regulatory concerns:
health & safety
environment
other concerns:
compatibility
ensuring compatibility
machining performance
mist suppressants
Related pages:
Health issues
Environment
Glossary term:
compatibility
health and safety
environmental characteristics
disposal of MRF
chips and filter media
| Compatibility: |
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| Fluids must
be compatible with |
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| production
parts and machines |
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| process
chemicals |
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| fluid pumps
and delivery system |
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| other
fluids |
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Assuring
compatibility |
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| non-tacky
residue |
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| corrosion
protection
oils should be non-emulsifiable
galvanic cells
system components
filtration equipment
waste treatment
possible combinations of fluids and greases need to be evaluated
Performance
characteristics
machining
MRF characteristics
Mist suppressants |
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| The National Center for Manufacturing Sciences’ Metalworking
Fluids Optimization Guide (NCMS Guide) describes many criteria that may be used
to select one or more fluids for your operations. The NCMS Guide groups the
criteria into categories to assist with the selection process and contains an example of a
MRF selection process. |
| You should establish a process for selecting a MRF. The NCMS Guide includes
an example of a MRF selection process that includes evaluation of these groups of criteria
in this order: |
Regulatory concerns
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operator acceptability
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toxicity
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misting and handling
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disposability
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recyclability
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biodegradability
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| MRF compatibility and performance characteristics |
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 | compatibility with equipment and parts |
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corrosion inhibition and cleanability
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filterability
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| physical characteristics of the MRF |
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| Each fluid class and various products within each class offer the user
different health and safety, environmental, compatibility and performance characteristics;
often, the selection process requires trade-offs of some characteristics for other, more
desirable, characteristics. |
| What are the health
and safety characteristics that influence fluid selection? |
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| toxicity of the fluid components individually, as well as the toxicity of the fluid
mixture (see toxicity references). |
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| flammability of the fluid (important for straight oils) |
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| aerosol (mist) generating potential of the
fluid |
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| physical characteristics of the fluid, such as corrosive properties |
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| What are the environmental characteristics that influence
fluid selection? |
| You may want to select fluids based partly on the properties of the fluid
concentrate and on the ease of fluid disposal. The U.S. EPA regulates emissions and
disposal under the Clean Air Act, the Clean Water Act, and the Resource Conservation and
Recovery Act. Additionally, some states may have requirements that exceed the federal
requirements. While it is well beyond the scope of this Guide to fully explain these
complicated regulatory requirements, additional information or considerations can be found
in Environment. For more detailed information
on volatile organic compounds
(VOC) in metal removal fluid, follow the above hyperlink. |
When disposing of metal removal fluids, remember that many components contribute to the
biological or chemical oxygen demand of the waste stream. Also, fluid contaminants, such
as tramp oil and dissolved metals, accumulate and add to disposal problems. When used
fluids are to be disposed of, you are required to consider both the fluid components and
the contaminants in order to meet environmental regulations. Used metal removal fluids are
only one component of a facility’s total waste stream, often only a secondary
component. Waste treatment of the fluid must be compatible with the treatment of the
combined stream.
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| Additionally, you must consider the disposal, recycling, or recovery of
generated chips and filter media. |
What does compatibility
entail?
| Compatible materials are those that will not react with each other to
neutralize or alter desired chemicals or create unwanted chemicals or conditions. |
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| Production parts and machines: Select fluids with appropriate
compatibility with the parts being machined, ground or lapped and with the machine tool,
understanding the MRF processing conditions employed. For example, machined parts that are
temporarily stored may require improved corrosion protection from the MRF. Protection of
brass or copper, either as a part being machined or as a component of the machine tool,
may be important. The residue characteristics of a MRF may be an important consideration
for machine tools with electronic sensing instruments. |
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| Process chemicals that are likely to be added to the MRF should be
screened for compatibility. MRF’s are designed to leave a
protective film on the part. There have been instances where part cleaners and MRF
interacted and caused downstream staining problems with non-ferrous materials. |
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| Fluid filter material, fluid pumps, and MRF delivery systems: These
must be compatible with the MRF. |
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| Other fluids: Possible combinations of MRFs, biocides,
additives, machine cleaners, floor soaps, hydraulic oils, way lubricants, seal greases,
machine paint, rust proofing agents, and carry-over materials should be evaluated. |
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| Make use of commercially available tests to determine the compatibility
with other fluids in your system. Also, consult with your fluid manufacturer. |
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How can compatibility be assured?
| To assure the highest level of compatibility, the following factors
should be considered: |
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| After the water has evaporated from the MRF, the residue should be non-tacky. This
residue should be easily dispersed by the lubricants used on the machine tools. |
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| The MRF should be capable of providing deep-hole corrosion protection and stability in
the presence of chemical or biological contaminants. |
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| In most cases, lubricating oils and way lubricants used in machine tools should be
non-emulsifiable in dilute MRF. Lubricating oils and hydraulic fluids should readily and
completely separate from dilute MRF, even after severe mechanical mixing. However, it is
impossible to achieve this with soluble oil MRFs, which contain emulsifiers in their
formulation. And sometimes, emulsified tramp oil is necessary to the performance of the
process. |
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| Users should be aware of the possible creation of galvanic cells where non-ferrous
metals, such as copper, aluminum or zinc, come into contact with MRFs. Users may select an
MRF that contains "yellow metal" or bimetallic corrosion inhibitors when
machining copper, brass or aluminum material. |
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| Compatibility tests of MRF should extend to all system components that may be exposed to
it, such as valve seats, elastomers, seal materials, and pump housings. |
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| All products used in MRF should be tested to ensure that they function effectively with
the particular MRF filtration equipment in use. (See "Filtration Systems.") |
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| All products should be tested to ensure that they do not interfere with the waste
treatment process in use at a particular site. |
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| Possible combinations of MRFs, biocides, additives, machine cleaners, floor
soaps,hydraulic oils, way lubricants, seal greases, machine paint, rustproofing agents and
materials carried over from previous processes should be evaluated.
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What aspects of performance
should be considered in selecting a fluid?
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Select MRFs that offer the desired performance, including tool life, surface finish,
finished part integrity and dimensional control, cycle time, chip formation
characteristics, power usage and grinding ratio ("G" ratio). The level of
performance depends on fluid composition, discussed earlier, as well as the
characteristics of the material being machined or ground and the machining or grinding
process itself.
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| Physical characteristics of the MRF |
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Select MRFs with the desired physical characteristics, such as ease of mixing,
stability, ability to absorb or reject tramp oil (whichever is preferred for the process)
and level of foam (if any) generated by the metal removal process. Some water-miscible
MRFs are more sensitive to water quality than others. Users should understand that some of
these physical characteristics might change as the fluid ages. Consult the MRF
manufacturer for specific recommendations.
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Will mist suppressants help reduce plant mist levels?
Fine mists are produced when MRF streams break up during use. This occurs when the
fluid is applied and interacts with the spinning tools or parts. Small mist droplets are
easily suspended in air and can escape containment or collection. Mist suppressants work
at the source, enlarging the size of the mist droplets so that they do not stay suspended
in air as long. The use of mist suppressants may also reduce fluid loss and vapor
generation. Mist suppressants should be carefully evaluated to ensure their effectiveness
and effective lifetime. See additional information on mist suppressants.
Consult with your supplier regarding mist suppressants. |
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Contact Chris Roman, 