Group Two (The Calipers)We’re “DEAD ON!”

Anthony MenicucciAnthony Menicucci Keith JansenKeith Jansen Bill FanBill Fan

Chris KingChris King Nathan BurnsNathan Burns

“Fundamental Of Machining”and

“Cutting-Tool Materials and Cutting Fluids”

Above: Lathe cutting tool

Side: Nano Drill-Bit = 1 um2

Types of Machining

Straight Turning and Cutting Off

Slab MillingSlab Milling

End MillingEnd Milling

Types Of Chips producedTypes Of Chips produced

•Continuous

•Discontinuous

•Serrated or Segmented

•Built Up Edge

Continuous and Discontinuous ChipsContinuous and Discontinuous Chips

Chip BreakersChip Breakers

Chip Breakers can be used to prevent discontinuous chips from forming.

Serrated or SegmentedSerrated or Segmented

(f)

(b)(a) (c)

(d) (e)

Serrated chips, looked at under a microscope, resemble a saw tooth pattern because of the semi-continuity of the chip as in Figure (a).

(a)

Built Up EdgeBuilt Up Edge

Built Up edges affect the performance of a cutting tool because of their hardness and the perceived dulling of the tool.

Chip

BUE

Hardness of a BUEHardness of a BUE

230

Chip

Oblique cuttingOblique cutting

Most machining operations involve oblique cutting. Why, on the most basic level, is this this so?

Other forms of oblique cuttingOther forms of oblique cutting

Quick ReviewTypes of Machining

Turning and Cutting off

Slab Milling

End Milling

Chip Formation

Continuous

Discontinuous

Built Up Edge

Oblique Cutting

21.4 Temperatures in Cutting21.4 Temperatures in Cutting

As in all metalworking processes where plastic As in all metalworking processes where plastic deformation is involved, the energy dissipated in deformation is involved, the energy dissipated in cutting is converted into heat which in turn, raises cutting is converted into heat which in turn, raises the temperature in the cutting zone.the temperature in the cutting zone.

Major EffectsMajor Effects

Excessive temperature Excessive temperature lowers the strength, lowers the strength, hardness, stiffness, and hardness, stiffness, and wear resistance of the wear resistance of the cutting tool; tools also cutting tool; tools also may soften and undergo may soften and undergo plastic deformation; plastic deformation; thus tool shape is thus tool shape is alteredaltered..

Major EffectsMajor Effects

Increased heat causes uneven dimensional changes Increased heat causes uneven dimensional changes in the part being machined, making it difficult to in the part being machined, making it difficult to control its dimensional accuracy and tolerances.control its dimensional accuracy and tolerances.

Major EffectsMajor Effects

Excessive temperature rise can induce Excessive temperature rise can induce thermal damage and metallurgical thermal damage and metallurgical changes in the machined surface, changes in the machined surface, adversely affecting its properties.adversely affecting its properties.

Temperature DistributionTemperature Distribution

The maximum temperature is about The maximum temperature is about halfway up the tool-chip interface.halfway up the tool-chip interface.

Techniques for Measuring Techniques for Measuring TemperatureTemperature

Thermocouples embedded in the tool.Thermocouples embedded in the tool. Thermal emf (electormotive force) at the tool-chip Thermal emf (electormotive force) at the tool-chip

interface, which acts as a hot junction between two interface, which acts as a hot junction between two different materials.different materials.

Infrared radiation from the cutting zone may be Infrared radiation from the cutting zone may be monitored with a radiation pyrometer.monitored with a radiation pyrometer.

Traditional Infrared Thermometer

21.5 Tool Life: Wear and Failure21.5 Tool Life: Wear and Failure

Tool wear is a major Tool wear is a major consideration in all consideration in all machining operations. machining operations. Tool wear adversely Tool wear adversely affects tool life, quality of affects tool life, quality of the machined surface the machined surface and its dimensional and its dimensional accuracy, and cutting accuracy, and cutting operationsoperations

Tool WearTool Wear

Crater WearCrater Wear Tool-chip interfaceTool-chip interface Predominant at high speedPredominant at high speed Mitigated by efficient use of Mitigated by efficient use of

carbidescarbides

Flank wearFlank wear Tool-work piece interTool-work piece inter Predominant at low speedsPredominant at low speeds

Tool WearTool Wear

(a) Crater Wear(a) Crater Wear (b) Flank wear on a carbide tool(b) Flank wear on a carbide tool

Flank WearFlank Wear

Tool Life CurvesTool Life Curves

Effect of work piece microstructure on tool life in turning. Tool Effect of work piece microstructure on tool life in turning. Tool life is given in terms of the time(min) required to reach a flank life is given in terms of the time(min) required to reach a flank wear land of a specified dimension. (a) ductile cast iron. (b) wear land of a specified dimension. (a) ductile cast iron. (b) Steels, with identical hardness. Note the rapid decrease in tool Steels, with identical hardness. Note the rapid decrease in tool life as the cutting speed increases.life as the cutting speed increases.

Tool Life CurvesTool Life Curves

Tool life curves for a variety of cutting tool materials. The negative Tool life curves for a variety of cutting tool materials. The negative inverse of the slope of these curves is the exponent n in the Taylor tool inverse of the slope of these curves is the exponent n in the Taylor tool life equation. (b) Relationship between measured temperature during life equation. (b) Relationship between measured temperature during cutting and tool life (flank wear). Note that high cutting temperatures cutting and tool life (flank wear). Note that high cutting temperatures severely reduce tool life.severely reduce tool life.

Extended Taylor’s EquationExtended Taylor’s Equation

Crater WearCrater Wear

Relationship between crater wear rate and average tool chip interface temperature.(a) High speed steel, (b) Carbide, ( c ) C5 carbide

Other Types of Wear, Chipping and Other Types of Wear, Chipping and FactureFacture

(a) Schematic illustration (a) Schematic illustration of types of wear of types of wear observed on various observed on various cutting tools.cutting tools.

(b) Catastrophic tool (b) Catastrophic tool failures.failures.

Chapter 21 Sections 6 & 7

21.6 Surface Finish and Integrity21.6 Surface Finish and Integrity

21.7 Machinability 21.7 Machinability

21.6 Surface Finish and 21.6 Surface Finish and IntegrityIntegrity

Surface Finish describes the geometric Surface Finish describes the geometric features of a surface.features of a surface.

Surface integrity pertains to the material Surface integrity pertains to the material properties. properties.

Building exterior suffers from unsightly damage of mold infestation due to high humidity.  The strong oxidation effect of photocatalyst effectively removes mold and protects the surface integrity

Effects of tool-tip profileEffects of tool-tip profile

Built-up edge has the greatest influence Built-up edge has the greatest influence on surface finish.on surface finish.

(a) (b)

Figure 20.21 Surfaces produced on steel by cutting, as observed with a scanning electron microscope: (a) turned surface and (b) surface produced by shaping. Source: J. T. Black and S. Ramalingam.

Effect of tool-tip profileEffect of tool-tip profile

Ceramic and diamond tools generally Ceramic and diamond tools generally produce better surface finish than other produce better surface finish than other tools because of their much lower tools because of their much lower tendency to form a BUE.tendency to form a BUE.

Dull ToolsDull Tools

Large radius along its edge. Large radius along its edge. If tip radius of the tool is large in relation to If tip radius of the tool is large in relation to

the depth of cut, the cool simply will rub the depth of cut, the cool simply will rub over the machined surface.over the machined surface.

May cause surface damage, such as May cause surface damage, such as tearing and crackingtearing and cracking

Vibration and chatter Vibration and chatter

Vibration and chatter will affect the dimension of Vibration and chatter will affect the dimension of the workpiece surface finish adversely.the workpiece surface finish adversely.

Vibrating tool periodically changes the dimensions Vibrating tool periodically changes the dimensions of the cut. of the cut.

Excessive chatter also can cause chipping and Excessive chatter also can cause chipping and premature failure of the more brittle cutting tools. premature failure of the more brittle cutting tools.

Factors influencing surface Factors influencing surface integrityintegrity

Temperatures generated during Temperatures generated during processing and possible metallurgical processing and possible metallurgical transformations.transformations.

Surface residual stresses. Surface residual stresses. Severe plastic deformation and strain Severe plastic deformation and strain

hardening of the machined surfaces, hardening of the machined surfaces, tearing, and cracking. tearing, and cracking.

Finish Machining and Rough Finish Machining and Rough MachiningMachining

In finish machining, it is important to In finish machining, it is important to consider the surface finish to be producedconsider the surface finish to be produced

In rough machining, the main purpose is to In rough machining, the main purpose is to remove a large amount of material at a remove a large amount of material at a high rate. Surface finish is not a primary high rate. Surface finish is not a primary consideration. consideration.

Finish and Rough MachiningFinish and Rough Machining

21.7 Machinability21.7 Machinability

Machinability can be defined in terms of Machinability can be defined in terms of four factors:four factors: 1. Surface finish and surface integrity of the 1. Surface finish and surface integrity of the

machined part.machined part. 2. Tool life.2. Tool life. 3. Force and power required.3. Force and power required. 4. The level of difficulty in chip control.4. The level of difficulty in chip control.

Machinability Machinability

Good Machinability indicates good surface Good Machinability indicates good surface finish and integrity, long tool life, and low finish and integrity, long tool life, and low force, and low power requirement.force, and low power requirement.

Tool life and surface roughness are Tool life and surface roughness are considered to be the most important considered to be the most important factors. factors.

Machinability Ratings (index)Machinability Ratings (index)

Standard material: AISI 1112 steel, with a Standard material: AISI 1112 steel, with a rating of 100.rating of 100.

This means; for a tool life of 60min, this This means; for a tool life of 60min, this steel should be machined at a cutting steel should be machined at a cutting speed of 100ft/min (30m/min). speed of 100ft/min (30m/min).

Some examples; 3140 steel at 55; free-Some examples; 3140 steel at 55; free-cutting brass at 300; 2011 wrought cutting brass at 300; 2011 wrought aluminum at 200.aluminum at 200.

Machinability of ferrous metalsMachinability of ferrous metals

Machinability of steels, alloy steels, Machinability of steels, alloy steels, stainless steels, and cast iron. stainless steels, and cast iron.

21.7.1 Pg: 638.21.7.1 Pg: 638. Effects of various elements in steels.Effects of various elements in steels.

Presence of aluminum and silicon in steel is Presence of aluminum and silicon in steel is harmful. harmful.

Carbon and manganese have various effects Carbon and manganese have various effects depending on their composition. depending on their composition.

Machinability of nonferrous Machinability of nonferrous metalsmetals

Examples of nonferrous metals are:Examples of nonferrous metals are: Aluminum, Copper, Magnesium, Titanium, Aluminum, Copper, Magnesium, Titanium,

and Zirconium.and Zirconium.

21.7.2 Pg: 64021.7.2 Pg: 640

Machinability of miscellaneous Machinability of miscellaneous materialsmaterials

ThermoplasticsThermoplastics Thermosetting plasticsThermosetting plastics Polymer-matrix compositesPolymer-matrix composites Metal-matrix and ceramic matrix Metal-matrix and ceramic matrix

compositescomposites Graphite and CeramicsGraphite and Ceramics

WoodWood 21.7.3 Pg: 64121.7.3 Pg: 641

Thermally assisted machining (hot Thermally assisted machining (hot machining)machining)

Metals and alloys that are difficult to Metals and alloys that are difficult to machine at room temperature can be machine at room temperature can be machined more easily at elevated machined more easily at elevated temperatures.temperatures.

A source of heat (such as a torch, induced A source of heat (such as a torch, induced coil, electric current, laser-beam, electron-coil, electric current, laser-beam, electron-beam, and plasma arc) is focused onto an beam, and plasma arc) is focused onto an area just ahead of the cutting tool. area just ahead of the cutting tool.

Hot machiningHot machining

General advantages;General advantages; Reduced cutting forceReduced cutting force Increased tool lifeIncreased tool life Higher material-removal ratesHigher material-removal rates Reduced tendency for vibration and chatter.Reduced tendency for vibration and chatter.

Chapter 22Chapter 22Cutting-Tool Materials and Cutting FluidsCutting-Tool Materials and Cutting Fluids

Cutting Tool PropertiesCutting Tool Properties

Hot hardnessHot hardness High hot hardness means higher speeds and feed High hot hardness means higher speeds and feed

rates (higher production rates and lower costs).rates (higher production rates and lower costs).

Toughness and Impact strengthToughness and Impact strength Tool does not chip or fractureTool does not chip or fracture

Thermal shock resistanceThermal shock resistance Wear resistanceWear resistance

Tool does not have to be replaced as oftenTool does not have to be replaced as often

Chemical stability and inertnessChemical stability and inertness To minimize adverse reactionsTo minimize adverse reactions

Hot hardnessHot hardness

Cutting Tool MaterialsCutting Tool Materials

High-speed steelsHigh-speed steels Cast-cobalt alloysCast-cobalt alloys CarbidesCarbides Coated toolsCoated tools CeramicsCeramics DiamondDiamond

High-speed steelsHigh-speed steels Molybdenum (M-series)Molybdenum (M-series)

Contains up to 10% MolybdenumContains up to 10% Molybdenum High abrasion resistanceHigh abrasion resistance Low distortion during heat treatingLow distortion during heat treating Low costLow cost 95% of all high-speed steels are M-series95% of all high-speed steels are M-series

Tungsten (T-series)Tungsten (T-series) Improved strength and hot hardnessImproved strength and hot hardness More expensive than M-seriesMore expensive than M-series

Cast-cobalt alloysCast-cobalt alloys

38 to 53% cobalt38 to 53% cobalt High hardnessHigh hardness Not as tough as high-speed Not as tough as high-speed

steelssteels Used for deep continuous Used for deep continuous

roughing cutsroughing cuts High feed ratesHigh feed rates

CarbidesCarbides

Tungsten carbides (WC)Tungsten carbides (WC) Bonded together in a cobalt Bonded together in a cobalt

matrixmatrix SinteredSintered 6 to 16% cobalt6 to 16% cobalt Have largely replaced HSS toolsHave largely replaced HSS tools Used for cutting steels and cast Used for cutting steels and cast

ironsirons

CarbidesCarbides

Titanium carbides (TiC)Titanium carbides (TiC) Bonded in a Nickel-Bonded in a Nickel-

molybdenum matrixmolybdenum matrix Higher wear resistance Higher wear resistance

than WCthan WC Not as tough as WCNot as tough as WC Used for cutting steels Used for cutting steels

and cast ironsand cast irons Suitable for higher Suitable for higher

speeds than WCspeeds than WC

InsertsInserts

Cuts down on tool Cuts down on tool changing timechanging time

Increases number of Increases number of cutting pointscutting points

Have advanced chip Have advanced chip breaker featuresbreaker features

Come in various Come in various shapes and sizesshapes and sizes

InsertsInserts Insert shape determines strengthInsert shape determines strength Various ways if holding insert in placeVarious ways if holding insert in place

Coated toolsCoated tools

Coating propertiesCoating properties Lower frictionLower friction Higher adhesionHigher adhesion Higher resistance to Higher resistance to

wear and crackingwear and cracking Acting a a diffusion Acting a a diffusion

barrierbarrier Higher hot hardness Higher hot hardness

and impact resistanceand impact resistance

Coating materialsCoating materials

Titanium-nitrideTitanium-nitride Low friction and high Low friction and high

hardnesshardness

Titanium carbideTitanium carbide Improves wear Improves wear

resistance on WCresistance on WC

CeramicsCeramics DiamondDiamond

Increases tool life ten Increases tool life ten fold compared to other fold compared to other coatingscoatings

22.6: Alumina Based Ceramics22.6: Alumina Based Ceramics

Ceramic ToolsCeramic ToolsPrimarily made of aluminum oxidePrimarily made of aluminum oxide Introduced in the early 1950sIntroduced in the early 1950sAfter being cold pressed into insert shapes After being cold pressed into insert shapes

under high pressure and sintered at high under high pressure and sintered at high temperature, they are known as “white temperature, they are known as “white ceramics”.ceramics”.

22.6: Alumina Based Ceramics22.6: Alumina Based Ceramics

CharacteristicsCharacteristics Chemically stableChemically stable Not very toughNot very tough High abrasion resistanceHigh abrasion resistance Hot hardnessHot hardness Poor tensile strengthPoor tensile strength

22.6 Alumina Based Ceramics22.6 Alumina Based Ceramics

Cermets (Black Ceramics)Cermets (Black Ceramics) Consist of ceramic materials in a metallic matrixConsist of ceramic materials in a metallic matrix Typically: 70% Aluminum Oxide, 30% Titanium Typically: 70% Aluminum Oxide, 30% Titanium

CarbideCarbide Not widely used due to high costNot widely used due to high cost

Cermets tip cutting blade.

22.7: Cubic Born Nitride22.7: Cubic Born Nitride

Cubic Boron NitrideCubic Boron Nitride cBN: 2cBN: 2ndnd hardest material available hardest material available

Formerly known as BorazonFormerly known as Borazon

Polycrystalline cubic boron nitride is bonded to a carbide Polycrystalline cubic boron nitride is bonded to a carbide substrate by sintering under high pressure and temp.substrate by sintering under high pressure and temp.

High thermal conductivityHigh thermal conductivity

Excellent wear resistanceExcellent wear resistance

CBn coated cutting insertsCBn coated cutting inserts

22.8: Silicon-Nitride-Based 22.8: Silicon-Nitride-Based CeramicsCeramics

Consist of silicon nitride, aluminum oxide, yttrium Consist of silicon nitride, aluminum oxide, yttrium oxide, and titanium carbide.oxide, and titanium carbide.

Characteristics:Characteristics: ToughTough Hot hardnessHot hardness Good thermal shock resistanceGood thermal shock resistance

Sialon sink roll bearing

22.9: Diamond22.9: Diamond

Characteristics:Characteristics: Hardest material known todayHardest material known today High wear resistanceHigh wear resistance Low frictionLow friction Maintains a sharp cutting edgeMaintains a sharp cutting edge Produces a very accurate cut and good surface Produces a very accurate cut and good surface

finish.finish. Most effective in light uninterrupted finishing cuts.Most effective in light uninterrupted finishing cuts.

22.9: Diamond22.9: Diamond

Synthetic diamonds are preferred because natural Synthetic diamonds are preferred because natural diamonds have flaws which at times make them diamonds have flaws which at times make them unpredictable.unpredictable.

Image of a synthetic Russian diamond

22.9: Diamond22.9: Diamond

Polycrystalline Diamond ToolsPolycrystalline Diamond Tools Known as compactsKnown as compacts May be used as dies for fine wire drawingMay be used as dies for fine wire drawing Between .5 and 1 mm of diamond are bonded to a Between .5 and 1 mm of diamond are bonded to a

carbide substrate. (similar to cBN tools)carbide substrate. (similar to cBN tools)

Image of a compact

22.10: Whisker-Reinforced Tool 22.10: Whisker-Reinforced Tool MaterialsMaterials

Due to the high reactivity of silicon carbide with ferrrous Due to the high reactivity of silicon carbide with ferrrous metals, SiC tools are unsuitable for machining irons and metals, SiC tools are unsuitable for machining irons and steels. steels.

Whisker-reinforced cutting tools include:Whisker-reinforced cutting tools include: silicon-nitride based tools with silicon-carbide whiskerssilicon-nitride based tools with silicon-carbide whiskers Aluminum-oxide based tools reinforced with 25- 40 % silicon-Aluminum-oxide based tools reinforced with 25- 40 % silicon-

carbide whiskers carbide whiskers

Image of whisker-reinforced ceramics

22.11: Tool Costs and 22.11: Tool Costs and Reconditioning of ToolsReconditioning of Tools

Factors that affect tool cost:Factors that affect tool cost: MaterialMaterial SizeSize ShapeShape Chip-breaker featuresChip-breaker features QualityQuality

22.11: Tool Costs and...22.11: Tool Costs and...

• Typical costs of a typical .5 inch insert:

• Cubic Boron Nitride:– $60-90

• Diamond-coated carb.:– $50-60

• Ceramics– $8-12

• Coated carbides:– $6-10

• Uncoated carbides: – $2-10

• Diamond-tipped insert:– $90-100

Tooling costs account for approximately 2 to 4 % of manufacturing costs.

22.11: Tool Costs and...22.11: Tool Costs and...

Reconditioning tools allows for longer use.Reconditioning tools allows for longer use. ResharpeningResharpening Recoating of coated toolsRecoating of coated tools Tools will only be reconditioned if it is economicalTools will only be reconditioned if it is economical Often times tools will be recycledOften times tools will be recycled

Equipment used in the reconditioning of cutting tools

22.12: Cutting Fluids22.12: Cutting Fluids

Purpose of cutting fluidsPurpose of cutting fluids Reduce friction and wearReduce friction and wear Cool cutting zoneCool cutting zone Flush chips away from the cutting zoneFlush chips away from the cutting zone Protect the machined surface from environmental corrosionProtect the machined surface from environmental corrosion

These factors improve tool life and help make a These factors improve tool life and help make a better more efficient cut.better more efficient cut.

Image of cutting fluid and its container

22.12: Cutting Fluids22.12: Cutting Fluids

Lubricants reduce frictionLubricants reduce friction

Coolants effectively reduce high temperatures of tools/ Coolants effectively reduce high temperatures of tools/ work pieceswork pieces

At times, using a cutting fluid may cause the material to At times, using a cutting fluid may cause the material to become “curly”, which concentrates the heat closer to become “curly”, which concentrates the heat closer to the tip. This is detrimental because it decreases the the tip. This is detrimental because it decreases the tool’s life. tool’s life.

It is these defects that have turned machinists to “near-It is these defects that have turned machinists to “near-dry machining” (22.12).dry machining” (22.12).

22.12: Cutting Fluids22.12: Cutting Fluids

Types of cutting fluids:Types of cutting fluids: Oils:Oils: mineral, animal, vegetable, compounded, and synthetic mineral, animal, vegetable, compounded, and synthetic

oils. Only used in operations where temp rise is oils. Only used in operations where temp rise is insignificantinsignificant.. Emulsions: Emulsions: mixture of oil and water and additives. Good for mixture of oil and water and additives. Good for

operations where temperature rise operations where temperature rise is significantis significant.. Semisynthetics: Semisynthetics: chemical emulsions containing little mineral chemical emulsions containing little mineral

oil diluted in water with additives that reduce size of particles.oil diluted in water with additives that reduce size of particles. Synthetics: Synthetics: chemicals with additives, diluted in water, without chemicals with additives, diluted in water, without

oil.oil.

Image of a “synthetic” cutting fluid.

22.12 Cutting Fluids22.12 Cutting Fluids

Methods of ApplicationMethods of Application Flooding:Flooding: most common; rates of up to 225 L/min for multi- most common; rates of up to 225 L/min for multi-

tooth cutters; poor visibility; 100- 2000 Psi.tooth cutters; poor visibility; 100- 2000 Psi. MistMist:: most effective w/ water based fluids; requires venting most effective w/ water based fluids; requires venting

but is popular because of good visibility; similar to using an but is popular because of good visibility; similar to using an aerolsol can; 10- 80 Psi.aerolsol can; 10- 80 Psi.

High-pressure systemsHigh-pressure systems: use a powerful jet/nozzle to target : use a powerful jet/nozzle to target the hot area; 800- 5000 Psi; can be used as a chip-breaker the hot area; 800- 5000 Psi; can be used as a chip-breaker to clear debris away.to clear debris away.

Through the cutting tool system: Through the cutting tool system: passages are made in passages are made in the tool/ tool handle that allow for a direct route for the the tool/ tool handle that allow for a direct route for the coolant to the hot area.coolant to the hot area.

22.12 Cutting Fluids22.12 Cutting Fluids

Special Considerations for use of cutting fluidsSpecial Considerations for use of cutting fluids Machines need to be washed after fluids have been Machines need to be washed after fluids have been

used.used.

Used cutting fluids may undergo chemical changes. Used cutting fluids may undergo chemical changes. Settling skimming centrifuging and filtering help to avoid Settling skimming centrifuging and filtering help to avoid any bad effects they may cause.any bad effects they may cause.

Cutting fluids containing:Cutting fluids containing: Sulfur should not be used on Nickel based alloys.Sulfur should not be used on Nickel based alloys. Chlorine should not be used with TitaniumChlorine should not be used with Titanium

22.12: Near-dry and Dry Machining22.12: Near-dry and Dry Machining

Introduced in 1990’s to minimize use of metalworking Introduced in 1990’s to minimize use of metalworking fluids. fluids.

In these processes, chips are removed from the cutting In these processes, chips are removed from the cutting zone by application of pressurized air.zone by application of pressurized air.

Dry machiningDry machining:: Used for turning, milling, and gear cutting on steels, steel alloys, Used for turning, milling, and gear cutting on steels, steel alloys,

and cast irons.and cast irons.

Near-dry cuttingNear-dry cutting:: The application of a mist of a mixture of water and cutting fluid The application of a mist of a mixture of water and cutting fluid

(vegetable oil) inserted through the spindle of the machine tool, (vegetable oil) inserted through the spindle of the machine tool, 85 psi.85 psi.

22.12: Near-dry and Dry Machining22.12: Near-dry and Dry Machining

Cryogenic Machining: Cryogenic Machining: Cryogenic gases such as nitrogen and carbon dioxide are used Cryogenic gases such as nitrogen and carbon dioxide are used

as a coolant. They are shot through a small nozzle at as a coolant. They are shot through a small nozzle at temperatures around -200 C; good for tool life, good for the temperatures around -200 C; good for tool life, good for the environment.environment.

Image of a liquid nitrogen cooling system.