Bai Giang May Nhua

8/10/2019 Bai Giang May Nhua

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K THUT KHUN MU

(CNG NGH GIA CNG POLYME)

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ti: 1.My p phun (nguyn l lm vic) 2. B phn p phun v ha do

3. Khun(mt khun c th) 4. B phn kp 5. B phn iu khin v h thng truyn ng 6.Thit k khun bng solidwork, pro-e,

7 Tnh ton khun bng moldflow 8. My thi (nguyn l lm vic) 9. K thut p phun kh (gas injection mold) 10. K thut p phun sandwich (sandwich injection mold)

11. K thut p phun nn ( injection compression mold) 12. K thut p phun sau (back- injection mold) 13. My n (nguyn l lm vic) H thng lm mt

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Ti liu tham kho

1. THNH THANH SN

C S K THUT GIA CNG POLIME

2. V HOI NTHIT K KHUN MU CHO SN PHM NHA

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Mt s thut ngNozzle: bc phun

Blow mold: khun thiInjection Blow mold: khun thi pExtrusion Blow mold: khun thi n

Injection mold: khun p phunCavity: lng khun

Thermoplastic: nha nhit do

Shrinkage: co ngtParting plane: mt phn khunRam: piston

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CHNG 1:

NGUYN L C BN CANHA

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1. Phn loi v nh ngha vt liu polyme

Nha v cc vt liu n hi l tn capolyme hu c nhn to c sn xut t hnhp hu c c trng lng phn t thp.

C ba nhm vt liu polymer khc nhauhon ton:

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Nha nhit do c th nu chy c nhiuln, c kh nng phn hy, t phng ln vi nhiu

dung mi. nhit bnh thng, chng thayi t trng thi mm dai n do hoc rt cng.Nha nhit do chim th phn ln nht trongngnh nha.

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Nha nhit do trong th tng t nh knhv cu trc phn t. Chng khc vi nha nhit

do tng t pha l, c mu c nh sa. Khimt loi nha trong nh knh, bo m lnha nhit trong.

Hp a CD l mt v d ca nha nhittrong. CD c sn xut t nha nhit trong nhknh, do trong sut. Tuy nhin n c phmt lp c tnh phn x(nhm hoc vng). Vic

ph nhm, vng ging nh knh. V vy tialaser khng i xuyn qua CD m phn x li.

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Vt liu n hi khng th nng chy, hatan nhng c th lm phng ln. nhit

phng n c trng thi mm do. Cc sn phmlm t vt liu n hi nh l siu, lp xe. Caosu t nhin l trng hp c bit ca loi vt

liu ny.Nha nhit cng th cng. Chng khng

th nh hnh bng bin dng do, khng nng

chy, chu c nhit cao. Chng khng ha tanv kh kh khn lm phng ln. Chng cngv gin nhit bnh thng.

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Nha nhit do

+ Hng tiu dng v chi tit mi mn thp

PP (Polypropylene) PS (Polystyrene)PE (Polyethylene): HDPE v LDPE

PVC(Polyvinyle chlorid)

PMMA(Polymethyl metacrylate)

+ Nha k thut: chu mi mn, chng va p,bn chc

PC(Polycarbonate)

PA (Polyamide- nylon): PA 6 v PA 6,6

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ABS (styrene co-polymers)

PPC (Polyphenylene oxide)

Nhn bit cc cht do

dng phng phpth nung nng

Cht nhit do s tr nn mm trc khi

ti 200 CCht n hi s si bt v bt u ra nt

trc khi mm ra.

Dng km gi mt mu cht do trn ngn laxanh n cn. Quan st v bng khu gic cth nhn bit kh chnh xc cc loi cht do

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STT Nha Mmra

Btla

Mu la Chytip

Khi Mi Duhiu

1 ABS c D Vng b hng c B

hng

hng Hi ging

cao su(mi)

2 PA khng kh xanh l, nhvng

khng t G Si btkhibt la

3 PP C D Vng xanh l y

c t Dunng

Mm nhit cao

4 PVC C kh Vng xanh lc y

khng Trng hng D hngn

5 PS C D Da cam c Bhng

Du Khi bn

6 PF khng kh vng khng t Kht La si

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1.2 Cc dt tnh bin dng ca nhaCc vt liu polyme c cc c tnh khc

nhau khi gia nhit. Cc c tnh ny ph thucvo nhiu yu t khc nhau bao gm cu trc hahc ca phn t polyme v lc lin kt ni phnt

p phun l phng php gia cng ch yu.N cch khc, vt liu phi tn ti trng thi do c th gia cng. Trng thi do c c trng

bng cc tnh cht dng chy nht.Tnh cht bin dng khi chu nhit l c

tnh ca vt liu polymer.

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Tg: nhit chuyn tip thy tinh , Tf: nhit nng chy, Td: nhit phn hy.

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Mt khi vt qu nhit chuyn tip thytinh, cc lc ni phn t tr nn qu yu cc

ngoi lc lm tch cc phn t ln vi nhau.Cng ng sut gin, trong khi gin ditng. khong nhit ny, nha t ti trngthi do hoc n hi nh cao su

Cng ng sut gim, trong khi gindi tng ln. khong nhit ny, nha tn ti trng thi mm do hoc nh cao su.

Khi nhit tip tc tng cao, lc ni phnt hon ton bin mt. Polyme tip tc trng thimm do n trng thi chy. S chuyn tip ny

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c biu din bng khong nhit chy(Tf).Nhit ny khng th ch nh mt cch chnh

xc. Cc phng php gia cng chnh nh p phunthc hin trong phm vi nha nhit do

Nu nhit vt qu nhit phn hy (Td)

th polyme b phn hy.

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1.3 Cc phng php nh hnh vcompound

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p phun l mt trong cc phng php s l{ch yu. N thc hin trng thi nha nhit do,

ngha l trn nhit chy, nhit nng chy kttinh, di nhit phn hy.

Ngun liu phi trn (conpound) c ngha l

vt liu th. N c cc dng: ht nh, bt, ht ln.Nguyn liu phi trn phi c lu trtrong iu kin kh ro. V m khng vt qu

gii hn cho php (0,1 -:- 0,3 i vi nha nhitdo). Tuy nhin i vi compound m t c thc sy nhit khong 120 -:- 130 trongvng 8 n 12 gi

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1.4 Nng chy ca nha1.4.1 nht

Trong qu trnh p phun, polyme tn ti trng thi nha nhit do. nht ca cht lng lthc o cn ca dng chy. Vi cht lngnewton, nh nc , nht c nh ngha bng

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hnh dung nht l g? Hai thng ccng kch thc mt thng ng nc, mt

thng ng cht sn, hai thng c hai vi ycng ng knh. Tin hnh m vi cng mt lc.Ta thy thi gian chy ht nc nh hn thi gianchy ht sn. Ta ni nc c nht thp hn.

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1.4.2 Sc cng b mt v

Bin dng ca tc dng chy trong ng

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Khi cht lng chy trong ng, vn tc lnnht gia mt ct ngang ca ng. Vn tc gim

dn hng v thnh ng. Ti thnh ng vn tcbng khng.

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1.4.3 Vn tc v nhit

nht ca cht lng gim khi nhit

tng. nht ca nha nhit do nng chykhng ch ph thuc vo sc cng b mt m cnph thuc vo nhit . nht gim khi nhit

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Bn cnh nht, cc yu t khc cngnh hng n tnh c th gia cng ca nha

trong vic gia cng p phun. Bng sau trnh bymt s loi nha c s dng trong gia cngp phun, cung nh cc tnh cht quan trong

trong gia cng( v d nh, co ngt, kh nngchy, khong nhit gia cng)

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Chiu dy thnh sn phm nha nhit do

TT Vtliu Chiudy min (mm) Chiudy trung bnh (mm) Chiu dy max

(mm)

1 PA 0.38 1.6 3.2

2 PC 1.0 2.4 9.5

3 LDPE 0.5 1.6 6.4

4 HDPE 0.9 1.6 6.4

5 PP 0.63 2.0 7.6

6 PS 0.76 1.6 6.4

7 PVC 1.0 2.4 9.5

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Quan h gia nghing thnh vi cao vchiu dy thnh.

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CHNG 2:

CNG NGH N

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Sn phm sn xut bng my n

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2.1 CIM

nlphngphp gia cng chyudng

cho nhanhitdov vtliunhinhcaosu, trong vt liu trng thi chy nhtcy lin tcqua mtkhe hc titdin

nhtnhgil utohnh.Phngphp nlin tcchp dngcho

vt liu n hi v nha nhit do, cn i

nhanhit rn th ch dng phngphp ngin ontrn my npiston.

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c im ca phng php n lin tc

+ Sn phm ch nh hnh theo hai chiu

+ Nng sut my rt cao

+ Sn phm: mng mng, tm phng, s, ng,bc cp, dy dn, cc sn phm rng

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4.2 MY NTRCVT4.2.1 Phn loi

A- Phn loitheo strcvt- My 1 trchay nhiutrc- i vi my nhiu trc, cc trc c th n

khp hoc khng n khp, quay cng chiuhay ngc chiu. Do cu to truyn ngphctp,nn my nhiutrct csdngtrong cng nghip n to hnh, m thngdng trnv nhaha hnhp

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B- Phn loi theo cng dng:SX ng cng

SX mngmng

Trng ph vSX tm

c di p sut

Cn tm

SX s, si

n chi

tit dngprofil

n

SX ng mmSX profil

n phi thi kh

SX mng ngSX mng phng

Bc dy v cp

SX mng phc hp v

tm phng

SX mng ng

SX dy phng

SX mng phng

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4.2.2 Cu to my n trc vt

Do tnh cht n gin, d vn hnh trong

cng nghip polime, my n 1 trc vt thngc s dng gia cng sn phm

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A- Ca cp liu: ca np liu c th c tit dintrn, ch nht, hay vung, thnh ng, xing,tip xc hay vng su xung.

Dng ca np liu hnh c thng c sdng khi nguyn liu dng bng di

Chiu di ca ca np liu khng b hn

mt bc rng vt

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3. Vng phi liu: nguyn liudngchynht.

Trong qua trnh di chuyn ca nguyn liutcanpnutohnh, nguyn liuthayi trng thi t rn n mm cao, ri chy

nht,nn khi lngring thay i,v do trcvt phic mths nn no ,cho nntrcvt c mttrong cc dngsau:

Xt vmtchc,trcvt c chiucao rngkhng ibnhn. Tri li,xt vmtthitk,ch to v tnh nng k thut th trc vt cbckhng innhhn.

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Dng 4.4 e vi vng phi liu t 5 n 10Dthng s dng cho gia cng cc loi nha dchy, bn nhit nh PE, PB, PA, PUB, PC. Vicc loi nha c im nng chy r rng v PSth dng vt thng dng l 4.4f. Cn gia

cng cc loi nha nh ABS, CA, PVC, ngi tadng vt 4.4a

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Mt trong nhng kch thc c nh hngnhiu n cht lng sn phm l chiu di

trc vt, v n nh hng n thi gian lu lica nguyn liu trong my.

Ty theo mc ch s dng, chiu di ca

trc vt thay i trn mt khong rng. giacng cao su, chiu di vt so vi ng knhL/D bin thin t 3 n 4. Cn i vi vt dnggia cng nha nhit do, L/D t 15 -:- 20.

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Chiu di ca cc vng phn chia trn trcvt tuy c tnh cht quy c nhng rt quantrng, nht l chiu di vng phi liu. Nhngmy c chiu di vng phi liu ngn ccthng s nhit , p sut, nng sut rt binng. Tri li, my c chiu di vng phi liu

di cc thng s trn nh hn ng thi psut cng ln hn.Trc vt thng c ch to thp khng

r. Mt trong nhng i hi quang trng ivi vic ch to trc vt cng ca kim loidng

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h hi h


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ch to trc vt, v phi c h s ma st canguyn liu gia c ln b mt phi b, v mttrong nhng yu t m bo nng sut cao l

h s ma st ca vt liu polyme trn b mttrc vt phi b hn h s ma st trn b mtxylanh. Trong nhiu my m bo iu

kin trn, phi tin hnh lm ngui xylanh.Chiu co ca rng vt phi c tnh ton m bo bn, thng khng vtqu 0,007 ln ng knh, v cng phi m

bo c s n nh ca dng chy nn chiucao cng khng vt qu 0,1 ln b rng rnhvt.

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Chiu cao rng vt n

T s L/D 15 20 25 30

Chiu cao

rng vt(mm)

4,0-:-4,5 4,5-:-5,3 5,6-:-6 5,5-:-6,5

Vt n thng c gia cng vi t s nnp t 1,5/1 n 4/1C- Xylanh

Xylanh ca my n c ch to thnh 2

lp, lp ngoi chu lc, lp trong chu ma st v nmn v thay th d dng.

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Ty theo cch t nng, lp ngoi c 1 hay2 v. Nhng my dng gia cng cao su

thng c 2 v c th gia nhit bng hinc, hoc tc nhn nhit khc, v i hinhit khng cao, nhng c yu cu kimsot nhit cht ch.

Cn dng gia cng cht do, v ngoithng 1 lp, c t nng bng in tr vi hi nhit cao.

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D- utohnh

B phn ny gi nhim v to hnh sn

phm, v tnh a dng ca sn phm n nnutohnh cngadng: utohnh mngmng,utohnh ng,utohnh bcdydn, utohnh profile

yu cuutohnh l

- Khng c imdngtrn dng chy

- Tnthtp sutnh

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h h b


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S cu to mt s u to hnh tiu biu

a/ u to hnh tmphng kiu ui c

b/ u to hnh tmphng kiu ng gp

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u to hnh

sn xut ng vphing

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u to hnh sn sut mng ng

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u to hnh bc dy dn

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Ngoi cc b phn chnh trn, my ncn c cc b phn khc nh li lc, bhng dng,

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F. Li lc v tm li lc

- l li thp khng g dng lc tp chtkhi khi nha nng chy , khng cho vou khun

- Tm li lc l tm kim loi trn c

khoan nhiu l dng to p lc ngc lm tng hiu qu trn v nha ha ca vt

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Sn phm sau khi c nh hnh dnglin tc, ty theo mc ch s dng v loi

sn phm, ngi ta c th ct thnh t oncn thit.

Vic lm ngui sn phm khi thot ra khi

u to hnh c th bng khng kh hay nc.

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4.2.4 S bin i trng thi v chuynng ca nguyn liu trong rnh vt

1/ Vng np liu: vng ny vt gi chc nng lti vt liu. Chuyn ng ca nguyn liu tuntheo qui lut ma st kh v s o ln khi

vt liu cha r rng, s chuyn ng ca vtliu mang c im chuyn ng khi, s thayi khi lng ring l kt qu ca vic vt

liu b nn p trong rnh vt.

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2/ V h h (l h ) t i t


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2/ Vng nha ha(lm chy): vt ng vai trnha ha khi hn hp. Nguyn liu vngny l hn hp nha lng v nha bt, chuynng ca nguyn liu tun theo qui lut mast rn c bi trn, hin tng o ln xuthin r nt hn.

3/ Vng phi liu hay nha lng: Trc vt ngvai tr nh mt my bm. Nguyn liu hon ton chuyn sang trng thi chy nht,tuy chuyn ng mang tnh cht chuyn ng

khi, nhng khc vi vng np liu, ychuyn ng tun theo cc qui lut ma stnht vi s hnh thnh cc lp mng.

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Tnh nng ca my n trc vt ph thuc


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Tnh nngcamy ntrcvt phthucvo n thchin3 nhinvny nhthno.Trn nguyn tctngqut camy nc thxc nhbngsphn tch tnh nngcatngvng sau kt hp li. Tuy nhin khi vngphiliukhng bqu ti,th chng ta c ths dng cc kt qu phn tch vng ny tnh ton vn hnh my. Ngoi ra t kt quphn tch ny chng ta c thrt ra cmtsktluntngqut vcc ctrngnh

ng nht v nhit ca sn phm, v tcn,Cho nn trong cc phnsau chngta chtinhnh

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phn tch vng phi liu ca my trong coinh mt my bm loi vt.

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4.3 c im dng chy ca nha trongrnh vt

4.3.1 M t dng chy:Nha lng di chuyn trong vt n l do

chuyn ng tng i ca vt so vi xylanh. tnh ton, thng chng ta xem trc vt

ng yn, cn xylanh chuyn ng quay vivn tc V = 2..R.NKhi xylanh quay, lp nha lng tip xc vi

thnh xylanh s c vn tc thnh xylanh, vntc ny gim dn theo b su ca rnh vt vbng 0 ti y trc vt

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D t h h t V


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Do rng vt hnh xon c nn vn tc V cphn thnh 2 thnh phn

V: hng dc theo trc vtVx: vung gc vi ng trc

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Nu u ra ca trc vt h, chng ta c 2dng chy:

+ Dng chy dc trc, V, quyt nh lu lngca nha c n ra

+ Dng chy ngang, Vx, dng chy ny khngnh hng n lu lng n ca nha,

nhng c tc dng o trn cht lng trongrnh vt, to s ng u nguyn liu.Dng chy khi u ra ca vt h gi l

dng chy nht v n hnh thnh do s chuynng tng i ca xylanh, lu lng dngchy ny l lu lng cc i ca my n.

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Khi u ra ca vt b cn( do li lc u


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Khi u ra ca vt b cn( do li lc, uto hnh), th p sut c hnh thnh ti utrc vt. Chng ta xem nh c mt dng chy

ngc hay dng chy p sut ( v do s sai bitp sut) c hnh thnh. Thc t khng cdng chy ny, m dng chy dc trc b gimkhi u ra cn tr, d phn tch, vi khinim dng chy p sut, chng ta c th xemnh dng chy dc trc ca vt l tng dngchy nht v dng chy p sut, tc lu lng

ca dng chy dc trc bng hiu s lu lngca dng chy nht v dng chy p sut.

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Khi u ra b bt kn hon ton lu lng


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Khi u ra b bt kn hon ton, lu lngdc trc ca nha bng khg, ngha l hiu ng2 dng chy thun nghch bng nhau. Khi p sut hnh thnh ti u trc vt l ca i.

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Ngoi hai dng chythunv chynghchnhhngnlulng cavt n. Chng

ta cn c dng chy r, ch yu l do s saibit p sut ca nha lng 2 bn rng vt.Dng chyny chyqua khe hgianhrngvt v thnh xylanh. Shincadng chyrlm gim lu lng chung ca vt n. Tuynhin khi khe hb v nha lngc nhtcao, th tntht lu lng cadng chy r

l khng ngk,nn khi tnh ton thng tch ndng chyny

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4.3.2 Cc phng trnh xc nh c tuyn cavt

a/ Dng chy dc trc tnh ton v lu lng v p sut v nhachy trong rnh vt, vi m hnh mt phng

song song, dng chy trong rnh tit din chnht.

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Nngsutcamy n

nngsutM = dng dctrcdng pxutdng r

dng dctrc=1

22. 2....

Dngknh trcvtn- tcquay catrcvtH- su rnh vt trong vngbmv nh

lng

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CHNG 3:

MY P PHUN

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3.1 c im


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3.1 c im- Thi gian chu kz ngn

- Sn lng ln, nhit (khong 230

0

C) v psut gia cng cao- Sn phm gai cng c kch thc chnh xc

theo 3 chiu v c to hnh trong khun kn

- Qu trnh nha ha to hnh c thchin trong hai giai on ring bit, trongnhng b phn khc nhau ca my: nha ha

trong xylanh nguyn liu, to hnh trongkhun.

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- Qu trnh to hnh ch tin hnh sau khi


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Qu trnh to hnh ch tin hnh sau khi ng kn hai na khun li vi nhau.

- Ty theo loi nguyn liu, ch nhit cakhun khc nhau. i vi nha nhit donhit khun thp hn nhit nha lng.i vi nha nhit rn, nhit khun caohn nha lng.

- Khi vng to hnh ca khun c lp ynguyn liu th khun mi chu tc dng lc

piston p gin tip qua nha lng

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- Nng sut ca phng php p phun cao, ty


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Nng sut ca phng php p phun cao, tytheo kch thc v hnh dng sn phm mch kz p phun theo i

- Phng php ny tit kin nguyn liu

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V nguyn l{, kch thc my c chn


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V nguyn l{, kch thc my c chntng ng vi kch thc ca sn phm. Nhngiu ny khng lun lun ng khi kt hp nhiu

sn phm nh vi nhau. Nhiu sn phm nhc sn sut mt ln trn my ln th kinh thn khi sn xut tng ci trn my nh.

Th thch ca sn phm c xem xt trctin khi chn my. Sn phm cng nng th cngnhiu nguyn liu phi c cung cp bi b phnp v ha do trong khong thi gian cho trc.

Ngoi th tch ca sn phm, kch thc ca ncng c xem xt. Din tch hnh chiu ca snphm, din tch chiu theo hng kp, xc nhvic chn my.

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Din tch hnh chiu

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c sn phm tt khng c ba via lc


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c sn phm tt, khng c ba via, lcphn khun phi nh hn lc kp.

Vt liu khc nhau c tnh cht khc nhauv phi gia cng cc iu kin khc nhau. Do, cng phi c nhiu my p phun khc nhau.Tuy nhin, tt c cc my p phun c th tnghp thnh cc kiu chnh sau:

Gia cng nha do thng s dng my pphun ngang. V mt phn khun t theophng ng, sn phm hon thnh c thrt vo thng cha, khi chng ri khi khun

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B phn nha ha v p do gm:


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B phn nha ha v p do gm:

1. Phiu cp liu

2. Xylanh nguyn liu3. Trc vt va lm nhim v nha ha va gi

nhim v to p sut y nguyn liu vo

vng to hnh ca khun. thc hinnhim v ny, b truyn ng ca trc vtphi to c chuyn ng ti lui v quay

trn.4. u phun

5. B phn truyn ng

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Trong cc b phn ny th xylanh v trc vt


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ng vai tr quan trng hn c.Xylanh c cu to nh my n trc vt

thng 2 lp: lp ngoi chu lc v lp trongchu n mn ha hc v chng mi mn.Xylanh c th c thnh mt on lin tc

hoc thnh tng on m khi lp t c thlin kt vi nhau bng cc mt bch v bulong.Nhim v quan trng ca xylanh l to b mttruyn nhit.

Trc vt gi nhim v nh my n trc vttc l ti nguyn liu, nha ha v ta p suty vt liu, tuy nhin y c im khc bit.

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- Nhim v ti vt liu v nha ha c thc


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hin bi tc ng quay trc vt

- Nhim v to p sut y vt liu khi xylanhnguyn liu c thc hin bi chuyn ngti lui ca trc vt.

Do cu to ca trc vt my p phunkhc vi my n. di tng i ca vt sovi xylanh ngn hn so vi my n, v cn chakhong cch trc vt chuyn ng ti lui

Mt c im khc bit na so vi myn l trong my p phun trc vt chuyn nggin on theo tng chu kz.

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3 C kh nng lp kht vo ng rt rnh chnh


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trong giai on c, v c kh nng khng chonha lng trong xylanh nguyn liu chy rakhi ng rt rnh chnh trong giai on nhaha.

Cc kiuuphun

uphun

tiuchun

uphunvt

ngc

uphunc bikim

sot

u phunchy t do

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3 B PHN HA DO V P PHUN


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3.B PHN HA DO V P PHUN

Cc chc nng chnh ca b phn p phun c thchia thnh cc phn nh sau:

- Lm nng chy ht nha

- Vn chuyn- Tch cha

- p

- To p sut gi

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Nng chy


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Polymer c nhiu dng khc nhau. Nha

nhit do thng dng ht nh hnh tr, hocht u c ng knh khong 2-3mm v di 2-3mm.

B phn ha do v p phi bin i cc htny thnh chy nht ng u, c th in ylng khun. Ni cch khc nha chy nht phic th rt. Vi mc ch ht nha c gia

nhit, cho ti n nng chy nht. Vic ny tc do ma st gia cc ht nhc, cng nhnhit c truyn t bn ngoi ( dn nhit v ilu)

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Do b phn ha do v p phi c gia


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Do b phn ha do v p phi c gianhit. Vi nha nhit do, vic lm nng ny do

cc tm in tr kp xung quanh xy lanh. Nhitc th c t mt gi tr xc nh.

T dng ht chuyn sng nng chy

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S ng u


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g

Sn phm c mu minh ha cho mt

nhim v khc ca b phn p v ha do. sn sut cc sn phm c mu bng my pphun, mu mong mun phi c trn vi htnha. L{ do l a s nha nhit do hoc l

khng mu hoc l c mu sng v trong m trng thi t nhin ca n. Trong mt s trnghp, vic trn ln ny c thc hin bi nh

sn xut ht nha. Tuy nhin, thng thng victrn ln ny c thc hin ti nh my snsut nha.

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Ngoi mu sc, cc cht ph gia cng c


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Ngoi mu sc, cc cht ph gia cng cs dng, nh cht chng oxi ha (cht n nh)

hoc cht in y. Nhng cht ny lm gimgi thnh ht nha, v chng r hn vt liu nn.

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3.2 HA DO


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Ht nha c vo phiu. Ht nha ri

khi phiu, vo vng ly liu ca trc vtTrc vt quay chuyn ht nha hng vpha bc phun. Trong qu trnh di chuyn vpha trc ht nha tip xc vi thnh xylanhnng.

Nhit ma st cng to ra trong qu trnh dichuyn ny. S trn ln ca nha chy nht-

yu t cc kz quan trng trong c sn phncht lng cao- b nh hng bi nhit thnh xyanh v tc quay trc vt.

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Nhit nha do c gia nhit n 180 -:-


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300 C, hn hp cao su c gia nhit khong100 C trnh xy ra phn ng ha hc sm.

p sut ngc tc dng ln trc vt. psut ngc ny cng cn tr nha di chuyn vpha trc. S cn tr ny lm tng s trn lnthm.

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Mi trc vt c mt hnh dng hnh hc c th.


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Hnh hc ca trc vt truyn thng my nha

g Hnh hc ny xc nh kch thc ca trc vt.

: dung sai: Gc nngh: chiu cao rng

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nha ha do nhanh v ng u, trct c chia lm 3 ng


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vt c chia lm 3 vng.

Vng cp liu(phn pha trc ca trcvt), nguyn liu c np t phiu v chuyn ti

bc phun. Phn gia ca trc vt (vng chuynbin hoc vng nn) chiu cao rng gim lmnguyn liu b nn, kh thot ra v nng chy.

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Vng trc trc vt, ngoi vic trn ln


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nguyn liu din ra. p sut cng sinh ra trongnguyn liu.

Mt khi nha ha do chuyn v phabc phun, n c cha trc khi b p vokhun. Nha nng chy phi c p vo khun

vi vn tc rt cao. Kh nng ca b phn hado th khng cung cp nha chy nhtnhanh nh vy, trong khi cng t c mc

trn ln cao. Cho nn, nha chy nht phic tch tr gia giai on ha do v p

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Vi l{ do , hu ht cc my p phun cho


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nha nhit do, trc vt c th di chuyn dctrc. Tuy nhin cng c cc thit k khc. Nguyn

liu di chuyn dc trc trc tp trung trc utrc vt(khoan trc). Khi iu ny sy ra, trc vtphi di chuyn v pha sau. Khi trc vt di chuyn

mt on xc nh trc v mt lng nhamong mun tch trc trc vt, th trc vtdng quay v khng c nguyn liu c thm.

Nguyn liu khng c thot ra khi bc

phun bt kz thi im no ngoi tr trong thigian p, v iu ny s lm gim lng nguynliu c sn cho hot ng p. Vi l{ do , bc

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phun phi c b phn ng trong giai on ha do.C nhiu loi bc phun kha thc hin chc nng


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C nhiu loi bc phun kha thc hin chc nng .Hnh bn di l bc phun kha kim.

Trong giai on ha do l xo y kim p vo lbc lm ng bc phun (hnh tri). Trong giai on pkim b y ra bc phun c m, cho php nhachy qua bc phun.

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Bc phun kha khng th s dng choh h h th h h t i


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nha nhy cm cao v nha c th phn hy tiv tr ng. Bc phun m c s dng cho cc

loi nha ny (PVC) hoc gim gi thnh my.Khng th ngn cn hon ton nha thot ra vibc m. iu ny phi tnh ton trong giai on

p (bng cch gim nn khi kt thc giai oncp liu).

Ngay khi lng nguyn liu tch ly

khoan p, hot ng ha do kt thc. Nguynliu sn sng cho p.

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3.3 P PHUN


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3.3 P PHUN

Chc nng th hai ca b phn p phun v

ha do l p thnh phn ha do - nha chynht cha khoan p - vo lng khun. Qutrnh ny phi xy ra nhanh nha lng khng

b ng c trong giai on p. Vt liu b ngc trong khi ang p, s lm cho sn phm bkhim khuyt. V nha nng chy khng lngnh nc v v i khi n cn in y mt s

lng khun rt phc tp. Do , cn phi c mtp sut rt cao in y mt lng khun hocnhiu lng khun trong cng iu kin

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Van mt chiu


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Van ny c gi l van mt chiu. N l

mt van trt t vo u trc vt. Khi p sutdc trc vt cao hn p sut trong khoan p, thvan cho php nha i vo khoan p m khngcn tr. Khi ngc van ng li

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My p phun ngang

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My bn quay, nhiu b phn kp c s dngcho mt ln p V vy my ny thch hp cho cc


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cho mt ln p. V vy my ny thch hp cho ccsn phm c thi gian lm ngui hoc gia nhit di.

Ngy cng c nhiu sn phm phc tm nhngchi ph sn sut phi hp l t ngnh cng nghipnha nhiu thch thc mi. Cc phng php gia

cng nha truyn thng c th khng cn p ngcc thng s k thut, cc quy trnh c bit, nhkhun p nhiu thnh phn c p dng. Vi khun

p nhiu thnh phn, t nht hai b phn p c lpvi mt b phn kp. Phng php ny cho php hailoi vt liu c mu khc nhau c p chng lnnhau, mt ln p

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My sn sut CD hon chnh


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My sn sut CD hon chnh

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Cc qu trnh p phun c bit


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Cc qu trnh p phun c bitVic sn xut cc sn phm phc tp cht

lng tt phi tri qua nhiu giai on trung giannhng gi thnh hp l t cho cc nh snxut my p phun thch thc mi. Cc phng

php p phun truyn thng c th khng cn png cc cc i hi mi ny.

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3.3.2 p phun kt hp (ng thi)


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V nguyn l{, tt c cc k thut p phuntrnh by s l{ hai hay nhiu vt liu khc nhaugi l k tht k thut p phun kt hp. Nhngthng ch s dng hai thnh phn, v vy cngc coi nh p phun kp.

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Khi sn sut bng k thut sandwich, vtliu c s dng bn ngoi trong khi vt


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liu c s dng bn ngoi, trong khi vtliu ti s dng lm thnh phn li. iu ny s

dng mt lng ng k vt liu ti s dng, mkhng lm nh hng n v bn ngoi ca snphm.

Phm vi ng dng ca phng php pphun-kh c tm th trong cc sn phmthnh mng v di. N cng c s dng chosn phm c b mt ln nh ca ca my

photo. y n ng dng cho cc gn, giatng cng, lm gim cong vnh.

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3.3.3 Phng php p phun-nn


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Phng php ny c s dng cho sn

phm c thnh mng, du m trn sn phm.

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p phunnn c th phn thnh 2 bc:p phun v nn Trong giai on p phun mt


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p phun v nn. Trong giai on p phun, mtlng chnh xc nha nng chy c p vo

khun, khun c m ng chiu di on cnnn. Ti thi im th tch lng khun ln hnth tch sn phm c sn xut, nha nng chytch t thnh mt khi. Trong giai on nn, khiny b v nn thnh hnh trong lng khun khing na khun di ng. Bt u giai on nn,ng rt phi c ng ngn nha lng thot

khi lng khun.DVD c sn xut bng phng php pphun-nn, c chiu dy bng mt na CD.

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3.3.4 Cng ngh p phun sau (back)


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y l phng php sn xut, cn nhiu

bc. Cc sn phm trang tr c sn xutbng phng php ny. Sn phm bao gm chtnn nha nhit do v vt liu trang tr, ch yul phim hoc vi. Vt liu trang tr c t votrong khun v p vt liu to thnh nn. Snphm ng dng cng ngh ny nh: v inthoi, ca xe hi

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5 B PHN KP


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5.1 Kt cu v chc nng

Nha, c trn u v nng chy trongb phn ha do v p, c p vo lng khuntrong hot ng p. nha ong cng

hnh thnh sn phm. Ngay khi sn phm ong cng, n c ly ra khi khun bng vicm khun ti mt phn khun.

Khun phi ng cht trong giai on p nha nng chy ch chy vo lng khun mkhng chy ra mt phn khun. Tuy nhin, khun

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phi c th m sn phm c th c ly rakhi l kh l kt th h kz


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khi lng khun lc kt thc chu kz.

V ngi ta dng qui trnh p phun l snxut nhiu sn phm vi thi gian ngn, vic dichuyn ca khun nn cng nhanh cng tt,nhng phi rt chnh xc.

B phn kp c trch nhim thc hin ccnhim v m v ng mt cch cht, cng nhdi chuyn nhanh v chnh xc.

B phn kp gm mt tm c nh v mttm di ng. Mi na khun c lp trn mitm ny

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Ph thuc vo thit k ca my p phun,b h k th t t h


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b phn kp c th t v tr ngang hoc ng. gia cng nha nhit do, b phn kp thngnm ngang sn phm v cun phun cn li cth rt ra khi khun. Tm di ng c th dichuyn n mt khong cch xc nh do mt

c cu truyn ng thch hp.

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l{ ny cng c s dng trong my p phun.Nhng s dng ny ngy nay b gii hn mt s


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Nhng s dng ny ngy nay b gii hn mt strng hp ngoi l.

B phn kp ci ch, gi g ngy nay lh thng c chim u th i vi my p phun.N khng ch l mt h thng c, v thy lc

cng c s dng di chuyn ci ch trongh thng. Tuy nhin, nguyn l{ n vn l mth thng c.

H thng ci ch c hai u im:+ S dng cc khu c chiu di khc nhau c

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th di chuyn ti ln m ch s dng mt lcnh


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nh.

+ C th c vn tc thp khu ny nhng thuc vn tc cao khu kia.

Ch { rng lc c th truyn tng th vn

tc gim.S dng hai u im trn ca h thng cich di chuyn cc thnh phn ca my pphun cng nhanh cng tt. Ngoi ra b phn kpnn c di chuyn chm khi khun gn nhc ng hon ton, ngn cn hai nakhun va chm vn tc cao.

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Khi khun c m, ch cn truyn lc di chuyn cc na khun Tuy nhin khi ng


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di chuyn cc na khun. Tuy nhin, khi ngkhun, cn truyn mt lc rt ln gi khun

chng li p sut p. C hai trng thi c thc thc hin kh hiu qu vi c cu ci ch.

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di chuyn cc khu, mt piston tngi nh l cho tt c cc trng hp. Mt khi


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i nh l cho tt c cc trng hp. Mt khikhun ng th cc khu phi dui hon ton,

khng cn dng thm bt kz lc no.C nhiu thit k c cu ci ch khc nhau.

Vic chn la ph thuc vo lc kp v vn tc,

m khun phi di chuyn.

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B phn kp thy lc c hai u im.Chng c th c iu chnh rt nhanh vi cc


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Chng c th c iu chnh rt nhanh vi cckch thc khun khc nhau, v chng khng bnh hng bi s thay i nhit . Trong khi c cu ci ch ch cho lc ln nht khi n dihon ton, piston thy lc c th truyn lc

ti bt kz v tr no dc theo khong di chuyn.Lc truyn bng tch ca p sut nhn vi

din tch piston.

p sut trong my p phun b gii hn t200 -:- 250 bar. Do , cn lc ln gi khunngi ta s dng piston c din tch ln.

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B phn kp thy lc c mt s nhcim. Mt lng ln lu cht cn thit in


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y piston c din tch ln vi hnh trnh di.

Tuy nhin, din tch piston ln ch cn khilc kp c s dng. Gi tr lc nh dichuyn khun. Do thng mt xylanh nh

thc hin vic di chuyn kt hp vi xylanh kpln.

Xylanh nh truyn chuyn ng vi vn

tc cao mt cho kch thc trng i nh cabm. Sau lc kp c thc hin bngxylanh ln.

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Bn cnh hai loi b phn kp chnh( c vthy lc), cng c s kt hp c hai h thng. Tt ccc h thng u c u v nhc im. Ni cchkhc khng mt thit k ti u chung cho b phn

kp. Vic chn h thng no c s dng b quytnh bi hiu qu kinh t. V d nh khun mt haynhiu lng khun v kh nng tng thch ca my.

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6. H THNG TRUN NG V IU KHIN

6 1 H thng truyn ng


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6.1 H thng truyn ng.Hai loi truyn ng c s dng cho

vic thc hin chuyn ng. Mt l thy lc vmt l in. Thng c hai c s dng trongmt my

6.1.1 Truyn ng thy lc.Ngy nay vic thc hin chuyn ng quay

v tnh tin c th thc hin bng thy lc.

Trong trng hp , piston hoc m t thylc c s dng. Piston thc thin chuynng tnh tin trong khi m t thy lc thchin chuyn ng quay.

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Mt s k{ hiu ca h thng thy lc

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Van in t


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Van b kch hot khi cun dy c in, van v tr a v du i qua van. Khi cun dy khng

c in, l xo y van v v tr b v ng du bkha.

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Truyn ng in c th thc hin chuynng tnh tin cng nh quay. Chuyn ng


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g g q y y gquay thc hin bi m t quay. Chuyn ng

tnh tin c thc hin bng thanh rng vbnh rng, truyn ng tay quay hoc trc vt bicng nh m t tnh tin.

So vi truyn ng thy lc, truyn ngin tiu th nng lng v ting n thp.Chng cng yu cu t bo tr, v chng hot

ng khng cn h thng thy lc trung tm.Tri li, truyn ng thy lc chi ph thp.

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6.2 iu khin

B iu kin hoc iu chnh ca my


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B iu kin hoc iu chnh ca mythng c t trong cabin iu khin k my.Ngoi cc thit b hin th, cabin iu khin cngcha cc thnh phn in, in t v b iukin.

cc my i c, thng thng cc thams my c ci t bng cc cng tc hnhtrnh c t trc tip trn cc modul chnh

hoc cc nt nhn trn cabin iu kin.

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7 QUY TRNH P PHUN


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7.1 Cc giai on ca qui trnh p phunQuy trnh p phun c cc giai on sau: p,

gi p sut, lm ngui, ly liu, ly sn phm.

nha nhit cng v vt liu n hi, giai on lmngui c thay th bng giai on gia nhit.

Quy trnh p phun bao gm nhiu giai onring bit hoc cc giai on ni tip nhau. Ngynay chu trnh ny c s l{ t ng hon ton.

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Cc giai on ca mt chu trnh p phunThs.L V Hi

7.2 Bt u


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bt u sn xut, tt c cc b phn phi v trban u

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7.2.1 B phn kp v khun

B phn kp m ra Khng c sn phm


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B phn kp m ra. Khng c sn phm

trong lng khun. B phn p phi v tr rt v.Khun c iu chnh n nhit quy nh.

7.2.2 B phn lm do

Trc vt v xylanh ca b phn lm doc gia nhit n nhit qui nh. Nguynliu nng chy v mm xut hin kkhoan p

u trc vt. Vi b ng li nguyn liukhng chy ra ngoi.

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7.2.4 H thng thy lc v in


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Cc chuyn ng chnh c thc hin

bng thy lc. Tuy nhin ngy nay, cc my thchin bng in hoc lai (in v thy lc) anggia tng mt cch ng k. Khi ngi vn hnh

nhn nt bt u chu trnh th khun phi ngli.

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7.3 Giai on p


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Cc b phn ca my giai on p


B phn kp di chuyn hai na khun livi nhau. Lc kp c hnh thnh, v vy khacht khun

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7.3.3 iu khin


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B iu khin phi m bo rng cc bphn chuyn phi kt hp vi nhau p sut vvn tc nh. Cc v tr ny i hi cao v

chnh xc ca b iu khin.

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7.3.4 Thy lcH h h l hi h


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H thng thy lc phi c cng sut cao nht

trong giai on p. Bn cnh duy tr lc kp, hthng thy lc cng phi c th p nha nng chynht vo lng khun vi vn tc cao nhng chnhxc. hon thnh nhim v ny, h thng thy lcthng c cc cn tr bc phun v khun.

Khi bt u qui trnh p, nha chy nht trong khoang p. Bc phun ng li, nguyn liu

khng th thot. Ngay khi b phn ha do dichuyn v pha ng rt ca khun, bc phun m racho php nha lng i vo lng khun.

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Ti thi im , trc vt di chuyn v phabc phun. Nha lng b y ra khi khoan pha


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bc phun. Nha lng b y ra khi khoan phatrc trc vt, i vo lng khun.

Nha chy nht phi ong cng li tronglng khun, sn phn c th ly ra c. Do khun s dng cho nha nhit do phic lm lnh hoc cn bng nhit nhaong cng.

Ngay khi nha chy nht tip xc vi

khun , n bt u ngui v ong cng. V vy,qu trnh p phi nhanh.

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iu ny i hi p sut rt cao, v nhalng ch cn nht thay v s dng nhit cao.


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Nha chy nht phi thng c cc cn tr do

bc phun, ng rt, lng khun cng nh mt scn tr khc nh ma st thnh khun. Do psut trc u trc vt c th hn 2000bar(29.000psi) trong qu trnh p.

S cn tr bc phun, ng rt v lngkhun lm p sut gim theo hng dng chy.Mt d vy, p sut cao vn xut hin trong

khun. B phn kp phi c kh nng gi khunmt cch chc chn chng li p sut ny.

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Hnh 7.5 trnh by ng cong p suttrong khun, trc trc vt v h thng thy lc


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g g ytrong my. C th thy rng p sut trong khunt gi tr ln nht, khi nha chy nht c pvo y khun hon ton.

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Thc t p sut trong h thng thy lcnh hn p sut hnh 7 5 p sut thy lc tc


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nh hn p sut hnh 7.5. p sut thy lc tc

dng ln piston truyn lc ln u piston trcvt. Lc ny to ra p sut cao khoan p. Lcny t n p sut ti hn ca giai on p.Hu ht hn hp nha vn trng thi lng, vvy hu nh ton b p sut ny c truynvo khun. Nu p sut vn duy tr qua imny, p sut trong khun c th ln thng

lc kp khun. Khun b tch ra, nha thot rangoi.

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7.4 Giai on gi p sutNgay khi nha chy nht in y khun n


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Ngay khi nha chy nht in y khun, nbt u ngui. Qu trnh ngui ny bt u t thnhkhun v hng n tm. Khi ngui, nha gim thtch, ni cch khc, n co ngt.

Nu p sut ngt hon ton sau giai on p,

sn phm s tch hi thnh khun hi n ngui. kchthc ca sn phm s khng c kim sot.iu ny c th trnh. Vi iu kin vng bn

trong sn phm cn trng thi nht, p sut trn

nha chy nht vn duy tr. Lng nha b sungc p vo khun vi s lng va b congt. D nhin, iu ny ch c th lm vi iu kin

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phn trong ng rt mm. l mt l{ do tisao ng rt nn t v tr dy nht ca snphm nu c th Giai on gi p sut ch


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phm, nu c th. Giai on gi p sut ch

dng mt p sut va p b nguyn liucho co ngt. Giai on ny phi ko di choti khi ng rt cng, ni cch khc, cho tikhi nha chy nht khng th p c vo

khun.Tri vi giai on p, dng chy khng b

cn tr trong giai on gi p. Vi li, thc tkhng c s di chuyn nguyn liu xut hintrong giai on ny. Vi l{ do , p sut ginhn chung c th ci t mc thp hn psut p

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Ci t p sut mc thch hp l iuquan trng. Nu p sut gi qu thp, hoc nu


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khong thi gian p sut gi qu ngn, s to ra

sn phm b bin dng. ng cong l{ tngcho p sut lng khun

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Vic chuyn tip t giai on p sang gip sut xut hin vo thi im chnh xc th


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c bit quan trng. Nu chuyn tip qu sm,

p sut rt xung. iu ny a n nguy himl in y hon ton lng khun l khngth. Nu chuyn tip qu tr, u nhn p sut

xut hin. Hot ng lu vi nhiu ln nhnhn p sut nh vy c th gy nguy him chomy v khun

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7.4.1 B phn kp v khunB phn kp ng li, ging nh trong giai

C kh ht i h L


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on p. Cc na khun p cht vi nhau. Lc

kp phi tng thm do lc phn khun. Lc nydo p sut p tc dng ln din tch hnh chiulng khun.

7.4.2 B phn ha doB phn ha do di chuyn hng v khun.Bc phun m ra v trc vt chu tc dng ca psut. Mc ch ca p sut ny l y nha chy

nht t khoan trc trc vt vo lng khun choti khi y, sau dng p sut gi, b co ngtca sn phm, ti khi ng rt cng.

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Lc bt u giai on gi p sut, lngkhun c in y hon ton Mt lng


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khun c in y hon ton. Mt lng

nh c p vo tip theo b co ngt.Nhng ti lc kt thc giai on gi p sut, mtlng nh nha vn cn trong khoan p.Nguyn liu m ny to nn p sut gi trcvt vi lng khun hoc ng rt. Nguyn lium ny c s dng cho ln p sau.

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7.4.3 iu khin

Trong giai on gi p sut, b iu khin


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Trong giai on gi p sut, b iu khin

my phi m bo rng p sut thy lc, dichuyn trc vt, vn mc ci t. iu nys cho php p b sung lng vt liu va vo khun b co ngt ca sn phm. Vimc ch , hu ht cc my c nhiu mc psut gi khc nhau chn la. Cc mc nythch hp vi hnh hc ca sn phm.

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7.4.4 Thy lc

p sut thy lc trong giai on gi p th


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thp hn so vi trong giai on p. Ch pc c trng bng vn tc trc vt cao v psut cao, trong khi ch gi p c ctrng bng vn tc trc vt thp v p sut

tng i thp. Vic chuyn tip t ch trc sang ch sau phi c thc hin cckz chnh xc v trong thi gian ngn nht c th.

Giai on p v gi p i km vi hai giaion khc:

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7.4.5 Giai on lm ngui

By gi nguyn liu ang trong lng


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y g g y g g gkhun. Nha n lng khun trng thy chyv phi ong cng do nh hng ca nhit khun tng i thp. S ong cng ca snphm phi c iu khin khng c ng

sut khng mong mun pht trin trong snphm. Cc ng sut ny lm cong vnh snphm.

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7.4.6 Giai on cp liu

ng rt trn sn phm ong cng, v


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vy ngn cn vic p lng nha b sung. Do b phn ha do c th thc hin nhim vkhc ca n. Nguyn liu khc c th cchun b cho chu kz tip theo.

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Giai on gi p kt thc ngay khi ng rt

ong cng, ni cch khc, ngay khi n b hnkn. T lc ny khng c nguyn liu c avo lng khun. Trong giai on p v gi p,

nguyn liu trong lng khun bt u nguido nhit thnh tng i thp. Lp ngoicng ong cng rt nhanh. Do thi gian

ngui ngay t lc p.

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Vic lm ngui din ra lu hn gia snphm. Phn nhit tha ca phn cn li nha


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chy nht c truyn n lp bn ngoi tithnh khun. Nha c tnh dn nhit km. Tnhdn nhit ca nha km hn 100 ln so vi kimloi.

Truyn nhit c th c xc nh bngcc phng trnh ton hc. Cho nn ta c thtnh ton thi gian lm ngui ca sn phm

trong khun.

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Thi gian lm ngui ph thuc vo khongthi gian m ta mun sn phm lm ngui trongkhun Khng nht thit ch cho ti khi sn


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khun. Khng nht thit ch cho ti khi sn

phm hon ngui n nhit ca khun.Thnh ngoi sn phm lm ngui va , nc th ly ra khi khun trong trng thi cngvng. sn phm ngui trong khun vi thi

gian di hn cn thit l lng ph. L{ do l thigian lm ngui my khng sn sut.Vic chn thi gian lm ngui l cc kz

quan trng. Ngoi cc phng trnh phc tptnh thi gian lm ngui cng c cc phngtrnh n gin.

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7.5.1 Phng trnh tnh thi gian lm ngui.

TTs 42


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tc (s): thi gian lm nguiS(mm): chiu dy sn phmTm (K): nhit nha chy nht ti giai on pTw (K): nhit khunT

E(K): nhit bin dng (nhit ti tm ca

sn phm, khi ly sn phm ra).aeff: h s dn nhit.

wE

wm

effc TT

TT

a

s

t

4ln

2

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Phng trnh gn ng

t = 2s2


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tc = 2s

Chiu dy ln nht ca sn phm c chn.7.5.2 B phn p v khun

B phn p v khun trong giai on gi

p th tng t nh trong giai on lm ngui.7.5.3 B phn ha do

Trong khong thi gian lm ngui, nguynliu c chun b trong b phn ha do choln tip theo.

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7.5.4 H thng thy lc v iu khin.V giai on lm ngui l giai on ch ca


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my, khng c hot ng no xy ra.

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7.6 Giai on cp liu


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Trong khong thi gian cp liu, sau giaion p v gi p, nguyn liu mi phi cchun b s lng.

Nguyn liu trn phu ri vo trc vt v dichuyyn dc theo rng vt hng v bc phun.

Nhit c truyn ti nguyn liu t

thnh ca xyanh ca b phn ha do. Victruyn nhit ny c gi l dn nhit.

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Nguyn liu b bin dng do trc vt quayv b nng thm do ma st. nh hng ny gia d hi i h h


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tng do chiu cao rng vt gim theo hng v

bc phun. Do nguyn liu b nn lin tc tngln . Nguyn liu c trn u. Trng thi psut khong trng gia trc vt v thnh xyanh

lm cho khng kh bn trong b chuyn hngv vng np liu.

Vic trn v nn nguyn liu ln m

bo tnh cht ca nguyn liu ng u. Lcnguyn liu n u trc vt, n nng chy.N tch ly trc trc vt trc bun cha.

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Khi trc vt di chuyn dc trc v pha trc, nto ra p sut.

Trong hu ht cc trng hp nng lng


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Trong hu ht cc trng hp, nng lng

s dng thng ma st nguyn liu ln hn lm nng thnh xylanh. Do , lng nnglng c s dng ph thuc vo vn tc trc

vt v p sut ngc ci t. Vn tc trc vt chiphi thi gian chun b nguyn liu.

Khi ci t cc thng s, m bo rng thi

gian ha do khng vt qu thi gian lmngui. L{ do l thi gian ha do thay i theotnh cht ca nguyn liu.

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Giai on lm ngui ca sn phm xy rang thi vi giai on cp liu. Ngay khi gian


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on cp liu kt thc, nguyn liu sn trongkhoan p cho chu kz tip theo. Trong khongthi gian ch, ch hon thnh giai on lmngui sn phm, trao i nhit xy ra gia

nguyn liu chy nht khoan trc trc vt vithnh xyanh. Trong thi gian ch ny nguynliu hoc khng c qu ngui hoc hp th

nhit qu nhiu v bt u phn hy.

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B phn kp v khun khng lin quani i h d


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trong giai on ha do.

7.6.2 B phn ha do

Vic chun b nguyn liu bt u ngay sauhon thnh giai on gi p. Nu van mt chiubc phun c s dng, n s ng ngay khi giaion gi p kt thc. Trong trng hp ny, bphn ha do rt ra khi khun trnh truyn

nhit t bc phun n khun ngui hn.

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Nu van mt chiu bc phun khng cs dng, b phn ha do c th khng rt khikh h ti khi i i li kt th


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khun cho ti khi giai on cp liu kt thc.

Tri li, nha c th thot ra khi bc phun.Trong qu trnh ha do, trc vt b qua bi

m t thy lc. Nguyn liu i xung t phiu

v vo vng cp liu. Trc vt quay chuynnguyn liu ti u trc vt v i qua van mtchiu. Nguyn liu tch khoan p trc u

trc vt y trc vt ngc li. Ngay khi nhanng chy trc vt ngc ti tc dng lncng tc gii hn hnh trnh, trc vt ngng quay.

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7.7 Ly sn phm


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Ngay khi thi gian lm ngui kt thc - nicch khc, khi sn phn ong cng trongkhun, khun m ra. Hai na khun tch ra xa cho php sn phm c y ra.

Vic y thng c thc hin bng cccht kim loi, m l mt phn ca khun. Cccht ny y sn phm khi b mt lng khun.

y m bo rng cc cht khng lm nguyhim sn phm.

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Nhng sn phm cht lng cao v nhycm, cng nh cc sn phm phi s l{ tip ngay

khi l hi kh h


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sau khi ly ra, phi khng c php rt vothng hoc bng ti. Chng nn c ly ra khikhun bng thit b gp.

Bn cnh vic co ngt ca sn phm, giai

on bin dng ca sn phm cng xy ra. Sbin dng ph thuc vo hnh hc ca sn phm.S bin dng l do s thay i chiu dy ca

thnh sn phm. S bin dng v co ngt c thkhc phc bng vic ci t cc thng s my

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S bin dng ca sn phm

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7.7.1 B phn kp v khunKhi thi gian lm ngui kt thc, tm di

ng pha kp m ra v dng li ti v tr


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ng pha kp m ra v dng li ti v tr

lp trnh. Sn phm vn dnh vi na khun ding. Cc na khun phi di chuyn xa sn phm c th y ra hoc ly ra m khngng vo na khun kia.

Vic y bt u ngay khi b phn kp mkhun. Vi mc ch , cc cht phi t trongna khun di ng. Cc cht chuyn ng

tng i so vi khun, cc cht b y bng hthng thy lc.

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Trong hu ht cc trng hp sn phm c ly rado cc cht y bng c. Vi cc sn phm mm hocnhy cm cc cht thng c thay th bng khnn


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nn.

Trong mt s trng hp c bit ca sn phmnhit nha do, nhng thng vi hn hp cao su,sn phm khng th ly ra bng t ng. Sn phmphi ly ra bng tay, v vi hn hp cao su, cc snphm phc tp (cng nh sn phm c phn m)thng c sn xut t cc khun n gin, do tnhcht c th un cong v co gin. Vic ly sm phm

nh vy rt phc tp, ch c thit b gp rt c bitmi c th c s dng cho vic t ng. V vy, vicly sn phm bng tay vn s dng trong cng nghipgia cng hn hp cao su.

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Sau khi y sn phm, cc cht y rt v. Bphn kp v khun v tr ban u cho chu kz tiptheo.


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7.7.2 B phn ha doTrong giai on cp liu, b phn ha do a

chun b sn sng nguyn liu cho chu kz tiptheo. V vy n hon thnh nhim v ca n, v v tr ch.7.7.3 B phn iu khin v thy lc

Trong giai on y, cc cht khng th c

php di chuyn qu nhanh v iu ny c th tsn phm. Vic di chuyn m khun cng nn btu t t trnh lm nguy him n sn phm.

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CHNG 4


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THIT K KHUN

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Cc thnh phn ca khun


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1tm kp pha trc2Tm khun trc3 tm khun sau


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3tm khun sau

4tm kp pha sau5tm 6khi 7tm gi8tm y9vng nh v

10cht dn hng; 11bc dn hng; 12bc m

rng; 13b nh v; 14cht hi v; 15cht y; 16bc dn hng cht; 17cht ; 18bc cun phun

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khun 3 tm


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- Sn phm ln khng b tr c ming phun tm- Sn phm c nhiu ming phun tm hoc nhiulng khun cn ming phun tm

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Khun nhiu tng


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Kt cu khun c bn

1 Kt cu khun n gin nht


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2 khun c li ghp


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3 ming ghp c c khun trc v sau


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4 Khun nhiu lng khun


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H THNG CP NHA


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H thng knh dn v cngNguyn l


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Nha chy t bc phun a vo khun vphn chia cho cc lng khun. y l nhim vca h thng knh dn v ng rt. B phn ny

khc nhau vi tng loi khun. Nha nng chyri khi bc phun vo ng rt v knh dn rin cng ca lng khun

Cc yu cu t ra vi h thng knh dnv cng c th pht biu n gin nh sau:

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H thng knh dn v cng phi c thit k, nha in y cc lng khun ngay lp tcv ng b vi p sut nh nhau.


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v ng b vi p sut nh nhau.

H thng knh dn c thit k ph hpvi v tr ca cc lng khun. Vic thit k vb tr cng l chc nng u tin ca cng vic

thit k khun v cc c tnh k thut cakhun

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Khi nha mi chy vo


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chiu dy lp ngcng tng ln

Chiu dy ng cngkhng i. Khi lng

nhit mt bng nhit tnha v do ma st

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on vng ngui chm dng chy khng b cn tr


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Mi quan h gia S D W


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Cun phun cho khun hai tm


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Kch thc bc cun phun


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B = A + 0,5-:-1mmR = X + 2-:-5mm

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Mt ct ngang knh nha


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Trnh b ong cng cn tr dng chy


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di knh nha n cc lng khun nh nhau


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u im: p sut nh nhauNhc im: Tng chiu di tng i ln

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Cch b tr knh nha cho khun nhiu lngkhun


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Cc khuyt tt khi b tr ming phun sai1. Vt b ngn li


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Vt qu di

Vt qua titdin hp

Cch khc phc

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2. Sn phm b cong

Khc phc


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3. ng hn Khc phc


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ng hn

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4. S to ui


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Khc phc

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5. Hm co


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Khc phc

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6.cn kh


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Khc phc: t l thot kh nh hoc thay i

vi tr ming phun

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A. Ming phun cun phun: nha qua bc cun

Cc kiu ming phun


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phun vo trc tip lng khun. li du ln trn sn phm v cng ct b

B. Ming phun cnh

Khcphc

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d. Ming phun kiu ng ngmT ct khi sn phm b y ra khi khun, t hoa vn, gn


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t gn

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F. ming phun kiu a


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H THNG YChc nng ca h thng y l ly sn

phm ra sau khi m khun.


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phm ra sau khi m khun.

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Cht hi B

Khong y

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Cch b tr cht y v hi


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V tr t cht y


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Thnh sn phm mng nn dng li y


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H THNG Y

1. Cht y trn.


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Cc l phi c doa.L gia cng trc nhitluyn L = 4xDL nhit luyn L = 3xD

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4. Thanh yDng y cc sn phm ln. Thanh y phi


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cch b mt li t nht 0,5mm.

Thanh niThs.L V Hi

Khi sn phm ph ln b mt nh thanh y


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5. Tm tho


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H thng y cung phun - knh nha - ming phun1. y cun phun


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2. y knh nha


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Chty

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3. y ming phun


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S y ko

i khi sn phm cn c ly ra bng haitao tc l y v ko.


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Thanh ko

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IU KHIN NHIT KHUN


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D . Nn chia h thng lm ngui thnh nhiuvng lm ngui trnh cc knh lm ngui qudi dn n s chnh lch nhit ln.

E. Ch { lm ngui nhng ch dy ca sn phm

F. Tnh dn nhit ca vt liu khun cng rtquan trng

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V tr ca b phn lm ngui.


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H thng lm ngui cho sn phm n gin

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Ming ghplm ngui


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khng hiuqu

Ci thin vic lm nguitm ghp

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Lm ngui li

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Lm ngui hnh xon c


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Lm ngui ti cc gc


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4.4 H thng gia nhit/lm nguiMc ch l to ra sn phm n nh v

h h h l kh


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cng t nha chy nht trong lng khun.Khi gia cng nha nhit do, n c gianhit trong b phn ha do. Nhit ny nha chy nht v nha chy nht ny c p

vo lng khun. Nhit phi c ly ra sau khi nha chy nht trong lng khun, nc th ong cng thnh sn phm cui cng.Khun s dng cho nha nhit do phi c khnng mang nhit ra khi sn phm.

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Trong qu trnh gia cng nha nhit cngv hn hp cao su l mt trng hp khc. MtLng nhit xc nh c truyn vo nguyn

li t b h h d t h l i


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liu trong b phn ha do tr chng litrng thi lng. Tuy nhin sn phm trong khunkhng b ong cng do vic lm chng nha

chy nht m do phn ng ha hc. gia cngsn phm t cc nguyn liu nh vy, khunphi c kh nng dn nhit vo sn phm.

Do kt cu khun s ng cho hai loinguyn liu ny khc nhau c bn

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Khun c s dng cho nha nhit doc cc knh quanh lng khun. Nc chythng qua cc knh ny. to ra mt h thng


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knh, cc knh ngang dc c khoan trongkhun. Cc knh ny sau c ng ti cc v

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tr xc nh, to nn mt h thng lun honcho cht lm ngui/gia nhit. Nhit ca micht ny khong 30 -:- 100 C. Nhit chnh

h th l i h


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xc ph thuc vo loi nha.Thanh gia nhit thng c s dng cho

khun nha nhit rn hoc hn hp cao su. Cc

thanh nhit c t trong cc l khoan trongkhun c nhit khong 150 -:- 200 C.

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Cng c th s dng h thng cn bngnhit, s dng mi cht lng gia nhit. Do yu

cu nhit cao, nn ngi ta s dng du dnnhit.

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Nhim v chnh ca my p phun l cha vphn phi nha nng chy, lm ngui v nh

h h h t kh l h khi


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hnh sn phm trong khun, ly sn phm khikhun. (nha nhit rn/vt iu n hi, dnnng lng lu ha/hot ha). Nhim v th

hai l hp thu lc truyn chuyn ng, dnhng sn phm khi rt khi khun.

Nha c chuyn vo khoan p trong giai

on ha do. Dc theo ng i n b nngchy v trn u.

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S lng sn phm to ra trong mt chu k cth ln ti 100. Khi ta dng khun nhiusn phm


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4.2.2 Thit k cng


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Cng kiu ng rt (sprue gate) c s dng

cho sn phm thnh dy, mc cn tr thp vmt ct ngang ln. Dng cn cho php vt liuchy d dng

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Khi sm phm b li ra, cng b ko ra khibc phun. Do cng vn cn trn sn phm vphi c thm cng on ct b. Cng kiu ng

rt c s dng cho sn phm k thut cao v h h h d


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rt c s dng cho sn phm k thut cao vsn phm c thnh dy.

Tri li cng kiu kim b ko t ti v tr

ni vi sn phm, khi ly sn phm. V vy cngkim ch li mt du nh trn sn phm, khngyu cu lm sch hoc rt t. N thch hp chovic t ng.

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Cng mng s dng cho sn phm trnng trc. Nha c phn n cng v chyu vo lng khun. Phng php ny trnh

c ng hn m sy ra vi cc kiu cngkh T hi ki hi th hi


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c ng hn m sy ra vi cc kiu cngkhc. Tuy nhin, cng kiu ny phi thc hinthm cng on ct.

Cunphun

mng

Cunphun

vng

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Cng vng s dng cho sn phm trnhoc ng.

Cng kiu film, chc nng ca n ging

nh cng mng N s dng cho sn phm


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nh cng mng. N s dng cho sn phmphng v h tr in y lng khun. Hockhng li ng hn hoc vt nh trn sn

phm.

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Cc phin bn khc nhau ca ng rt uc nhc im, vt liu tha trong h thng knhdn v cng. bo v mi trng v gim chi

ph ngi ta c trnh b tha nguyn liu bng


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ph, ngi ta c trnh b tha nguyn liu bngcch iu khin nhit h thng knh dn vcng duy tr kh nng chy ca vt liu

vng ny

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H thng knh dn nng c s dng chovic gia cng nha nhit do. Cn h thng knhdn lnh s dng cho gia cng vt liu n hi.

H thng knh dn nng c s dng hu htcho khun nhiu lng khun


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H thng knh dn nng c s dng hu htcho khun nhiu lng khun

H thng

knh dn nng

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4.3 LNG KHUNNha chy qua h thng knh dn v cng

vo lng khun. Sn phm c hnh thnh bng

cch ong c nha nng chy (nha nhit do)


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cch ong c nha nng chy (nha nhit do),phn ng ha hc (nha nhit rn, vt liu nhi)

Lng khun chnh l nh m ca sn phm.Bt k qu trnh c no, vic ong c snphm iu lm gim th tch sn phm. Ni cchkhc, sn phm b co rt.

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V d v lng khun


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Bt kz khun c no, c lng khun, uphi ch to ln hn sn phm mt t. Kch thcln hn ny phi bng lng co rt. Nh vy sn

phm thu c mi c kch thc ng. Nhanhit do c c co rt 5-:-8%. Trong khi nha nhit trong l 1-:-2%Ths.L V Hi

Bn cnh co rt do vt liu, cng c mt loisai lch kch thc khc gia lng khun v snphm hon chnh, giai on cong vnh.


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Giai on cong vnh xy ra do tc lmlnh khc nhau cc vng sn phm c chiu dykhc nhau

Sn phmmong

mun

Sn phmthu c

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nhng vng cc b c th, chng li s co rtv cong vnh.Cng thng to ra mt du trn sn

phm. Nhn chung, du ny khng nn xut hin phn c th nhn thy ca sn phm Tuy


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phn c th nhn thy ca sn phm. Tuynhin, cng lc c mt gii hn v s phctp c th cho php ca vic thit k h thng

ng keo. y cng l mt nhim v cho vicchn ng i di nht c th chp nhn ci vi mt loi nha chn hoc mt thmnguyn liu do h thng ng keo ln hn. Vi

l do , v tr lng khun trong khun cng chumt s gii hn trong vi trng hp.

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4.5 H thng liMt khi sn phm ng cng trong khun,

m bo rng sn phm c th ly c ra khikhun Vi mc ch khun bao gm hai


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khun. Vi mc ch , khun bao gm haina, n c th m ra ti mt phn khun.

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Ngay khi khun c m ra, sn phm cth c ly ra ti mt phn khun. Trongtrng hp n gin nht, vic ny c thc

hin bng tay Tuy nhin qui trnh p phun cthit k mt cch c bit sn xut cc sn


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hin bng tay. Tuy nhin, qui trnh p phun cthit k mt cch c bit sn xut cc snphm ln vi tc nhanh v nn thc hin ch t ng hon ton. Ngoi ra, thi gianchu kz ph thuc vo thao tc ca ngi vnhnh. Vic ny c th lm thay i s lng snphm. Vi nha nhit do, ly bng tay ch c

s dng trong nhng trng hp ngoi l, sn phm nh cm hoc c hnh dng phc tp.

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Cc sm phm lm bng hn hp cao suth vic ly sn ra khi khun mt cch t ngv cng kh khn.

Nhn chung vic ly sn phm c thc

hin bng cc cht mt cch t ng m c


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hin bng cc cht mt cch t ng, m cthc hin bng c khi khun m ra ti mt phnkhun cui chu kz p phun. Cc cht ny m

bo rng, sn phm c ly khi lng khunmt cho c phn m, lc bm dnh v cc ngsut ni m c khuynh hng gi sn phm li

Cht li rt a dng v phong ph. Vic

chn cht phc thuc vo hnh dng sn phm,v tr ca n trong khun, v lc gi n.

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Cht li thng li du trn sn phm.Chng khng c s dng trn phn thy casn phm. Mt v d khc ca b phn li l b

li tay o c th truyn lc li ln hn Kiu li h d h h i


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li tay o, c th truyn lc li ln hn. Kiu ling ch yu c s dng cho cc sn phm ixng.

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Nu sn phm c phn m, m khng ths dng b phn li. Trong trng hp nh vy,khun phm c thit k c thm mt mt

phn khun na m cng m trong lc ly snphm


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phn khun na, m cng m trong lc ly snphm.

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Nhng sn phm khng c yu cu cao,sn phm c th rt ln bng ti hoc thngcha, sau khi li ra khi khun.

Ngoi tr sn phm c b mt cht lng

cao phi c ly bng thit b gp trnh


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cao, phi c ly bng thit b gp, trnhlm nguy him sn phm. Robot l mt v d cathit b gp. Mt thun li khc ca vic s dng

thit b gp: khi sn phm cn x l{ hon thinsau gia cng p phun. Trong trng hp ,thit b gp c th t sn phm vo ng v tr cho qui trnh tip theo. iu ny tit kim

thi gian v hiu qu.CD l mt v d cho ng dng ny

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Chng 6


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Chng 6

GIA CNG SN PHM BNG PHNGPHP TO HNH NHIT

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6.1 c im ca phng php

Phng php to hnh nhit cc sn phmnha nhit do c th xem l mt phngphp gia cng nha c in Qu trnh gia


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php gia cng nha c in. Qu trnh giacng c thc hin vi nguyn liu nhanhit do dng tm hoc dng ng. Bao

gm cc giai on sau:1. Ct nh hnh s b2. t nng

3. To hnh v lm ngui4. Ly sn phm v hon tt

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Khc vi cc phng php gia cng n, pphun, phng php to hnh nhit, vt liupolime ch c t nng n trng thi mmcao, v qu trnh to hnh l mt qu trnh gy

bin dng tm vt liu t n hnh dngi h l d h h i


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bin dng tm vt liu t n hnh dngcui cng, cho nn lc tc dng nh hn so vicc phng php trn.

Phng php ny c nhng u im sau:- Thit b n gin- Ph hp khi sn xut vi sn lng t, sn phm

kch thc ln.

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Tuy nhin do c im ca phng php lbin dng vt liu trng thi mn cao nn chtlng sn phm ph thuc rt nhiu vo ch v phng php gia cng, trong ng ch {

l: h l


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- To nn ng sut ni sn phm ln, a nsn phm khng nh v bn khng cao

- Sn phm c dy khng ng uDo nhng gii hn trn m phng php tohnh nhit ch c p dng ph bin khi cnhiu loi nha nhit do v phng php to

hnh chn khng ra i, cho php sn xut ccsn phm c cht lng cao.

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6.2 Cc phng php gia cng

6.2.1 Phng php gia cng.

Phng php php dp l phng php


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Phng php php dp l phng phpto hnh nhit c lc tc dng ln nht. Lcgy bin dng vt liu do chy p ca my, v

p sut dp ln n 5KG/cm2

. Do phngphp ny cng c s dng gai cng mts nha nhit rn dng tm nh nha epoxy

Ngi ta phn ra 3 loi dp to hnh:

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a. Dp trn khunPhng php dp trn khun c th p

dng cho tt c cc loi nha nhit do.

Trong qu trnh dp, do chy dp tip xci t li t khi h h th h h t


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Trong qu trnh dp, do chy dp tip xcvi vt liu trc khi hnh thnh hon toncho nn chy dp cn c nhit thch hp

trnh vt liu ngui ti cc im tip xcgy bin dng khng ng u v ng sutni gia tng.

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b. Dp ko


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Phng php dp ko cng c th c pdng cho cc loi nha nhit do khc nhau.Trong qu trnh gia cng, sau khi c tnng n nhit thch hp, tm vt liu blm bin dng di tc dng ca chy dp

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trong khi c gi trn kp. Do c tnh gaicng ny b dy ca sn phm khng ngu v nh hn b dy tm vt liu ban u,ngoi ra phng php ny thng p dng

cho cc vt liu c b su ko khng qu 1,5


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cho cc vt liu c b su ko khng qu 1,5ln ng knh (b rng) tn vt liu.

c th t c s ng u hn v b

dy sn phm, ngi ta dng b phn kp saocho tm vt liu c th trt khi tc dngchy. Khi , trong qu trnh ng khun, lxo nn v lc kp tm vt liu s gia tng dn

theo b su c ko cho n khi tm vt liub kp cht, khi

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c. Dp trn m n hi.


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S to hnh sn phm phng php nynh lc p ca chy dp v tnh n hi cacao su. c im ca phng php ny l ci

dp khng c hnh dng ca sn phm m chy

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7.2.2 Phng php thiTrong qu trnh thi to hnh, ngi ta s

dng p sut kh nn gy bin dng tm vtliu c gia nhit. Ngi ta phn thnh 2

loi: thi t do v thi trong khun


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g phng php thi t do vt liu khng

tip xc vi vt liu trong qu trnh gia cng,

nn sn phm c tnh quang hc rt cao, tuynhin phng php ny i hi dng c thitb nng, nn thng khng s dng tr khikhng to hnh bng cc phng php khc.

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Phng php thi trong khun thng c sdng sn xut cc sn phm nh trang tr, banh,chai, chi rng. Ty theo kh nng kt tinh ca vtliu trng thi mm cao, chng ta c th s dng

phng php thi ton hnh hay na hnh.


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Phng php thi ton hnh p dng cho ccloi nha c kh nng kt tinh trng thi mmcao, sau khi gia cng sn phm c y hnhdng. Trong khi i vi loi vt liu khng c

kh nng kt tinh trng thi mm cao, th vicgia cng c tin hnh cn 2 cng on: thi


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g g , gia cng c tin hnh cn 2 cng on: thina hnh v dn 2 na hnh vi nhau. p sut kht 0,2 -0,3KG/cm2

Phng php thi trong khun c u im lc th to c cc dng sn phm m ccphng php khc kh to c nh khi curng, cc hp cha c quai. Tuy nhin phngphp ny khng p ng c cho cc sn phmrng thnh dy.

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Nguyn l{ sn xut bng khun thi


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Qui trnh khun thi n


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Qui trnh khun thi p phun


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Qui trnh khun thi ko


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Sn phm c 3 vng chiu dy khc nhau


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7.2.3 Phng php to hnh chn khng

Phng php to hnh chn khng m

rng hng ng dng ca phng php tohnh nhit v yu cu thit b n gin nng


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g g g g p g p phnh nhit, v yu cu thit b n gin, nngsut cao, cho sn phm nhiu hnh dng khcnhau. C nhiu k thut to hnh chn khng,t k thut to hnh chn khng trc tip nvic kt hp chn khng v kh nn tohnh.

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a. To hnh trc tip di tc dng ca chn khngDo chnh lch p sut: chn khng trongkhun v p sut thng bn ngoi, vt liu bbin dng v p st vo thnh khun. Phng

php to hnh trc tip


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Phng php to hnh trc tip thch hp chocc sn phm c t l H/W (t l ko) b, thng

dng to hnh cc sn phm c s khc nhauhon ton v bn knh cong trn b mt, nhngkh trnh c cc vt trn b mt sn phmdo vic lm ngui ca tm vt liu khi tip xc

vi khu

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trc khi to hnh hon tt, th d sn xut bn ni, mt bp b, hp


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b. To hnh chn khng kt hp chy nng trnh cc vt trn b mt sn phm do

s lm ngui tm vt liu ti cc tip im

u tin gia tm vt liu v khun, ngi ta d h t h h b


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s dng chy nng to hnh s b. ychnh l phng php to hnh kt hp nhy

nng, phng php ny cho sn phm uhn v c th s dng vi t l nn cao hnphng php to hnh trc tip.

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c. To hnh chn khng kt hp vi ko tm trnchy

Phng php to hnh ny c th xem l

s kt hp ca dp ko v chn khng, gipto c cc ng cong ngc v cc dng


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g g g gphc tp m phng php dp ko khngthc hin c.

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LI MT BN


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Cc sn phm phi c li mt bn


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Mt s lu { khi s dng li mt bn1. Chuyn ng ca li mt bn phi ng k ly sn phm ra c nh nhng. Khong xdch ca li mt bn phi ln hn chiu sau ct


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t nht 1mm.

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2. Khi li mt bn m hoc ng phi c c chn mi hng chuyn ng.


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3. Li mt bn cn c h thng dn hngchuyn ng ph hp.


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4. Phi trnh cc gc nhn trn b mt chuynng ca li trnh ci xc b mt


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5. C gn thit k li mt bn c chuyn ngc khi m khun.

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5. H thng li mt bn trang b h thng bi sphoc h thn l xo h thng li mt khng bri xung v trng lng ca n hoc trong khibo dng v x l{ ni chung.


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6. Nu dng khi trung gian, m bo rng limt bn khng trt khi khi trung gian.


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Tc ng bng cht xinH thng cht xin l mt trong nhng h thngph bin nht tc ng ln li mt bn. l

1 h thng thng dng ko li mt bn 1khong 0 20mm ph thuc vo cao ca li


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g p mt bn.

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Cc thng s ca cht xinQ> +5


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Tc ng bng cam chn ch


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Tc ng bng ng cam


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Tc ng bng l xo


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Chuyn ng vo ca li do khi p thc hin

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Tc ng bng thu lc


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Tc ng gc


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