LUBRICANT andCOOL ANT FLUIDS

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THE ULTIMATE LUBRICANTS AND ADDITIVES

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TABLE OF CONTENTS

PAGE----------------------------------------------------------------------------------------------------------------------------------------------------------------01 IntroductIon 4

02 FunctIons oF coolAnts For cuttInG And GrIndInG 4

03 clAssIFIcAtIon oF mEtAlworkInG FluIds 5

04 ProPErtIEs oF mEtAlworkInG FluIds 7

05 oPErAtIonAl concEntrAtIon oF mEtAlworkInG FluIds 9

06 notE on comPosItIon oF mEtAlworkInG FluIds 9

07 wAtEr quAlIty 10

08 PrActIcAl tIPs For thE usE oF mEtAlworkInG FluIds 12

09 PrEPArAtIon, mAIntEnAncE And clEAnInG oF thE mEtAlworkInG FluId tAnk wIth "synEco dEtErwAsh" And "synEco dPG" sErIEs 13

10 PrEPArAtIon oF thE coolAnt 13

11 contAmInAtIon oF thE FluId In sErVIcE 14

12 BEhAVIour oF thE FluId In sErVIcE 15

13 chArActErIstIcs oF mAtErIAls In sErVIcE And tools 18

14 sErVIcE synEco chEck uP - sErVIcE synEco tEst 22

15 dIsPosAl oF ExhAust FluIds 22

16 BIodEGrAdABIlIty oF "Flr" 23

17 "Flrs" By synEco 24

18 AuxIlIAry EquIPmEnt: rEFrActomEtEr, ProPortIonInG dEVIcE, BElt oIl skImmEr, Ph mEtEr 25

19 clAssIFIcAtIon Iso 6743/7 FAmIly: mh , mA For cuttInG oIls 25

20 dIstrIButIon oF thE Product cAtEGorIEs oF FAmIly "m" In AccordAncE wIth thE APPlIcAtIon rAnGE. 27

21 BElt oIl skImmEr

22 ProPortIonInG dEVIcE 29

23 othEr synEco Products AFtEr cuttInG oPErAtIon 31

24 BIBlIoGrAPhy 31

Note on fluids for cutting and grinding

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01 - INTRODUCTION TO METALWORKING FLUIDS

since their first appearance, in the second half of the last century, metalworking fluids have evolved conside-

rably, to meet the constantly higher needs of processing performance of metals and alloys increasingly hard or

tough, in full compliance with the rules of hygiene and safety in the workplace, which are finally getting the pro-

per consideration by the manufacturers and interest by the users.

02 - FUNCTION OF COOLANTS FOR CUTTING AND GRINDING

In order to understand and evaluate the importance of a metalworking fluid (Flr), we must begin with an analy-

sis of the mechanical processing, trying to identify those parameters that are more influenced by the physical pro-

perties and the chemical composition of the metalworking fluid.

during metal cutting, a certain amount of heat is generated by plastic deformation of the metal and phenomena of

external friction, in particular, the rubbing of the chip on the tool.

the heat thus produced has to be removed for the most part from the chip (about 80%), while the rest is distribu-

ted between the workpiece and the tool in ratios varying with the cutting speed.

the instantaneous temperature of the cutting tool may even exceed 1000° c in the processing of high-alloy steels,

if we do not provide adequate cooling, and in any case, it can stabilize at 600÷800°c.

If we are not able to limit the heat generation and to remove the generated heat, the following cases are possible:

- change in the molecular structure of the workpiece and the tool (tempering).

- deformation and cracking due to thermal stresses in the workpiece and the tool.

- thermal expansion of the workpiece, resulting in a mismatch of finished size compared to expected size.

- welding of metal machining on the tool, resulting in a profile change of the tool itself, its abnormal wear and

increased power consumption of the cutting action.

the welding of particles of the material being machined to the surfaces of the tool will have the effect of high tem-

peratures that are reached locally in some points of the tool, the workpiece and the chip, and strong cutting pres-

sures, even of 200 - 250 kg/mm2 .

In order to define briefly the function of the metalworking fluids, we can say that they must "cool and lubricate".

"cool", by removing the heat generated during processing and "lubricate" by decreasing the friction of sliding bet-

ween the tool and the workpiece and between the tool and the chip.

A necessary condition for the coolant to do its effect, is that it fits between the surfaces to be lubricated (main side

- machined surface - side of the tool - chip) and wets the surface to be cooled.

For this purpose, the following conditions are required:

- the jet or jets must be oriented so as to direct the fluid to the cutting area;

- the jet pressure must be such as to overcome the air cushion that is formed in the cutting area due to the air

entrainment by friction;

- the amount should be sufficient to remove the generated heat.

some metalworking fluids present special "anti-weld" or "EP" (Extreme Pressure) features, for their ability to com-

bine chemically, in the points of incipient welding, with the metal of the workpiece and the chip, giving rise to com-

pounds of not high hardness and low friction coefficient.

these compounds reduce the friction and consequently the development of heat and play an anti-weld action on

the metal surfaces.

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03 - CLASSIFICATION OF METALWORKING FLUIDSthe metalworking fluids can be divided into the following two categories:

3.01 - Non-miscible Coolants (non-miscible in water).

the formula involves the use of 80% -90 % of oils and antiwear additives, corrosion protection, anti-foaming addi-

tives for the rest; the base is generally paraffinic or non-toxic or synthetic, with low tendency to evaporate.

the use of oils regenerated with vacuum distillation or acid-treated or weakly solvent-refined is not recommended

due to the presence of polycyclic aromatic hydrocarbons (PAhs).

the high costs of disposal of Flrs miscible with water and the problems of isolation of electrical and electronic

equipment are re-evaluating the use of non-miscible Flrs in particular processing, such as grinding and turning,

with products formulated for long duration, for which it is appropriate to precisely control the operating tempera-

ture, in order to limit oxidation.

they are used as such, and consist mainly of some particularly refined mineral and non-toxic oils, with low noack

volatility, in which different additives can be dissolved: oils, natural or synthetic greases, EP additives containing

chlorine, sulphur, phosphor, etc.

this category includes the syneco products (dd, Auro, new Auro, hs).

the production of non-miscible cutting oils depends on individual operations, processed metals, new generation

machines characterized by high productivity.

For some years, the production of non-miscible cutting fluids has been governed by law and by customers depart-

ments for control and safety.

Particular attention is paid to the use of regenerated mineral oils, for their ability to form PcBs (polychlorinated

biphenyls), with halogenation of aromatic compounds, for the behaviour at high operating temperatures.

we briefly report the most frequently used oils:

- Chlorinated oils, with additives such as EP, chlorine-based, at a certain temperature they form solid films of

metal chlorides with metals, characterized by low friction coefficient; generally they can operate below 350° c ,

but particularly stabilized additives may exceed this value.

- Sulphur oils, also of EP type, divided into products suitable to copper (not active) and staining or active products

which, in operation, form films of metal sulphides with low friction coefficient.

- Sulphur-chlorinated oils with EP performance: they combine the properties of the two additives for operations

on metals with low machinability. while sulphur, more reactive, forms films of metal sulphides at high temperatu-

re and with low friction coefficient, such as to contain the generated heat and the temperature in the cutting area,

chlorine, with the formation of films of metal chlorides, with low friction coefficient, helps to stabilize the tempe-

rature and cools it down.

- Oil with Sodium or Calcium sulphonates: enhances the EP properties and avoids, when exhausted, problems of

disposal costs.

WHOLENOT EMULSIFIABLE WATER-BASED

EMULSIFIABLE

SYNTHETICEMULSIFIABLE AMINERAL-BASED OIL

MINERAL OIL +SOLUBLE OIL ADDITIVES

PARTIALLYSYNTHETIC

FLRs

SOLUBLE

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during the process of cutting or deformation of the workpiece, these non-reactive additives form a film adsorbing

the carbonate particles from the metal surfaces.

this film has a low shear stress and a high melting point, to allow for greater cutting speed and faster feed rates.

the reduced friction improves the surface finishing, reducing any scratches and erosions.

Free of chlorine and phosphorus, they have a synergistic action with sulphur components, being able to actually

increase the cutting performance when they are combined.

maintenance and control of oil in service are recommended and required at a certain interval: the oil characteri-

stics and the level of additives and contamination must be checked at least once a year, in order to make appro-

priate corrections.

during the machining, the heat removed from the cutting area does increase the oil temperature, if not properly

controlled, according to the various applications, and this produces the oil oxidation and a possible degradation. It

is important to eliminate the scrap that can catalyze, also in this case, the oil oxidation and an advanced reduction

of its properties and characteristics.

03.02 - Metalworking fluids to be mixed with water.Flrs miscible in water, combine the high capacity of heat dissipation intrinsic in water with the lubricant power

of the other substances contained therein. In general, they come in the form of emulsions or solutions.

the emulsion is a dispersed system, obtained from the mixture of two fluids (water and oil). the oil is the internal

phase, the one that distributes in drops in the carrier fluid or external phase (water).

the emulsifiable Flrs are divided into:

03.02.01 - Emulsifiable oil-based FLRs: consisting of mineral oil (40 to 80%), emulsifiers and oil-soluble additi-

ves. they look like a milky emulsion (the size of the oil droplets varies from 1 to 5 microns); in the choice of base

oils, mineral oils with content of paraffinic or naphthenic hydrocarbons with a low tendency to evaporate are pre-

ferred.

In this series we can find: Syneco Emulsionabile N, Emal, Argo, Argo T925, Super Argo.

03.02.02 - Emulsifiable partially synthetic FLRs: consisting of predominantly mineral oil (5 to 30%) , emulsi-

fiers (polyethylene oxides), additives soluble in water and additives soluble in oil. they look like a translucent opa-

lescent emulsion (the size of the oil droplets is less than 1 micron).

Syneco Emulsint and Emulsint K645 are partially synthetic.

03.02.02 - Solutions: these Flrs do not contain oil, but are composed basically by chemicals dissolved in water

(esters, salts, additives soluble in water).

they are mainly used in grinding processes, but can also be used for the removal of chips. they look like clear solu-

tions.

this series includes: syneco Biosint 40, 80, k185.

Among the most important additives of Flrs miscible in water we can find:

• Ionic emulsifiers (alkaline soaps, sulphonated soaps, salts of carboxylic acids, phenols, etc.);

• non-ionic emulsifiers (e.g. polyethylene oxides);

• corrosion inhibitors (alkaline salts, alkanolamines, boron compounds, nitrites, etc.);

• Polar additives (oils of animal or vegetable origin, esters of organic acids);

• E.P. Additives (chlorine, sulphur, Phosphorus)

• Biocides , disinfectants (formaldehyde, triazine derivatives, phenol derivatives, boron compounds, quaternary

ammonium liberators of formaldehyde, derivatives of heavy metals such as hg and Pb, etc. );

• Anti-wear: (tricresyl phosphate, thiosulphate and phosphates);

• Anti-fog : (generally, they are polymers that facilitate coalescence);

• stabilizers: (alcohols, glycols, etc.);

• Anti-foam: (silicones);

• Viscosity improvers: (polymers and copolymers);

• other: (dyes, fragrances, etc.).

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04 - PROPERTIES OF METALWORKING FLUIDS

A mechanic machining must obtain a finished piece that complies with the size tolerances and surface finish from

a given origin material.

the Flrs must meet, in the first place , the following requirements:

- cooling

- lubrication

- cleaning effect

- other

04.01- Cooling

the heat generated on the cutting point, in the case of machining by chip removal, must be reduced by the Flr to

ensure the compliance of the workpiece size and extend the life of the tool.

the cooling capacity of the fluid is affected by the following parameters:

- Flr type and composition

- Flr volume adducted to the cutting point per unit of time

- shape of the Flr flow and direction of adduction of the same

- temperature of Flr, in particular in case of non-miscible oil.

04.02- Lubrication

the lubrication is required to reduce the friction between the tool and the workpiece and the consumption of

energy between the workpiece and the chips.

It affects the surface finishing of the workpiece and the tool life.

the lubricant power of a Flr depends on the following parameters:

- type and composition of the Flr (EP additives, mineral oil content, miscibility in water).

- Pressure and temperature at the cutting point and operating parameters, such as cutting speed.

- characteristics of the material composing the workpiece and the tool.

04.03 - Cleaning effect

"cleaning effect" means the ability of an Flr to remove chips from the cutting point.

this is a particularly important task in case of grinding operations since, for an operation of the grinding wheel

with the minimum of friction, it must be ensured that it remains free from chips and grinding dust from abrasion

that can cause problems during processing.

the cleaning effect of an Flr depends, besides the type and composition of the same, on the quantity and the pres-

sure with which the fluid is delivered to the cutting point.

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04.04- Other

the points listed below are part of the so-called secondary needs; the list is not comprehensive:

04.04.01• Biological and physical stability of the used Flr.

04.04.02 • no compounds hazardous for the health of the operators in case of contact with the Flr .

04.04.03 • Good storage stability of the Flr where it is concentrated.

04.04.04 • Good corrosion protection.

04.04.05 • Good filterability.

04.04.06 • Good efficiency in separation from chips, metals and abrasives.

04.04.07 • Good compatibility with the materials that make up the tooling machine.

04.04.08 • Good compatibility with the skin, it does not produce any fumes, odours and mists.

04.04.09 • Pre-treatment without problems with exhausted Flr.

04.04.10 • Good wetting power.

04.04.11 • cost effective (in the preparation and operation).

In case of product mixed with water:

04.04.12 • Easy mixing in water.

04.04.13 • stability of ph.

04.04.14 • Good anti-foam behaviour, even with fresh water.

04.04.15 • Good behaviour regarding the formation of residues, even with hard water.

04.04.16 • Good resistance to contamination.

04.04.17 • Insensitivity to calcium and magnesium salts.

the fact that some of the above-listed requirements are contradictory to each other (see the wetting power and

cleaning effect in one case and the anti-foam behaviour), makes clear that the definition of a profile of needs as a

basis for the recommendation of a product, is of fundamental importance.

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05 - OPERATING CONCENTRATION OF METALWORKING FLUIDS

the manufacturer of metalworking fluids, having examined the type of machining and tooling machine and the

quality of water, shall recommend the most appropriate product and the concentration, in his opinion.

this recommended concentration must be carefully maintained in order to optimize all the variables involved in

an engineering process, and controlled by an elaeometer refractometer.

with too high a concentration, the following problems may arise:

- Foaming

- odours and skin irritation

- waste of product

conversely, with too low a concentration:

- Instability of emulsions and deposit formation

- Poor anti-rust action

- wear of tools and insufficient surface finishing

- Poor resistance to microbial contamination.

06 -NOTE ON COMPOSITION OF METALWORKING FLUIDS

In recent years, we have experienced a profound transformation from the standpoint of formulation, not only in

order to improve the performance of metalworking fluids and to better adapt them to increasingly sophisticated

machining and materials, but especially to meet precise needs of "environmental compatibility"; this means low

toxicity of the components, minimum of interference with the working environment and easy purification of

exhausted fluids.

we do not want to go into the details of formulation of various products, but only give simple information about

some common components of metalworking fluids that have recently been the subject of discussion for their effects

on the health of operators of tooling machines and work environment.

06.01- NITRITESthe nitrite and in particular, sodium nitrite, are very effective and low cost corrosion inhibitors for the ferrous

materials.

Furthermore, their toxicity is relatively low and in fact they are widely used as preservatives of meat.

these characteristics have fostered their wide use in metalworking fluids.

recently, however, it was discovered that the nitrites, in appropriate conditions, can react with secondary and ter-

tiary amines and give rise to nitrosamines, which are, in general, defined carcinogens, even if among them, some

are very dangerous and other are less.

the secondary and tertiary amines are among the most common components of metalworking fluids.

the reactions between nitrites and amines occur readily in acidic environment, as, for example, the stomach of

operators working on tooling machines, working with metalworking fluids and causing more or less extensive

nebulisation. the droplets, dispersed in the air, are easily ingested by people who are in the surrounding environ-

ment and, when in contact with the acidic gastric juice, find favourable conditions to form nitrosamines.

It was also demonstrated that nitrosamines may form also in alkaline environment, especially in microbiological

way, and therefore they may also be absorbed by the body through the skin, by simple operator's contact with the

coolant fluid.

this does not mean that a coolant containing nitrites and amines must necessarily also contain nitrosamines, but

it is clear that its use may generate the conditions necessary for their formation.

the secondary and tertiary amines are chemical compounds widely present in nature and also in the human body,

so it would make no sense to remove these products from the coolants, while it is easier to replace the nitrites with

other corrosion inhibitors.

It remains however the problem of the content of nitrites in preserved meat. with a normal diet, a person ingests

daily an amount of nitrites, in theory, more than sufficient to form dangerous quantities of nitrosamines. Also bear

in mind that in most cases there is no accumulation of nitrosamines in the body, as they can be easily degraded.

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In conclusion, although the market has not yet a clear view of the problem of nitrosamines, and therefore can't yet

draw any definitive conclusions, the market for industrial refrigeration is shifting, as a precaution, to products

without nitrites.

06.02 - PTBB ACID (para-tertiary butyl benzoic acid)this acid has been widely used in metalworking fluids, as corrosion inhibitor, in lieu of nitrites.

A few years ago, however, its mutogenic action has been demonstrated on the internal organs of guinea pigs or rab-

bits, and therefore its use is now strongly discouraged. the major Italian engineering industries, users of metal-

working fluids, expressly require that PtBB acid is removed from formulations.

06.03- MINERAL OIL the mineral oil, obtained by distillation and refining of oil, is the most common component of non-miscible, emul-

sifiable and semi-synthetic metalworking fluids. Its composition is not well defined, because it is constituted by a

large variety of paraffinic, naphthenic and aromatic hydrocarbons, different in quantity and quality, according to

the origin of crude oil, the distillation cut and the type of refining. According to the prevalence of the different

types of hydrocarbon, the mineral oil is called "paraffinic" or "naphthenic". It would be more correct to call them

"predominantly paraffinic" or "predominantly naphthenic" because, in any case, they contain quantities, albeit

limited, of paraffinic, naphthenic and aromatic hydrocarbons.

From the point of view of environmental protection and health, it is very important to establish the content of

polycyclic aromatic hydrocarbons (PAh) in a mineral oil. these are hydrocarbons with four or five condensed aro-

matic rings, the best known of which is benzopyrene, and they are carcinogenic.

the set maximum PAh tolerable concentration is equal to 0.03%. this obviously affects more immediately non-

miscible cutting oils, which are used without dilution and are constituted, on average, 90% of mineral oil.

PAhs can be removed by refining the mineral oil.

the acid conventional refining, still applied to many naphthenic oils, does not eliminate the PAhs appreciably and

therefore these oils tend to be progressively discarded from the market.

the solvent refining, already applied to paraffinic oils, ensures instead the almost total elimination of PAhs.

For non-miscible cutting oils, it is therefore preferable to the use solvent-refined paraffinic oils.

For fluids to be mixed with water, the replacement of naphthenic oils with paraffinic oils is not so simple, because

the latter, due to their structure, are more difficult to emulsify. thus, it is necessary to reformulate the products,

by enhancing emulsifiers, obtaining fluids acceptable from the point of view of application, but at higher costs.

Another possibility is given by naphthenic oils refined by hydrogenation, a process that significantly reduces the

PAhs.

Bear also in mind that, for their use, the aqueous metalworking fluids are diluted about 20 times; thus, the risk ari-

sing from PAhs is significantly reduced as their concentration is well within the limits stated above.

06.04- BACTERICIDESthe aqueous mixtures of metalworking fluids, in operating conditions, could be contaminated by microorganisms

that, once entered the fluid, find the right environment to their proliferation.

the origin of these microorganisms can be manifold: from the ambient air, finished parts, hands of the operators,

waste that are thrown recklessly in the tanks of the tooling machines.

For the proliferation of these germs, the presence of water is necessary; the use of normal concentrations of metal-

working fluids (1-10 %) create ideal conditions for their development. At higher concentrations, generally, the sub-

stances in the coolant play an inhibitory action. therefore, the concentrated products may be considered sterile.

not all of the microorganisms that enter in a coolant survive; indeed, it has been experimentally established that

the majority of pathogenic germs fails to develop and disappears in a short time.

Except for some rare cases, it can be said that the possible harmfulness of coolants on the human body is of che-

mical-physical nature (alkalinity, detergents, etc.) and not microbiological.

microorganisms live and develop feeding with the constituents of the coolant and therefore their proliferation is

always accompanied by the degradation of the fluid and by the decay of its characteristic properties (corrosion,

separation, formation of deposits, foam, bad odour).

In order to limit the microbial contamination in metalworking fluids, first all the common standards of personal

and environmental hygiene must be implemented, preventing the fluids in operation become receptacle of garba-

ge in the workshop.

In addition, to effectively combat and prevent the proliferation of microorganisms, there are two possibilities: to

formulate products with poorly biodegradable raw materials, so as not to provide food to these microorganisms, or

to use biocides, both introducing them in the formula of the concentrate, and adding them to the fluid in operation.

the first method tends to "non-biodegradable" products.

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A few years ago, the trend was "biodegradable" products, when the meaning of this term, and especially the laws

regulating industrial waste, were not clear yet.

the term "biodegradable" meant a product that could be released, after use, without any treatment, in the sewage

or, even worst, in surface waters.

when it has been understood that even "biodegradable" products had to be treated before disposal and that, on the

other hand, just by definition, they were produced without any resistance to microbial contamination, they have

been completely abandoned.

the second possibility involves the addition of biocides to kill the microorganisms and prevent their development.

the use of these substances involves certain risks and therefore biocide products should be accurately dispensed

and their misuse shall be avoided.

too low doses have little effectiveness and indeed, for the phenomenon of habituation, they can create strains resi-

stant to that kind of treatment.

on the other hand, an excessive dose of biocide provides sterilization to the fluid, but can cause damage to the body

of operators who are in contact with it.

For the use of biocides therefore, the advice of the suppliers of metalworking fluids must be followed, both for the

choice of the type and quantity.

If the biocide is entered in the concentrated coolant, also in this case, the user is not relieved of the responsibility

of the dose: in fact, the concentration of biocide is directly proportional to the concentration of product mixed with

water.

the accuracy of the dose is obtained, in this case, with the accuracy in maintaining a correct concentration of

coolant.

the most commonly used biocides belong to very different chemical classes. Among the best known biocides we

can list: phenolic derivatives, formaldehyde donors, isothiazole derivatives, pyridine derivatives.

the properties required to a biocide are: broad-spectrum efficiency (bacteria, yeasts, fungi), low toxicity to the

human body, at least at the concentrations of use, and easy disposal, i.e. compatibility with various treatment

systems of exhausted fluids.

In particular, in recent times, the use of phenol derivatives has been objected, because they are too toxic and becau-

se they are incompatible with some purification systems.

this is true up to a certain point: there are compounds, such as o-phenylphenol, which have low toxicity and are

easily degraded by biological way, in diluted solutions.

however, other compounds such as chlorophenoles ( in particular pentachlorophenol), have high toxicity and are

rightly banned from modern formulations.

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07- WATER QUALITY

water quality is of the utmost importance for a correct use of metalworking fluids.

the duration of an emulsion, filter efficiency, formation of foam and also the tool life are directly influenced by the

quality of the water.

therefore, it is essential that the water used to dilute the metalworking fluid is carefully analyzed in order to deter-

mine the type of metalworking fluid and operating conditions that are best suited to its characteristics.

rainwater is soft and devoid of minerals.

the water of the rivers and lakes can have a very different salt content, depending on the amount of dissolved

minerals. the well water is generally very rich in dissolved salts.

the salts dissolved in the water can cause corrosion of tooling machines and workpieces, can promote the forma-

tion of deposits on machines and filters, and can also affect the growth rate of microorganisms.

the main property of water affecting the metalworking fluids is the hardness.

the hardness of water is essentially due to the presence of soluble salts of calcium and magnesium and is expres-

sed in different units of measurement; the most commonly used are:

°d German degree = mg of calcium oxide / kg. water

°F French degree = g of calcium carbonate /100 kgs of water

the conversion between the two units is:

1 d = 1.78 ° F

In Italy, the hardness of water is normally expressed in French degrees.

with hard water, emulsions are more unstable and show a greater probability of formation of deposits and a more

difficult corrosion control.

In this case, therefore, in order to achieve the correct performance with the same metalworking fluid, it is advi-

sable to operate at concentrations higher than normal (a few percent).

with fresh water, a big problem may be the formation of foam. In this case, use lower concentrations of metalwor-

king fluid.

In addition to calcium and magnesium, other elements may have the same negative effects on cutting fluids: iron,

aluminium and zinc, although less frequent, may occasionally cause serious problems.

other salts are directly responsible for the corrosion of ferrous materials. In particular, with waters rich in chlo-

rides and sulphates it is much more difficult to have a good corrosion control.

Even in this case, use lower concentrations of metalworking fluid.

08 - PRACTICAL TIPS FOR THE USE OF METALWORKING FLUIDS

As a result of the topics examined in this article, follow the tips below to optimize the use of metalworking fluids:

08.01- keep the concentrated products in their original packages, in covered warehouses, avoiding extreme

temperatures (<0 - > 35 ° c). use the product within one year from delivery.

08.02 - maintain full cleaning of tooling machines and work area, preventing contamination of fluids with any

type of waste.

08.03 - maintain full personal hygiene.

08.04 - maintain proper concentration. the use of automatic mixers is recommended. If the dilution of the metal

working fluid is manual, pour the product into the water and never vice-versa .

According to the type of operation and machined material, the concentration of the product in the

machine can be enriched or impoverished and therefore, to maintain the operational concentration

constant, it is necessary to vary the refilling concentration. Periodically check the actual concentration

in the tank by refractometer.

08.05 - keep the maximum fluid level in the tank of the tooling machine. Its volume has been calculated according

to the requirements of processing, the pump flow rate, etc.

too low a level can result in poor settling of the scraps and foam, due to air suction by pumps.

08.06 - In the fluid, during operation, avoid an excessive accumulation of lubricating oils, possibly removing them

by touch, after a machine stop.

the belt oil skimmer proposed by syneco is recommended.

08.07 - Avoid uncontrolled use of additives and bactericides.

08.08 - Ensure constant aeration of the fluid at a temperature of around 20° c.

the emulsion collection tank must be kept covered and the charge should be maintained in circulation.

In case of shutdown for a weekend or for long periods of time, adjust the air insufflation.

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09 - PREPARATION, MAINTENANCE AND CLEANING OF THE FLR TANK

In order to maintain the emulsion and prevent the proliferation of anaerobic bacteria, it is good to clean the tanks

at regular intervals.

to do this, after checking the main indicators of the state of the emulsion with Syneco CHECK-UP, (ph , bacterial

count), use Syneco Deter Wash directly in the tank, at a concentration of 15/20% in volume, for 6/8 hours and

then dispose the exhausted emulsion.

then, clean with water to remove residues of the treatment. At the end, proceed with filling the tank with fresh

emulsion.

the treatment of the Flr charge for the necessary control of microorganisms is intended to contain bacteria (of

varied origins), fungi and yeasts, the latter present in very damp environments.

the available bactericides are:

- Syneco G 25 for fungi and yeasts;

- Syneco DPG 50 and DPG 75 for bacteria with different spectrum of action;

to be used according to the suggestion of Service Syneco CHECK-UP, in the right dose according to surveys car-

ried out on the Flr sample.

the limit of bacterial concentration, not to be exceeded, is 106 bacteria per ml of solution. A tolerable level of con-

tamination is 102 ÷ 103 bacteria per ml.

to maintain this level of contamination, we recommend the use of DPG25, DPG 50 and DPG 75, different biocides,

to be used alternately to lower the risk of formation of bacterial strains resistant to a particular biocidal product.

In case of presence of fungi and yeasts, DPG 25, high efficiency fungicide has to be used, as it is capable of pre-

venting the formation of colonies of fungi and the consequent difficulties of filtration, clogging of the nozzles and

pipes.

to maintain a good level of prevention of fermentative phenomena, a comprehensive check is recommended, at

least quarterly, of the emulsion (ph, bacterial count, separated oil).

the check will be performed according to the criteria of Service Syneco CHECK-UP: using the appropriate con-

tainers, the syneco dealer will send a sample of emulsion in use to our Analysis laboratory, taking care to indica-

te all the data necessary for the identification of the customer and the machine on the label.

10 - PREPARATION OF THE COOLANT

the Flr and the water should be mixed in a clean, separate, not galvanized container. Proceed so that the Flr is

pumped (poured) in the established quantity of water, in a thin stream and under constant stirring. Alternatively,

use the Flr dispensing devices available on the market.

Volumetric dispensers are considered the best.

during the product preparation, take into account the following factors:

• water temperature: ideal between 10 and 20 ° c

• water ph: ideal between 6 and 8 (a lower ph value may compromise the effectiveness of the anti-corrosion emul-

sion)

• water hardness > 15 ° F <35 ° F (recommended).

the following are some rules that should be followed in preparation of the emulsion:

10.01- Always add oil to water and never vice-versa. If water is added to oil or if the amount of water is too low, oil

is dispersed in water with the consequent formation of a creamy substance. this substance, called inverted emul-

sion, can't be changed. therefore, the amount of water must be at least three times (preferably six or seven) higher

than that of the oil.

10.02 - stir vigorously while you add the oil and continue to stir well after adding. too soft stirring or too rapid

addition of the oil can cause the formation of an inverted emulsion, since the local concentration of the oil, while it

is being poured, can become too high. too soft or short stirring does not provide the mechanical force necessary to

obtain an emulsion of high quality.

10.03 - the oil should be at room temperature. the lower is the viscosity of the emulsifiable oil, the easier is its sub-

division into tiny globules. If the oil is too cold or too viscous, the emulsion is of poor quality.

After preparing the emulsion, add water to adjust the concentration.

As a result of the regular checks, add new emulsion to the system to increase the concentration of the oil. It's a bad

practice to add pure emulsifiable oil into the tank of the machine of the centralized system.

the only flow of the fluid in the circuit is likely not to ensure a sufficient mixing.

14

small quantities of emulsions, up to 100 litres, can be prepared by stirring manually.

For larger quantities, use motor-driven stirrers, although it would be preferable to the use ejectors, which repre-

sent an efficient system of emulsification.

the equipment used for the preparation of the emulsions must always be clean; contaminants can react with the

emulsifier and compromising its properties. It is also preferable to use tap water, since water drawn from other

sources may contain substances harmful to the emulsifier.

Precautions: the use of proportioning device is recommended (explained further on page 29).

11 - CONTAMINATION OF COOLANTS

the contamination of water-based fluids is caused by several factors, which must be properly eliminated or con-

trolled.

11.01 - contamination with solids.

solid substances, such as metal particles and grinding dust, can be directly harmful to water-based fluids, since

the just cut metal favours the oxidative degradation of the oil. the small size particles, suspended in the emul-

sion, tend to agglomerate, resulting in the formation of deposits difficult to be removed; if these residues undergo

a bacterial attack, the fluid and the residues must be removed and subsequently the disinfection of the entire

system is required. the equipment containing the Flrs should be kept clean by means of continuous filtration.

11.02 - contamination with lubricant oil. need for de-oiling.

Additives in the lubricant for tooling machines (guides, hydraulics, spindles) can react with the emulsifier and

cause the emulsion breaking or reacting with the salts of synthetic fluids and form deposits.

Furthermore, the oil been separated from the emulsion, or the casting oil, prevent aeration and promote bacte-

rial attack to both emulsions and synthetic fluids for cutting, with reference to summary in table A (p.17).

11.03 - contamination with organic waste.

organic waste, such as pieces of food containers, cigarette butts and fruit peels contain bacteria, fungi as well as

hand perspiration and saliva. these contaminants are the most common causes of bacterial spoilage of all water-

based fluids. Good cleaning is essential to keep tight control of bacterial growth.

11.04 - Bacterial contamination

Bacteria and fungi feed from emulgator on the water-oil separation surface.

then the emulsion must be discharged and the system disinfected. In the emulsions, two different types of bacte-

ria can be found:

• Aerobic : requiring oxygen to be active

• Anaerobic : active only in absence of oxygen

the latter are particularly dangerous because they give rise to corrosive compounds that give the emulsion a

bluish gray colour and give off a very bad odour, also known as the "smell of monday morning". to reduce the

negative effects caused by bacteria, the emulsions should be kept constantly in circulation, so as to ensure aera-

tion; although aeration stimulates the activity of aerobic bacteria, it prevents one of the most dangerous anaero-

bic bacteria, which cause the break of the emulsion and the bad smell.

It has been observed that the bacterial activity (both aerobic and anaerobic) fails to deteriorate emulsions prepa-

red with distilled water. unfortunately, in distilled or softened water (7-15 ° F), the amount of foam formed by

the Flrs becomes intolerable and it is necessary to find a compromise between hardness and foam. In practice,

it is advisable to operate with a water hardness around 15/20° F in order to minimize the problems of foam.

such hardness of the water can be obtained:

• by means of ion exchange resins, if dealing with very hard water.

• by the addition of oxide or calcium nitrate, if dealing with very soft water.

water with hardness above 34° F can cause precipitation of calcium soaps that are observable on the machines

in the form of white deposits clogging the filters of the circuit of the Flrs.

the refractometer is an optical device, easy to use, which analyzes a sample (drop) of Flr and reveals its concen-

tration.

If emulsions are analyzed, the reading in percentage is made directly on the device (Argo, superargo, superargo

t925, Emulsint, Emulsint k645, Emal); for products in solution, the table shown above indicates the correction

factor of the reading carried on the unit.

the exact concentration of the Flr is important for:

• the anti-rust protection.

• the lubricating effect on the tool.

• the anti-foam characteristics.

the determination of the exact concentration of the Flr allows:

• maintaining a good rust protection for the machine and the finished parts

• maintaining a good surface finishing of the workpiece, i.e. the surface roughness

• maintaining a long life of the tool without regrinding it, resulting in downtime

• maintaining long replacement intervals of the charge while avoiding the deterioration resulting in the formation

of residues which need to be removed.

the main in-service checks are as follows:

• concentration of the emulsion with the refractometer.

• ph, presence of bacteria.

• Appearance and odour of the emulsion. 15

12 - BEHAVIOUR OF THE COOLANT

In service, it is necessary to control the concentration of the oil.

during light cutting operations, the water-based fluid undergoes, usually, a depletion since the oil adheres to the

workpiece.

contrary, in heavy duty operations, water loss by evaporation, caused by the development of heat, assumes con-

siderable importance and results in increased oil concentration.

It is considered an exception to the rule that the loss of water and oil compensate each other.

It follows that the concentrations of water-based fluids always undergo changes in the course of the working,

making necessary periodic checks and adjustments of concentrations.

the easiest way to implement checks is the use of an oleometer refractometer, a tool that allows the immediate rea-

ding on a single drop of fluid.

there are pocket-type refractometers for just this purpose (Fig. 1).

®®

®

Fig.1

Product olEomEtEr reading

concEntrAtIon BIOSINT 40 BIOSINT 80 BIOSINT K 185

0,5 - 0 -1 0 0,4 0,252 0,5 1 0,803 1 1,5 1,254 1,5 2 25 2 3 2,56 2,5 4 2,87 3 5 38 3,5 5,5 3,759 4 6 4,5

10 4,5 6,5 5,5

16

the summary table B highlights some tips to improve the durability of Flr in service.

Bactericidal content with pH Meterthe emulsifiable oil may contain a bactericide added directly from the manufacturer.

the bactericide may also be added by the user after the preparation of the emulsion.

the bacteria do not grow in an alkaline environment, therefore, once dissolved in the solution, bactericides cause

an alkaline reaction in the fluid with a ph value greater than 7.

Periodic measurement of the ph value with a ph meter

the use of the ph meter allows detecting the variation of the ph, which must not fall below the value of 7.5-8, and,

if necessary, intervening in the control of bacterial proliferation.

considerably important is also the odour and appearance check of the emulsion into operation. For example, a

brown colour indicates the presence of iron oxides, while the presence of oil spots indicates a leak from spindles

and guides. the smell of hydrogen sulphide indicates high presence of bacteria (see Table C).

the presence of bacterial colonies can mainly lead to:

1) In the Flr

• degradation of the ingredients with the destruction of the emulsifiers, additives and subsequent formation of

decomposition products.

• Fall of the ph value

• Formation of a oily collar and resulting in the reduced lubricant and coolant action for thinning

• reduction in the effective life of the Flr

• replacing the Flr

2 ) In the circulation system of the Flr

• separation of cutting oil

• clogging of the pipe and nozzle

• Foaming

• difficult filtration

• need for general cleaning

3 ) In the production

• Parts not sufficiently protected against oxidation

• lower quality (e.g. surface finishing) and reduction of tool sharpening

• downtimes and loss of production

4 ) In the workplace

• unpleasant and nauseating odours caused by the formation of hydrogen sulphide

• health hazards through micro-cracks of the skin

In relation to the ph and the concentration of the Flr, the measures to be taken (cleaning of the circulation

system, check of the Flr filtration, removal of oil from the surface, renewal of the charge, cleaning the entire

system, etc.) must be examined on a case by case basis with a certain frequency, as reported in Table D.

The human skin is sensitive to chemical attack of alkaline agents; then, verify that the ph of the emulsion is

always between 8.5-9.

It's still a good idea that operators use protective equipment during processing (gloves, goggles, etc.).

the bactericidal originally present in the emulsion will degrade due to bacterial action, when in use.

If the ph value of the emulsion drops below of 7.5-8, it is advisable to take it back to the initial value by the addi-

tion of a bactericide; this latter should be added only after consultation with the supplier of the emulsifiable oil.

In the workshops, use a suitable indicator (litmus paper) to measure the ph value; when immersed in the emul-

sion, it takes on different colours, depending on the ph.

most of the litmus papers take the following colours:

orange = acid = ph less than 7

Green = neutral = ph equal to 7

Blue = basic = ph higher than 7

there are on the market various types of litmus paper and it is therefore advisable to always read the instructions

and reference specified by the manufacturer of the indicator.

17

Below are the summary tables relating to the use of the water-based Flr.

In summary :

table A: inconveniences caused by contamination of extraneous oils or casting oils from mu (tooling machines).

table B: tips to extend the life of Flrs and reduce the problems in operation.

table c: emulsion problems due to microorganisms.

table d: frequency of checks during use.

table E: tips following the check of used Flr.

12.01 - Table A - Problems due to the presence of extraneous oils (casting oil from the machine).

PROBLEM TYPE OF INTERVENTION

- Alteration of the concentration............... change in the percentage and negative results- Bacterial Proliferation............................... the presence of oil on the surface of the tank prevents aeration and

promotes the development of anaerobic bacteria.- separation of chips and debris................. high separation difficulties.- refrigerant effect....................................... high concentration of oil not expected to be in circulation in the system

reduces the cooling effect and tool life.- mist.............................................................. heavy machining with high cutting speed and depth of cut, the

presence of contaminant oil produces mist and aerosols.- Filtering power............................................ the filter pores are clogged by oil and must be replaced frequently.- sludge........................................................... Emulsion and/or solution with contamination oils may give rise to

sludge with debris and processing scraps that, once deposited in the dead spots of the system, become a breeding ground for microorganisms.

12.02 - Table B - Instructions to increase the duration of FLR in operation and contain the incon-veniences.

PROBLEM TYPE OF INTERVENTION

- maintain a fixed level in the tank or in the storage tank................................................. check of temperature at about 20° c.- make a vigorous circulationeven on weekends or summer break........................ oxygenation of the Flr.- carry out filtration to remove chips dust..................................................................... Promote contamination.- Prevent the accumulation of Flr in the presence of casting oil on the surface............................................................... Facilitate aeration or forced oxygenation.- remove the oil from the surface of the tank.................................................................... use the oil skimmer

- check the oil concentration in the Flr to obtain product and/or water, as needed.

12.03 - Table C - Damage to the emulsion due to microorganisms.

- Production of substances harmful to the operator

- destruction of the emulsifying preparations with separation of oil and additives (anti-rust and EP in particular)

- change in ph (corrosion and stains on machined pieces).

- Foaming

- Presence of unpleasant odour.

- Formation of sludge with clogging of filters and ….

- wound infections and development of dermatitis.

the variables in the Flr management problem are numerous and affect the operation in different way, but appro-priate frequent daily and weekly checks allow maintaining the efficiency of the Flr.

table d summarizes and suggests the frequency of checks for every problem.

18

Table D:

PROBLEM FREQUENCY OF THE INTERVENTION

- Presence of free oil on the surface of Flr .................................. weekly- Emulsion stability ........................................................................... weekly- concentration................................................................................... weekly- Ph value........................................................................................... weekly- microbial contamination............................................................... weekly- colours and odours ........................................................................ everyday- Instability and separation of the emulsion in the tank............. everyday- Fluid level in the tank..................................................................... everyday

Following the checks, immediate intervention is possible; the problem shall be reported to Service Syneco CHECK-UP

Table E - Instructions to increase the duration of FLR in operation and limit the inconveniences.PROBLEM TYPE OF INTERVENTION

- changes in concentration of the fluid.................................. Add Flr (low values)Add water (high values)

- Free oil on the tank surface................................................... remove with oil skimmer (see page 28).- low level of the fluid in the tank .......................................... Fill with prior verification of the concentration.- Foaming..................................................................................... use less sweet water, check concentration and call

technical service of syneco.- microbial contamination......................................................... consult technical service of syneco to add 'biocides'

product.- Instability of fluid.................................................................... Verify concentration and add Flr.- change in ph ........................................................................... If too high (9.5 to 10), add water.

If too low, consult technical service of syneco .- unpleasant smell...................................................................... Ventilate the charge, make the emulsion circulating.

consult technical service of syneco promptly.- change in corrosion protection power ................................. check the concentration and ph.

consult technical service of syneco.

13 - CHARACTERISTICS OF THE MATERIAL BEING PROCESSED AND TOOLS

the characteristics of the material being processed (indices of workability) and the tool in the various machining

operations are to be considered together with the characteristics of the machine and that is: feed and depth of cut,

along with cutting speed and power consumption.

13.01 - Indices of workabilityuna classificazione dei materiali secondo la loro truciolabilità è contenuta nell’elenco che segue può essere utile

per un approssimativo orientamento:

GROUP 1: materials that require non-severe processing chip removal, such as aluminium and aluminium alloys

easily machinable, magnesium and magnesium Alloys (that should not be machined with water-mixed metalwor-

king fluids, since there is danger of the fire!) copper and copper alloys easily machinable.

GROUP 2: materials that require medium processing chip removal, such as grey cast iron and malleable cast iron

(e.g. GG -25), case hardening and quenching steels, unalloyed and low-alloy steels (e.g. c15 resp. ck60 ), steels for

automatic machines and structural steels (10sPb resp. st60 -2).

GROUP 3: materials that require heavy processing chip removal, such as high-alloy steels and quenching steels

(e.g. 20mncr5 resp. crmo4 25) , steel for ball bearings (e.g. 100cr6 ), steels resistant to rust and acid (e.g.

x40cr13), nickel-chromium steels (e.g. 18crni8 ), cast steel and cu alloys machinable with difficulty (Bronze).

GROUP 4: machinable materials that require very severe processing chip removal, such as tool steel or chromium-

19

molybdenum steels (e.g. 18crmo4) , nickel and nickel alloy (e.g. 16nicr11) steels, manganese and manganese -

silicon (e.g. 50mnsi4), spring steel or silicon steel (e.g. 55si8) , titanium and titanium alloys.

unfortunately, the boundaries between one group and another are uncertain and therefore, the purpose of the

table above is just for indication.

13.02 - Materials for toolsFor the manufacture of tools suitable for metal cutting, clearly, materials having a number of requirements shall

be used. the more stringent are the requirements, the more there is a tendency towards higher productivity. In

general, materials for tools must have the following characteristics:

- high hardness (in any case, greater than that of the metal to be cut)

- high toughness

- hardness and toughness even at high temperatures.

there are therefore many materials in which predominates one or more of these characteristics, and these mate-

rials can be grouped as follows:

- carbon steel

- tungsten steel (high speed steel)

- chromium - tungsten hss steel (super-high speed steel)

- stellites

- hard metals (sintered)

- wear-resistant thin coatings

- ceramic materials

- superhard materials

13.02.01 - CARBON STEELthe steels containing a percentage of carbon between 0.5 and 1.4%, suitably treated and hardened, possess high

hardness and medium toughness (as the percentage of c increases, the hardness increases and the toughness

decreases); however they can not withstand temperatures higher 200° c. For this reason, their use has been gra-

dually decreased with the increase of the cutting speed and the average power of the tooling machines. currently,

carbon steel tools have practically disappeared from the workshop and their use is limited to tiny tools mostly used

by hand, such as twist drills, male thread devices, saws, etc.).

13.02.02 - TUNGSTEN STEEL (high speed steel)tungsten high speed steels (also called tough steels) found limited use in some turning tools, twist drills, milling

cutter, male thread devices, etc. they possess cold hardness comparable to that of a normal carbon steel, but have

higher toughness and can withstand temperatures up to 400° c approx. without a significant drop of their hard-

ness.

13.02.03 - SUPER-HIGH SPEED STEEL (HSS)they are the most widespread steels, as they are able to withstand very high working temperatures, for certain

types up to 700° c.

In practice, these steels contain tungsten, nickel, chromium, Vanadium alloy to a greater or lesser extent and are

named based on the predominant metal: cobalt steel, chromium steel, vanadium steel, etc.

13.02.04 - STELLITESthey are composed mainly of tungsten (~ 20 % ), chromium (~ 23%) and cobalt (50%).

they are so hard that they can only be shaped in melt strips and mill-processed.

the characteristic of these alloys in respect of high speed steels is to preserve virtually unchanged the characte-

ristics of hardness and toughness, even if brought to red (> 800° c), which enables the stellite tools to withstand

higher working speed; they also possess a lower coefficient of friction, which decreases the development of heat by

the friction of the chip and higher resistance to hot abrasion.

these tools also allow working parameters intermediate between those of high speed steels and those of so-called

hard metals, as we will review below.

A particular type of stellite consists of the tantung alloys, on which a certain percentage of columbium carbide

and/or tantalum carbide is added .

these carbides have the property to further lower the coefficient of friction and increase the toughness.

20

13.02.05 - HARD METALSthe definition of hard metals includes a certain amount of materials manufactured by hot sintering of mixtures of

powders of carbides of tungsten, tantalum, titanium with powder of another metal (usually cobalt) acting as a

binder.

synthetic alloys thus obtained have very high hardness both at ordinary temperature and high temperature.

In general, the higher is the content of carbides and lower that of cobalt, the greater is the hardness.

with the hardness, however, the fragility increases; this is always so high that the hard metals are used, such as

stellite, in the shape of small plates mounted on steel supports by brazing or by mechanical clamping systems.

Because of their hardness, such plates can be machined only with abrasive wheels made of carborundum or dia-

mond.

the main advantages offered by the use of tools with carbide hard metal insert are of various types:

- strong working speed (high productivity);

- Easy replacement of worn cutting media with new one without the need for sharpening (reduction of downtimes);

- Economy of use ;

- Very good finishing.

13.02.06 - Thin anti-wear and anti-collision coatings the need to lower production costs has led in the last decade to the massive use, in the market of the tools, of sur-

face hardening coatings based on titanium, first with the use of titanium nitride (tin) and then, especially for ope-

rations of interrupted cutting, of titanium carbonitride (ticn). these coatings are applied mainly with the cVd

(chemical Vapour deposition) and PVd (Physical Vapour deposition) processes.

typical coatings applied by cVd technique are titanium nitride (tin), titanium carbide (tic), titanium carboni-

tride (ticn), aluminum oxide (Al203), often combined in multi-layer and chromium nitride (crn).

In particular, the need to work materials at very high speed, the desire to reduce the use of metalworking fluids

(pollution problems or the need to reduce costs), or the inability to have a proper lubri-coolant action (deep dril-

ling), the need to operate on difficult to machine materials (superalloys, titanium alloys, cast irons, stainless

steels) has led to the development of a coating with high performance in these very difficult conditions, where high

heat develops: the titanium and aluminium nitride (tiAln), solid solution of titanium nitride and aluminum nitri-

de, is applied by PVd.

13.02.07 - CERAMIC MATERIALSthe so-called ceramic tools are made with plates based on coridone (aluminum oxide) linked to lower levels of

other oxides (of chromium, silicon, magnesium, titanium and manganese), sintered at high temperature

(1700 °c).

the ceramic tools have recently had a certain diffusion, as they have turned out to be suitable for high speed

machining with not deep run of materials, also very hard (hardened steels). the high fragility excludes its use in

the processing of materials with surface irregularities.

13.02.08 - SUPER-HARD METALSthe diamond is the hardest material available to man.

the diamond can be used in the form of small plates embedded in special tools and is used for finishing very pasty

materials (pure aluminium or copper) at high speed, for example in the processing of collectors of electric machi-

nes.

13.3 - CHARACTERISTICS OF THE TOOLSthe material of which the tools are made of can be decisive for the choice of the fluid for cutting:

- Carbon Steel: lose their hardness, obtained by means of quenching, at temperatures ranging between

200° c and 300° c, while for lower temperatures, they possess a high hardness, only lower than that of the hard

carbides.

the cutting fluid must therefore have a high cooling power, i.e. it must be water-based, such as synthetic emulsions

or solutions.

- High and super-high speed steel: fluids of all kinds can be used for cutting, and the choice depends on

other factors: type of machining, workpiece material, cutting characteristics, etc.

however, to avoid reaching critical temperatures for the good preservation of the tool edge, the fluid must also pos-

sess good cooling capacity.

21

moreover, the fluid must always have lubricant and anti-welding capacity, the latter to limit the tendency of the

chip to weld to this type of material.

- Hard carbides or hard non-ferrous alloys: particular care must be adopted to keep the plates to a con-

stant thermal regime, avoiding sudden changes in temperature that unavoidably lead to tool breakage.

sometimes the temperature constancy can be better ensured by a pure oil, even light, rather than by a water-based

fluid with too energetic a cooling action.

however, aqueous emulsions dispensed with continuity can be used and in overflowing measure, so as to comple-

tely submerge the working area; it is recommended that the liquid is dispensed under pressure or that effective

chip breaker are used, in order to avoid any interruption in the flow of liquid caused by the generated chip.

It is necessary to consider the need to maintain the tool at a temperature not excessive, not to preserve the hard-

ness, which is still high even in hot conditions, but to prevent softening of the fastening material of the plate to the

tool rod; for this purpose, the latest solutions propose plates of hard material secured by screws at the end of the

tool rods.

- Ceramic materials: thanks to their properties of hardness, chemical stability and wear resistance,

maintainable even at high temperatures, the fluids are required properties of lubrication and cooling of the work-

piece in order to achieve the best surface finishing.

In grinding operations, the tool consists of a set of elementary tools or abrasive grains incorporated in a solid sup-

port of lower hardness.

Elementary tools and support constitute the wheels, which may have different sizes and features.

the size of the abrasive grains, i.e. the grain, is one of the parameters that characterize the wheels: in fact, coar-

se, medium and fine grain wheels are available.

Even the active materials constituting the wheels can be of various types; there are materials which are now defi-

ned as "conventional", such as silicon carbide or aluminium oxide, and other "innovative" as the diamond and cBn,

called superabrasive, and able to work very hard pieces such as ceramics, carbides and some metal objects obtai-

ned by sintering.

the lubrication, for the latter type of grinding wheels, generally requires non-miscible oils, since the relative speed

between the workpiece and the tool is higher than that used with conventional abrasives.

In the grinding processes, the cutting speed greatly affects different elements such as the penetration of the cut-

ting edges of the grinding wheel, the amount of material removed per unit of time, the mechanism of material

removal, the surface roughness obtainable on the workpiece and the distribution of heat in the area of contact with

the piece to be machined.

By increasing the speed, the chip section that is deformed whenever a abrasive grain penetrates the workpiece

decreases, but conversely, the frequency of the penetration increases.

consequently, the total force acting on each grain decreases and therefore the "total force" is reduced during the

grinding process.

Furthermore, with the increase of the cutting speed, the workpiece heats lesser and lesser.

this is because the contact time of each abrasive grain with the workpiece is reduced, decreasing the thermal con-

duction, while most of the heat will be consequently removed by the chip.

Also the choice of metalworking fluid and pressure is important to minimize the generation of heat, all this also to

lengthen the duration of the grinding wheel.

then, the use of cBn (cubic crystalline Boron nitride) wheels, with their extreme hardness and wear resistance

in comparison to conventional wheels, allows increasing the removal rate and productivity, while keeping constant

the roughness and the wheel wear, or increasing the quality, i.e. obtaining a low roughness and great reduction of

the grinding wheel wear.

the grinding wheels are intended for coarse grinding, namely the removal of relatively high amount of material

from the pieces, with considerable heat production; instead, fine-grained wheels are intended to super-finishing or

polishing with removal of small amounts of material and resulting in reduced production of heat.

the cutting fluids used in the operations of grinding, roughing or medium finishing are water-based in order both

to remove the substantial amount of heat produced and to take away completely and rapidly the very minute and

abundant removed materials that tend to stick to the grinding wheel and slow it down.

low oil concentration (max 2-2.5 %) emulsions or aqueous solutions of synthetic products are used, as they have

a stronger detergent action on the wheels.

In the fine grain grinding or in the operations of super-finishing such as lapping and stone honing, are generally

22

used very fluid non-miscible oils optionally containing EP additives, in order to preserve the surface of the machi-

ned pieces from alterations related to overheating of the premises.

non-miscible oils are also used when performing cutting operations with strong depth of cut using grinding wheels.

the choice of the fluid to be used for cutting can also be influenced by the geometrical characteristics of the tools.

In fact, it is obvious that varying the geometry of the tool and its setting with respect to the workpiece, may vary

the way in which the chip is formed and developed, and consequently the choice of the fluid.

14 - SERVICE SYNECO CHECK UP - SERVICE SYNECO TEST

syneco performs a monitoring of the water-based fluid with the taking of samples for the analysis in the labora-

tory: this includes water used in the preparation.

currently, a real-time check with Service Test and Syneco Check Up is provided, using:

- Eleaometer and/or refractometer;

- litmus test and/or ph meter;

- Bacterial counts

and a check of :

- colour, odour, presence of extraneous oil, temperature, filtration efficiency, surface finishing, rust-oxidation pro-

tection.

15 - DISCHARGE OF EXHAUSTED FLUIDS

As it is known, the emulsions of metalworking fluids, in order to be discharged into a sewer system or surface

water system, must undergo the process of purification, which eliminate most of the substances contained in them,

because these substances would be toxic to the environment or otherwise would alter its biological balance.

the purification of an emulsion essentially consists in breaking the emulsion itself and eliminating the separated

oily phase to obtain a clear aqueous phase.

this first process is commonly known as "de-oiling".

Generally, also with totally synthetic products it is necessary to proceed to a de-oiling because, after use on tooling

machines, they always contain foreign substances, such as lubricating oils, in amounts significantly higher than

the limits allowed by the laws. often the de-oiling for these products is very easy and consists into a simple decan-

tation.

the de-oiling of an emulsion can be performed with different methods; below are the most important ones:

1 ) Acid separation

2 ) adsorption on fixative grounds

3 ) flocculation with metal salts

4 ) ultrafiltration.

with all these methods, it's possible to obtain a final aqueous phase within the limits imposed by the law as

regards the content of oily substances in general.

In this aqueous phase are, however, water-soluble substances which, even if not toxic, combine to form the c.o.d.

(chemical oxygen demand) of the solution, to which the law imposes strict limits.

®

23

the final c.o.d. may vary depending on the method used for de-oiling; for each method, tips are possible to redu-

ce the value, but with the depuration obtainable today, in practice c.o.d. values are higher than the legal limits.

the removal of this residual c.o.d. can be obtained by different ways, for example by adsorption on activated

carbon or biological treatment.

without going into any particular problems related to these processes, it is intuitive that the purification of

metalworking fluids with obtaining of water, which is within the limits set by law, involves delicate procedures

and checks; therefore, all users who are not able to build specific plants operated by trained personnel, contact

companies expert in purges that collect the exhausted emulsions from individual plants by issuing a receipt of

complete discharge of any liability.

16 - BIODEGRADABILITY OF METALWORKING FLUIDS

In recent years there is a growing interest in the behaviour of the metalworking fluids in the environment, mea-

ning the evolution and the effects that these products have in the environment.

highly degradable products have been formulated so to offer an alternative to microbiologically more resistant

products.

those who wish to use a "biodegradable" product can sometimes not fully understand the meaning of this defini-

tion.

For many people, a "biodegradable" product is something that can be discharged without any purification treat-

ment, after use, directly into the sewer or, even worse, in surface waters, without violating anti-pollution laws. this

is absolutely not true.

to understand the problem, we must first say that there is a standard method for determining the degree of bio-

degradability of a metalworking fluid and therefore the concept of biodegradability of a metalworking fluid can be

applied to fluids only in a qualitative way.

currently "biodegradable" means that a material can be degraded by biological processes or final products accep-

table by the environment that receives them.

In other words, this product should consist of non-toxic substances, considered non-polluting.

moreover, a fluid, in order to be easily treated in conventional purification systems, must not give rise to inter-

mediate persistent residues, must not have effects on water that receives it and its possible re-use, and should not

produce abnormal proliferations in the marine environment.

It should also introduce the concept of time needed for the biological degradation.

many substances are biodegradable if they remain for a long time in a treatment system.

however, the term biodegradable means a substance degradable in the normal residence time in the purification

system.

since the biological degradation is a process of oxidation, which occurs namely with an absorption of oxygen, to get

an idea of the amount of biodegradable substances contained in water to be purified, the B.o.d. (biological oxygen

demand) and the c.o.d. (chemical oxygen demand) are used.

the c.o.d. is the amount of oxygen required to chemically and completely oxidize (and hence degrade) the sub-

stances contained in the water under examination, while the B.o.d. is the amount of oxygen actually consumed for

the biological process.

17 - FLR - METALWORKING FLUIDS BY SYNECO

SYNECO EMULSIONABILE N:- Emulsifiable oil for medium-light machining with milky emulsion.

SYNECO ARGO:- Emulsifiable cutting oil, milky emulsion, used in medium machining.

SYNECO SUPERARGO T 925:- Emulsifiable EP oil for heavy machining, concentration from 3 to 9 % for turning and milling, 5 to 11% for tap-

ping, drilling and up to 15% for broaching.

SYNECO SUPER ARGO:- Fluid for cutting that forms milky microemulsions for extremely heavy machining. 2÷10%

SYNECO EMULSINT:- water-soluble semi-synthetic fluid for metal cutting of medium difficulty. 2÷3%.

SYNECO EMULSINT K 645:- naphthenic base fluid with milky emulsion of easy forming, good stability and durability to easily machinable

materials.

SYNECO BIOSINT 40 and BIOSINT 80:- synthetic fluids for steel and alloys grinding. 0.8÷1.5%.

SYNECO BIOSINT K 185:- synthetic metalworking fluids for turning, milling, threading, tapping. 1.5÷3%.

SYNECO EMAL:- Emulsifiable oil for the specific processing of Aluminium. 2÷10%.24

For a readily biodegradable substance, the B.o.d. will tend therefore to be equal to the c.o.d., while for a non-bio-

degradable substance, to a specific c.o.d. corresponds a very low and even null B.o.d.

the Italian law (mErlI law no. 319 of 10 may 1976) regulating discharges of waste water imposes very strict

limits also with regard to the B.o.d. (and c.o.d.) of waste water; so even those who employs "truly biodegradable"

coolants, before discharging them, must use a purification process for lowering the B.o.d. (and therefore the

c.o.d.) below the permitted limits.

the limits imposed by the law are currently at:

Bod = 40 mg o2/lt

c.o.d. = 160 mg o2/lt

while a cooling fluid at a concentration of 2% has a c.o.d. of 5,000.

It should also keep in mind that, during use, foreign substances, such as heavy metal ions, mineral oils of lubrica-

tion, etc., may accumulate in the fluid; the limit for discharge of such substances is extremely low, so that even for

them, a purification process is needed.

In conclusion, the discharge of a biodegradable product can lead to as many drawbacks of that of conventional pro-

ducts.

keeping in mind that the biodegradable product generally costs much more with the same yield, it is more easily

microbiologically attacked for its own structure; this is why, so far, its use has not proved advantageous if not in

cases in which, after a preliminary purification, it is possible to send the waste water to a biological treatment

system.

25

SYNECO DPG -Series (25, 50, 75):• Biocidal products of different formulation to be used alternately to lower the risk of formation of bactericidal

strains resistant to a specific biocidal product.

SYNECO DETERWASH:• detergent and disinfectant liquid to 10% in water for cleaning Flr systems.

All Flrs produced by syneco are formulated in terms of primary importance to the respect of the health of

users and the environment.

For the above reasons the lubricant bases used by our company are exclusively of paraffinic origin and highly

refined, in order to reduce to a minimum the content of aromatic carbon.

the addition of our Flrs is totally absent from nitrites, Phenols and heavy metals (lead, cadmium, etc.).

18 - AUXILIARY EQUIPMENT: REFRACTOMETER, PROPORTIONINGDEVICE, BELT OIL SKIMMER, PH METER

In the previous pages we have already mentioned the Refractometer/elaeometer (p.15) for the check of the Flr

percentage in the fluid, suitable for any processing to be carried out with a certain frequency.

For the Flr and the emulsion preparation, the proportioning device (p. 29) is useful.

the elimination of lubricating oil, coming from the same tooling machine, also called casting oil, is carried out with

extreme simplicity and low cost by the belt oil skimmer (page 28).

the measurement of the degree of acidity, basicity, or neutrality of the emulsion or solution, i.e. the ph value, is

done with the ph meter.

For periodic testing, it is recommended to have the refractometer/elaeometer and ph meter available on an

ongoing basis; these two control tools can be supplied on request by syneco.

For further analysis, it is preferable to instead use the Service Syneco CHECK- UP.

19 - CLASSIFICAZIONE PER OLI DA TAGLIO: ISO (6743/7)

Stanimuc of turin, unI Federated Body, in addition to tables named:

"Lubricants for Tooling Machines"

has recently prepared the 2000 edition, and according to the need of producers and users, has proposed a classi-

fication of fluids for metal cutting and forming, i.e. such as to allow identifying the product depending on the type

of application.

In this series of products it is not easy to guarantee performance in laboratory tests, but a classification, combined

with subsequent specific laboratory tests, allows providing the user with the most appropriate choice of products.

the proposed classification is Iso 6743/7 and provides for: cutting, Grinding, Edm, deformation of metals with

punching, pressing, milling, extrusion, hot and cold forging, extrusion, moulding, laminating, with a specific indi-

cation:

a) processes in which the lubrication needs are dominant;

b) processes in which the cooling needs are dominant;

therefore, in this case, the criterion that fits for cataloguing fluids indicates in the beginning a type of lubricant

with only protective properties, to further consider characteristics such as the reduction of friction, EP, milky or

transparent/translucent or combined appearance.

26

ISO 6743/7 CLASSIFICATION (MH Family).

non-mIscIBlE luBrIcAnts For mEtAl mAchInInG In whIch luBrIcAtIon nEEds ArE domInAnt.

CODE TYPE OF PRODUCT AND NEEDS OF USE ISO-L

mhA Fluids with possible anti-corrosive properties

mhB type mhA fluids with friction reduction properties

mhc type mhA fluids with “extreme pressure” additives

mhd type mhA fluids with E.P. properties, chemically active

mhE type mhB fluids with E.P. properties, chemically not active

mhF type mhB fluids with E.P. properties, chemically active

mhG Grease, paste, was, to be applied pure or diluted with a type mhA fluid

mhh soap, powder, solid lubricant and mix thereof

ISO 6743/7 CLASSIFICATION (MA Family)

EmulsIFIABlE luBrIcAnts For mEtAl mAchInInG In whIch coolInG nEEds ArE domInAnt

CODE TYPE OF PRODUCT AND NEEDS OF USE ISO-L

mAA concentration that, mixed with water provides milky emulsion with anti-corrosion properties

mAB type mAA concentration with friction reduction properties

mAc type mAA concentration with E.P. properties

mAd type mAB concentration with E.P. properties

mAE concentration that, mixed with water provides translucent emulsions with anti-corrosion properties

mAF type mAE concentration with friction reduction properties and/or extreme pressure

mAG concentration that, mixed with water provides transparent solutions with anti-corrosion properties

mAh type mAG concentration with friction reduction properties and/or extreme pressure

mAI Grease and paste to be applied mixed with water.

27

20 - DISTRIBUTION OF PRODUCT CATEGORIES OF "M" FAMILY INACCORDANCE WITH THE APPLICATION RANGE

sh

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ng

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g op

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ion

s

Abr

asio

n

Ed

m

sta

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ing

Fac

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illi

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Gin

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win

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ing,

For

min

g

lam

inat

ion

oPErAtIon

Iso

cAtEGory

synEco

product

L-MHA

L-MHB

L-MHC

L-MHD

L-MHE

L-MHF

L-MHG

L-MHH

L-MAA

L-MAB

L-MAC

L-MAD

L-MAE

L-MAF

L-MAG

L-MAH

L-MAI

DRY STAMP

AURO FR

AURO DD

AURO DD

IMBIUSINT

SIRIO AURO 3

•

• • • • •

• •

• •

• •

•

• •

• •

• •

•

• •

•

• • •

•

•

•

•

•

• •

•

•

•

•

EMAL EMULSIONABILE N

ARGO SUPER ARGO

ARGO SUPER ARGO

EMULSINT EMULSINT K645

BIOSINT 40 - BIOSINT 80 - FILOIL

BIOSINT K185

very suitable product

recommended product

SUPER ARGO T925

28

21-SYNECO BELT OIL SKIMMER

Convenient and compact system for the removal of extraneous oils from emulsions

The removal of extraneous oils from emulsions constitutesa practice which must absolutely not be neglected.

An emulsion free of extraneous oils prolongs tool life, minimizes the possibility of the development of unpleasant

odours and irritation to the skin of the workers.

the heart of the oil skimmer is made from the special toothed belt in polyurethane reinforced with steel fila-

ments.

the polyurethane has a great affinity for oily substances while the capacity of adhesion of the same to water is

minimal.

the removal of emulsion is thus almost insignificant.

the double-pulley system provides tension to the belt and continuity of operation.

the knife removes oily substances drained by the belt and conveys them to a container.

A 1" plastic tube, included in the package, pour it all into a container.

An l-bracket enables easy mounting in both vertical and horizontal surfaces.

so it can be applied to open and closed tanks.

the belt oil skimmer weighs only 4 kgs and can be easily used in several tanks, by moving it, from time to time,

depending on the needs.

the standard model, with a capacity of collection equal to one litre per hour, has an 11 revs/minute motor.

A model with an 18 revs/minute motor is also available.

®

Characteristics:

• Voltage:

220 Vsingle-phased, 50/60 hz

• Power absorbed:

50 watt

THECNICAL CHARACTERISTICS:

THE FOLLOWING MATERIALS ARE USED FOR THE BELT OIL SKIMMER:

• Aluminium: for the motor cover

• steel: for the pulleys, supports and gear-motor unit

• stainless steel: for the knife and collection conveyor;

• connections: for the belt (reinforced with steel wires)

29

22 - PROPORTIONING DEVICE mod. PISTON

The tranquillity of the correct preparation of the emulsions.

To get the best results from your metalworking fluid, itsproper preparation is essential.

“THE EXACT CONCENTRATION”

too concentrated emulsions irritate the skin of the operators and constitute a waste.too light emulsions lead to premature wear of the cutting tool, worsen the surface finish of the workpiece, causingcorrosion problems to the machine, favouring bacterial fermentation and the formation of unpleasant odours.

"THE CORRECT HOMOGENIZATION"

It's important to ensure the stability of the emulsionsince its preparation.

this avoids the separation of oil that originates unde-sired built-up on the machines.

the proportioning device, model Piston, is unique onthe market.

unlike the other mixing devices, based on theVenturi effect, the obtained concentration of theemulsion is not minimally influenced neither bywater supply pressure nor by the variation of thesame.

the practical selection system of concentrationmakes any error impossible.

SIZE:

• diameter: 10,5 cm• total height: 47 cm• overall widht: 16 cm• weight: 1,7 kg

30

• operation capacity:min.: 10 l/hmax.: 2500 l/h

• dispensing interval:min.: 10 l/hmax.: 2500 l/h

• operating Pressure:mod. PIston 16 da 0,3 bar a 6 barmod. PIston 150 da 0,3 bar a 6 barmod. PIston 210 da 0,5 bar a 4 bar

• capacity of the hydraulic motor: 0,51 every 2 clacks of the piston

• max operating temperature: 50°c

• In-built 350 micron filter.

• connections:3/4” gas male

• operation:no power supply;the hydraulic motor acts as mixer.

CARATTERISTICHE TECNICHE:

31

23 - Other Syneco products after cutting operation:

synEco DEWATERING:- anti-rust protection, to remove water from machined pieces.

synEco ANTIRUST DP:- anti-rust protection with oily film.

synEco ANTIRUST 21:- : anti-rust protection with non-toxic oily film.

synEco ANTIRUST 22:- : anti-rust protection with oily film for outdoor application.

synEco ANTIRUST 22/L:- wax protection, to be removed with hot water.

24-BIBLIOGRAPHY:

-”syneco Fluidi lubrorefrigerante” - Ed. syneco (01/99)

-”Acciai speciali da costruzione” - Ed. Ims-monza

-”note sui fluidi da taglio e da rettifica” - Ed. lubrizol

-”tecnologia meccanica” - Ed. secciani-Villani

-rivista “tecno utensili” - maggio 95

-schülke 8 mayr Italia (mI)

-stanimuc “Proposta classifica per oli da taglio - Iso 6743/7” (to)

cibs@snet.it

SYNECO SpA - Via Abruzzi, 10/1220098 SAN GIULIANO MILANESE (MI) - ITALYtel: +39 02 9880840 r.a. - fax: +39 02 9880351www.syneco.it - e mail: info@syneco.it

SYNECO:LUBRICANTS & SERVICES

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