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AViewonWearMechanismofMetallicCardClothi

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AViewonWearMechanismofMetallicCardClothi

    3 A View on We a r Mec h a nis m of Met a llic Ca r d Cl ot hi ng

    1 3 2 1 ( ) ( ) )(W U L i a ng , WA N G We n2qi a n g , N I Hu a i2s he ng 倪淮生 1 Col le ge o f M ec h ani cal En gi nee ri n g , D on g h ua U ni ve rsi t y , S h an g h ai 201620 , Chi na 2 Cente r o f A nal y sis an d M eas u re ment , D on g h u a U ni ve rsi t y , S han g hai 201620 , Chi na Abs t r a ct : The we a r mec h a nis m of met a llic c a r d cl ot hi ng ,

    us e d i n t ext ile i n d us t r y , w a s a na l yze d . A f a s t we a r t es t f or 1 Exp e ri m e n t al Pr o c e d u r e met allic c a r d cl ot hi ng r a c ks w as de vel op e d , w hic h w a s us e d

    a s collect i ng t he we a r met a l p a r t i cl es . The f a il ure t yp e of Th e s a mp les of me t allic c a r d cl ot hi ng us e d f o r w e a r

    c a r d cl ot hi ng w a s a n al yze d by t he me a n of s c a n ni ng elect r on t es t w e r e A C 2820 s up p lie d by S h a n g h ai Yua n d o n g Ca r d

    Cl ot hi n g CO . , L TD . , a n d f ail u r e c a r d cl ot hi ng w as ( ) mic r os cop y S EM a n d f e r r o2sp ect r u m t ec h nol ogy . The

    A C2810 c olle c t e d f r o m S h a ng h ai N o . 17 C ot t o n Mill . T hes e res ul t s s how t h a t t he m a i n we a r mec h a nis m of met a llic c a r d

    s a mp les a r e all m a de of 72B s t e el . A f ast wea r mac hi ne was cl ot hi ng is l ow l oa d a n d hi g h rep et i t i on i nt e r va l f a t i gue we a r

    de vel op e d f or si mulati ng t he wea r p r ocess of ca r d wi re t eet h c a us e d by f rict i on f orce bet wee n f i be r a n d met a l wi re t eet h . [ 3 ] acc or di ng t o t he w or ki ng conditi on of t he ca r d cl ot hi ng . The ap p r op ri a t e q ue nc hi ng mic r os t r uct u re , w hic h i mp r oves

    Fig. 1 s hows sc he matically t he f unda me nt al p ri ncip le of t he f ast t he we a r res is t a nce of t he met a llic c a r d cl ot hi ng r a c k is a ls o

    ( wea r t est . 2 t o 6 p ieces of met allic ca r d cl ot hi ng le ngt h is dis c us s e d .

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    t he f i xt ure f or measuri ng f ricti on f orce . A f ricti on disc of <30 f a t igue wea r ; met a l2f i be r f rict i o na l c o u n t e rp a r t

    c m is ma de of 100 pieces of cl ot h pile d up t oget he r a nd r uns at A Document code : CLC number : TS 103 . 8

    ( ) a sp ee d of 1 440 r/ mi n. The f ixt ure ca n oscillat e i n t he Article ID : 1672 5220 20080320324204 di recti on of right a nd lef t . The f ricti on f orce ca n be easily

    c ha nge d t h r ough a djusti ng t he ve rtical p ositi on of t he f ixt ure .

    A magnet w rapp e d up by a p iece of clea r p ap e r is p lace d besi de Int r o d uc t i o n

    t he f ricti on disc , w hic h ca n t a ke t he met al p a rticles of f , as

    s howe d i n Fig. 1. The ref ore t he magnet ca n at t ract t hese wea r M e t allic c a r d cl ot hi n g is a ke y p a r t of t h e c a r d

    micr o2p a rticles , t he n p ut t he m i nt o CCls oluti on a nd use f e r r o2 4 m ac hi ne . Th e q uali t y of c a r d cl ot hi ng af f e c ts t h e quali t y of

    sp ect r omete r t o ma ke sa mples , t hus t he i nf or mation a bout t hese c a r di n g f i be r si g nif ic a nt l y , a n d i t h as be e n k n ow n t h a t

    micr o2p a rticlesπ s hap e , size , qua ntit y a nd so on , ca n be easily f ail ur e t yp e of me t allic c a r d cl ot hi n g is w e a r . A cc o r di ng t o

    obt ai ne d by use of S EM. A J SM25600 L V S EM was also use d t o t he w o r ki n g c o n di t i o n of t h e c a r d m a c hi nes , me t allic c a r d

    a nalyze t he micr ost ruct ure , wea r surf ace t op ograp hy. cl ot hi n g a n d f i be r m a ke up a f ric t i o n al c o u nt e rp a r t , w hic h

    h as t h e c h a r a c t e r is t ics as f oll ows : t h e f i be r o r a c olle c t i o n

    of f i be rs f l oa ts o n t h e t ip of c a r d wi r e t e e t h , w h e n t h e c a r d

    m ac hi ne is c a r di ng t h e f i be r , s o t h e w e a r occ urs m ai nl y o n

    t he c a r d wi r e t e e t hπs up p e r p a r t . W hile t h e c a r d wi r e t e e t h

    w e a r h ap p e ns , i ts s h a rp ness de t e ri o r a t es gr a duall y s o t h a t i t

    will c a us e q uali t y of c a r di n g f i be r t o de g r a de .

    Wi t h r e ga r d t o t h e w e a r t yp e of me t allic c a r d [ 1 2 ] cl ot hi n g , t h e r e a r e s e ve r al li t e r a t u r es o n t his asp e c t . I t

    h as be e n r ep o r t e d t h a t t h e r e m a y be se ve r al f o r ms of w e a r ,

    s uc h as a b r asi ve w e a r c a us e d by h a r d p a r t icles i n f i be r ,

    i mp a c t f o r c e of t h e f i be r , e ve n f ric t i o n he a t , h ow e ve r ,

    f e w e vi de nc es t o s up p o r t t h ese mec h a nis ms di r e c t l y h a ve

    be e n f o u n d u n t il n ow . Th e r ef o r e , i t is nec ess a r y t o

    de m o ns t r a t e t h e r e al mec h a nis m of me t allic c a r d cl ot hi n g Fi g . 1 Th e f u n da me nt al p ri ncip l e of f as t w ea r t es t w e a r .

    3 R ec ei ve d da t e : 2007206204

    3 C o r r esp o n de nc e s h oul d be a d d r ess e d t o W U L i a n g , p r of . , E2mail : w uli a n g @d h u . e d u . c n

    ( ) ( )J o ur nal of D o n ghua Uni v e rs i t y En g . Ed . Vol . 25 , N o . 3 2008 325

    t he p r ess u r es N, Na n d f ric t i o n al f o r ces F, Fas s h ow n 1 2 1 2

    i n Fi g . 5 . Th e r e a r e wi n di n g f o r c e P a n d f ric t i o nal f o r c e F 2 Re s ul t s a n d Dis c us s i o n 3

    e xe r t i n g o n t h e t o ot h e dges as s h ow n i n Fi g . 6 . 2 . 1 The wear fa il ure of metall ic card clothing

    Th e me t allic c a r d cl ot hi ng a n d t h e f i be r c o mp r is e a

    sp e ci al c o up le of f ric t i o n al c o u nt e rp a r t i n t h e c a r di n g

    m ac hi ne . W he n c a r di n g ma c hi ne is w o r ki n g , t h e s h a rp

    ga r ne t t wi r e t e e t h p ie r c e t h r o ug h t h e f l oc ks a n d t h e f i be r

    l a ye r , t he n h ol d a n d c a r d t h e c ot t o n o r t h e c h e mic al f i be rs .

    Th e t e e t h t ips u n de r t a ke al m os t all t h e c a r di ng t as ks . Fi g . 2

    s h ows sc h e m a t ic all y t h e out li ne c h a nges of a t o ot h t ip

    bef o r e a n d af t e r w e a r . I t c a n be s e e n t h a t a d ot t e d li ne of

    a bc d is a c o mp le t e out li ne of a ga r ne t t wi r e t e e t h bef o r e Th e f o r c es ap p l yi n g o n t h e Fi g . 4

    f r o nt f a ce of wi r e t e e t h w e a r a n d yis a n ef f e c t i ve w o r ki n g hei g h t . A s oli d r o u n d 0

    li ne a d o n t h e t o ot h t ip as s h ow n i n Fi g . 2 r ep r ese n ts a n

    out li ne of a t o ot h t ip af t e r w e a r . T his m a kes t h e s h a rp ness

    of t h e w i r e t e e t h decli ne s e ve r el y a n d t h e a c t ual w o r ki n g

    α a n gle o n t he t ip of wi r e t e e t h be c o me l a r ge , w hic h c a us es t

    he c a r d cl ot hi ng t o l os e i ts a bili t y of g rip p i n g f i be r

    gr a d uall y a n d h as t r e me n d ous i nf l ue nc e o n c a r di ng q uali t y .

    Fi g . 5 The f or c es ap p l yi n g Th e wi n di ng f o r c es Fi g . 6

    o n t h e si de f a c es ap p l yi ng o n t h e

    t e e t h e d ges of wi r e t e e t h

    2 2 R + U , t h e n o r m al Th e n o r m al p r ess u r e is , N = Fi g . 2 Th e outli ne c ha n ges of a t e e t h tip

    bef o r e a n d af t e r w e a r 2 2 f ric t i o n al f o r c e is , F = μN = μ R+ U, w h e r e μ is t h e

    3 s hows t he f ailure of cyli nde r wi re t eet h . Figure It ca n f ric t i o n al c oef f icie nt , U is a c o mp o ne n t f o r c e of N i n t h e be see n obvi ously t hat t he t eet h tip keep origi nally s ha rp a ngle , di r ec t i o n of Y a xis , R is a c o mp o ne nt f o r ce of N i n t h e but has bee n w or n seve rely a nd bec omes a r ound tip af t e r wea r di r ec t i o n X a xis . L e t t h e w ei g h t of si ngle f i be r be Ma n d 0 f ailure . The wea r als o occurs on t he t op f ace , w or ki ng f ace f ric t i o n al c oef f icie nt be t w e e n f i be r a n d wi r e t e e t h be 0 . 22 , a nd t w o f r ont e dge a ngles of t he wi re t eet h . i t c a n be e n c alc ul a t e d t h a t t h e n o r m al p r ess u r e N is a b o ut [ 4 ] 260 MN a n d f ric t i o n al f o r c e is a b o ut 61 MN . O t h e r 0 0

    f o r c es s uc h as N, N, P , F, F, Fa r e als o i n t he s a me 1 2 1 2 3

    qua nt i t y l e vel . T he n o r m al p r ess ur e N a n d e xt r usi ve

    p r ess u r es N, Nm a ke t h e wi r e t e e t h def o r m . Th e 1 2

    f ric t i o n al f o r c es F , F, Fc a us e t h e w e a r of t he t e e t h f a c e 1 2

    a n d t he f ric t i o nal f o r c e Fr es ul ts i n t h e t e e t h e dges bl u n t3

    be c a us e of w e a r .

    2 . 3 Wear mechan ism of metall ic card clothing

    A cc o r di n g t o t h e r es ul t of f o r ce a n al ysis , i t c a n be

    k n ow n t h a t t h e c o n t ac t s t r ess be t w e e n f i be r a n d me t al

    f ric t i o n al f a ce is s m all be c a us e t h e f i be r is ve r y li g h t . I n

    t his f ric t i o n al c o u nt e rp a r t , t h e f i be r c a n be t h o ug h t of as

    ()Fi g . 3 Th e f ail u r e of t h e c yli n de r wi r e t oot h S EM a n el as t ic b o d y a n d t he f i be r2me t al f ric t i o n al c o u n t e rp a r t

    [ 3 ] h as c h a r a c t e ris t ics of visc oel as t ici t y . T he r ef o r e , w he n 2 . 2 Force analysis of metall ic card clothing

    t he r el a t i ve sli de sp e e d be t w e e n t h e el as t ic b o d y a n d t h e D u ri n g t h e p r ocess of c a r di ng , t he f i be r is g rip p e d b y

    t he t e e t h t ip p a r t . This m a kes t he f r o n t f a c e of t he wi r e ef f e c t i ve ri gi d b o dy i nc r e as es , t h e p h e n o me n o n c alle d t e e t h u n de r t a ke a n o r m al p r ess u r e N a n d a f r ic t i o n al f o r c e h a r de ni ngwill occ ur i n t he el as t ic b o d y . This ki n d of F as s h ow n i n Fi g . 4 . T he si de f ac es of t he wi r e t o ot h be a r ef f e c t m a kes t h e n o r m al p r ess u r e N i nc r e ase wi t h t h e

    ( ) ( )J o ur nal of D o n gh ua Uni v e rs i t y En g . Ed . V ol . 25 , N o . 3 2008 326

    I n t his s t u d y , S EM is us e d t o a nal ysis t h e s urf a c e i nc r e as e of sli de sp e e d be t w e e n t he f i be r a n d t he me t al wi r e [ 3 ] m o rp h ol ogy of t h e wi r e t e e t h , w hic h a r e b ot h t es t i n g t e e t h . Fo r a gi ve n l oa d W , a c t ual me a n s t r ess σ ac t i n g

    s a mp les a n d t he f aile d s a mp l es c olle c t e d f r o m c ot t o n σo n e ve r y mic r o2asp e c t is l a r ge r t h a n na me s t r ess .Th e app f ac t o r y mill , as s h ow n i n Fi g . 8 . I t c a n be f ou n d t h a t t he r e r el a t i o ns hip be t w e e n t h e m is as f oll ows :

    a r e n o g r o o ves c a us e d b y t h e a b r asi ve h a r d p a r t icles , b ut A appσσ = ,app t he r e a r e s e ve r al t hi n p ie c es of p a r t icles f alli n g a w a y f r o m A act t he s u rf a ce , a n d m a n y mic r o2c r a c ks o n t h e f ric t i o n al w he r e A is t h e n a me c o n t ac t a r e a , A is t h e s u m of app act s urf a c es a r e als o s e e n o b vi ousl y . a c t ual c o n t ac t a r e a of e ve r y mic r o2asp e c t . A l t h o ug h t h e f ric t i o n al f o r c e be t w e e n f i be r a n d me t al wi r e t e e t h is s m alle r t h a n t h a t of me t al f ric t i o n al c ou nt e rp a r t , t h e w e a r of t h e wi r e t e e t h is s t ill o bvi o us a n d m uc h m o r e o b vi o us

    ( af t e r s e ve r al ye a rsπ w o r ki ng t i me t h e p r oc essi ng f i be r 5 5 ) w ei g h t a b o ut 3 ×10 - 5 ×10 k g . L e t us s up p os e t h a t a p i ec e of f i be r is o nl y c a r de d o ne t i me b y a me t al wi r e t o ot h , t h e n t h e me a n c a r di ng n u m be rs f o r e ve r y me t al wi r e 6 7 ( ) t o ot h will r e a c h 1 . 53 ×10 - 10 t i mes i n i ts lif e sp a n . If t he w<