2.2 force, power in metal cutting q&a for student

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Force & Power in Metal Cutting

BySKMondalCompiledby:SKMondalMadeEasy

ESE2003 ConventionalDuring turning a carbon steel rod of 160 mm diameter by acarbide tool of geometry; 0, 0, 10, 8, 15, 75, 0 (mm) at speed of400 rpm, feed of 0.32 mm/rev and 4.0 mm depth of cut, thefollowing observation weremade.

Tangential component of the cutting force, Pz = 1200 NAxial component of the cutting force P = 800 NAxial component of the cutting force, Px = 800 NChip thickness (after cut),

For the abovemachining condition determine the values of(i) Friction force, F and normal force, N acting at the chip toolinterface.(ii) Yield shears strength of the work material under thismachining condition.(iii) Cutting power consumption in kW.

Ans F = 800 N N = 1200 N 256 7 Mpa 4 021 KW

=2 0.8mm.

Compiledby:SKMondalMadeEasy

GATE 1995ConventionalWhile turning a C15 steel rod of 160 mm diameter at315 rpm, 2.5 mm depth of cut and feed of 0.16mm/rev by a tool of geometry 00, 100, 80, 90,150, 750,0(mm), the following observationsweremade.Tangential component of the cutting force = 500 N

Axial component of the cutting force = 200 NChip thickness = 0.48 mm

Draw schematically the Merchants circle diagramfor the cutting force in the present case.

Ans. F = 2 9 1 , N = 457.67 N, Fn = 3 5 5.78 N, Fs = 40 8.31 NFriction angle = 32.49oCompiledby:SKMondalMadeEasy

ESE2000(Conventional)The following data from the orthogonal cutting testis available. Rake angle = 100, chip thickness ratio =0.35, uncut chip thickness = 0.51, width of cut = 3mm, yield stress of work material = 285 N/mm2,mean friction coefficient on tool force = 0.65,5,Determine

(i) Cutting force (Fc)(ii) Radial force (Ft)(iii) Normal force (N) on tool and(iv) Shear force on the tool (Fs ).

Ans. Fc = 1597 N; Ft = 678 N; Fs = 1265 N; F = 944.95 N, N =1453.8 N


ESE2005ConventionalMild steel is being machined at a cuttingspeed of 200 m/min with a tool rake angle of10. The width of cut and uncut thickness are 2mm and 0.2 mm respectively. If the averagep y gvalue of coefficient of friction between thetool and the chip is 0.5 and the shear stress ofthework material is 400 N/mm2,

Determine (i) shear angle and [Ans. 36.7o

(ii)Cutting and thrust component of themachine on force. [Ans. Fc = 420 N, Ft = 125 N ]Compiledby:SKMondalMadeEasy

IAS2003MainExaminationDuring turning process with 7 6 6 8 30 1 (mm)ASA tool the undeformed chip thickness of 2.0 mm andwidth of cut of 2.5 mmwere used. The side rake angle ofthe tool was a chosen that the machining operationcould be approximated to be orthogonal cutting Thecould be approximated to be orthogonal cutting. Thetangential cutting force and thrust force were 1177 N and560 N respectively. Calculate:[30 marks](i) The side rake angle [Ans. 12o ](ii) Coefficient of friction at the rake face [Ans. 0.82](iii) The dynamic shear strength of the work material

[Ans. 74.43 Mpa] Compiledby:SKMondalMadeEasy

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GATE2006CommonDataQuestions(1)Inanorthogonalmachiningoperation:Uncutthickness=0.5mmCuttingspeed=20m/min Rakeangle=15Widthofcut=5mm Chipthickness=0.7mmWidthofcut 5mm Chipthickness 0.7mmThrustforce=200N Cuttingforce=1200NAssumeMerchant'stheory.Thecoefficientoffrictionatthetoolchipinterfaceis(a)0.23 (b)0.46(c)0.85 (d)0.95

Ans.(b)Compiledby:SKMondalMadeEasy

GATE2006CommonDataQuestions(2)Inanorthogonalmachiningoperation:Uncutthickness=0.5mmCuttingspeed=20m/min Rakeangle=15Widthofcut=5mm Chipthickness=0.7mmWidthofcut 5mm Chipthickness 0.7mmThrustforce=200N Cuttingforce=1200NAssumeMerchant'stheory.Thepercentageoftotalenergydissipatedduetofrictionatthetoolchipinterfaceis

(a)30% (b)42%(c)58% (d)70% Ans.(a)


GATE2006CommonDataQuestions(3)Inanorthogonalmachiningoperation:Uncutthickness=0.5mmCuttingspeed=20m/min Rakeangle=15Widthofcut=5mm Chipthickness=0.7mmWidthofcut 5mm Chipthickness 0.7mmThrustforce=200N Cuttingforce=1200NAssumeMerchant'stheory.Thevaluesofshearangleandshearstrain,respectively,are

(a)30.3 and1.98 (b)30.3 and4.23(c)40.2 and2.97 (d)40.2 and1.65Ans.(d)


GATE2003CommonDataQuestions(1)A cylinder is turned on a lathe with orthogonalmachining principle. Spindle rotates at 200 rpm. Theaxial feed rate is 0.25 mm per revolution. Depth of cut is0.4 mm. The rake angle is 10. In the analysis it is foundth t th h l i that the shear angle is 27.75

Thethicknessoftheproducedchipis(a)0.511mm (b)0.528mm(c)0.818mm (d)0.846mmAns.(a)


GATE2003CommonDataQuestions(2)A cylinder is turned on a lathe with orthogonalmachining principle. Spindle rotates at 200 rpm. Theaxial feed rate is 0.25 mm per revolution. Depth of cut is0.4 mm. The rake angle is 10. In the analysis it is foundth t th h l i that the shear angle is 27.75Intheaboveproblem,thecoefficientoffrictionatthechiptoolinterfaceobtainedusingEarnestandMerchanttheoryis(a)0.18 (b)0.36(c)0.71 (d)0.908

Ans.(d)Compiledby:SKMondalMadeEasy

GATE2008CommonDataQuestion(1)Orthogonal turning is performed on a cylindrical workpiece with shear strength of 250 MPa. The followingconditions are used: cutting velocity is 180 m/min. feedis 0.20 mm/rev. depth of cut is 3 mm. chip thicknessti Th th l k l i o A lratio = 0.5. The orthogonal rake angle is 7o. Apply

Merchant's theory for analysis.Theshearplaneangle(indegree)andtheshearforcerespectivelyare(a)52:320N (b)52:400N(c)28:400N (d)28:320NAns.(d)


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GATE2008CommonDataQuestion(2)Orthogonal turning is performed on a cylindrical workpiece with shear strength of 250 MPa. The followingconditions are used: cutting velocity is 180 m/min. feedis 0.20 mm/rev. depth of cut is 3 mm. chip thicknessti Th th l k l i o A lratio = 0.5. The orthogonal rake angle is 7o. Apply

Merchant's theory for analysis.Thecuttingandfrictionalforces,respectively,are(a)568N;387N (b)565N;381N(c)440N;342N (d)480N;356NAns.(b)


IES2010The relationship between the shear angle ,the friction angle and cutting rake angle is given as


IES2005Which one of the following is the correctexpression for the Merchant's machinabilityconstant?(a) 2 +(a)(b)(c)(d)(Where = shear angle, = friction angleand = rake angle) Ans. (a)

2 + 2 +2 +


GATE1997Inatypicalmetalcuttingoperation,usingacuttingtoolofpositiverakeangle=10,itwasobservedthattheshearanglewas20.Thefrictionangleisg(a)45 (b)30(c)60 (d)40

Ans.(c)


IAS 1999In an orthogonal cutting process, rake angle of thetool is 20 and friction angle is 25.5. UsingMerchant's shear angle relationship, the value ofshear angle will be(a) 39 5 (b) 42 25(a) 39.5 (b) 42.25(c) 47.75 (d) 50.5

Ans. (b)


IES2003In orthogonal cutting test, the cutting force =900 N, the thrust force = 600 N and chipshear angle is 30o. Then the chip shear force is(a) 1079 4 N (b) 969 6 N(a) 1079.4 N (b) 969.6 N(c) 479.4 N (d) 69.6 N

Ans. (c)


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IES2000In an orthogonal cutting test, the cutting force and

thrust force were observed to be 1000N and 500 N

respectively. If the rake angle of tool is zero, the

coefficient of friction in chiptool interface will be

( ) ( ) ( ) ( )1 1a b 2 c d 2 2 2Ans.(a)


IES1996Which of the following forces are measured directly bystrain gauges or force dynamometers during metalcutting ?1. Force exerted by the tool on the chip acting normally tothe tool face.2. Horizontal cutting force exerted by the tool on the workpiece.3. Frictional resistance of the tool against the chip flowacting along the tool face.4. Vertical force which helps in holding the tool inposition.(a) 1 and 3 (b) 2 and 4(c) 1 and 4 (d) 2 and 3 Ans. (b)Compiledby:SKMondalMadeEasy

GATE2007Inorthogonalturningofmediumcarbonsteel.Thespecificmachiningenergyis2.0J/mm3.Thecuttingvelocity,feedanddepthofcutare120m/min,0.2mm/revand2mmrespectively.Themaincuttingf i NiforceinNis(a)40 (b)80(c)400 (d)800

Ans.(d)


GATE2007In orthogonal turning of low carbon steel pipe withprincipal cutting edge angle of 90, themain cuttingforce is 1000 N and the feed force is 800 N. The shearangle is 25 and orthogonal rake angle is zero.E l i M h t th th ti f f i tiEmploying Merchants theory, the ratio of frictionforce to normal force acting on the cutting tool is(a) 1.56 (b) 1.25(c) 0.80 (d) 0.64

Ans. (c)


IES1997Consider the following forces acting on afinish turning tool:1. Feed force2 Thrust force2. Thrust force3. Cutting force.The correct sequence of the decreasing order ofthe magnitudes of these forces is(a) 1, 2, 3 (b) 2, 3, 1(c) 3, 1, 2 (d) 3, 2, 1 Ans. (c)


IES1999The radial force in singlepoint tool duringturning operation varies between(a) 0.2 to 0.4 times the main cutting force(b) 0 4 to 0 6 times the main cutting force(b) 0.4 to 0.6 times the main cutting force(c) 0.6 to 0.8 times the main cutting force(d) 0.5 to 0.6 times the main cutting force

Ans. (a)


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IES1995The primary tool force used in calculatingthe total power consumption in machining isthe(a) Radial force (b) Tangential force(a) Radial force (b) Tangential force(c) Axial force (d) Frictional force

Ans. (b)


IES2002In a machining process, the percentage ofheat carried away by the chips is typically(a) 5% (b) 25%(c) 0% (d) %(c) 50% (d) 75%

Ans. (d)


IES1998In metal cutting operation, the approximateratio of heat distributed among chip, tooland work, in that order is(a) 80: 10: 10 (b) 33: 33: 33(a) 80: 10: 10 (b) 33: 33: 33(c) 20: 60: 10 (d) 10: 10: 80

Ans. (a)


IAS 2003Asthecuttingspeedincreases(a) Moreheatistransmittedtotheworkpieceandlessheatistransmittedtothetool(b) Moreheatiscarriedawaybythechipandlessheatist itt dt th t ltransmittedtothetool(c) Moreheatistransmittedtoboththechipandthetool(d) Moreheatistransmittedtoboththeworkpieceandthetool


IES2001Power consumption in metal cutting ismainly due to(a) Tangential component of the force(b) Longitudinal component of the force(b) Longitudinal component of the force(c) Normal component of the force(d) Friction at the metaltool interface

Ans. (a)


IAS 1995Thrustforcewillincreasewiththeincreasein(a) Sidecuttingedgeangle(b)Toolnoseradius(c) Rakeangle(d)Endcuttingedgeangle

Ans.(a)


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IES2010Consider the following statements:In an orthogonal, singlepoint metal cutting,as the sidecutting edge angle is increased,

1. The tangential force increases.g2. The longitudinal force drops.3. The radial force increases.Which of these statements are correct?(a) 1 and 3 only (b) 1 and 2 only(c) 2 and 3 only (d) 1, 2 and 3 Ans. (c)


IES1993A 'Dynamometer' is a device used for themeasurement of(a) Chip thickness ratio(b) Forces during metal cutting(b) Forces during metal cutting(c) Wear of the cutting tool(d) Deflection of the cutting tool

Ans. (b)


IES2011Theinstrumentordeviceusedtomeasurethecuttingforcesinmachiningis:(a)Tachometer(b)Comparator(c)Dynamometer(d)Lactometer

Ans.(c)


IAS 2003The heat generated in metal cutting canconveniently be determined by(a) Installing thermocouple on the job(b) Installing thermocouple on the tool(c) Calorimetric setup(d) Using radiation pyrometer

Ans. (c)


IES1998The gauge factor of a resistive pickup ofcutting force dynamometer is defined as theratio of(a) Applied strain to the resistance of the wire(a) Applied strain to the resistance of the wire(b) The proportional change in resistance to theapplied strain(c) The resistance to the applied strain(d) Change in resistance to the applied strain

Ans. (b)Compiledby:SKMondalMadeEasy

IES2000Assertion (A): In metal cutting, the normallaws of sliding friction are not applicable.Reason (R): Very high temperature isproduced at the toolchip interfaceproduced at the toolchip interface.(a) Both A and R are individually true and R isthe correct explanation of A(b) Both A and R are individually true but R isnot the correct explanation of A(c) A is true but R is false(d) A is false but R is true Ans. (a) Compiledby:SKMondalMadeEasy

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GATE1992The effect of rake angle on the mean friction angle inmachining can be explained by(A) sliding (Coulomb) model of friction(B) sticking and then sliding model of friction(C) sticking friction(D) Sliding and then sticking model of friction

Ans. (b)


IES2004Assertion (A): The ratio of uncut chip thickness toactual chip thickness is always less than one and istermed as cutting ratio in orthogonal cuttingReason (R): The frictional force is very high due to theoccurrence of sticking friction rather than slidingg gfriction(a) Both A and R are individually true and R is the correctexplanation of A(b) Both A and R are individually true but R is not thecorrect explanation of A(c) A is true but R is false(d) A is false but R is true Ans. (b)


GATE1993The effect of rake angle on themean friction angle inmachining can be explained by(a) Sliding (coulomb) model of friction(b) sticking and then siding model of frictiong g(c) Sticking friction(d) sliding and then sticking model of friction

Ans. (d)

Compiledby:SKMondalMadeEasy Compiledby:SKMondalMadeEasy

2.2 force, power in metal cutting q&a for student

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