THIT K V CH TO H THNG KNH DN NHA

THIT K V CH TO H THNG KNH DN NHA

trng H S PHM K THUT HCMKHOA O TO CHT LNG CAO

THIT K V CH TO H THNG KNH DN NHA

GVHD:Ths. TRN MINH TH UYNSVTH: L VN TI MSSV:11144162

I. H THNG CP NHA NGUI (COOL RUNNER)

1.Tng quan v h thng cp nha nguia. c im:

3 b phn chnh: Cung phun(spure). Knh dn nha (runner). Cng vo nha(gate).

b. Nguyn tc hot ng Knh dn dn nha do t vi phun n cc lng khun. Khun nhiu lng khun nha t vng phun qua cung phun v h thng knh dn, sau ti cc lng khun. (Khun mt lng khun ch cn cung phun).c. Nguyn tc thit k in y tt c cc lng khun. La chn v tr ming phun ph hp tnh thm m, c hc ca sn phm. Ly sn phm nhanh

2. Thit k ch to h thng knh dn nguia. Cung phunMt s loi cung phun:

Hnh 1: Bc cung phun dng 2 bu lng Hnh 2:Bc cung phun dng 4 bu lng

Hnh 3: Bc cung phun c l xo gim xcCh : H thng cung phun c s dng thng thng nht c bc cung phun. Ngi ta thng dung bc cung phun d thay th v gia cng. tng tui th ca khun, ngi ta gn l xo di cung phun gim va chm c hi cho khun v vi phun. Dng vng nh v gn u bc cung phun bo m s ng tm gia vi phun v cung phun.

Hnh 4: Lp ghp gia bc cung phun v cng nh v.Ch :Kch thc ca cung phun ph thuc vo cc yu t sau: Khi lng, dy thnh ca sn phm, loi vt liu nha c s dng. di ca cung phun phi ph hp vi b dy ca cc tm khun. Cung phun c thit k sao cho c di hp l m bo dng nha t b mt p lc nht trn ng i.

Hnh 5: Kch thc hp l ca cung phun.Ch : Gc cn ca cung phun cn phi ln thot khun nhng nu qu ln s lm tng thi gian lm ngui, tn vt liu, tn thi gian ct cung phun ra khi sn phm. Nu gc cn qu nh c th gy ra kh khn khi tho cung phun khi m khun. V vy gc cn ti thiu nn l 1 Trn khun, cung phun c ly ra cng lc vi ly sn phm. Do , cn c b phn ko cung phun khi m khun. Ngi ta li dng phn nha gi cung phun lm ui ngui chm

Hnh 6: Kch thc phn git ui keo.

b. Knh dn nha Knh nha l an ni gia cung phun v ming phun. Chng lm nhim v a nha vo lng khun V th khi thit k chng cn phi tun th mt s nguyn tc k thut m bo cht lng cho hu ht sn phm. Sau y l mt s nguyn tc m ta cn phi tun th: Gim n mc ti thiu s thay i tit din knh dn.

Nha knh dn phi thot khun d dng.

Ton b chiu di knh dn nn cng ngn cng tt, c th nhanh chng in y lng khun m trnh khng mt p lc v mt nhit trong qu trnh in y.

Kch thc ca knh nha ty thuc vo tng loi vt liu m khc nhau. Mt mt knh nha phi nh lm gim ph liu, rt ngn thi gian ngui (nh hng n chu k ca sn phm), gim lc kp. Mt khc phi ln chuyn mt lng vt liu ng k in y lng khun nhanh chng v t b mt p lc.

Hnh 7: Knh dn nha.

Hnh 8: Mt s tit din knh dn.Loi knh dnu imNhc im

Din tch b mt ct nh nht. t mt nhit, t ma st C li ngui chmgip duy tr nhit v p sut. Kh cho vic gia cng ng tm gia hai na khun -> t

Ch xp sau knh dn trn v tnh nng. D gia cng hn v ch cn gia cng trn mt phn khun. Tn nhiu vt liu hn. Mt nhit nhanh hn knh trn do dien tch b mt ln hn

D gia cng. Din tch v mt ln hn knh hnh thang hiu chnh nn mt nhit nhanh hn. Tn vt liu

D gia cng. Do tit din ngui khng u nn lm tng ma st, p sut khng u. Xy ra s c, tc dng chy, kh thot khun, ma st ln

Sch Thit k v ch to khun phun p nha trang 21 so snh cc loi knh dn ngi ta dng ch s ng knh thy lc v s cn dng. Khi ung knh thy lc cng ln th s cn dng cng b. Ta tnh ng knh thy lc da vo cng thc sau.

Trong : Dh: ng khnh thy lc (mm) A: din tch b mt ct ngang(mm2). P: Chu vi mt ct ngang (mm) C th tnh bng cng thc khc

Trong : D: ng knh knh dn. W: khi lng sn phm. L: Chiu di knh dn.Hoc:

Trong : D: ng knh knh dn tham kho. : h s chiu di. th 1: Dng th sau xc nh D v

G: khi lng ca sn phm (g). S: B dy danh ngha ca sn phm (mm).

Mi quan h gia ng knh knh dn tham kho vi khi lng sn phm v b dy thnh sn phm

th 2: Mi quan h gia h s chiu di v chiu di knh dn Dc : ng knh knh dn chnh (mm). Dn : ng knh knh dn nhnh (mm). N : S r nhnh.Mt s cch b tr knh dn nha

Mt s hnh nh thc t.

M phng 3D dng nha chy.

M Phng ng xut .

c. Ming phun Ming phun l phn nm gia knh dn nha v lng khun. Khi thi k ming phun cu ch cc c im sau: Ming phun phi t v tr cao( vt liu in y sn phm). V tr ming ti u t ming phun v tr khng quan trng v khng li ng dn Ming phun thng gia kch thc nh nht Cc Loi ming phun:1. Ming phun trc tip:

Hnh 8: Ming phun trc tip.

Hnh 9: Ming phun trc tip v vt ct li sn phm.

Hnh 10: Ming phun trc tip.

Hnh 11: Thit k ming phunSch Thit k v ch to khun phun p nha trang 282.Ming phun kiu cht:

Hnh 12: Ming phun kiu cht Kiu ny thng dng vi cu trc khun 3 tm hoc nhng lng khun ln cn nhiu ming phun, hoc cho loi khun c nhiu lng khun. H thng knh nha thng l hnh thang hay hnh thang hiu chnh tit din ngang tin vic gia cng v lp cht ko ming phun khi m khun. u im: Ca loi ny l c th b tr nhiu ming phun vo lng khun i vi nhng lng khun ln, gip cho vic in y nhanh chng v tt hn. Nhc im: Tuy nhin c th gy qu nhit i vi loi vt liu c cu trc si di v c nht km.

Hnh 13: Cu to chi tit ming phun kiu im cht. Kch thc ca ming phun im cht quan trng, nu im cht qu to hoc phn cn qu nh th du vt ca n thy rt r.

Hnh 14: Kch thc cho thit k ming phun im.Sch Thit k v ch to khun phun p nha trang 29Hnh 15: Ming phun kiu im cht.

Hnh 16: V tr cht ko trn khun.

\Hnh 17: Cc kiu l cht ko di trn knh dn.3. Ming phun cnh

Hnh 18: Ming phun cnh.

c im: L kiu ming rt thng dng n c th s dng cho cc loi sn phm c thnh mng hoc trung bnh bi kt cu n gin v khng cn chnh xc cao. Ming phun kiu cnh c t trn mt phn khun, v in y lng khun t bn hng, trn hay di.

Hnh 19: Ming phun cnh.Kch thc thit k

Trong : L=(0.80.9) x R I=0.6 0.7 b dy thnh sn phm C=0.8 1.5mm T=1 5 mmHay

Trong : L=0.08 inch (2mm) T=(0.5) W=(2)xTHoc: B dy thng bng 80-100% b dy thnh c th n 3.5mm v b rng t 1-12mm. Chiu di ming phun khng qu 1mm, 0.5mm l gi tr ti u.

Hai cch thit k khc nhau ca ming phun cnh

Hnh 20: Ming phun cnh cn l 30 - 450

Hnh 21: Ming phun cnh cn l 10 - 200

4. Ming phun kiu gi:c im: Tng t nh ming phun kiu cnh, ch khc l ming phun nm lp trn b mtsn phm.

Hnh 22: Ming phun kiu gi

Hnh 23: Kch thc ming phun kiu gi

Kch thc bng 10-80% b dy thnh, b rng 1-12mm. Chiu di mingphun khng qu 1mm, ti u l 0.5mm.

5. Ming phun kiu then

c im: Thng dng cho cc sn phm mng v phng nhm gim ng sut ct trong khun. Lc ct cao tp trung xung quanh ming phun b hn ch bi then, then ny c ct sau khi m khun. Kch thc thit k: B rng nh nht l 6mm, b dy nh nht bng 75% chiu su lng khun.

Hnh 24: Ming phun kiu then6. Ming phun kiu ng ngmc im: Loi ny cng rt thng dng, c u im l n t ct khi sn phm b y ra khi khun. c bit vi kiu ming ny ta c th t n trn cc ng hoa vn, ng gn n i cc du vt ca ming phun. Vi ming phun kiu ny th s thot khi d dng hn v vt liu in y phn y sn phm trc cn kh theo ng phn khun thot ra ngoi d dng v du vt ming phun cng kh nhn thy hn.

Hnh 25: Ming phun kiu ng ngm.

Hnh 26: Ming phun kiu ng ngm dng thng.

Hnh 27: Ming phun ngm dng congCh : Ming phun kiu ngm thng c dng cho khun 2 tm c nhiu lng khun, thit k sn phm nh cn ct knh dn mt bn.Phn loi :a) Ming phun ngm dng thng

Hinh 28: Cc dng ming phun ngm dng thng

Hnh 29: Qu trnh ct ming phun ngm dng thng.b) Ming phun ngm dng cong

Hnh 30: Qu trnh ct ming phun ngm dng cong.

Hnh 31: Kch thc cho thit k ming phun ngm tiu chun.

Hnh 31: Kch thc cho thit k ming phun ngm hiu chnh.

Hnh 32: Kch thc thit k knh dn v cun phun kiu ngm.

Hnh 33: Kch thc thit k ming phun ngm dng cong.7. Ming phun kiu bangc im: C kch thc mng nht so vi cc loi khac, loi ny khng thng dng lm, s dng cho cc chi tit c cnh thng, c th dng khc phc hin tng to ui.

Du vt ca ming phun rt ln v chi ph ct b ming phun c tnh vo sn phm. Ph hp cho sn phm ln v phng (c bit l sn phm lm bng nha Acrylic) v n gip gim cong vnh cho sn phm nh s phn b ng u.

Hnh 34: Ming phun kiu bng

Hnh 35: Kch thc cho thit ming phun kiu bangCh : Kch thc ca ming phun kiu ny mng sp x 0.2-0.6mm, ng knh ca knh dn song song thng 0.6-1mm. Ming phun kch thc nh, dy 0.25-0.5mm. chieuf di ca ming phun ngn, tt nht t 0.5-1mm. 8. Ming phun kiu qut

c im: Ming phun kiu qut thc cht cng l ming phun cnh c b rng b bin i. Ming phun kiu ny to dng chy m v cho php in y lng khun mt cch nhanh chng nn rt ph hp vi nhng sn phm ln v dy. Thm vo ming phun kiu qut cng to ra dng chy lan to nn gip trnh c ng hn ni c b dy mng trn sn phm. Tuy nhin phai chi ph cao khi ct ming phun.

Hnh 36: Ming phun cnh qut.

Hnh 37: Ming phun kiu qut v vt ming phun li trn sn phm

Kch thc thit k

Hnh 38: Kch thc thit k ming phun kiu qutCh : Thng thng b dy ti a ca cng hnh qut khng vt qu 80% b dy ca sn phm. Nu sn phm qu mng chng hn 0.8mm th b dy cu cng phun c th chn l 0.7mm. B rng ca cng qut thng t 6mm n 25% chiu rng ca tm khun. i vi nhng sn phm ln b rng thng bng chiu rng ca tm khun.

9. Ming phun kiu ac im: Thng dng cho cc chi tit dng tr rng m c yu cu cao v ng tm v khng c ng hn ming phun kiu ny thc cht l ming phun mng bao vng quanh thnh sn phm. Khi nha qua cung phun, nh mng phun vng quanh thnh sn phm m lng khun in y mt cch ng u.Hnh 39: Ming phun kiu a.

Hnh 40: Kch thc mt kiu ming phun dng a khc.10. Ming phun kiu vngc im: Ming phun kiu vng thch hp cho nhng sn phm c dng tr di c tit din mng, gip hn ch vt hn, kt kh trong qu trnh in y v gim ng sut tp trung quanh ming phun. C hai loi ming phun kiu vng: vng ngoi v vng trong.

Hnh 41: Ming phun kiu vng

Hnh 42: Ming phun kiu vng ngoi v vng trong.

a)thit k cho ming phun kiu vng ngoib)Thit k cho ming phu kiu vng trongHnh 43 : Thit k ming phun kiu vng.

11. Ming phun kiu nan hoa

Hnh 44: Ming phun kiu nan hoa

c im: Cn gi l c nhiu ming phun, thng dng cho nhng sn phm c hnh ng, d ct b v tit kim c vt liu. Nhc im l sn phm c th bng hn v khng trn hon ton. Kch c ng knh thng thng ca cng l 0.8-5mm.

ui ngui chm: phn vt liu ch r nhnh khng b ng c sm gy nghn dng ta nn thit k thm ui ngui chm. ui ngui chm s gip qu trnh in y din ra nhanh v tt hn. N thng nm nhng nhnh giao nhau ca knh dn.

Hnh 45: ui ngui chmV d:

H thng knh dn nha cho 4 lng khunKch thc cun phun:

Hnh 46: Chn kch thc cung phun

BB Chn knh dn tit din trn: ng knh knh dn theo l thuyt:t= 8 mm D= 8+1.5 =9.5 mm

Hnh 47: Chn ming phunDo thit k hai cng vo nha nn chn: L= 2mm(chiu di ming phun)W=1mm (ng knh ming phun)II.H THNG CP NHA NNG (HOT RUNNER)

A.CHC NNG : 1. a nha nng vo trong long khun , khi dng nha i ra t my p1. Lun gia nha nng chy trong h thng knh dnYu cu k thut:

1. Nhit phn b ng nht trn dng chy (h thng cp nhit b lng nhit mt v nhit n nh trn ton knh dn)1. Gim thiu kh nng mt p sut khi dng nha nng chy qua knh dn1. C kh nng iu khin trng thi ming phun nh mt ci van nhit

2. M : khi phun nha vo lng khun2. ng : khi m khun ly sn phm

1. Chng r r trong h thng1. Phi d i mu trong mt s trng hp1. Tnh b, t bit b phn cp nhit1. D lp rp vo khun1. D dng lm sch v thay th thnh phn b mn hoc hng1. Tm manifold phi ch to chnh xc1. Tm manifold v nozzle phi gin n1. H thng dn in tr khng tip xc trc tip vi manifold nng.1. S dng nhng chi tit ph nhng ni cn thitB.CU TRC :Chc nng : Bc cun phun:

1. K ni u phun ca my phun1. Lm kn h thng dng chy t my n vi phun1. Gim p xut khi cn1. Lc nha nng nu yu cuKnh dn phn phi nha n cc vi phun

1. Vn chuyn phn phi dng nha nng1. Duy tr nhit nha l mt hng s trong khi phun1. Truyn p xut cho dng nha

Vi phun

1. Cp nha nng ti ming phun1. Duy tr nhit nha l mt hng s trong khi phun

Ming phun1. Cung cp nha nng n lng khun1. Duy tr ng dn nha vo lng khun1. Ngt dng chy nha

u im:1. Gim thi gian chu k p1. Hn ch vic s dng knh dn ngui (Cold Runner) c th nhng ph liu st li hay phi nghin li1. Hn ch lng ph nha (Phn loi,Nghin li lu tr),t tit kim lao ng v gim nng lng tiu th1. Ci thin bn v cht lng chi tit1. Gim p xut phunHn ch:1. H thng HR phi c s dng cho nhng ng dng v cho nhng vt liu ring bit1. S nguy him v nhit khi s dng cc loi nha nhy nhit1. B iu khin nhit yu cu phi chnh xc1. Gi thnh ch to cng nh bo tr cao

1.BC CUN PHUNA. Chc nng: 1. Gip dn nha t vng phun phun ca my n manifoldB. c im:1. Gia nhit cho bc cun phun v iu khin nhit ging nh cc b phn khc trong knh dn nng . C.Phn loi:3 loi c bn1. Cung phun dng m1. Cung phun c bung gim p1. Cung phun dng ng

1. Cung phun dng m1. Knh dn c cun phun dng m c th hnh tr hay hnh nn (ngn nga tht thot nha t cun phun khi nozzle b ly ra)1. Cn ph hp gia knh dn gia cun phun v knh dn ca mt nozzle1. Cung phun c bung gim p1. Gim p xut dng nha chy do trong h thng HR , ngn chn dng nha b cng v tht thot t Nozzle khi khun m nhanh v khng kh bn trong bc cun phun b chy1. Cung phun dng ng1. H tr van mt chiu trong knh dn, c th cho dng nha thng qua do vi phun b ko v cho khng kh i vo bn trong

2.KNH DN MANIFOLDA. Chc nng:1. Gin tip vn chuyn v phn phi dng nha nng n ming phun nozzle v n cc lng khun

B.Cu to v c im:1.Thn manifold lm t hp kim hoc thp khng g2. Rnh nha : dn nha lng chy trong n, cng nhn cng tt3.Cht gii hn : phi kn trnh r r nha hoc khng b trt khi chu p sut cao trong qu trnh hot ng, nhng cng phi d tho lp khi bo tr h thng4.Cht xuyn : m bo nha khng r r vi p xut cao5.u ren : d dng cho lp rp6.Lp bc in tr manifold : lm t kim loi d un , dn nhit tt . Cung cp v di tr nhit cho manifold7.Nhit tr hnh ng : b tr quanh manifold b nhit mt mt trn b mt manifold. Khng lm nha qu nhit s dn n chy , to vch en trn sn phmC.Yu cu k thut thit k Manifold:1. c lng sn phm v vt liu da trn tiu chun v c im k thut1. Xc nh cng vo nha ph hp1. Xc nh chui nozzle ph hp trn cc nhn t : i mu, thnh mng, chiu dng chy, vt liu d mn, thi gian chu trnh nhanh v mt sn phm hon ho1. Tnh ton s lng sn phm da trn : kch c my phun, lc kp, khong cch ngn nht gia cc Nozzle1. Bn thit k Nozzle cng i xng cng tt1. Chn nhng Manifold tiu chun vi kch thc ph hp1. Thit k cc chi tit khun hot runner9. S dng tm cavity plate cho vi phun di , tang cng v bn cho khun. Thit k knh dn ngui gia tm khun xung quanh cc vi phun Nozzle9. S dng tm kp (Black plate) dy ti thiu 50mm9. Thit b kp ph hp gia tm Back plate v tm khun gi vi khun (Nozzle cavity plate) m bo bt kn gia Manifold v Nozzle9. S dng mt tm cch nhit 9. S dng cc tm insert cng lm ngui v cc knh ngui bao quanh tm inserta.Cu trc khun cho manifold:1. Tm Black plate v tm bolster tch ri1. Nhng ci hc c gia cng cho Manifold, gip cc thnh phn vng chc hn v tho lp d dng (tt c cc b phn HR iu c th tho lp c) c khong h t nht 1mm bao quanh.b.Kp chc:1. S dng bu lng kp cht gn Manifold nht m bm kp chc c.Thit k h thng lm ngui cho Black plateC mt u vo , u ra v nhng nt (plug) bt cc u cn li . Lm ngui y r quan trng v lng nhit tp trun phn ln yd.Cc kch thc quan trng ca mt Manifold:Kch thc M : b dy ca ManifoldKch thc M1 : chiu rng ca ManifoldKch thc J2 : l ng knh knh dn nha nm trong Manifolde.Tnh ton s gin n v nhit

Vi l kch thc ca Manifold (mm) L kch thc ca Manifold trong khun(kch thc gin n) (mm) L nhit ca Manifold (C) L nhit ca khun (C) L h s gin n nhit (1/C)

C.VI PHUNA. Chc nng:1. Dn nha nng n ming phun, gin tip a nha t knh dn nng n lng khunB.Cu to v c ima.Cu to1Nozzle tip2 Vng m3 Cht van4 Thit b gia cng nhit5 Cp nhit in6 Thn NozzleB. c im chung1. C dy dn nhit n ming phun1. Chi tit quan trng, t c yu cu cao:3. Nhit im u v im cui ca vi phun chnh lch thp3. Cch nhit gia vi phun v khun3. Khng nha ng cng ti ming phun3. D dng lm sch, tho lp3. C kh nng thch ng vi hnh dng ca khun v tnh cht ca nha1. Vi phun c gia nhit t bn trong hay bn ngoi . Vt liu c tnh dn nhit cao hp kim ng. B phn gia nhit c t bn cnh hoc t h thng knh dn Manifold n vi phun1. t tnh nhit nn tuyn tnhC. Phn loi:1. Vi phun gia nhit ngoi1. Vi phun gia nhit trong1. Vi phun cch ly1. 1. Vi phun gia nhit ngoi

1. Rnh nha trn bao quanh bc1. Bc c bao quanh bi mt hay nhiu loi in tr khc nhau1. V c bao quanh mt lp kh, cch ly nhit vi lng khun1. Cp nhit in c gn vo Nozzle(1 in tr gn u nozzle , ci khc nm cui nozzle 1. v ming phun) cung cp tn hiu phn hi v b iu khin nhit ca Nozzleu im :0. Thit lp n gin0. Chi ph thpNhc im:0. Khng c u im v nha ng c nha ti ming phun0. i hi chu k nhanh duy tr trng thi chy0. Giai on khi ng lu n nh nhit chy0. Gp vn kh nng in y sn phm

1. Vi phun gia nhit trong

0. Mt Knh dn nha chy qua mt bc . 0. C mt u gia nhit t tm knh dn to mt hnh vnh khuyn0. Mt cp nhit in c t trong u gia nhit ny ly tnh hiu phn hi v b iu khin1. u im1. Gia tang s phn phi nhit1. Nhc im2. Chi ph cao hn2. Nhit cn bng gia cc chi tit trong khun2. Nhit cn bng gia cc thnh phn kh2. Phi tnh ton gin n gia cc chi tit ca khun

1. Vi phun kiu cch ly

0. Bao gm tm manifold gia nhit bn ngoi v nhit dn n lm nng c nozzle v cc nhnh, loi ny ph bin vi nhng thit k ring (vt liu dn nhit tt hp kim ng)0. Nozzle ni vi Manifold bng mi ghp ren c kh nng truyn nhit ln nht

1. u im:

1. Gia tng s phn phi nhit 1. iu khin nhit tt hn1. Nhc im:2. Chi ph cao v thit k phc tp2. Phi tnh ton h s gin n

D. Thit k v tnh ton s gin n v nhit La chn chiu di Nozzle phi ph hp vi chiu di khun (gn nht c th) Trng lng nha phun ra trong mt Nozzle Vt liu nha v cht ph gia V tr ming phun Cc thng s quan trng trn Nozzle

Chiu di thc ca Nozzle = L + + qVi: L l chiu di loi Nozzle c la chn (mm) l gi tr gin n ca Nozzle (mm) q la khe h ming phun

Gi tr c tnh nh sau:

l chiu di Nozzle (mm) l chiu di Nozzle luc gin n (mm) L h s gin n nhit ca vt liu(1/C) l nhit b chia nha (C) L nhit ca khun (C) 1. MING PHUN (GATE)A.Chc nng: Phun nha vo trong lng khunB.Yu cu k thut ca ming phun: Chng li s ng c v ngt dng chy nha Khng c ko s hay nh git Mt p sut nh Khu vc dng chy l nh nht li du vt ming phun l nh nhtC.Phn Loi ming phun:1. Ming phun dng m1. Ming phun kiu van1. Ming phun kiu van tun t1. Ming phun kiu vancore1. Ming phun dng mDng cho mi vt liu tinh th v v nh hnh ca nhaThng s: 0. ng knh ming phun0. Vung lm mt ming phun0. iu khin nhit nh ming phun1. li mt vt nh trn b mt chi tit1. Ming phun thng ln vo1. Khng ph hp vi vt liu chy cao v ng sut ct cao1. ng kn ming phun bng ha rn1. u im:1. D ch to1. S dng cho mi vt liu nha1. Nhc im1. dd1. Vic nha b ko dy. Do nhit ming phun qu cao th cht nha c th b nha c thng xuyn qua1. Vic hnh thnh ui nha c th gy kh khn trong qu trinh in y khun11. Gii php l to hc nh hnh ht u trong li pha i din ming phun

1. Ming phun kiu van1. ng m cht van cho dng nha t ming phun chy vo lng khun. Cht m van c vn hnh bng thy lc1. Trc khi p, cht van v tr tht vo. Ming phun m rng lm cho nha d dng chy vo lng khun1. Trc khi nha ti ming phun ha rn hon ton th cht di chuyn n v tr ng van1. u im:3. Gim chu k p3. To ra ming phun hon thin khng c ko si hoc nh git. li vch nh hn so vi cc ming phun tiu chun3. Lm tt trn tt c cc loi nha. Tr loi nha c tc nhn gy mi mn3. 1. Nhc im4. Cht thng khi y sn phm ra s lm vt liu ti ch h lm tng ming phun trn sn phm v tng mi mn gia cht vi l ming phun (s dng cht cn khc phc phn no)4. Phi bo m nh tm tt gia ming phun v cht van hn ch mi mn

1. Ming phun kiu van tun t1. Lc u mt ming phun s m v c in y . Khi nha chy qua ming phun th hai, ming phun ny m tip v tip tc in y ming phun th ba. Ming phun th ba m v c tip tc nh vy cho n khi in y phn cn li ca sn phm1. u im:1. Loi ny loi tr s hnh thnh ca ng hn.

1. Ming phun kiu vancore1. Kiu ny ng dng p nhng sn phm c dng l ti tm chi tit nh bnh rang nha, chi tit dng ng, chi tit bnh rang nha.1. Mt s kiu ng m van ming phun khc1. S dng van thy lc, kh nn ri kt hp vi khun mt lng khun, s dng kn dn nng, vi ming phun kiu van

III. KT LUNSo snh cc loi khun v knh dn (cool runner v hot runner)Loi Khunu imNhc im

Khun 2 tm c knh dn ngui(cool runner) Gi thnh thp D ch to Sn phm n gin b tr c nhiu lng khun Do vn cn bng dng i hi ming phun b tr thng hng vi lng khun Loi khun 2 tm nhiu lng khun gp nhiu hn ch i vi cc sn phm nha nht nh.

Khun 2 tm c knh dn nng (hot runner) Tit kim vt liu Khng c vt ca ming phun trn sn phm Gim thi gian chu k iu khin c s in y v dng chy ca nha Gi thnh cao hn khun 2 tm c knh dn ngui Kh i mu vt liu H thng iu khin nhit d b hng Khng thch hp vi vt liu chu nhit km

Khun 3 tm Gi thnh thp hn khun 2 tm c knh dn nng t hng hc hn khun c knh dn nng C th ph hp vi vt liu chu nhit km Chu k p tng do hnh trnh ca dng nha di Lng ph vt liu Cn p sut cao in y

H thng knh nng u im nhiu so vi h thng knh dn ngui, v mt kinh t ln v mt cng ngh .

TI LIU THAM KHO: THIT K V CH TO KHUN PHUN P NHA( T.S PHM SN MINH THS TRN MINH TH UYN)WEB THAM KHO : http://tailieu.vn/doc/bao-cao-he-thong-kenh-dan-nguoi-1721165.html(H Minh Vit-L Vn Cng-06112CLC Bi bo co H Thng Knh Dn Ngui)

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