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Milling(machining)
Millingisthe machiningprocessof usingrotary cuttersto remove material[1]
fromaworkpiece
advancing(orfee...
As material passesthroughthe cuttingareaof a millingmachine,the bladesof the cuttertake swarfsof
material atregularinterva...
machines(orchangingsetupof the same machine) tocut the nextop.Today, CNCmillswithautomatic
tool change and 4- or 5-axiscon...
movingthe knee upanddownrequiresconsiderable effortanditalsobecomesdifficulttoreachthe
quill feedhandle (if equipped).Ther...
Metal lathe
Centerlathe with digital readout andchuck guard.Size is460 mmswingx 1000 mmbetweencenters
A metal lathe or met...
The headstock (H1) housesthe mainspindle (H4),speedchange mechanism (H2,H3),andchange gears
(H10). The headstockisrequired...
Some latheshave onlyone leadscrew thatservesall carriage-movingpurposes.Forscrew cutting,a half
nut is engagedtobe drivenb...
Compoundrest
The compound rest (or top slide) (2) isusuallywhere the tool postismounted.Itprovidesasmaller
amountof moveme...
Rotatingabrasive wheel onabenchgrinder.
A grindingmachine, oftenshortenedto grinder,isany of various powertools ormachine ...
removeshighv
Hacksaw
From Wikipedia,the free encyclopedia
Typical full-size hacksawframe,with12"blade
A hacksaw is a fine-...
have a handle,usuallyapistol grip,withpinsforattachinganarrow disposable blade.The framesmay
alsobe adjustable toaccommoda...
Hole to Hole:11 7/8 inches/300 mm
Overall blade length:12 3/8 inches/ 315 mm (nottightlycontrolled)
MountingHole diameter:...
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Machines

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Machines

  1. 1. Milling(machining) Millingisthe machiningprocessof usingrotary cuttersto remove material[1] fromaworkpiece advancing(orfeeding) ina directionatan angle withthe axisof the tool.[2][3] Itcoversa wide varietyof differentoperationsandmachines,onscalesfromsmall individual partstolarge,heavy-dutygang millingoperations.Itisone of the mostcommonlyusedprocessesinindustryandmachine shopstoday for machiningpartstoprecise sizesandshapes. There are twomajor classesof millingprocess:  In face milling,the cuttingactionoccurs primarilyatthe end cornersof the millingcutter.Face millingisusedtocutflat surfaces(faces) intothe workpiece,ortocut flat-bottomedcavities.  In peripheral milling,the cuttingactionoccursprimarilyalongthe circumference of the cutter, so that the cross sectionof the milledsurface endsupreceivingthe shape of the cutter.Inthis case the bladesof the cuttercan be seenasscoopingoutmaterial fromthe work piece. Peripheral millingiswellsuitedtothe cuttingof deepslots,threads,andgearteeth. Millingcutters Main article:Millingcutter Many differenttypesof cuttingtoolsare usedinthe millingprocess.Millingcutterssuchas endmills may have cuttingsurfacesacrosstheirentire endsurface,sothattheycan be drilledintothe workpiece (plunging).Millingcuttersmayalsohave extendedcuttingsurfacesontheirsidestoallow forperipheral milling.Toolsoptimizedforface millingtendtohave onlysmall cuttersattheirendcorners. The cutting surfacesof a millingcutterare generallymade of ahard and temperature-resistantmaterial, so that they wearslowly.A lowcostcuttermay have surfacesmade of highspeedsteel.More expensive but slower-wearingmaterialsinclude cementedcarbide.Thinfilmcoatingsmaybe appliedtodecrease frictionorfurtherincrease hardness. Theyare cuttingtoolstypicallyusedinmillingmachinesormachiningcentrestoperformmilling operations(andoccasionallyinothermachine tools).Theyremovematerial bytheirmovementwithin the machine (e.g.,aball nose mill) ordirectlyfromthe cutter'sshape (e.g.,aformtool such as a hobbing cutter). Surface finish A diagramof revolutionridgesonasurface milledbythe side of the cutter,showingthe positionof the cutterfor each cuttingpassand howit correspondswiththe ridges(cutterrotationaxisisperpendicular to image plane)
  2. 2. As material passesthroughthe cuttingareaof a millingmachine,the bladesof the cuttertake swarfsof material atregularintervals.Surfacescutbythe side of the cutter (asin peripheral milling)therefore alwayscontainregularridges.The distance betweenridgesandthe heightof the ridgesdependonthe feedrate,numberof cuttingsurfaces,the cutterdiameter.[4] Withanarrow cutterand rapidfeedrate, these revolutionridgescanbe significantvariationsinthe surface height. Trochoidal marks,characteristicof face milling. The face millingprocesscaninprinciple produceveryflatsurfaces.However,inpractice the result alwaysshowsvisibletrochoidalmarksfollowingthe motionof pointsonthe cutter'sendface.These revolutionmarks give the characteristicfinish of aface milledsurface.Revolutionmarkscanhave significantroughnessdependingonfactorssuchas flatnessof the cutter'sendface and the degree of perpendicularitybetweenthe cutter'srotationaxisandfeeddirection.Oftenafinal passwithaslow feedrate isusedto compensate fora poormillingsetup,inordertoreduce the roughnessof revolution marks.In a precise face millingoperation,the revolutionmarkswill onlybe microscopicscratchesdue to imperfectionsinthe cuttingedge. Gang milling Heavygang millingof millingmachine tables Gang millingreferstothe use of two or more millingcuttersmountedonthe same arbor(thatis, ganged) ina horizontal-millingsetup.All of the cuttersmayperformthe same type of operation,oreach cuttermay performa differenttype of operation.Forexample,if severalworkpiecesneedaslot,aflat surface,andan angular groove,agood methodtocut these (withinanon-CNCcontext) wouldbe gang milling.Allthe completedworkpieceswouldbe the same,andmillingtime perpiece wouldbe minimized.[5] Gang millingwasespeciallyimportantbefore the CNCera,because forduplicatepartproduction,itwas a substantial efficiencyimprovementovermanual-millingone featureatan operation,thenchanging
  3. 3. machines(orchangingsetupof the same machine) tocut the nextop.Today, CNCmillswithautomatic tool change and 4- or 5-axiscontrol obviate gang-millingpractice toa large extent. Equipment Millingisperformedwith millingcutters attachedtoamillingmachine. Types and nomenclature Mill orientationisthe primaryclassificationformillingmachines.The twobasic configurations are vertical andhorizontal.However,there are alternate classificationsaccordingtomethodof control,size, purpose andpowersource. Mill orientation  Watch video Vertical mill Vertical millingmachine.1:millingcutter2:spindle 3:top slide oroverarm4: column5: table 6: Y-axis slide 7:knee 8: base In the vertical mill the spindle axisisverticallyoriented. Millingcutters are heldinthe spindle androtate on itsaxis.The spindle cangenerallybe extended(orthe table canbe raised/lowered,givingthe same effect),allowingplungecutsanddrilling.There are twosubcategoriesof vertical mills:the bedmilland the turret mill.  A turret mill has a stationaryspindle andthe table ismovedbothperpendicularandparallel to the spindle axistoaccomplishcutting.The mostcommonexampleof thistype isthe Bridgeport, describedbelow.Turretmillsoftenhave aquill whichallowsthe millingcuttertobe raisedand loweredinamannersimilartoa drill press.Thistype of machine providestwomethodsof cuttinginthe vertical (Z) direction:byraisingorloweringthe quill,andbymovingthe knee.  In the bedmill,however,the table movesonly perpendiculartothe spindle'saxis,while the spindle itself movesparallel toitsownaxis. Turret millsare generallyconsideredbysome tobe more versatile of the twodesigns.However,turret millsare onlypractical as longas the machine remainsrelativelysmall.Asmachine size increases,
  4. 4. movingthe knee upanddownrequiresconsiderable effortanditalsobecomesdifficulttoreachthe quill feedhandle (if equipped).Therefore,largermillingmachinesare usuallyof the bedtype. Horizontal mill Horizontal millingmachine.1:base 2: column3: knee 4 & 5: table (x-axisslide isintegral)6:overarm7: arbor (attachedto spindle) A horizontal mill hasthe same sortof x–y table,butthe cuttersare mountedona horizontal arbor(see Arbormilling) acrossthe table.Manyhorizontal millsalsofeature abuilt-inrotarytable thatallows millingatvariousangles;thisfeature iscalleda universaltable.While endmillsand the othertypesof toolsavailable toavertical mill maybe usedina horizontal mill,theirreal advantage liesinarbor- mountedcutters,calledside andface mills,whichhave acrosssectionratherlike a circularsaw,but are generallywiderandsmallerindiameter.Because the cuttershave goodsupportfromthe arborand have a largercross-sectional areathanan endmill,quite heavycutscanbe takenenablingrapid material removal rates.These are usedtomill groovesandslots.Plainmillsare usedtoshape flat surfaces.Several cuttersmaybe gangedtogetheronthe arbor to mill acomplex shape of slotsand planes.Special cutterscanalsocut grooves,bevels,radii,orindeedanysectiondesired.These specialty cutterstendto be expensive.Simplex millshave one spindle,andduplex millshave two.Itisalsoeasier to cut gears ona horizontal mill.Some horizontal millingmachinesare equippedwithapower-take-off provisiononthe table.Thisallowsthe table feedtobe synchronizedtoa rotary fixture,enablingthe millingof spiral featuressuchas hypoidgears. A SiegX2 miniature hobbyistmillplainlyshowingthe basicpartsof a mill.
  5. 5. Metal lathe Centerlathe with digital readout andchuck guard.Size is460 mmswingx 1000 mmbetweencenters A metal lathe or metalworkinglathe isa large class of lathesdesignedforprecisely machiningrelatively hard materials.Theywere originallydesignedtomachine metals;however,withthe adventof plastics and othermaterials,andwiththeirinherentversatility,theyare usedina wide range of applications, and a broad range of materials.Inmachining jargon,wherethe largercontextisalreadyunderstood, theyare usuallysimplycalled lathes,orelse referredtobymore-specificsubtypenames(toolroom lathe,turret lathe,etc.).These rigid machine tools remove material fromarotatingworkpiece viathe (typically linear) movementsof variouscuttingtools,suchas tool bits and drill bits. Construction The designof lathescan varygreatlydependingonthe intendedapplication;however,basicfeaturesare commonto most types.These machinesconsistof (atthe least) aheadstock,bed,carriage,and tailstock.Bettermachinesare solidlyconstructedwithbroadbearingsurfaces(slide-ways) forstability, and manufacturedwithgreatprecision.Thishelpsensure the componentsmanufacturedonthe machinescanmeetthe requiredtolerancesandrepeatability. Headstock Headstockwithlegend,numbersandtextwithinthe descriptionrefertothose inthe image
  6. 6. The headstock (H1) housesthe mainspindle (H4),speedchange mechanism (H2,H3),andchange gears (H10). The headstockisrequiredtobe made as robustas possible due tothe cuttingforcesinvolved, whichcan distorta lightlybuilthousing,andinduce harmonicvibrationsthatwilltransferthroughtothe workpiece,reducingthe qualityof the finishedworkpiece. The main spindle isgenerallyhollowtoallow longbarstoextendthroughtothe work area.Thisreduces preparationandwaste of material.The spindle runsinprecisionbearingsandisfittedwithsome means of attachingworkholdingdevicessuchas chucksor faceplates.Thisendof the spindle usuallyalsohasan included taper,frequentlyaMorse taper,to allow the insertionof hollow tubular(Morse standard) tapersto reduce the size of the taperedhole,andpermituse of centers.Onoldermachines('50s) the spindle wasdirectlydrivenbya flatbeltpulley withlowerspeedsavailablebymanipulatingthe bull gear.Later machinesuse a gearbox drivenbya dedicatedelectricmotor.A fully'gearedhead'allows the operatorto selectsuitable speedsentirelythroughthe gearbox. Beds The bed isa robustbase that connectsto the headstockandpermitsthe carriage and tailstock,tobe movedparallel withthe axisof the spindle.Thisisfacilitatedbyhardenedandground bedwayswhich restrainthe carriage and tailstockina settrack. The carriage travelsbymeansof a rack and pinion system.The leadscrew of accurate pitch,drivesthe carriage holdingthe cuttingtool viaagearbox driven fromthe headstock. Typesof bedsinclude inverted"V"beds,flatbeds,andcombination"V"andflatbeds."V"and combinationbedsare usedforprecisionandlightdutywork,whileflatbedsare usedforheavyduty work.[citation needed] Whena lathe is installed,the firststepisto level it,whichrefersto makingsure the bedisnot twistedor bowed.There isnoneedtomake the machine exactlyhorizontal,butitmustbe entirelyuntwistedto achieve accurate cuttinggeometry.A precisionlevel isauseful tool foridentifyingandremovingany twist.Itis advisable alsotouse sucha level alongthe bedtodetectbending,inthe case of a lathe with more than fourmountingpoints.Inbothinstancesthe levelisusedasa comparatorrather than an absolute reference.(aboutabdulrehman) Feedand leadscrews The feedscrew(H8) isa longdriveshaftthatallowsaseriesof gearstodrive the carriage mechanisms. These gearsare locatedinthe apron of the carriage.Both the feedscrew and leadscrew(H7) are driven by eitherthe change gears (onthe quadrant) or an intermediategearbox knownasa quick change gearbox (H6) or Nortongearbox.These intermediate gearsallowthe correctratioand directiontobe setfor cuttingthreads or wormgears.Tumblergears(operatedby H5) are providedbetweenthe spindle andgeartrainalongwitha quadrant plate thatenablesagear trainof the correct ratio and directiontobe introduced.Thisprovidesaconstantrelationshipbetweenthe numberof turnsthe spindle makes,tothe number of turnsthe leadscrew makes.Thisratioallowsscrewthreadstobe cut on the workpiece withoutthe aidof a die.
  7. 7. Some latheshave onlyone leadscrew thatservesall carriage-movingpurposes.Forscrew cutting,a half nut is engagedtobe drivenbythe leadscrew'sthread;andforgeneral powerfeed,akeyengageswitha keywaycutintothe leadscrewtodrive apinionalongarack thatis mountedalongthe lathe bed. The leadscrew will be manufacturedtoeither imperial ormetricstandardsandwill requireaconversion ratioto be introducedtocreate threadformsfroma differentfamily.Toaccuratelyconvertfromone threadformto the otherrequiresa127-tooth gear,or on lathesnotlarge enoughto mountone,an approximationmaybe used.Multiplesof 3and 7 givinga ratio of 63:1 can be usedto cut fairlyloose threads.Thisconversionratioisoftenbuiltintothe quickchangegearboxes. The precise ratiorequiredtoconverta lathe withanImperial (inch) leadscrew tometric(millimeter) threadingis100 / 127 = 0.7874... . The bestapproximationwiththe fewesttotal teethisveryoften37/ 47 = 0.7872... . Thistranspositiongivesaconstant -0.020 percenterroroverall customaryand model- maker'smetricpitches(0.25, 0.30, 0.35, 0.40, 0.45, 0.50, 0.60, 0.70, 0.75, 0.80, 1.00, 1.25, 1.50, 1.75, 2.00, 2.50, 3.00, 3.50, 4.00, 4.50, 5.00, 5.50 and 6.00 mm). Carriage Carriage withlegend,numbersandtextwithinthe descriptionrefertothose inthe image In itssimplestformthe carriage holdsthe tool bitand movesitlongitudinally(turning) or perpendicularly(facing) underthe control of the operator.The operatormovesthe carriage manually viathe handwheel(5a) or automaticallybyengagingthe feedshaftwiththe carriage feedmechanism (5c). Thisprovidessome relief forthe operatorasthe movementof the carriage becomespower assisted.The handwheels (2a,3b, 5a) on the carriage and itsrelatedslidesare usuallycalibrated,both for ease of use and to assistinmakingreproduciblecuts.Calibrationmarks will measure eitherthe distance fromcenter(radius),orthe workpiece'sdiameter,soforexample,onadiametermachine where calibrationmarksare inthousandthsof aninch,the radial handwheel dial will read.0005 inches of radiusperdivision,or.001 inchesof diameter.The carriage typicallycomprisesatopcasting,known as the saddle (4), and a side casting,knownasthe apron (5). Cross-slide The cross-slide (3) rideson the carriage and has a feedscrew thattravelsatrightanglesto the main spindle axis.Thispermits facing operationstobe performed,andthe depthof cut to be adjusted.This feedscrewcanbe engaged,throughagear train,to the feed shaft(mentionedpreviously)toprovide automated'powerfeed'movementtothe cross-slide.Onmostlathes,onlyone directioncanbe engagedata time asan interlockmechanismwill shutoutthe secondgeartrain.
  8. 8. Compoundrest The compound rest (or top slide) (2) isusuallywhere the tool postismounted.Itprovidesasmaller amountof movement(lessthanthe cross-slide) alongitsaxisviaanotherfeedscrew.The compoundrest axiscan be adjustedindependentlyof the carriage orcross-slide.Itisused forturningtapers,tocontrol depthof cut whenscrewcuttingorprecisionfacing,ortoobtainfinerfeeds(undermanual control) than the feedshaftpermits.Usually,the compoundresthasa protractor markedinits base (2b),enablingthe operatorto adjustitsaxisto precise angles. Tailstock Tailstockwithlegend,numbersandtextwithinthe descriptionrefertothose inthe image Steady, followerandother rests A steadyrest Grindingmachine From Wikipedia,the free encyclopedia Thisarticle includesalistof references,relatedreadingorexternal links,butitssourcesremain unclear because it lacks inline citations.Please improvethisarticle byintroducingmore precise citations. (April2009)
  9. 9. Rotatingabrasive wheel onabenchgrinder. A grindingmachine, oftenshortenedto grinder,isany of various powertools ormachine tools usedfor grinding,whichisatype of machiningusingan abrasive wheelasthe cuttingtool.Each grainof abrasive on the wheel'ssurface cutsa small chipfromthe workpiece viasheardeformation. Grindingisusedto finishworkpiecesthatmustshow highsurface quality(e.g.,low surface roughness) and high accuracy of shape anddimension.Asthe accuracyindimensionsingrindingisonthe orderof 0.000025 mm, inmostapplicationsittendstobe a finishingoperationandremovescomparativelylittle metal,about0.25 to 0.50 mm depth.However,there are some roughingapplicationsinwhichgrinding
  10. 10. removeshighv Hacksaw From Wikipedia,the free encyclopedia Typical full-size hacksawframe,with12"blade A hacksaw is a fine-toothedsaw,originallyandprincipallyforcutting metal.Theycanalsocut various othermaterials,suchasplasticand wood;forexample, plumbers andelectricians oftencutplasticpipe and plasticconduit withthem.There are handsaw versionsandpoweredversions(powerhacksaws). Most hacksawsare handsaws witha C-shapedframe thatholdsablade undertension.Suchhacksaws
  11. 11. have a handle,usuallyapistol grip,withpinsforattachinganarrow disposable blade.The framesmay alsobe adjustable toaccommodate bladesof differentsizes.A screw orothermechanismisusedtoput the thinblade undertension. Panel hacksawsforgothe frame and insteadhave a sheetmetal body; theycan cut intoa sheetmetal panel furtherthana frame wouldallow.These sawsare nolonger commonlyavailable,buthacksawblade holdersenable standardhacksaw bladestobe usedsimilarlyto a keyhole saworpad saw.Powertoolsincludingnibblers,jigsaws,andangle grindersfittedwithmetal- cuttingbladesanddiscsare nowusedfor longercutsinsheetmetals. On hacksaws,aswithmost frame saws,the blade can be mountedwiththe teethfacingtowardoraway fromthe handle,resultingincuttingactiononeitherthe pushorpull stroke.Innormal use,cutting verticallydownwardswithworkheldinabenchvice,hacksaw bladesshouldbe settobe facing forwards.Some frame saws,includingFretSawsandPiercingSaws,have theirbladessettobe facingthe handle because theyare usedtocut by beingpulleddownagainstahorizontal surface. Blades Juniorhacksaw Bladesare available instandardizedlengths,usually10or 12 inchesfora standardhandhacksaw. "Junior"hacksawsare typically150mm long.Poweredhacksawsmayuse large bladesinarange of sizes, or small machinesmay use the same handblades. The pitch of the teethcan be anywhere fromfourteentothirty-twoteethperinch(tpi) forahand blade, withas fewas three tpi fora large powerhacksaw blade.The blade chosenisbasedonthe thicknessof the material beingcut,witha minimumof three teethinthe material.Ashacksaw teethare sosmall, theyare setina "wave"set.Asforothersaws theyare set fromside toside to provide a kerf or clearance whensawing,butthe setof a hacksaw changesgraduallyfromtoothtotooth ina smooth curve,ratherthan alternate teethsetleftandright. Hacksaw bladesare normallyquite brittle,socare needstobe takento prevent brittle fracture of the blade.Earlybladeswere of carbonsteel,now termed'low alloy'blades,andwere relativelysoftand flexible.Theyavoidedbreakage,butalsowore outrapidly.Exceptwhere costisa particularconcern,this type isnow obsolete.'Lowalloy'bladesare still the onlytype available for the Juniorhacksaw,which limitsthe usefulnessof thisotherwise popularsaw. Hacksaw blade specifications:The mostcommon blade isthe 12 inchor 300 mm length.Hacksaw bladeshave twoholesnearthe endsformountingtheminthe saw frame and the 12 inch / 300 mm dimensionreferstothe centertocenterdistance betweenthese mountingholes.[3] 12 Inch Blade
  12. 12. Hole to Hole:11 7/8 inches/300 mm Overall blade length:12 3/8 inches/ 315 mm (nottightlycontrolled) MountingHole diameter:9/64 to 5/32 inch/ 3.5 to 4 mm (nottightlycontrolled) Blade Width:7/16 to 33/64 inch/ 11 to 13 mm (nottightlycontrolled) Blade Thickness:0.020 to 0.027 inches/0.5 to 0.70 mm(varieswithtoothpitchandother factors) The kerf producedby the bladesissomewhatwiderthanthe blade thicknessdue tothe setof the teeth. It commonlyvariesbetween0.030and 0.063 inches/0.75 and1.6 mm dependingonthe pitchandset of the teeth. The 10 inch blade is alsofairlycommonandall the above dimensionsapplyexceptforthe following: Hole to Hole:9 7/8 inches/ 250 mm Overall blade length:10 3/8 inches/ 265 mm (nottightlycontrolled)

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