Internal finishing of capillary tubes by magnetic abrasive finishing using a multiple pole-tip system

7 Pages·1.536 MB·English

by  Kang J., Yamaguchi H.

PrecisionEngineering36 (2012) 510–516

ContentslistsavailableatSciVerseScienceDirect

Precision Engineering

journal homepage: www.elsevier.com/locate/precision

Technicalnote

Internal finishing of capillary tubes by magnetic abrasive finishing using a

multiple pole-tip system

JunmoKang,HitomiYamaguchi∗

DepartmentofMechanicalandAerospaceEngineering,UniversityofFlorida,Gainesville,FL32611,UnitedStates

a r t i c l e i n f o a b s t r a c t

Articlehistory: Duetodifficultiesincontrollingmagneticabrasiveinthefinishingareaduringinternalmagneticabra-
Receiv ed15August2011 sive fin ishing(MA F) ofcapillary tubes,the finished le ngth islimite din practice tojust afewtime sthe
R17ecDeeivceedm ibne r re2v0is1e1d form pole -tip width . The a cc umulatio n of mu ltip le short finishin g p asses is n ecessary for long - tube finish ing,
whichresultsinexcessivefinishingtimes.Theuseofamultiplepole-tipsystemwithatool,asolidrod
Accepted18January2012
consistingofalternatingmagneticandnonmagneticregions,wasproposedtoovercomethisissue.The
Available online 10 February 2012
toolenablesmultiplefinishingregionstobeengagedsimultaneously.Thispaperclarifiesthefinishing

characteristicsandmechanismandshowstheeffectsofthetool’smagneticproperties(includingthe
Keywords:
intervalsbetweenmagneticandnon-magneticregions)onthetoolandabrasivemotionandtheinterior
Magneticabrasivefinishing
MCaeptiallsatrayb l teubauesten iticstainlesssteel fiponliesh-tiinpgf echedarlaecntgerthis,tiwcsh iocfh caalploilwlasryt htuebMesA. FThpirso pceaspsetro alascoh piervoepoasuens iafo srimmlpylefi nmisehthedods utorf adceeteirnmhianlef tthhee
Multiplepo le-tipsyst em timeoft heex istings inglep ole-tip syst em.

Heattreatment © 2012 Elsevier Inc. All rights reserved.

1. Introduction total finished length in practice to just a few times the pole-tip

width.Tofinishtheentiresurfaceofalongtube,severalshortfin-

Inthemagneticabrasivefinishingprocess,materialisremoved ishingstepsarerequired,andthisapproachleadstoalongfinishing

asaresultoftherelativemotionbetweentheworkpiecesurface time.

andmagneticabrasiveundertheinfluenceofamagneticfield.Con- Toovercomethisissue,anMAFprocessusingamultiplepole-tip

trolofthemagneticfieldatthefinishingareaisrequiredinorder systemhasbeenproposed[14].Magneticpropertiesofametastable

togeneratethemagneticforcenecessaryforfinishing.Thesmaller austeniticstainlesssteeltoolcanbechangedbyheattreatment,and

thetubediameter(e.g.,capillarytubes),themorecriticalisthecon- multiplepartialheat-treatmentsonasingletoolcanprovidealter-

trolofthemagneticfield.Asimplemethodtoadjustthemagnetic natingmagneticandnon-magneticregions.Theinsertionofsuch

fieldwithoutmodifyingthefinishingequipmentistochange(1) atoolintoacapillarytubewiththemagneticabrasivegenerates

magnetic properties or geometry of the magnetic abrasive [1–3] multiplefinishingregionsasthemagneticabrasiveisattractedto

or (2) magnetic properties, geometry, or concentration of mag- theborderbetweenthemagneticandnon-magneticregionsonthe

netictools(suchasferrousparticles,aferrousrod,orapermanent singletool.This(1)facilitatesthedeliveryofthemagneticabrasive

magnet)insertedwiththemagneticabrasiveorconventionalabra- deepintothetubeand(2)realizesthesimultaneousfinishingof

siveslurry[4–11].Theeffectivenessofthesetechniqueshavebeen multipleregions.

demonstratedforcapillarytubes,widelyusedinmedicalapplica- Theobjectivesofthispaperare(1)toclarifythefinishingcharac-

tionsandinprecisionanalyticalinstruments[12,13].However,the teristicsandmechanismthatcontrolthemultiplepole-tipsystem

defaultfinishedlengthinthetubeaxialdirectionislimitedbythe and improve the finishing efficiency and (2) to achieve a uni-

pole-tip width. For example, a pole-tip width of 4mm has been formly finished surface over the entire finished area. First, this

consideredadequateforcapillarytubeswithinnerdiameters(ID) paperwillstudythedesignofalternatingmagneticproperties(e.g.,

between0.4mmand1mm[12].Feedingthepoletipinthetube lengths of magnetic and non-magnetic regions) of the tool. Sec-

axialdirectiontheoreticallyallowstheentireinternalsurfaceofa ond,theinteriorfinishingexperimentsofcapillarytubes(1.06mm

longtubetobefinished.However,difficultiesassociatedwiththe ID) will show the key parameter—the relationship between the

insertionofthemagneticabrasiveintothefinishingarealimitthe intervalsbetweenmagneticandnon-magneticregionsofthetool

and pole-tip geometry—to realize the multiple pole-tip system.

The experimental results will clarify the finishing mechanism.

∗ Finally,asimplemethodisproposedtodeterminethepole-tipfeed
Corresponding author at: University of Florida, 226 MAE-B, Gainesville, FL
lengthtocontroltheroughnessuniformityovertheentirefinished
3261E1-m, Uanilitaeddd rSetsast:ehs.i tToeml.:i y+@1u 3fl5.2ed 3u92(H 0.8Y1a2m; afagxu:c +h1i) .352 392 1071. area.

0141-6359/$–seefrontmatter© 2012 Elsevier Inc. All rights reserved.

doi:10.1016/j.precisioneng.2012.01.006
J.Kang,H.Yamaguchi/PrecisionEngineering36 (2012) 510–516 511

Fig.2. Schematicandphotographofmultiplepole-tipsystem.

Fig.1. Schematicandphotographofsinglepole-tipsystem.

pushesagainstthetubesurface.Analogoustothesinglepole-tip

2. Processingprinciplesofsingle-poletipand system,rotatingthetubeenablestherelativemotionbetweenthe

multiple-poletipsystems magneticabrasiveandtubeinnersurface,resultinginanefficient

surfacefinishing.Thenumberofpole-tipsetscanbeincreasedif

Fig.1showsaschematicofamagneticabrasivefinishingpro- needed.Foraconstantpole-tipwidth,thefinishingareawillbea

cesswithasinglepairofpoletips(hereaftercalledasinglepole-tip functionofthetotalnumberofpole-tipsets.

system) and a photograph of the finishing machine. The desired Thegeometryofpole-tipsetsinbothsingleandmultiplepole-

magneticfieldinthefinishingareaisgeneratedbytwopermanent tipsystemsusedinthispaperareshowninFig.3.Thewidthofthe

magnetsattachedtoasteelyoke.Magneticabrasiveinthetubeis poletip,whichdefinesthedefaultfinishedlength,is18mm.The

magnetized,anditispushedagainstthetubesurfacebymagnetic pole-tipsetforthesinglepole-tipsystemhastwomagnets.Inthe

force.Asthetubeisrotatedathighspeed,themagneticabrasive caseofthemultiplepole-tipsystem,eachpoletiphasonemagnet,

exhibitsrelativemotionagainstthetubesurfaceandthusremoves andthetwomagnetsarecoupledbyasteelyoke,whichis54mm

materialfromthetubesurface.Thedefaultfinishedlengthisdeter- long(paralleltotheworkpieceaxis).

minedbythepole-tipwidthinthetubeaxialdirection,andmotion Fig.4showschangesinmagneticfluxdensityBy,measuredbya
ofthep ol etip alongth etube a xise xten dsth efinished area . Hallse ns or(sen singare a: ∅1.0mm) ,wit hdistan ce Xinbothp ole -

ReductionofthetubeIDmakesthisapproachdifficult.Forexam- tipsystems.Thereisnosignificantdifferenceinthemagneticflux

ple,magneticabrasivetendstobuildupintheareacorresponding densityBy betweenthetwosystems.Bothsystemsshowasimi-

totheentrysideofthepole-tipedges—insteadofbeingdistributed lartrend:themagneticfluxdensityanditsgradientincreasefrom

attheregioncorrespondingtothepoletipwithfollowingtheline the center toward the edges of pole tips. The magnetic abrasive

ofmagneticforce—andplugsthetube.Regardlessofthepole-tip isattractedbymagneticforcetowardthepole-tipedges.Without

motion,themagneticabrasiveremainsattheinitialpositionand assistanceofamagnetictool,thistrendencouragesthepluggingof

finishingisnotperformed.Thisisduetoalackofmagneticforce

actingonthemagneticabrasive,andthemagneticforceyieldsto

friction between the magnetic abrasive and tube inner surface.
Sinceth emagnet icfo rceisafu nctionof mag netic field strength 18 12 Yoke 54 12 .
.10
annedti ci tps rgorpaedriteyn ot,f itth cea pno blee- tciopn otrro tlhleed mbayg tnheet igc etoomole itnryse artnedd mwaitgh- S mPe argmnaentse nt S N 2 1100
magneticabrasive.
16

Fig.2showsaschematicandaphotographofamethodusing
18 1 Pole tips 18 18 1
amultiplepole-tipsystem.Inthisstudy,apairofpoletipsisadded (mm)

toasinglepole-tipsystemandyokedtogethertogeneratemag- (a) Single pole tip (b) Multiple pole tips

neticfieldsintwofinishingareas.Thefinishingareaisdoubledas

magneticabrasiveisintroducedintotworegionsofthetubeand Fig.3. Geometryofsingleandmultiplepole-tipsets.
512 J.Kang,H.Yamaguchi/PrecisionEngineering36 (2012) 510–516

Fig.4. Changesinmagneticfluxdensityofsingleandmultiplepole-tipsystemsat

Y=0mm.

themagneticabrasiveintheregioncorrespondingtothepole-tip

edgeswhenthetubeIDislessthan1mm.

3. Designofalternatingmagneticpropertiesofthetool

Themagneticpropertiesofthetoolplayanimportantrolein Fig.6. Motionofeachtoolwithmixed-typemagneticabrasiveforapole-tipstroke

realizing the proposed method. Their effects on the tool behav- lengthof18mm.

ior in the multiple pole-tip system were experimentally studied

usingtoolswiththreekindsofmagneticproperties.Fig.5showsa Each tool was inserted in a clear polypropylene plastic tube
photo graph ofth reem agnet ize d54mm longtools with i ronpar - (3mmo uter diam eter,0.7 mm w allth ickness),whic hwass eton
ticles:ToolA is mad eofcarbons tee l,To olBi s304 stain lesss teel, th ema chine showninF ig.2 (b).E ight milligrams( 8mg)o fam ixtu re
andTo olC is pa rtially he at-trea ted30 4sta in le ssst eel.Inthe case of i ron parti cles an d mag netic abra sive (called m ixed -t y pe mag-
of T ool A , the iron pa rticles are m ore a ttracted by the t ool ends ne ticab rasive)w assu ppliedwi ththema gnetic tool.Thepo le-tip
be cause of the resid ualmagn etism and magnetic sha pea nisot ropy. setw asfedat 0.59 mm/s,an dthe fee dlengthw ass etat 18mm.
Tool B e xh ibit s magne tic anisotro py, which wa s gene rated dur- The tub ewa s rotate dat2 00m in−1 ,and thebe havi oro ft he tool,
ingc ol dwork( deformatio n-induced marten sitet ransformat ion), and mixe d-typ emagn eti cabr asivein side the tubewas ob serv ed.
and the iron p articles are attracted t o the tool e nds only. In the F ig.6schema ticallysh owstheb ehavi oro fthe thre emagnetic
case ofT oolC ,theiron par ticlesarea ttr acte dto bothe ndso fm ag- toolsw it hmixed-typem agnet icab rasivewh ile the tube isrotated.
netic re gion sf ollo wing theresid ual magnetis m. The cente rr egion Fig.6 (a)is thecasewit hToolA.I nitially,t hemi xed -type m agnetic
(18m mlong) ofthesta inle sssteelT oolCwash eat-t reated ,andit abra sive w ass uppl iedin totw o regionsc orr espondingto thepole
has afa ce-cen te red- cubicstr uctur e[15 ]. This crystaltransf orm a- tips.Onc ethe pole-tip sets tarte dmovin g,somemixed -ty pem ag-
tion d iminishesthemagn etismand divid esth emagn eticsection netic abras ive stucktot hec arbons teeltool surfac eregardless ofthe
into tworegions [15 ,16]. pole- tipmotio nbec au seo fthefer roma gne tismoft hetool.Th ec ar-

bonsteeltoolpushesthemixed-typemagneticabrasiveagainstthe

innertubesurfacewithastrongmagneticforce.Thisincreasesthe

frictionforcebetweenthetoolandinnersurfaceofthetube,and

thisfrictionforcepreventedthetoolfromfollowingthepole-tip

feedintheexperiment.

Fig.6(b)showsthecaseofToolB,whichexhibitsanisotropic

magnetismandlowermagneticsusceptibilitythanthemixed-type

magnetic abrasive. The mixed-type magnetic abrasive separated

intotwofinishingsectionsbecauseitisattractedtothepoletips

morethantoToolB.ToolBsimplyliesonthemassofmagnetic

abrasive. While the pole tips are moving, the mixed-type mag-

neticabrasivefollowsthepole-tipmotion.BothendsofToolBare

attracted to the magnetic field according to its anisotropic mag-

netism;ToolBtherebystaysinitsinitialpositionregardlessofthe

pole-tipandmagneticabrasivemotion.

Fig. 6(c) shows the case with Tool C. The borders of mag-

neticregionsofthetoolcorrespondtothepole-tipedgesandare

attractedtothemagneticfield.Themixed-typemagneticabrasive

isattractedbythepoletips,andoncethepoletipsarefedalong

thetubeaxis,boththemixed-typemagneticabrasivesandtoolfol-

lowthepole-tipmotion.Asaresult,themagneticabrasiveshows

Fig.5. Photographsofironparticleswithmagnetizedtools. smooth relative motion against the tube inner surface needed
J.Kang,H.Yamaguchi/PrecisionEngineering36 (2012) 510–516 513

Table1

Experimentalconditions.

Workpiece 304stainlesssteeltube(∅1.27×∅1.06×100mm)

Workpiecerevolution 2500min−1

Pole-tipfeed Speed:0.59mm/s,numberofstrokes:180

Workpiece-pole-tipclearance 0.3mm(polytetrafluoroethylene(PTFE)tapethickness)
Lubricant Soluble-typeb arrel finishingcompound(pH: 9.5,vi scosi ty:755MPasat30◦C)

Pole-tipsystem Singlepole-tipsystem Multiplepole-tipsystem Multiplepole-tipsystem

Pole-tipstrokelength 18mm 18mm 18mm

Magnetictool – ToolC(seeFig.5(c)) ToolD(seeFig.7(a))
Ironparti cles( 150–300(cid:2)m 1 2mg 6.4m g ×2 6.4m g ×2

dia.):80wt%
Alum inu moxide(WA) 3mg 1.6mg×2 1.6mg×2
magnetica brasiv e(80(cid:2)m

meandia.):20wt%

forinternaltubesurfacefinishing.Thisexperimentalobservation Inturn,tubesurfacefinishingispredominantlyperformedinfour

demonstratestheconditionsrequiredtofacilitatethedeliverability places.Ifthelengthofthemagneticregionisreducedfrom18mm

ofthetoolandmagneticabrasiveinthemultiplepole-tipsystem to 3–4mm, and a region is created on the tool corresponding to

byconformingtothepole-tipmotion: eachpole-tipedge,themagneticfluxconcentratesatthepole-tip

edges,doublingthenumberofborderstoattractmagneticabra-

(1) the tool must have alternating magnetic and non-magnetic sive.Finishingisdominantlyperformedatthefourregionswhere

regions,and themixed-typemagneticabrasiveisencouragedtoremainbythe

(2) thebordersofthemagneticregionoftoolmustcorrespondto tool/poleconfiguration.

thepoletipedges. Fig.7showstheconfigurationoftheheat-treatedmagnetictool

(ToolD)withaphotographofmagneticabrasivewiththetoolbased

Inthemultiplepole-tipsystemusingthe54mmlongToolC,the onthatdesign.Themagneticabrasiveisattractedtotheborders

defaultfinishedlengthistheregioncorrespondingtotwo18mm ofthemagneticregions.ComparedtoToolC(Fig.5(c)),thisdou-

wide pole tips. If the pole-tip feed is sufficient to cover the gap bledthenumberoftheplaceswherethemagneticabrasiveisheld.

betweentwopoletips(18mm),the72mmlengthshouldbefin- VisualobservationofToolDwithmixed-typemagneticabrasivein

isheduniformly.Inpractice,somemixed-typemagneticabrasive atransparentpolymerictubeshowedthatToolDholdsthemixed-

adherestothesurfaceofthetubebecausethefrictionbetweenthe typemagneticabrasiveatfourplacesandthatthepole-tipmotion

mixed-typemagneticabrasiveandtubesurfaceexceedsthemag- issmoothlyfollowed.

neticforceactingonthemixed-typemagneticabrasivetofollow Thenextsectionwilldiscussthecharacteristicsofa72mmlong

the pole tip motion. The region corresponding to the chuck-end tubefinishedusingToolCandToolDinthemultiplepole-tipsys-

edgeofthepoletipmusthavetheleastamountofmagneticabra- tem.Thefinishingexperimentsusingthesinglepole-tipsystems

sive.Asaresult,thedeeperthefinishingareawasinthetube,the willalsobediscussedforcomparison.Notethat,tofinishthesame

rougherthefinishedsurfacewasduetothelackofmagneticabra- 72mmlength,thesinglepole-tipsystemrequiresatwo-steppro-

sive.Accordingly,theinitialinsertionofmagneticabrasivedeeper cesswith18mmpole-tipfeedstroke.

into the tube and the deliverability of the mixed-type magnetic

abrasive play important roles in accomplishing the desired fin-

ishing performance. The alternating magnetic property and the

intervalbetweenthemagneticandnonmagneticregionsmustbe

designedtosatisfythesematters.

InthecaseofToolC(showninFig.6(c)),magneticfluxflows

from one end of the magnetic region to the other end, and the

magneticabrasiveisattractedfollowingtheflowofmagneticflux.

Fig.7. PhotographsofironparticleswithmagnetizedToolDandthetoolmotion

withpole-tipstroke. Fig.8. ChangesinsurfaceroughnesswithdistanceX.
514 J.Kang,H.Yamaguchi/PrecisionEngineering36 (2012) 510–516

magnetic abrasive and 23.1% by the stainless steel tool). In both
cases,90 (cid:2)Loflub rican twas init ially supplied into thetu be ,and
50(cid:2)L wa s a dd ed after every 20 pol e-tip stro kes. For each fin-

ishingexperiment,thetotalnumberofpole-tipstrokeswas180.

Aftereachexperiment,thetubewascleanedusingethanolinan

ultrasonic cleaner and sectioned along the tube axis. The inner

surfacewasevaluatedusinganopticalsurfaceprofilerandastere-

omicroscope. The optical surface profiler has a lateral resolution

of 275.7nm and a vertical resolution of <0.1nm. The material

removalwascalculatedbycomparingtheweight(measuredusing
amicro- balan cewith10 (cid:2) gresolution )be forean dafterfinis hing.

Thefinishingexperimentwasrepeatedatleastthreetimesunder

eachconditiontoconfirmtherepresentativetrends.

Fig.8showstherelationshipbetweensurfaceroughness(the

averageoftenmeasurements)anddistanceXinthecasesofthe

multiple pole-tip system using Tool C, multiple pole-tip system

using Tool D, and single-pole tip system. No magnetic tool was

usedinthesinglepole-tipsystem(seeTable1).Theroughnesses

at X=0 and 74mm are measurements of unfinished surfaces. In

theMAFprocess,thefinishingoperationisperformedbymassesof

mixed-typemagneticabrasivealignedwiththelinesofmagnetic

force.Duetotheunstablemixed-typemagneticabrasivemotion,

thefinishingcapabilitygenerallydiminishesattheborderscorre-

spondingtothepoletipedges.Asaresult,theareasaroundX=0,

36,and72mmwerelessfinished,whichismoreclearlyshownby

theresultsfromthesinglepole-tipsystem.

Thematerialremovalrealizedbythemultiplepole-tipsystem

usingToolCwas7.85mg,anditwasaboutonethirdofthatperfin-

ishingstepofthesinglepoletipsystem:12.98mg(bythefirststep)

and11.05mg(secondstep).Thenumberofcuttingedgesactiveat

eachfinishingareaintheToolCcaseisestimatedtobeabouthalf

thenumberinthesinglepole-tipsystem.Thesinglepole-tipsystem

doesnotuseatool,andthemixed-typemagneticabrasiveforms

chainsbymagneticforceconformingtotheshapeofthetube.In

turn,themixed-typemagneticabrasiveremovesthematerialnot

only from the peaks but also the slopes of the surface asperities

overthefinishingarea,aslongasthemixed-typemagneticabrasive

entersthevalleyofthesurfaceasperities.Incontrast,themultiple

pole-tipsystemusesatool(asolidrod),andthemixed-typemag-

neticabrasivesandwichedbetweenthetubesurfaceandtoolatthe

regionscorrespondingtothepole-tipedgesplaysamajorrolein

removingthematerial.

As mentioned above, in the case using Tool C, some mixed-

typemagneticabrasiveadherestothesurfaceofthetubebecause

thefrictionbetweenthemixed-typemagneticabrasiveandtube

surfaceexceedsthemagneticforceactingonthemagneticabra-

sive.Theregioncorrespondingtothechuck-endedgeofthepole

tipmusthavetheleastamountofmixed-typemagneticabrasive

regardlessoftheback-and-forthmotionofthepole-tip.Thislack
Fig.9. Changesinpole-tipcoveragetimesandsurfaceroughnesswithdistanceX.
ofabrasivealsodiscouragedthefinishingoperation.Accordingly,

lessmixed-typemagneticabrasiveisinvolvedinthecuttingper-

4. Finishingcharacteristicsandmechanism formance in the multiple pole-tip system using Tool C than that

inthesinglepole-tipsystemcase.Thedifferenceinthematerial

Table1showstheexperimentalconditions.Stainlesssteeltubes removalratesandsurfaceimprovementisattributedtothesedif-

(1.27mmOD,1.06mmID,100mmlong,initialsurfaceroughness: ferentmechanisms.
2–3(cid:2) mR z)w erep repa red as work piece sfort hisstud y.Tenmil- The multiplepole-tipsystemusingToolDsmoothlyfinishedthe

limeters at one end of the tube was chucked, and the other end surfaceinanareadeepinsidethetube,correspondingtothepole

wassupportedbyaflexiblejigtoreducerun-outduringrotation. tiplocatedclosesttothechuck.Aroughnesswasachievedsimi-
The tuberotatio na ls peedw ass et at2500 min−1.T hepole -tipfeed lar tothati nthesin gle po le-tipsy st emcase.Th isre sultedfro mthe

length and rate were set at 18mm and 0.59mm/s, respectively. relativemotionofthesufficientlydistributedmixed-typemagnetic

Thefinishingexperimentsbegan5mmfromthefreetubeend.In abrasiveguidedbythetoolagainstthetubesurface.Afterfinishing

thecaseofthesinglepole-tipsystem,mixed-typemagneticabra- withToolD,thematerialremovalof14.2mgisapproximatelytwice

sive15mg(80wt%ferrousparticlesand20wt%magneticabrasive) thatobtainedintheToolCcase,butthematerialremovalperlength

wassupplied,whichtookup45.3%oftheenclosedvolumeofthe 0.20mg/mm is calculated about half of the single pole-tip sys-

finishing area. In the multiple pole-tip system, 47.3% of the vol- tem(0.36mg/mm).Theuseofasolidtoolencouragestheamount

umeateachfinishingareawastakenup(24.2%bythemixed-type of mixed-type magnetic abrasive participating in the finishing
J.Kang,H.Yamaguchi/PrecisionEngineering36 (2012) 510–516 515

Fig.10. Surfacetopographymeasuredbyopticalprofiler.

performanceandpushesitagainstthetubesurfacemorestrongly accordingtothefeedlength.Thepole-tiptakes61sforone18mm

thanToolC.However,sincethematerialispredominantlyremoved stroke. In this case, the positions X=18 and 54mm are covered

fromthepeaksofthesurfaceasperities,thematerialremovalrate forthelongestduration,whilethepositionsX=0,36,and72mm

mustbelowerthanthecasewiththesinglepole-tip. experiencealmostnocoverage.

Highvaluesofsurfaceroughness,similartotheunfinishedsur- Fig.9showstherelationshipbetweenpole-tipcoveragetime,

face,aremeasuredatthecenterofthefinishedarea.Theyshould roughnessoffinishedsurface,anddistanceX.Inthisstudy,every

beeliminatedbyenhancingthemixed-typemagneticabrasiveto 2mmmovementofthepoletip(correspondingto3.21s)isplotted

contactwiththetubesurface,whichcanbeachievedbyextending asthepole-tipcoveragetimeinthecourseofonefeed.Fig.9(a)

thepole-tipfeed.Althoughthefinishingresultisnotshowninthis showsthecasewithapole-tipfeedof18mm.Thepositionswith

paper,theroughnesspeakexhibitedaroundX=36mminthecase higher pole-tip coverage times exhibit lower surface roughness.

of the single pole-tip system was eliminated by lengthening the Theincreaseofthepole-tipcoveragetimeincreasesthecontacts

pole-tipfeedto24mminthefirstphaseand18mminthesecond betweenthemixed-typemagneticabrasiveandthetubesurface

phase.The6mmoverlapofthefinishedareabetweenthefirstand and thus facilitates material removal. At X=18 and 54mm, the
second pha se sfac ilitated the ma terialre mova lfromthe cen tera rea surf acero ughnessis lowertha n0.2(cid:2)m Rz du e to thel ong estp ole-

andimprovedtheuniformityofthefinishedsurface.Analogously, tip-coveragetime,173.4min,undertheconditions.Incontrast,the

extensionofthepole-tipfeedlengthshoulddiminishtheuneven- positionsX=0,36,and72mmexhibithigherroughnessduetothe

nessoftheroughnessinthefinishedareainthemultiplepole-tip lackofcontactbetweenthemixed-typemagneticabrasiveandtube

system. The next chapter will find a method to determine suffi- surface.

cientpole-tipfeedlengthbystudyingtherelationshipbetweenthe The areas between X=4 and 32mm and between X=40 and

pole-tipfeed,theoverlapoffinishingarea,andthefinishedsurface 68mm have pole-tip coverage times of more than 38.5min and
roughne ss. sur face roug hnessim provemen tfrom ∼ 3(cid:2)m Rzto ∼1(cid:2) mR z.In
other w ords, to ac hieve a rough ness l ess than 1 (cid:2)m Rz ov er t he

5. Pole-tipfeedlengthandsurfaceroughnessuniformityin entirefinishedarea,thepole-tipfeedlengthmustbesetsoasto

multiplepole-tipsystem resultinapole-tipcoveragetimeatX=36mmofatleast38.5min.

Toprovethisconcept,apole-tipfeedof22mmwaschosenforthe

Therelationshipbetweenthepole-tipfeedlengthandthefinish- experiments.TheareafromX=36to40mmistheareacoveredby

ingcharacteristics,especiallysurfaceroughness,arestudiedhere. bothpoletips,andthepole-tipcoveragetimethereiscalculated

The finishing experiment starts with the edge of pole-tip set (at tobe48.6min.Fig.9(b)showstheexperimentalfinishingresults

X=0), as shown in Fig. 8. The pole-tip set moves back and forth andthepole-tipcoveragetimeplottedagainstthedistanceX.The
516 J.Kang,H.Yamaguchi/PrecisionEngineering36 (2012) 510–516

roughnesspeakatX=38mmisdecreasedbecauseoftheincreased (4) Amethodwasproposedtodefinethepole-tipfeedlengthsuf-
pole-tipco verag e. Th e ro ughn es swasimp rovedto les sth an0.8(cid:2)m fic ienttoa chie veaunifo rm desir eds urfacero ughn esson the
Rz.Ifthe desireds urfa ceislessth an0 .5(cid:2)mRz,a p ole- tipco ver age entire tar getsurfa ce bycalcu latingp ole-tipc overagetim eo ver

timegreaterthan60minissuggestedbyFig.9(a).Tosatisfythis thetargetsurface.

condition,apole-tipstokeof24mmisproposed.The24mmpole-

tipfeedprovidesthesuperposedareafromX=36to42mmwitha Acknowledgements

coveragetimeof68.3min.AsseeninFig.9(c),theroughnesspeak

atthecenterisnolongerobserved,andthesurfaceroughnessis The authors gratefully acknowledge the University of Florida
ar ound 0.2(cid:2)m R z. Researc hFound ation(Gat orade)andthe UF OfficeofRe sea rchfor

Fig.10showsthethree-dimensionalshapes(measuredbyan theirsupportofthiswork.

opticalprofiler)oftheunfinishedinnersurfaceandthecenterof

theinnersurfacesfinishedwithpole-tipfeedsof18,22,and24mm. References

The surface finished with the 18mm pole-tip feed (Fig. 10(b)) is

similar to the unfinished surface (Fig. 10(a)). Fig. 10(c), with the [1] KoS,BaronYM,ChaeJW,PolishukVS.Developmentofdeburringtechnology
22 mm po le-ti p feed, sho ws som e asp erities that remai ned fr om ifnort e drrn ialltiinogn ba lucrorsn ufesrienng c meoa gnnleetaidci anbg readsig veem finanisuhfiancgt umri entgh oind2. I1ns:t Pcreon cteuerdyi.n2g0s0 o3f.
theinitialsurfacecondition.Inthesurfacewiththe24mmpole-tip p.367–72.
feed (Fig. 10(d))th easperiti es from thein itialc ond itio nar ebarely [2] Ya maguchiH,ShinmuraT.Studyonanewinternalfinishingprocessbythe
obse rved , and th e fin ished surf ace c onsi sts of c utting ma rks gener- oapfpmliacgantieotnic oaf b mraasgivneestico n abfir nasisivhein mgacc hha irnaicntge r–ist4itchs .rTe rpaonrsta, cetfifoe nctss ooff tdhie amJa eptaenr
atedbymixed-typemagneticabrasive.Thesefiguresconfirmthe So cietyofM echanical Eng ineersSer iesC1995;61(5 91):4470–5[i nJ apan ese].
mate ria lremovaltre ndsdescr ibedinFig .9. [3] Yamagu ch iH,Hanada K.Develo pment o fSphericalMagneticA bra siveMade
The p ole-tip f eed con ditions of 2 2mm (total finished length: byplasma Sp ray.ASM E JournalofMa nu facturing Sciencea ndEngine ering
20 08;130(3 ):0311 07.1–9 .
76mm) and 24mm (total finished length: 78mm) had mate-
ria l rem oval of 1 6.83 mg an d 18.7m g, and t he m ater ial re moval [4] rSeuszeuakric hK,o nTamkaahgansehtii cHg,r iOnhdainshgim He, thYoodneumsiunrgas Th,o Mrtifiybaesarkmi aEg, nUeetimcaatbsrua sTiv. eTsh–e
per length a re calcul ate d to be 0 .22m g/m m and 0.24 mg/mm, 1strepor t,t heeffecto fthemet alshort fiberc ontam inat iontomag neticabra -
sive s.In:P roce eding so fth eJSPE sprin gan nualmeeting.1 99 0.p.307– 8[in
respectively. Regardless of the extended pole-tip feed, the mate- Japan ese] .
rialremovalrateofthemultiplepole-tipsystemwaslessthanthat [5] ShinmuraT,YamaguchiH.Studyonanewinternalfinishingprocessbythe
ofth esingle pole -ti psy stem(0.3 6mg/mm ).This cond ition resu lted applicatio no fmagnetic ab rasive ma ch ining –inter nalfinish ingofst ain less
steeltubean dc leangasb omb.Inte rnationalJo urnalofJap anSociety of Mechan-
from the differences in the finishing mechanisms with and without icalE ngin eerin gSer ies C1995 ;38(4):798–8 04.
theuseofthemagnetictool.Moreover,itshouldbenotedthatthe [6] Shin muraT,Yam aguch i H,AizawaT.Anewinternalfinishingprocessofnon-
sing lep ol e-tip systemt ookt wicethet im e(6h), co mpare dto the ferromagn et ictubingby th eapplic ati on ofa magneti cfield–th edevel op ment
multip le pole-t ip syste m, to finish the s urfac e o f a 72 mm lon g tu be. onfa al oufnJiat ptyapneS fio nciieshtyinfgo rapP preacri astiuosn uEsninggin pee errmi na gn1e9n9t 3m;2a7g (n2e)t:s1. 3In 2t–e7r .national Jour-
[7] Zou Y H,Shin muraT .An ewintern almagnetic fieldassistedmachiningprocess
6. Conclusion uinsgino gf aa SmUaSg3n0e4tisct a mina lce hssinsitne ge ljitgu b–e .m Aadcvhainncinegd Mchaatr earcitaelrRisetsi ecsa rocfh i2n0si0d9e ; 6fi9n–i7sh0-:
143 –7 .
Theresultsofthisstudyaresummarizedasfollows: [8] KawakuboH,TsuchiyaK,ShinmuraT.Considerationonmechanismofpolish-
ingforcein m agneticp ol ishingmet ho dusingloosea br asive.Journa lo fJapan
Soc ietyfo rA brasiveT echnologi es2003; 47(12) :672– 6[inJapa nese].
(1) tAh ceounsdeitoiofna rteoqouliwreitdh toal treeranliaztei ntghem magunlteiptilce-apnodlen otinp- smyastgenmet iics [9] iNninsheridwa aHll, oShfiamatudba e Ku, tIidlioz inYg. Falu mida gdnyentaimcicco minpvoeustni gdatfl iounid o(fM pCoFl)is.hIinn:g Ptrhoe-
regi ons .Th e leng thof themagnet icregiono fth etoolmustbe ceedin gs o f t he 7th JFPS inte rn ational sy mposium o n flui d powe r. 2 008.
p.837–40 .
cdoerfirneespdo snod tthoatt htehep obloer-dtieprse dogf etsh.e magnetic region of the tool [10] hKio grhdopnresckiis iWon, Gfinoilsinhii nDg.. MJouurltnipalleo faIpnptelilclaigteionnt Mofa mteariganleStyosrtheemosloagnidcaSlt reuffcetcutr eins
(2) Generating as hort magnet icregiononthetoolwithedgescor- 2002 ;13:401–4 .
[11] SatoT,YamaguchiH,ShinmuraT,OkazakiT.Studyofsurfacefinishingprocess
responding to the pole-tip edges concentrates the magnetic flux using m agneto-rh eol ogicalflui d (MRF)– 2n drep ort :effects ofthefi nishing
atthepole-tipedges,whichdoublesthenumberofbordersof behav iorofMRF-basedslu rryo nfinis hi ngch aracter istics.J ou rnal ofJapan
th em agneticr egions toattra ctthem agn eticabra siv e.Theu se Societyfo rP recisionEng ineerin g2 006;72(11 ):1402–6[inJap anese].
[12] Yamagu chi H,Shinm uraT,Ikeda R.Studyofinternal fin ishingofaustenitic
of this method serves to attract the magnetic abrasive more stainlessste el capillarytu be sbym ag netica br asivefini shing.ASM E Journalof
stronglytothetoolbymagneticforceandimprovesthedeliv- Manufac turing Science andEn gin eering20 07;129(5 ):885–92 .
erability of the magn et icabrasive tode sired areasdee per inthe [13] YamaguchiH,K angJ.S tudy offerroust oolsininternalsurfaceandedgefin-
tube. Thi s a chi eves the u niform s ur face fini shing in the en tire iosfhtihneg oNfo flrte hxiAb mle ecraicp ail nlaMrya tnu ubfea sc tbuyr imnga gRneesteia cr ac bhraInssivtiet ufi tnioisnhoinfgS . MTrEa n2s0a1c0t i;o3n8s:
finishingarea. 17 7–8 4.

(3) Theinsertionofamagnetictoolwithmagneticabrasive(usedin [14] KangJ,YamaguchiH.Internalfinishingofcapillarytubesbymagneticabrasive
the multiple po le -tip syste m) f acilit ates the r emoval o f mat e- tfihneisthw ine gn tuys-ifnogu rat hm aent naustaalbAleS Pa Eusmteeneittiinc g s.t2 a0in1l0e.sps .s1t –ee4l. to ol. In: Procee dings of
raibarla fsriovmes tahned wpeicahkes dobf etthwe eseunrftahcee taosoplearnitdietsa rbgye tthsuer mfacaeg.nTehtiics [15] tYoaom lafogrucmhai gHne, tKica nabgr aJ,s ivHe asfihniims hoitnog .FC. IRM PetAansnta ablsl e-M aaunsutefancittuicr instgaiTnelcehssn osltoegeyl
achieves asmoothlyfi nishedsu rfac ewi thle ssmate rialrem oval 2011 ;60 (1):339–4 2.
[16] ChildressJ,LiouSH,ChienCL.Magneticpropertiesofmetastable304stain-
((aubseoduti nhatlhfe ins itnhgisle ppapoleer-)t tihpasny sthteem u)s.e of magnetic abrasive only l1e1s3s –s4t.eel w ith B CC struct ure. Journal d e Physique C olloques 19 88;4 9(C8):