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Gii Thiu Cng Ngh p Phun (Phn 1)Th t, 23 Thng 11 2011 17:41 S truy cp: 1122

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TNG QUAN V CNG NGH P PHUN 1.1 . CNG NGH P PHUN: 1.1.1. Khi nim v cng ngh p phun: Cng ngh p phun l qu trnh phun nha nng chy in y lng khun. Khi nha c lm ngui v ng cng li trong lng khun th khun c m ra v sn phm c y ra khi khun nh h thng y. Trong qu trnh ny khng c bt k phn ng ha hc no. 1.1.2. Chu trnh p phun : Chu trnh p phun gm bn giai on. Giai on kp (Claming phase): Khun ng li Giai on phun (Injection phase): Nha in y vo khun. Giai on lm ngui (Cooling phase): Nha ng c li trong khun. Giai on y (Ejector phase) : y sn phm ra khi lng khun.

Qun username/mt khu? ng k

TIN NI BTCREO 1.0 : Thay i phng php t duy thit k 10 Phng thc Thit k hiu Qu Trong CATIA Tng hp cc bi bo v phn t hu hn. SPACE CLAIM ENGINEER 2010, M RNG KH NNG THIT K H thng CAD CAM CNC Hng dn ci t Autocad 2010 Cc Tiu Chun C Bn V Trnh By Bn V

1.1.2.1. Giai on kp : Lc u phn di ng ca khun di chuyn nhanh n phn c nh nhng sau chm dn cho n khi khun ng hon ton ( khng xy ra ting ng ln ). Khi khun ng cng l lc p lc km rt ln c to ra chng li p cao t dng nha bn vo lng khun. iu ny rt quan trng v nu p lc km khng chng li ni p lc phun th khun s b h hi v sn phm c p c chc chn s gp khuyt tt.

1.1.2.2. Giai on phun : u tin nha nng chy v phun vo lng khun rt nhanh do trc vt tin v pha trc. Khi lng khun gn nh c in y khong 95% lng khun th qu trnh nh hnh sn phm din ra trong lng khun c nhit thp hn. Nha nng s ngui dn v xy ra hin tng co rt. Do , mt lng nha khong 5% s c phun vo b tr vo s co rt cho ti khi ming phun b ng cng li. Qu trnh ny ngn khng cho dng chy ngc.ca nha qua ming phun.

1.1.2.3. Giai on lm ngui : Giai on ny bt u sau khi qu trnh nh hnh kt thc. Khun vn ng v nha nng trong lng khun c lm ngui cho n khi ng cng, c th y ri khi khun. Trong sut giai on ny trc vt vn quay v li li chun b cho ln phun k tip. Thi gian tiu tn trong giai on ny ph thuc vo lng nha m ta p.

1.1.2.4. Giai on y : y l giai on cui ca qu trnh p phun. Lc ny phn di ng ca khun s m ra, ng thi tm y ca khun s b cn y ca my y v pha trc sn phm b rt ra ngoi khi khun. Khi sn phm ri ra khi khun th cn y s hi v sn sng cho mt chu k k tip. 1.2. MY P PHUN: 1.2.1. Cu to chung : My p phun gm cc b phn c bn sau.

1.2.2. H thng h tr p phun (Injection press support system): y l h thng gip vn hnh my,h thng ny gm bn h thng con. Thn my (frame) H thng in (Electrical system) H thng thy lc ( Hydraulic system) H thng lm ngui (cooling system)

1.2.2.1.Thn my : Lin kt cc h thng trn my vi nhau. 1.2.2.2.H thng thy lc: y l h thng cung cp lc y ng m khun, to ra v duy tr lc kp, lm cho trc vt quay v chuyn ng ti lui, to lc y cho cht v s trt bn trong.

1.2.2.3.H thng in: Cung cp ngun cho mt in (Electric system) v h thng iu khin nhit cho khoang cha vt liu nh bng nhit (Heater band) v m bo s an ton cho s vn hnh my bng cng tc. H thng ny gm t in (electrical power cabinet) v h thng dy dn.

1.2.2.4. H thng lm ngui: Cung cp nc hay dung dch lm ngui khun v ngn khng cho nha th cung phu (feed throat) nng chy. V khi nha cung phu nng chy th phn nha th pha trn kh chy vo khoang cha liu. B iu khin nc (Water temperature controller) cung cp mt lng nhit, p sut, dng chy thch hp lm ngui nha trong khun.

1.2.3. H thng phun : H thng phun lm nhim v a nha vo khun thng qua h thng cp nha, nn, kh kh, lm chy do nha, phun nha lng v nh hnh sn phm. H thng ny gm cc b phn. Phu cp liu (Hopper) Khoang cha liu (Barrel) Cc bng gia nhit (Heater band) Trc vt (Screw). B t hi (Non return assembly). Vi phun (Nozzle) Cc h thng phun: 1.2.3.1. Phiu cp liu (Hopper): Cha vt liu dng vin cp cho khoang trn.

1.2.3.2. Khoang cha liu (Baress): Cha nha v vt trn chuyn ng qua li bn trong n. Khoang trn c gia nhit nh cc bng cp nhit. Nhit xung quanh khoang cha liu cung cp t 20% n 30% nhit cn thit lm chy lng vt liu nha. 1.2.3.3. Bng gia nhit.(Heater band): Gip duy tr nhit khoang cha liu nha bn trong khoang lun trng thi do. 1.2.3.4. Trc vt(Screw): Nm trong lng, khoang cha liu v l b phn ha do v y nguyn liu trong lng vo khun. Trc vt c cu to gm 3 vng:

Vng nhp liu(feed zone): gn phu nhp liu dng chuyn nguyn liu v pha trc, nguyn liu mm v bt u chy (50%L). Vng nn p (transition zone): gia trc vt, dng nn nguyn liu dng (25%L). Vng nh lng ( Metering zone): Trn vo v to ng nht trc khi phun vo khun (25% L). 1.2.3.5. B hi t m hay van t m (Non return assemdly or non return valve): B phn ny gm c vng chn hnh nm u trc vt n c chc nng to ra dng nha bn vo khun. Khi trc vt ni v th vng chn hnh nm di chuyn v hng vi phun v cho php nha chy v pha u trc vt. Cn trc vt di chuyn v pha trc th vng chn hnh nm x di chuyn v pha phu v ng kn vi seat khng cho nha chy v pha sau.

Hnh 2.7: B hi t m 1.2.3.6.Vi phun: C chc nng ni khoang trn vi cung phun v phi c hnh dng bt kn khoang trn v khun. Trong qu trnh phun nha lng vo khun vi phun phi thng hng vi bc cung phun v u vi phun nn c lp kn vi phn lm ca bc cung phun thng qua vng nh v m bo nha khng b phun ra ngoi v trnh mt p.

1.2.4. H thng kp: H thng kp c chc nng ng m khun to lc kp gi khun trong qu trnh lm ngui v y sn phm ri ra khi khun khi kt thc mt chu k p phun. H thng ny bao gm cc b phn : + Cm y ca my (Machanis ejectors). + Cm km (Clamp cylinder).

+ Tm di ng (Moveable platen). + Tm c nh (Stationary platen). + Nhng thanh ni (Tie bars).

1.2.4.1. Cm y (Mechanic ejectors): Gm xy lanh thy lc, tm y, cn y. Chng c chc nng to ra lc y tc ng vo tm y trn khun y sn phm ri khi khun.

1.2.4.2. Cm km (Clamp cylinder): C hai loi chnh dng c cu trc khuu v xy lanh thy lc. H thng ny c chc nng cung cp lc ng m v lc gi khun, ng khun trong sut qu trnh phun.

1.2.4.3. Tm di ng (Moveable platen): y l tm thp ln vi b mt c nhiu l thng, chnh nh cc l thng ny m cn y c th tc ng lc vo tm y trn khun, ngoi ra tm di ng cn c cc l ren kp tm di ng ca khun. Tm ny di chuyn ti lui dc theo 4 thanh ni trong qu trnh p phun.

1.2.4.4. Tm c nh (Stationary platen): Cng l mt tm thp ln c nhiu l thng. Ngoi 4 l dn hng v cc l ren kp tm c nh ca khun tng t nh tm di ng. Tm c nh cn c thm l vng nh v m bo s thng hng gia vi phun v bc cung phun.

1.2.4.5.Cc thanh ni (Tie bars): N c chc nng dn hng cho tm di ng .

1.2.5. H thng iu khin : H thng iu khin gip cho ngi vn hnh my theo di v iu khin cc thng s nh : Nhit , p sut, tc phun, vn tc v tc ca trc vt.Qu trnh iu khin nh hng ti cht lng sau cng ca sn phm. H thng iu khin giao tip vi ngi vn hnh my qua nt iu khin (Control panel) v mm my tnh (computer screen).

1.2.5.1. Mn my tnh: Cho php nhp cc thng s, trnh by d liu ca qu trnh p phun cng nh cc tn hiu bo ng v cc thng ip. 1.2.5.2. Bng iu khin: Gm cc cng tc nt nhn dng vn hnh my. 1.2.6. Cc loi my p phun: + My p phun nhiu mu b tr song song. +My p phun nhiu mu b tr ng. + My p phun kiu tro khun. +My p phun piston c trc vis ha do ring

Tin mi hn: Gii Thiu Cng Ngh p Phun (Phn 4: Mt s nguyn tc thit k khun) ) - (03/12/2011) Gii Thiu Cng Ngh p Phun (Phn 3:Vt liu lm khun ) - (01/12/2011) Gii Thiu Cng Ngh p Phun (Phn 2:Vt liu nha ) - (24/11/2011) Tin c hn: Gii thiu - (11/09/2011)

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