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Benefits of Filtering Coolant

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Benefits of Filtering Coolant

There are many benefits of filtering machine Coolant.  Filtering machine coolant canextend the life of your machine coolant, reduce the growth of bacteria, and prevent damage to tools by filtering out particles in the coolant.  There are several benefits of Machine Coolant Filtering listed below.  For more information on the risks of unfiltered machine coolant, and ways to test your machine coolant visit our Machine Coolant Filtration Index, or visit our Machine Coolant Filter Units Section for more articles on The benefits of Filtering Coolant. 

1.  Longer machine life 

A machine that can go ten years without a problem in a clean shop, may need a major rebuild in as few as five years in a dirty shop.

Precision machines are priced from a few thousand dollars to many millions.  The life of the machine as well as the life between rebuilds, is an important economic consideration.

An inescapable fact is that all machines are sensitive to wear.  All the materials in any machine are susceptible to wear from diamond, and carbide dust as well as other particles.  No machine can entirely eliminate exposure to particles if the particles are small enough. 

Machining and grinding produce a large number of very small particles.  Chips and dust from carbide, ceramics, or cobalt/chrome alloys is different, but equally bad.  Tests show that most of these particles are under ten microns in size.  Ten-micron particles easily get under seals and work their way into bearings, slides, ball screws, bushings, ways, and hydraulic cylinders. 

Dirty machine coolant can cut the life of a machine in half. A machine can go ten years without a problem in a clean shop.  The same machine in a dirty shop can need a major rebuild in as few as five years.  Machine coolants need to be filtered for the same reason that oil in a car engine needs to be filtered.  The oils or machine coolant trap small, abrasive particles.  Unless these particles are removed, they abrade away critical surfaces. 

A large number of these particles are produced in the original operation.  If the machine coolant is not filtered, then the dirty machine coolant carries these particles back up into the work area.  As the machine coolant gets between the work piece, and the work, these particles are ground and reground.  They get finer and finer.  The finer they get the easier it is for them to get into critical spaces, and destroy machine tolerances. 

Machining creates big chips.  Everyone has some sort of program to handle big chips.  Even the worst shops shovel them out of the way when they start to bury the machine.   Unfortunately, many people think that all you need to do is to remove the big chips. 

Every big chip means lots of small chips the same way boulders are surrounded by little rocks.  It is the little chips that do the most damage. A great deal of expense is incurred by particles of tools, dust and metals that are too small to see or feel.  Probably the greatest source of unnoticed damage is the grit in machine coolant that gets sprayed on, and into machines. 

Several hundred times more damage is done by chips too little to see than is done by big chips.

2.  Longer time Between Rebuilds

3.  Less down-time

As the machine wears out, it will break down more often which means more down time. 

4.  Less equipment replacement

If equipment lasts longer then there is less need for replacement. 

5.  Faster operation

6.  Faster cycle times

7.  Fewer tool replacements

Dirty machine coolant loses its lubricity, which means it allows more heat to be generated.  In addition, dirty machine coolant also loses its ability to carry heat away from the work area.  Increased friction, increased heat, and impact with particles in dirty machine coolant all contribute to greatly increased tool wear.  The microscopic grit produced during machining is like fine sand.  You can run faster at cooler temperatures if you are using machine coolant that does not have sand in it.  Your tools will last longer if they are just cutting metal without having to work with sand, and grit in the way.  

Better quality 

9.  Measured as the smoothness of the worked surface

Parts machined with clean machine coolant typically have better surfaces than parts where the tool was scratching the surface with the grit in the machine coolant.  It also eliminates the instances where the occasional very large particle puts a big scratch on the surface. 

10.  Measured in  SPC consistency

Clean machine coolants mean the tools stay more nearly the same size for a longer period of time.  

In an operation where a drill makes fifty holes once an hour, the first hole will be a certain size.  As the drill heats up the tendency will be for the following holes to get slightly larger.  As the material heats with the drilling and then cools after the drilling, it will tend to grow during drilling, making the holes bigger and then shrink after drilling, which will shrink the holes.  At the same time wear tends to make the drill smaller. 

11.  Filtering to Produce better overall quality work

Clean machine coolant means less staining, less rust and less flash rust.  There are also instance where operators will rush work, reduce machine coolant use or eliminate machine coolant entirely, because the machine coolant stinks so badly or the coolant bothers their skin. 

12.  Reduced rework

Better work the first time means less rework. 

13.  Reduced scrap

Tighter tolerances and reduced defective parts. 

14.  Measured as tighter tolerances

Less heat, less tool wear, lower tool deflection, lower thermal expansion of the tool, and lower loss of rigidity due to heating all mean better quality. 

Greater Lubricity with clean machine coolant

15.  No burning

16.  Clean machine coolant will also help prevent problems with heating of the tools. 

Improperly managed machine coolants lose their lubricity.  Lubricity obviously reduces friction, which reduces heat, which can reduce or eliminate the possibility of burning.

17.  Less heat during machining, therefore, less change in surface condition

Some materials are more heat sensitive than others are.  During machining there can be a skin effect created where the skin of the part is different than the underlying material. This can come about in two ways.  The first way is similar to heat-treating.   The heat of machining causes a difference in the surface.  The second way is similar work hardening.  Classically as material was hammered it changed consistency.  As material is cut in drilling, milling, turning or other operations the surface can be changed.  Sometimes this is desirable and sometimes not.  In either case, it is something that should be controlled.

18.  Smoother cuts and grinds

Greater lubricity means less tool drag and tool grab during machining and greatly helps to reduce chatter. 

Reduced consumable costs

19.  Longer tool run life per sharpening

20.  Longer tool Life

21.  Longer machine coolant life

Properly managed machine coolant can be used for months and sometimes years. Clean machine coolant lasts much longer than dirty machine coolant.  A good machine shop will get six months to a year out of its machine coolant.  This is a big saving on machine coolant for most shops and an even bigger saving on labor.  We have seen a grinding shop go from a machine coolant change every three weeks to a machine coolant change every six months for an improvement of eight to one.   This shop bought six thousand dollars of our filter systems and saved ten thousand dollars the first year. 

22.  Longer grinding wheel life

23.  Less dressing required

The oils and greases in dirty machine coolants clog grinding wheels and dull tools, which means they wear out faster.   Dirty machine coolant is a slurry of metallic sand.  A sharp tool that is run in clean machine coolant will stay sharper longer than the same tool that is run in a slurry of machine coolant and metallic sand.  Tools of any kind wear faster if there is abrasive in the machine coolant.   Even fine abrasive such as the low micron range will wear a tool out faster.  The longer a tool stays sharp the longer it will be between replacements and sharpening or dressing.  Dressing and sharpening wear tools out so the more you can cut with the fewer sharpenings or dressings the better off you are. 

24.  More parts per dollar of raw material

Less scrap, tighter tolerances and reduced tool breakage all reduce scrap and rework. 

Reduced Labor

25.  Less machine maintenance

Machines run better; longer so there are fewer breakdowns.  They stay cleaner so there is less cleaning.  Properly managed machine coolant dramatically reduces the need for machine coolant changes and sump cleaning. 

26.  Less tool maintenance

The tools stay sharper, longer. 

27.  Finishing operations can be reduced or eliminated

Better finishes off the machine, mean less post machining work.

In a dirty shop the machines will go bad faster.  Then what will happen is that the machine will get sloppier. It will perform work to looser tolerances.  Looser tolerances mean uneven work so the tool will dull faster and the tool will be more likely to chip or break.  Sloppy machines are also more likely to produce poor quality parts that need more finishing. 

 Cleaner workplace

28.  Perhaps increased operator safety 

We are not experts, but a lot of experts think this is both true and important.  There are a million to a million and a half people in the US who are exposed to grinding and machining machine coolants.  These machine coolants and their contaminants cause skin rashes, allergic reactions, epidermal scarring, lung scarring, emphysema, severe emphysema and death. 

Top quality, trained, healthy employees are valuable assets to a firm.  Dr. Susan Kennedy, at the University of British Columbia has recently done industrial hygiene surveys that indicate that the problems with cobalt exposure in machine coolants are much greater than the government recognizes. 

An unfiltered sump could end up being about 25 to 30% sludge and particles.   The sludge and sharp particles hurt everybody when it gets into their lungs.  These are little sharp particles that do physical damage. 

There is also a problem with dissolved cobalt.  It causes hard metal disease.  (Hard metal diseases are different from heavy metal diseases although both are often linked to industrial practices.).  According to Ed Chessor of the British Columbia Workers’ Compensation Board, about 1 or 2 % of the population is particularly susceptible to cobalt.  They are in much greater danger than the average person is.  This is somewhat similar to the fact that some people are much more susceptible to damage from bee stings.  

Filtering grinding machine coolant makes the workplace safer.  It does not make the workplace safe.  Every workplace is different and you need to have individual assessments done to adequately ensure worker safety. 

The safety and health issues are incredibly important and very complex.   If you have any concerns you should call in a consultant from the government or a private consultant to do a thorough analysis. 

29.  Slows bacteria growth

Proper machine coolant management removes bacteria before they grow much, removes the places where they like to grow, maintains the chemistry of the machine coolant so it is harder for them to grow and removes the materials bacteria like to eat.

Bacteria grow in dirty sumps for two reasons.  The sludge is an excellent place for it to grow.  Tramp oils seal off the machine coolant and keep air out of it.  Filtering machine coolant prevents bacteria growth by removing the sludge where bacteria grow.  Filtering also removes tramp oils, which create an anaerobic environment as well as providing food for the bacteria. 

30.  Eliminate smells

Machine coolant stinks because it has bacteria in it that eat the oil and grease.  The bad smell is waste material from the bacteria.  Bacteria are in the air so you cannot keep them out of the sump completely.  The bacteria that create the worst smell are anaerobic, which is from the Greek meaning "without air". They grow best under water without air.  Filtering keeps the machine coolant stirred up and keeps mixing air in.  This keeps oxygen in the machine coolant and further prevents bacteria growth. 

31.  Help eliminate noise

If you keep grit out, lubricity up, and if your tools and machines are in good shape you are much more likely to hear low hums rather than louder rasping. 

Fewer problems than shops that use dirty machine coolants.

32.  Less OSHA exposure

OSHA likes clean workplaces.  OSHA also likes businesses that are making serious, successful efforts to provide good workplaces. 

33.  Less EPA exposure

34.  Less waste

35.  Cleaner waste

36.  Lower machine coolant disposal or recycling costs

37.  Reduces non-machine coolant waste and waste disposal costs

The use of cutting, grinding and machining fluids results in the estimated creation of well over ten million gallons of waste annually. 

38.  Turn an expense into income

One of the major expenses of the private sector firms is the cost of disposing of used grinding machine coolant.  Most firms were having it hauled away as hazardous waste.  They voluntarily had the waste classified as hazardous because it was the safest course.  One of these companies had been involved in Superfund clean up that cost them about $50,000.  This was a company that did about $700,000 a year in sales at the time.  The clean up took all the cash reserve and created a debt load that took three years to pay.  They were most eager to avoid any new environmental trouble. 

The use of cutting, grinding and machining fluids results in the estimated creation of well over ten million gallons of waste annually.

Filtering takes out the solid waste.  The waste from grinding carbide tools can be dried and sold for $0.10 to $0.15 per pound.

A shop can easily have 500 gallons of used machine coolant that is disposed of as hazardous waste.   Separation and evaporation can reduce this to a salable product and leave only 50 gallons of hazardous waste.  This is a considerable financial saving for the business.  It also reduces hazardous waste, which is a good thing for society in general.  .

Most companies are spending a lot more money on machine coolant management than they should.  In many cases the machine coolant is used three weeks and then hauled away as a hazardous waste at $300 a barrel.  In other cases a similar operation will use machine coolant six weeks or more.  When it is dirty it is separated and hauled away to be recycled at $75 to $90 a barrel.

If machine coolant is not handled properly the business can face a one-time fine of up to $25,000 for having hazardous waste without a license.  The company can face fines of up to $10,000 a day until the problem is resolved.  The EPA has also started looking for executives to send to jail for waste handling violations.