal costs Common Types Of Micro -Organisms • Aerobic bacteria -live in the presence of air Anaerobic bacteria -live in the absence of air(bad eggs) • Yeasts/ Moulds /Fungi -visible organism (rubber-like) Tramp Oil Oil from positive lubrication & leaks Often resulting in:• Bacteria attack • Coolant separation • Smoke and fume • High disposal cost Water Quality The presence of inorganic salts in coolant make up water will affect:Coolant stability Foaming Water Quality Ideal Water Low salts Excessive foaming Hardness = 100-200ppm. Chloride zero Sulphate zero High salts Soap formation Coolant instability Corrosion Bacterial attack Water hardness expressed as ppm. (parts per million ) as calcium carbonate. Coolant mixing Always add oil to water(use a mixing valve if possible) Always mix coolant before adding to the coolant sump Monitoring & control Always maintain concentration between specified limits. Monitoring & control If concentration becomes too high. – Possible. skin irritation – Expensive (product waste) – Foaming Monitoring & control If concentration becomes too low. • Bacterial attack • Corrosion • Increased disposal • Expensive Monitoring and control How is concentration measured? Refractometer Titration Instrumentation --- on-site --- on-site / lab. --- lab. Fluid Concentration Chart 12 .0 R E F R A C T O M E T E R R E A D I N G B R I X Hocut B60 10 .0 8 .0 6 .0 4 .0 2 .0 .0 0 1 2 3 4 5 6 7 8 FLUID CONCENTRATION (%) 9 10 How is Condition Measured? pH readings 4.5 5.0 5.5 6.0 acidic 6.5 7.0 neutral 7.5 8.0 8.5 9.0 9.5 alkaline soluble oils favours bacterial growth acceptable to skin good corrosion protection 10.0 Monitoring corrosion protection • IP 125 Steel swarf on a cast iron plate. (overnight test) • IP 287 Cast iron swarf on a filter paper. (2 hour test ) Soluble Oil Trials Machine Cleaning Antisep Biocidal Cleaner (A.B.C.) kills bacteria & dissolves dirt to ensure the new coolant has a good start. – 2-4% A.B.C. circulated with coolant for 24/48 hours – Empty & rinse – Refill with pre-mixed coolant at correct conc. Health and safety Skincare • • • • • • Handling concentrates Concentration control Hygiene Proper use of skin creams Good housekeeping HSE guide to metalworking Environmental & H&S Issues There is an increasing demand for products that are ‘FREE’- from e.g.:»Nitrite-free »Chlorine-free »PCA -free »Phenol-free »DEA-free Environmental & H&S Issues • Nitrite Can react with amines to form ‘nitrosamines’ (carcinogenic). • DEA -diethanolamine Can react with nitrogen from the air to form ‘nitrosamines. Nitrite/DEA in fluids is a health and safety issue, not environmental Environmental & H&S Issues • Chlorine Disposal by burning can form dioxin, a carcinogen Special incinerators needed for safe disposal Disposal cost is very high in Europe Chlorine is an environmental issue, not health and safety FLUIDCARE SERVICES Health risks and MWF mists HSE are demanding that metalworking fluids users should clearly demonstrate that they take every practicable step to control fluids, improve their condition and reduce exposure. More…………… Preventing respiratory diseases and metalworking fluids ScandMist air filtration equipment We recognise that the new guidance on health risks especially regarding asthma and respiratory diseases will pose problems for users. We offer a package of services aimed at helping customers identify the risks and effective measures of prevention and control. • Risk assessment • Fluids testing and bio-audits • Exposure monitoring • Atmosphere control New Scandmist air filtration products are also available to remove both mist and bacteria from machine enclosures. Click on the download to learn more about the issues and to see Houghton products and services. Visit www.hse.gov.uk/metalworking for further information.