Transcript Metal Cutting Fluids Why do we need them?

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
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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
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F
R
A
C
T
O
M
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T
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A
D
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G
B
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Hocut B60
10 .0
8 .0
6 .0
4 .0
2 .0
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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
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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.