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CUTTING FLUID

INTRODUCTION

Cutting fluids are very important in machiningprocesses. They areused: to reduce theeffects of friction.

to carryawayheatin machining operations. Excessiveheat can damage themicrostructure of metals.

Properuse of coolantscan make highermetal removalratespossible.

help to improve part qualityand dimensional accuracy.

Improve the toollife

flushingaway chips from the cuttingzone

TYPES OF CUTTING FLUID

Straight oils

Solubleoils

Semisynthetic fluids

Synthetic fluids

1. STRAIGHT OILS

Straight oils arenon-emulsifiable andareused inmachiningoperationsin an undiluted form.

They are composedof a base mineral orpetroleumoil andoften containspolar lubricantssuch as fats, vegetableoilsandestersas well asextremepressureadditives suchas Chlorine,Sulphur and Phosphorus.

Straight oils provide the best lubrication and thepoorest cooling characteristics among cuttingfluids.

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2. SYNTHETICFLUIDS

contain no petroleum or mineral oil base and

formulated from alkaline inorganic and organic

compounds along with additives for corrosioninhibition.

They are generally used in a diluted form (usualratio = 3 to 10%).

Synthetic fluids oftenprovide the best coolingperformance among all cutting fluids.

3. SOLUBLEOIL FLUIDS

SolubleOil Fluids form an emulsionwhen mixedwithwater.

The concentrate consists of a base mineral oil andemulsifiers to help produce a stable emulsion.They are used in a diluted form (usualconcentration = 3 to 10%).

provide good lubrication andheat transferperformance.

They are widely used in industry and are the leastexpensive among all cutting fluids.

4. SEMI-SYNTHETICFLUIDS

Semi-synthetic fluids are essentially

combinationof synthetic and solubleoil fluids

and have characteristics common to both

types.

Thecost and heat transfer performance ofsemi-synthetic fluids lie between those of

synthetic and soluble oil fluids.

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CUTTING FLUID APPLICATIONSTRATEGIES:

1. FloodApplication of

Fluid

2. JET APPLICATIONOF FLUID

a jet of cutting fluid is applied on theworkpiece directedatthe cutting zone

3. MIST APPLICATION OF FLUID:

cutting fluid is atomised

bya jet ofairand the

mist is directed at the

cutting zone

CUTTING FLUID EFFECTS IN MACHINING

Theprimary functionsof cutting fluids in

machining are :

Lubricating the cuttingprocess primarily at low

cutting speeds

Cooling theworkpiece primarily at highcuttingspeeds

Flushing chips away from the cuttingzone

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CUTTING FLUID EFFECTS IN MACHINING

Secondary functions include:

Corrosionprotection of themachined surface

enablingpart handling by coolingthe hot surface

CUTTING FLUID SELECTION CRITERIA

Process performance :

Heat transfer performance

Lubricationperformance

Chip flushing Fluid mistgeneration

Fluid carry-offin chips

Corrosion inhibition

Fluid stability (for emulsions)

Cost

EnvironmentalPerformance