analysis of drilling tool life—a review

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Int. J. Mech. Eng. & Rob. Res. 2015 Dhanraj Patel and Rajesh Verma, 2015

ANALYSIS OF DRILLING TOOL LIFE—A REVIEWDhanraj Patel1* and Rajesh Verma2

*Corresponding Author: Dhanraj Patel,[email protected]

Drilling is a cutting process that uses a drill bit to cut or enlarge a hole of circular cross-sectionin solid materials. The drill bit is a rotary cutting tool, often multipoint. The bit is pressed againstthe work piece and rotated at rates from hundreds to thousands of revolutions per minute. Thisforces the cutting edge against the work piece, cutting off chips (swarf) from the hole as it isdrilled. Here we are analyzing the drilling tool life, which showed us that there are differentparameters (Force, feeding Rate, MOQ, Tool Material, Tool Geometry, etc.), which are affectingthe Drilling Tool Life.

Keywords: Drill, Drilling tool, Drilling bid

INTRODUCTIONA drill is a tool fitted with a cutting toolattachment or driving tool attachment, usuallya drill bit or driver bit, used for boring holes invarious materials or fastening variousmaterials together with the use of fasteners.The attachment is gripped by a chuck at oneend of the drill and rotated while pressedagainst the target material. The tip, andsometimes edges, of the cutting tool does thework of cutting into the target material. Thismay be slicing off thin shavings (twist drills orauger bits), grinding off small particles (oildrilling), crushing and removing pieces of theworkpiece (SDS masonry dril l) ,countersinking, counterboring, or otheroperations.

ISSN 2278 – 0149 www.ijmerr.comVol. 4, No. 1, January 2015

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Int. J. Mech. Eng. & Rob. Res. 2015

1 Truba College of Engineering and Technology, Indore, MP.2 Mechanical Department of Truba College of Engineering and Technology, Indore, MP, India.

Drills are commonly used in woodworking,metalworking, construction and do-it-yourselfprojects. Specially designed drills are alsoused in medicine, space missions and otherapplications. Drills are available with a widevariety of performance characteristics, such aspower and capacity.

There are many types of drills: some arepowered manually, others use electricity(electric drill) or compressed air (pneumaticdrill) as the motive power. Drills with apercussive action (hammer drills) are mostlyused in hard materials such as masonry (brick,concrete and stone) or rock. Drilling rigs areused to bore holes in the earth to obtain wateror oil. Oil wells, water wells, or holes forgeothermal heating are created with large

Review Article

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drilling rigs. Some types of hand-held drills arealso used to drive screws and other fasteners.Some small appliances that have no motor oftheir own may be drill-powered, such as smallpumps, grinders, etc.

Drilling Machine: A Drilling Machine (alsoknown as a pedestal drill, pillar drill, or benchdrill) is a fixed style of drill that may be mountedon a stand or bolted to the floor or workbench.Portable models with a magnetic base gripthe steel work pieces they drill. A DrillingMachine consists of a base, column (or pillar),table, spindle (or quill), and drill head, usuallydriven by an induction motor. The head has aset of handles (usually 3) radiating from acentral hub that, when turned, move the spindleand chuck vertically, parallel to the axis of thecolumn. The size of a Drilling Machine istypically measured in terms of swing. Swing isdefined as twice the throat distance, which isthe distance from the center of the spindle tothe closest edge of the pillar. For example, a

16-inch (410 mm) Drilling Machine has an 8-inch (200 mm) throat distance.

Drilling Capacity: Drilling capacity indicatesthe maximum diameter a given power drill orDrilling Machine can produce in a certainmaterial. It is essentially a proxy for thecontinuous torque the machine is capable ofproducing. Typically a given drill will have itscapacity specified for different materials, i.e.,10 mm for steel, 25 mm for wood, etc.

For example, the maximum recommendedcapacities for the DeWalt DCD790 cordlessdrill for specific drill bit types and materials areas follows:

Figure 1: Schematic of Drilling Machine

Material Drill Bit Type Capacity

Wood Auger 7/8 in (22 mm)

Paddle 1 1/4 in (32 mm)

Twist 1/2 in (13 mm)

Self-feed 1 3/8 in (35 mm)

Hole saw 2 in (51 mm)

Metal Twist 1/2 in (13 mm)

Hole saw 1 3/8 in (35 mm)

Table 1: Capacity of Drilling Bit

Figure 2: Different Types of Drill Bits

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Drill Bit: Drill bits are cutting tools used tocreate cylindrical holes, almost always ofcircular cross-section. Drill bits come in manysizes and have many uses. Bits are usuallyconnected to a mechanism, often simplyreferred to as a drill, which rotates them andprovides torque and axial force to create thehole.

The shank is the part of the drill bit graspedby the chuck of a drill. The cutting edges of thedrill bit are at one end, and the shank is at theother.

Drill bits come in standard sizes, describedin the drill bit sizes article. A comprehensivedrill bit and tap size chart lists metric andimperial sized drill bits alongside the requiredscrew tap sizes.

Tool Geometry

• The spiral (or rate of twist) in the drill bitcontrols the rate of chip removal. A fastspiral (high twist rate or “compact flute”) drill

bit is used in high feed rate applicationsunder low spindle speeds, where removalof a large volume of swarf is required. Lowspiral (low twist rate or “elongated flute”) drillbits are used in cutting applications wherehigh cutting speeds are traditionally used,and where the material has a tendency togall on the bit or otherwise clog the hole,such as aluminum or copper.

• The point angle, or the angle formed at thetip of the bit, is determined by the materialthe bit will be operating in. Harder materialsrequire a larger point angle, and softermaterials require a sharper angle. Thecorrect point angle for the hardness of thematerial controls wandering, chatter, holeshape, wear rate, and other characteristics.

• The lip angle determines the amount ofsupport provided to the cutting edge. Agreater lip angle will cause the bit to cutmore aggressively under the same amountof point pressure as a bit with a smaller lip

Figure 3: Tool Geometry

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angle. Both conditions can cause binding,wear, and eventual catastrophic failure ofthe tool. The proper amount of lip clearanceis determined by the point angle. A veryacute point angle has more web surfacearea presented to the work at any one time,requiring an aggressive lip angle, where aflat bit is extremely sensitive to smallchanges in lip angle due to the smallsurface area supporting the cutting edges.

• The length of a bit determines how long ahole can be drilled, and also determines thestiffness of the bit and accuracy of theresultant hole. Twist drill bits are availablein standard lengths, referred to as Stub-length or Screw-Machine-length (short), theextremely common Jobber-length(medium), and Taper-length or Long-Series(long).

The diameter-to-length ratio of the drill bitis usually between 1:1 and 1:10. Much higherratios are possible (e.g., “aircraft-length” twistbits, pressured-oil gun drill bits, etc.), but thehigher the ratio, the greater the technicalchallenge of producing good work.

The best geometry to use depends uponthe properties of the material being drilled. The

following table lists geometries recommendedfor some commonly drilled materials.

Twist Drill Bits: The twist drill bit is the typeproduced in largest quantity today. It comprisesa cutting point at the tip of a cylindrical shaftwith helical flutes; the flutes act as anArchimedean screw and lift swarf out of thehole.

The twist drill bit was invented by Steven A.Morse of East Bridgewater, Massachusetts in1861. The original method of manufacture wasto cut two grooves in opposite sides of a roundbar, then to twist the bar (giving the tool itsname) to produce the helical flutes. Nowadays,the drill bit is usually made by rotating the barwhile moving it past a grinding wheel to cutthe flutes in the same manner as cutting helicalgears.

Twist drill bits range in diameter from 0.002to 3.5 in (0.051 to 88.900 mm) and can be aslong as 25.5 in (650 mm).

The geometry and sharpening of the cuttingedges is crucial to the performance of the bit.Small bits that become blunt are oftendiscarded because sharpening them correctlyis difficult and they are cheap to replace. Forlarger bits, special grinding jigs are available.A special tool grinder is available forsharpening or reshaping cutting surfaces ontwist drill bits in order to optimize the bit for aparticular material.

The most common twist drill bit has a pointangle of 118 degrees, acceptable for use inwood, metal, plastic, and most othermaterials, although it does not perform aswell as using the optimum angle for eachmaterial. In most materials it does not tend towander or dig in.

Aluminum 90 to 135 32 to 48 12 to 26

Brass 90 to 118 0 to 20 12 to 26

Cast iron 90 to 118 24 to 32 7 to 20

Mild steel 118 to 135 24 to 32 7 to 24

Stainless steel 118 to 135 24 to 32 7 to 24

Plastics 60 to 90 0 to 20 12 to 26

Table 2: Different Angles for DifferentMaterials

Tool Geometry

WorkpieceMaterial

PointAngle

HelixAngle

Lip ReliefAngle

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A more aggressive angle, such as 90degrees, is suited for very soft plastics andother materials; it would wear rapidly in hardmaterials. Such a bit is generally self-startingand can cut very quickly. A shallower angle,such as 150 degrees, is suited for drillingsteels and other tougher materials. This styleof bit requires a starter hole, but does not bindor suffer premature wear so long as a suitablefeed rate is used.

Drill bits with no point angle are used insituations where a blind, flat-bottomed hole isrequired. These bits are very sensitive tochanges in lip angle, and even a slight changecan result in an inappropriately fast cutting drillbit that will suffer premature wear.

efficiency. Field experience usually providesthe basis for operations in a particular area,but testing often is too costly and experiencetoo late. Consequently, a method fordetermining optimum drilling techniques andparameters for any particular drilling condition,with a minimum of engineering effort anddrilling experience is greatly needed.

The drilling parameters, or variables,associated with rotary drilling have beenanalysed and divided in two groups asindependent and dependent parameters(Barr and Brown, 1983; Ambrose, 1987; andShah, 1992). The independent variables arethose which can be directly controlled by thedrilling rig operator and dependent variablesare those which represent the response of thedrilling system to the drilling operation. Thereare, of course, many factors other than thosediscussed here that effect drilling efficiencyand footage cost. These include such factorsas formation hardness, abrasiveness of

Figure 4: Schematic of Drilling Process

LITERATURE REVIEWPrinciples of Drilling: The wide variations indrilling conditions encountered under fieldconditions make it difficult to develop generalrules of operation for maximum drilling

Figure 5: Drilling Variables Associatedwith Rotary Drilling

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connation and well depth. As these itemscannot be conveniently controlled, theirinfluence on costs must simply be accepted.

Dependent Variables

The dependent variables associated withrotary drilling represent the response of the

drilling system to the imposed conditions andare the penetration rate of the bit, the torqueand the flush medium pressure.

Penetration Rate: The Rate Of Penetration(ROP) of the rotary bit through rock, isexpressed in units of distance per unit time.

The rate of penetration is considered as oneof the primary factors which affect drilling costsand hence it is given a prior consideration whenplanning for optimised drilling. The subject ofdrilling rate has been extensively analysed fromboth the theoretical standpoint and the

experimental standpoint with the objective ofmaximising drill ing rate and improvingoperating efficiencies (Lummus, 1969 and1970; Eckel, 1967; Huff and Varnado, 1980;Kelsey, 1982; Holester and Kipp, 1984;

Ambrose, 1987; Warren and Armagost, 1988;Waller, 1991; and Shah, 1992). Miniature drillbits have been widely used in the laboratoryto study combinations of independent drillingvariables, as well as to relate drilling rate tomeasurable rock properties. The

determination of the rate of penetration is oneof the most important objectives, and istherefore considered and presented in detailin this thesis. Collectively, contributions to theunderstanding of these factors on thepenetration rate have been greatly exploited

in an effort to dril l faster and moreeconomically.

Torque: Torque is defined as the forcerequired to tum the drill rod, which leads to thebit rotating against the resistance to the cuttingand friction forces. In shallow boreholes, thetorque is the result of the forces resisting thecutting and shearing action generated at thebit/rock contact by the rotation of the bit. Indeep boreholes, additional torque is requiredto overcome additional forces between thedrill rods and the flushing medium. Torque isusually measured in Nm.

The torque required to rotate a bit is ofinterest for several reasons. First, it may giveinformation about the formation being drilledand/or the condition of the bit. Second, bittorque exerts a significant influence on the "bitwalk" experienced in directional wells. Finally,a prediction of bit torque may be useful inmatching a bit and mud motor for optimalperformance.

Several authors (Paone et al., 1969; Clark,1979 and 1982; Warren, 1983; Ambrose,1987; Waller, 1991; and Shah, 1992) havepresented theoretical bit torque relationshipsderived by testing many types of rocks withcoring and non-coring bits, and found that thepenetration rate increases with torque and acritical value of torque exists below whichpenetration does not occur. The torquerelationship for a given bit is determined largelyby the applied weight on bit and the depth ofpenetration of bit indenters.

Flush Medium Pressure: Drilling fluids in thewellbore can be in either a static or dynamicstate. The static system occurs when the fluidstands idle in the well. The dynamic stateoccurs when the fluid is in motion, resultingfrom pumping or pipe movement. The staticpressure of a column of fluid pressure is known

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as “hydrostatic pressure” which is an essentialfeature in maintaining control of well andpreventing kicks or blowouts. The hydrostaticpressure of a fluid column is a function of themud weight or density and the true vertical welldepth.

The Rate Of Penetration (ROP) obtainedwhile a well is drilled generally shows a steadydecline as well depth increases. The causesof the reduction in ROP with depth can bedivided into two categories:

1. A processes that affects the unbroken rock,and

2. Processes that act on the rock once it isbroken into chips.

The chip removal process is probably moreimportant in terms of total effect on ROP, butthe strengthening of the unbroken rock is notnegligible. Although several authors (Garnier,1959; Feenstra, 1964; and Warren, 1984) havediscussed in considerable detail the chipremoval process. This reduction of the ROPis often attributed to increasing “differentialpressure”, increasing hydrostatic head,increasing in-situ stresses, decreasingporosity with depth, and chip hold-down. Forthe flush medium to flow down the drill stringand up the annulus, a pressure difference mustexist between the flush descending within thedrill rods and that ascending in the annulusoutside the drill rods. The pressure requiredto cause flow has to counteract the differencein the fluid densities, due to suspended rockparticles and has to overcome the frictionalresistance to flow. Increasing the ROP of thebit increases the weight of suspended rockparticles and hence the differential fluidpressure. Pump pressure is used to overcome

the frictional resistance and weight imbalanceof suspended rock particles. Increasing thefluid flow rate also results in an increase in thedifferential pressure.

Formation Pore Pressure: The propertiesof the rock being drilled can, from the definitionof dril l ing variables discussed in theintroduction, be considered as an independentvariable, the drilling rig operator has no controlover it, as they help determine the responseto the drilling operation rather than being aresponse in itself. Formation pore pressurecan be major factor affecting drilling operationsespecially in deep wells. An operator planninga well needs some knowledge of overburdenand formation fluid pressure in order to selectthe necessary hydrostatic or drilling fluidpressure. If this pressure is not properlyevaluated, it can cause drilling problems suchas lost circulation, blowouts or kicks, stuckpipes, hole instability and excessive costs. Theformation pressure is related to pore spacesof the formations which contain fluids such aswater, oil or gas. The overburden stress iscreated by the weight of the overlying rockmatrix and the fluid-filled pores. The rock matrixstress is the overburden stress minus theformation pressure.

Independent Variables

The independent variables are the drillingfluids, bit load, the bit rotational speed, bit typeand the hydraulics horse power.

Bit Load: A range of terms are used todescribe this parameter such as thrust, bit load,bit pressure, axial load or axial pressure, andWeight On Bit (WOB). Weight on bit is a basiccontrollable drilling variable. A bit load needsto be applied for the bit to drill. The amount of

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bit load applied in practice depends on manyfactors, which include the type of bit, the bitdiameter, the presence of discontinuities in therock mass, the type of drill ing rig andequipment, etc., but it is primarily governed bythe physical properties of the rock being drilled.This is because the bit penetrates the rockwhen the pressure exerted by the bit indentersexceeds the strength of the rock and feeds itforward. The weight on bit requirementdepends on the size and geometry of the bitand the resistance (strength) of the rock. Therig must be capable of producing the requiredWOB with sufficient stability for drilling a givenhole size with a selected bit size.

A number of authors have conducted teststo investigate the effect of WOB on drillingperformance (Speer, 1958; Paone et aI.,1969; Schmidt, 1972; Clark, 1979 and 1982;and Osman and Mohammed, 1992). Theseinvestigations showed that low WOB resultsin free rotation of the bit, which produces lowrate of penetration and poor chip formation,excessive bit wear because of the bit slidingover the surface of the rock. High WOB, abovea critical value leads to the drill machinestalling. Maximum ROP is achieved whenoptimum value of WOB is reached, after which,an increase in WOB gives little increase in thepenetration rate. The limiting value of WOB isdetermined by the torque capacity of theequipment. The above researchers have alsoconcluded that the optimum WOB gives highpenetration rate and low bi t wear.Consequently, each drill has a characteristicoptimum WOB for maximum penetration whichcorresponds to good indentation at the bit rockinterface and to optimum indexing. Theoptimum WOB also depends on the otheroptimal drilling conditions.

Rotational Speed: The drilling processconsists of a series of fracture generatingevents. The drilling rate for a constant depth ofbit indenter, penetration will depend on the bitrotational speed. The relationship betweenrotational speed (RPM) and Rate OfPenetration (ROP) has been investigated bythe previously mentioned authors. It has beenconfirmed that generally there is a near linearrelationship between the two parameters insoft rocks. Drilling rate is not proportional torotary speed in medium and hard formationsdue to the requirement that some finite time isrequired for fracture development in hardrocks. For a given penetration rate to beachieved, the bit weight and rotational speedshould be continuously maintained, andadequate flush flow maintained to ensure rockcuttings removal from the hole. However, theincrease in bit rotary speed result in greaterwear on the bit and may also cause chatter,micro-chipping and cracking of cuttingindenters or teeth of the bit. The rotationalspeed may also be restricted by the stabilityof the rig and the drill rods.

Drilling Fluid: The term “drilling fluid” includesall of the compositions used to remove cuttingsfrom the borehole. An effective drilling processcan only be continued, when the bottom of thehole is maintained clean. This is achieved bya sufficient flow flushing medium, which canbe; air, water, oil, oil/water emulsion, mud orfoam (Moore, 1958). Drilling rate is proved tobe faster and bit life longer with air ascompared to water or mud. Drilling wasoriginally performed with air or water as adrilling medium used to cool the bit and flushaway the drill cuttings. As these two mediawere usually, easily available, cheap and

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satisfactory for the shallow boreholes and hardformations being drilled at that time. Toovercome problems such as boreholeinstability, a drilling fluid called mud wasdeveloped, consisting of water and bentoniteclay. Mud has a number of properties such asits caking ability, its higher density, viscosityand its thixotropic properties, which make itparticularly suitable for drilling deep and softformations that would otherwise prove difficultto drill. However, water is still commonly usedas a flushing medium and mud used only wherenecessary due to the drawback of the largequantities of bentonite needed to make themud and the extra equipment, which result inextra costs (Gray and Young Jr, 1973).Although at the present time numerous brandnames of drilling fluids are commerciallyavailable for a range of purposes andconditions, the main function of all these fluidsis the successful, speedy and satisfactorycompletion of the well. The selection of the typeof drilling fluid is largely determined by theexpected hole conditions. The adjustment ofdrilling fluid properties is intimately related tothe well depth, casing programme and thedrilling equipment.

Hydraulic Horsepower: Hydraulics has longbeen recognised as one of the most importantconsiderations in the design of drillingprogrammes. Improved bottom hole cleaningafforded by jet rock bits and high levels of bithydraulic horsepower permit the use of themost effective combination of weight androtary speed and minimises the risk of bitfouling. These benefits became apparentduring the early days of jet bit drilling ascontractors began to search for ways tomaximise the effectiveness of their hydraulic

systems. The results are extended bit life andfaster penetration rates. An increasing numberof commercial bits are becoming availablewith interchangeable nozzles, providing theflexibility of rig-site hydraulics optimisation.With these interchangeable nozzles, thehydraulic energy (or power) of the drilling fluidthat is dissipated across the bit face can beadjusted to match that portion of the rig’shydraulic power that is available for the bit afterother system losses have been considered.(Kendal and Goins, 1960; Randall, 1975;Tibbitts et al., 1979; Hollester and Kipp, 1984;and Kelly and Pessier, 1984). The degree towhich drilling rate was affected by bit hydraulichorsepower depends on the rock/drilling-fluidcombination.

Bit Type: Achieving the highest rate ofpenetration with the least possible bit wear isthe aim of every drilling engineer whenselecting a drilling bit. Because formationproperties and bit type are the largest factorsthat affect penetration rate, and obviously,formation properties cannot be changedbefore drilling and thus selection of the correctbit type is of major importance in achievinghigh rates of penetration. The rapid evolutionof the roller-cone bits and the perfection oftechniques for manufacturing diamond-impregnated core bits, have profoundlyinfluenced recent drilling practices. Bit footageand consequently, footage costs, havedramatically improved as a result of thesedevelopments. Advances in metallurgy andheat-treatment techniques and thedevelopment of lubricated sealed bearingshave made possible the widespreadintroduction of journal bearings. The bearingshave significantly prolonged bearing life.

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Milled-tooth cutting structures are beingreplaced by shaped inserts of carbidecomposition, reducing the tooth abrasion ofthese cutting elements. The longer insertsmake high penetration rates possible wellwithin the life of the bearings, allowing lowerover-all drilling costs to offset the increase inbit expenses. Cone offset and other featuresof milled tooth have been incorporated into thedesign of the carbide insert bit (Estes, 1971).The use of jets in the bit fluid bath hassubstantially improved hole cleaning and chipremoval, and the use of jets in plannedhydraul ics programmes has becomewidespread (Kendall, 1960; Eckel, 1967; andRabia, 1985). There are many proposedmethods for bit selection and often more thanone is used before reaching a decision.

Bit selection methods include:

1. Cost analysis.

2. Dull bit evaluation.

3. Offset well bit record analysis.

4. Offset well log analysis.

5. IADC bit coding.

6. Manufacturers’ product guides.

7. Geophysical data analysis.

8. General geological considerations.

Literature Based on Tool Life

Some research papers related to drilling toollife are followings:

Luis Miguel Durao et al. (2014) analyzedthe characteristics of carbon fiber reinforcedlaminates have widened their use fromaerospace to domestic appliances, and newpossibilities for their usage emerge almost

daily. In many of the possible applications, thelaminates need to be drilled for assemblypurposes. It is known that a drilling processthat reduces the drill thrust force can decreasethe risk of delamination. In this work, damageassessment methods based on data extractedfrom radiographic images are compared andcorrelated with mechanical test results, bearingtest and delamination onset test, and analyticalmodels. The results demonstrate theimportance of an adequate selection of drillingtools and machining parameters to extend thelife cycle of these laminates as a consequenceof enhanced reliability.

Peter Muchendu et al. (2014) analyzed theperformance of drilling bits has a directinfluence on cost and increase in the rate ofpenetration translates significantly to cost andtime saving. From a total sample of 56 wells,approximately 450 tri -cone bi ts wereconsumed at a cost of KSh 200 Millions.

The primary objective of this study is toanalyze and optimize 8½” tricone bits whichwere used to drill the 8½” diameter hole atOlkaria geothermal field. The pads had threewells each with the intention of exploring t inorder to determine resource availability formassive power production. The exercisecovered depth from 750 m to 3000 m usingthree rigs all with kelly drive systems. The datawere compared in average between the dailyand sectional drilling range for each well.Evaluation was on weight on bit, rev per minuteand strokes in regard to their ROP. Olkariaformation is mainly trachytic and rhyolite withpyroclastic on surface. Also, occasional minorsyenitic and deleritic dyke intrusive on bottomwith temperatures above 250 degreescentigrade encountered at 3000 m total depth.

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Yahiaouia et al. (2013), found The qualityof innovating PDC bits materials needs to bedetermined with accuracy by measuringcutting efficiency and wear rate, both relatedto the overal l mechanical properties.Therefore, a lathe-type test device was usedto abrade specific samples. Post-experimentanalyzes are based on models establishingcoupled relations between cutting and frictionstresses related to the drag bits excavationmechanism. These models are implementedin order to evaluate cutting efficiency and toestimate wear of the diamond insert. Fromhere, an original approach is developed toencompass cutting efficiency and wearcontribution to the overall sample quality towardabrasion. Four main properties of PDCmaterial were used to define quality factor:cobalt content in samples that characterizeshardness/fracture toughness compromise,other undesired phase as tungsten carbideweakening diamond structure, diamond grainssizes and residual stresses distributionaffecting abrasion resistance. PDC cutterswere submitted to wear tests and acomparison between all these cutters requiresan overlap of information. The PDC cuttersevaluation tends to balance ability to withstandabrasive wear and to be efficient as long aspossible. Archard's linear model permits anevaluation of wear rate but a long bit life couldbe related to a poor cutting performance. Forthis purpose, an exponential law properlyassociates cutting efficiency to excavationdistance and led to determine a cuttingefficiency coefficient. The cutting efficiencycoefficient on wear rate ratio establishes aquality factor and associate to sample wear,aggressiveness of the rock field and energyspent to cut it.

Kadam and Pathak (2011), analyzedexperimental investigation was conducted todetermine the effect of the input machiningparameters cutting speed, feed rate, pointangle and diameter of drill bit on Hass ToolRoom Mill USA made CNC milling machineunder dry condition. The change in chip load,torque and machining time are obtainedthrough series of experiments according tocentral composite rotatable design to developthe equations of responses. The comparativeperformance of commercially available singlelayer Titanium Aluminum Nitride (TiAlN) andHSS tool for T105CR1 EN31 steel under drycondition is done. The paper also highlight theresult of Analysis of Variance (ANOVA) toconfirm the validity and correctness of theestablished mathematical models for in depthanalysis of effect of finish drilling processparameters on the chip load, torque, andmachining time.

Nourredine Boubekri (2011), analised thecurrent trend in the metal-cutting industry is tofind ways to completely eliminate or reducecutting fluid use in most machining operations.Recent advances in technology have made it

Figure 6: Workpiece

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possible to perform some machining withoutcutting fluid use or with Minimum-QuantityLubrication (MQL). Drilling takes a key positionin the realization of dry or MQL machining.Economical mass machining of commonmetals (i.e., tool and construction-grade steels)requires knowledge of the work piececharacteristics as well as the optimalmachining conditions. In this study weinvestigate the effects of using MQL and floodcooling in drilling 1020 steel using HSS toolswith different coatings and geometries. Thetreatments selected for MQL in this study arecommonly used by industry under flood coolingfor these materials. A full factorial experimentis conducted and regression models for bothsurface finish and hole size are generated. Theresults show a definite increase in tool life andbetter or acceptable surface quality and sizeof holes drilled when using MQL.

Nazmul Ahsan et al. (2010) analised Thegrowing demand for higher productivity,product quality and overall economy inmanufacturing by drilling particularly to meetthe challenges thrown by liberalization andglobal cost competitiveness, insists highmaterial\ removal rate and high stability andlong life of the cutting tools. However, highproduction machining with high cutting velocity,

feed and depth of cut is inherently associatedwith the generation of large amount of heat andthis high cutting temperature not only reducesdimensional accuracy and tool life but alsoimpairs the surface finish of the product. Thedry drilling of steels (without using cutting fluids)is an environmentally friendly machiningprocess but has some serious problems likehigher cutting temperature, tool wear andgreater dimensional deviation. Conventionalcutting fluids (wet machining) eliminate suchproblems but have some drawbacks. Theypossess a significant portion of the totalmachining cost. Thus machining underMinimum Quantity Lubrication (MQL) conditionhas drawn the attention of researchers as analternative to the traditionally used wet and drymachining conditions with a view to minimizingthe cooling and lubricating cost as well asreducing cutting zone temperature, tool wear,surface roughness and dimensional deviation.In this work, improvements that were possiblewhen minimum quantity lubrication was usedin drilling AISI 1040 steel were examined.

Figure 3: Factors and Their Levelfor Experimentation

Figure 7: Schematic View of MQL Setup

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Results were compared with drilling under dryand wet conditions.

Wong et al. (2008) conducted anexperimental investigation to determine theeffect of drill point geometry and drillingmethods on tool life and tool wear in drillingtitanium alloy, Ti-6Al-4V. Uncoated carbidedrills with different type of geometry undervarious cutting speeds and drilling methodswere used in the investigation. Experimentalresults revealed that both the drill geometry anddrilling techniques affect the tool wear and toollife performance when drilling Ti-6Al-4V. It wasalso found that peck drilling outperformeddirect drilling in terms of tool life all cuttingspeeds investigated. Non uniform wear andchipping were the dominant failure mode ofthe tools tested under most conditions.

Hochenga and Tsao (2005), analyzed thatthe fiber-reinforced composite materialspossess advantage for structural purpose invarious industries. Delamination is consideredthe major concern in manufacturing the partsand assembly. Drilling is frequently applied inproduction cycle while the anisotropy and nohomogeneity of composite materials affect thechip deformation and machining behaviorduring drilling. Traditional and non-traditional

drilling processes are feasible for making fineholes for composite materials by carefullyselected tool, method and operatingconditions. In this article, the path towards thedelamination-free dril ling of compositematerial is reviewed. The major scenes areillustrated including the aspects of the analyticalapproach, the practical use of special drill bits,pilot hole and back-up plate, and theemployment of non-traditional machiningmethod.

Jaromír Audy (2013), analisedexperimentally the effects of TiN, Ti(Al, N) andTi(C, N) as well as a M35 HSS tool substratematerial on the drill-life of the GP-twist drills bydrilling the Bisalloy 360 steel work material.All these experiments have been statisticallyplanned in order to establish the 'empirical'drill-life-cutting speed equations for each of thethree coatings as well as to comparestatistically the effects of these differentcoatings on the dril l -l i fe. The resultsdemonstrated that although the coated drillsperformed very well at conditions much higherthan applicable for the uncoated drills, none ofthe three coatings offered any statisticallysignificant advantage over another coating interms of the drill life.

Table 4: Mechanical Propertiesof Ti-6AL-4V

Figure 8: Schematics of Drillingin Composite Materials

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PROBLEMS DEFINITIONNowadays there are several types of DrillingTools with Different Tool Geometry and Variousfactors (Force, feeding Rate, MOQ, ToolMaterial, Tool Geometry, etc.), which areaffecting the Drilling Tool Life. In this projectwill be focus only on Different tool Material withConstant Forces acting on the tool surface foranalyzing the Deformation in Drilling ToolGeometry and Find out the Factor of Safetyfor optimizing the Drilling Tool Life. On DrillingTool, there are many problems occur such asbreakage, wear, rough surface finish, short toollife and so on. This problem affects finishingof machined product, life of cutting tool andreduces productivity of Drilling. Through thisstudy, it will determine effects such as cuttingforces and Tool Geometry on workpiecesbased on three different materials.

OBJECTIVEThe Objective of the Solidwork Modeling andAnalysis are:

1. To study the effect of Drilling Tool Materialand Forces variation on the drilled workpiece.

2. To evaluate the Factor of Safety for Differentmaterial to analyze the Drilling Tool Life.

Thus we can optimize the drilling forces andtool geometry by analysis of deformation dueto changing in drilling tool material. Finally wecan analyze the deformation in drilling toolgeometry and drilling tool life.

FUTURE ENHANCEMENTBy this project work and Analysis, we canoptimized the Drilling Tool Life by consideringthe following factors,

• Drilling tool material.

• Drilling tool geometry

• Force on tool surface

• Drilling rate

• Minimum quantity of lubrication.

• Types of drilling machine.

Thus, we can optimize the drilling processby Mathematical Modeling, Software Modelingand Experimental Analysis for Improving theDrilling Tool Life.

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analysis of drilling tool life—a review

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