8/10/2019 TK khuon

1/63

8/10/2019 TK khuon

2/63

CHNG I

NGUYN L THIT KKHUN

I. NH NGHA

Khun l mt dng cnh hnh mt sn phm nha. N c thit

ksao cho c thc sdng cho 1 slng chu trnh yu cu.

Kch thc v kt cu ca khun ph thuc vo kch thc v hnh

dng ca sn phm. S lng sn phm yu cu cng l mt yu t rt

quan trng xem xt yu cu sn xut lot nh hay sn xut vi slng ln xc nh xem sdng lng khun hoc loi khun no cho

ph hp. Nhng yu ny nh hng trc tip ti khun v gi thnh

khun hoc sn phm.

II. CC THUT NGC BN

1. Cc thut ng:

Khun l cm nhiu chi tit lp vi nhau, nha c phun vo,

c lm ngui, v y sn phm ra.

Sn phm c to hnh gia hai phn ca khun. Khong trng gia 2

phn c in y bi nha v n mang hnh dng ca sn phm :

gi l lng khun, phn xc nh hnh dng bn trong ca sn phm c

gi l li khun.

Phn tip xc li khun v lng khun c gi l ng phn khun.

Ngoi li v lng khun cn cc bphn v chc nng ca chng c

gi l cc thit bphkin ca khun.

8/10/2019 TK khuon

3/63

Ghi ch :1 : Tm kp trc. 10 : Cht dn hng.

2 : Tm khun trc. 11 : Bc dn hng.

3 : Tm khun sau. 12 : Bc mrng.

4 : Tm kp sau. 13 : Bnh v.

5 : Tm . 14 : Cht hi.

6 : Khi . 15 : Cht y.7 : Tm gi. 16 : Bc dn hng cht y.

8 : Tm y. 17 : Cht .

9 : Vng nh v. 18 : bc cung phun.

2. Chc nng ca phkin khun:

2.1

Tm kp trc : kp phn cnh ca khun vo my p phun.

8/10/2019 TK khuon

4/63

2.2 Tm khun trc (lng khun): L phn cnh ca khun, to nn

thnh phn trong v phn ngoi ca sn phm.

2.3

Tm khun sau(li khun) : l phn chuyn ng ca khun, to nn

phn trong v phn ngoi ca sn phm.

2.4 Tm kp sau: kp phn chuyn ng ca khun vo my p phun.

2.5

Tm : gicho mnh ghp ca khun khng bri ra ngoi.

2.6 Khi : dng lm phn ngn gia tm v tm kp sau cho tm

y hot ng c.

2.7 Tm gi: gicht y vo tm y.

2.8

Tm y: y cht y trong qu trnh y sn phm.2.9 Vng nh v: m bo vtr thch hp ca vi phun vi khun.

2.10Cht dn hng: dn phn chuyn ng ti phn cnh ca khun

( lin kt chnh xc gia 2 phn ca khun). m bo s tng

quan gia lng khun v li khun, gip cho lng khun v li khun

lin kt chnh xc hn.

2.11

Bc dn hng: dn hng cho cht dn hng chnh xc hn, vtrnh lm hng cc tm kp sau khi cht dn hng i vo (n c th

thay thc).

2.12Bc mrng: ni tip bc dn hng nhm mc ch trnh mi mn

hoc lm hng tm kp sau khi ngnv tm .

2.13

B nh v : m bo cho s lin kt gia phn c nh v phn

chuyn ng.2.14Cht hi : lm cho cht y quay v v tr ban u khi y sn

phm ra khoi khun.

2.15

Cht y: dng y sn phm ra khi khun.

2.16Bc dn hng cht y: trnh mi mn v lm hng cht y,

tm y v tm gido chuyn ng mnh gia chng.

2.17Cht : Dn chuyn ng v cho tm 5. Trnh cho tm

khi bcong do p lc y cao.

8/10/2019 TK khuon

5/63

2.18Bc cun phun : ni vi phun v knh dn nha vi nhau qua tm

kp trc v tm khun trc.

III. CC LOI KHUN THNG DNG

1.

Khun h : l khun n gin nht trong s khun p nha, nh

hnh di. Khun ny c hnh thnh t hai b phn khun trn v

khun di. Na khun trn l b phn khun c gi l li khun

(core), cn na khun di l b phn khun ci, gi l hc khun

(cavity). ton b khun vo gia tm gia nhit, va gia nhit va

vt liu dng bt vo lng khun, t p vo na khun trn. Khi , do

p lc, vt liu tha trong lng khun s chy t thnh mp ct khunthnh bavia. Tuy nhin, ni chung kh t c chnh.hn na loi

b bavia cn c mt s nguyn cng sau . Vi li, trong trng hp vt

liu to hnh c vy bavia n vi, giy hay si asbest ln th c nhc

im l kh bo m lc to hnh, cng nh kh in y vt liu.

Hnh 1.1 : Khun h

Tm pha c nhTm gia nhit pha c nh

Tm khunTm y sn phm

Li

Vt h m

Tm khun pha di ngLng khun

Tm gia nhit pha di ng

Tm giTm y pha trnTm y pha d- i

Tm pha c nh

8/10/2019 TK khuon

6/63

8/10/2019 TK khuon

7/63

8/10/2019 TK khuon

8/63

Hnh 4.1 : Khun ghp

5.

Khun to hnh bng cch p chuyn (transfer) : Phng php to

hnh ny s dng my p p lc thng thng nh hnh 2.5, p lc tc

ng phun vt liu dng chy lng vo lng khun. Nhn chung, kt cu

khun n gin v cng c u im l thit b r tin.

Sn phmLi gia

Rm ghp

8/10/2019 TK khuon

9/63

Hnh 5.1 : Khun to hnh bng cch p chuyn

Trong trng hp s lng sn xut t, cng c th p dng hnh thc

ny. Nhng trng hp sn lng nhiu hoc kch thc chi tit ln, ta

c nh chy piston vo bn my p p lc (bn c nh) v lp ng

piston vo tm trung gian, v c nh phn lng khun vo bn di ng.

6.

Khun 2 tm : Khun 2 tm c 1 ng phn khun (parting line) n

chia khun lm 2 phn : phn c nh (fixed side) v phn di ng

(movable side).

Hnh 6.1 : Khun 2 tm

piston

Piston

u rt

Cht dn h- ng

Sn phm

Tm trn

Tm d- i

d- i

8/10/2019 TK khuon

10/63

8/10/2019 TK khuon

11/63

Trong khun 2 tm c sdng rt nhiu trong hthng khun v n

c nhng u nhc im :

u im : kt cu ca khun n gin hoc khun khng c rnh dn.

Gi thnh khun r, dchto.

H thng rt nha : ming phun trc tip hoc ming phun ngm v

ming phun trc tip (c sdng nhiu).

Vi ca rt ngm, ta c thtch chi tit ra khi rnh dn (bao gm u

rt v cng phn phi).

Nhc im: cng phn phi cnh v cng phn phi trc tip cn phi

loi brnh dn, nn chng kh c thtng ha v khng tit kim6.1 Khun 2 tm c knh dn ngui : Khun hai tm l loi khun phbin

nht. So vi khun ba tm th khun hai tm n gin hn,rhn v c

chu kp phun ngn hn.

Vi khun hai tm c mt lng khun th khng cn n knh dn nha

m nha sin y trc tip vo lng khun thng qua bc cung phun.

i vi khun hai tm c nhiu lng khun th ta cn quan tm nvic thit kknh dn v ming phun sao cho nha c thin y cc

lng khun cng lc (vn cn bng dng chy ca nha). Trc khi

bt u thit kkhun loi ny ta nn dng mt mu phn tch thtrn

phn mm nhm tm ra vtr t ming phun thch hp nht. Khi xt thy

v tr cc ming phun c tht thng hng vi cc lng khun th vic

dng khun hai tm l thch hp.

8/10/2019 TK khuon

12/63

Hnh 6.1.1 : Khun 2 tm c knh dn ngui

V vn cn bng dng v i hi cc ming phun phi c btr

thng hng vi cc lng khun m vic thit kkhun hai tm c nhiu

lng khun gp nhiu hn chi vi mt ssn phm nha nht nh.

Do khc phc nhc im ny ngi ta dng n khun ba tmhoc khun hai tm c knh dn nng.

8/10/2019 TK khuon

13/63

Hnh 6.1.2 : kt cu hnh khun 2 tm

6.2

Khun 2 tm c knh dn nng: Khun hai tm dng knh dn nng

lun gicho nha nng chy trong bc cung phun, knh dn v ming

phun, nha chng c khi no n chy vo lng khun. Khi khun m

ra th ch c sn phm (i khi c thm knh dn ngui) c ly ra

ngoi. Khi khun ng li th nha trong cc knh dn vn nng v tip

tc in y vo lng khun mt cch trc tip. Knh dn trong khun c

thgm cknh dn ngui v knh dn nng.i vi loi khun ny, cc ming phun phi c t vtr trung tm

ca cc lng khun. iu ny c ngha l cc knh dn phi c t xa

mt phn khun. Nhng iu ny khng gy bt ktrngi no cho vic

thit k. Loi khun ny cng ph hp vi khun c nhiu lng khun

vi kch thc nhhay nhng khun m hthng knh dn phc tp v

ph nhiu vt liu.

8/10/2019 TK khuon

14/63

Hnh 6.2.1 : Khun 2 tm c knh dn nng

7.

Khun 3 tm : So vi khun hai tm th hthng knh dn ca khun ba

tm c t trn tm thhai song song vi vt phn khun chnh. Chnh

nhtm thhai ny m knh dn v cung phun c thc ri ra khi

sn phm khi khun m(tct ui keo).

Hnh 7.1 : Khun 3 tm

Khun hai tm c dng khi m ton bhthng knh dn khng th

btr trn cng mt mt phng nh khun hai tm. iu ny c thl

do:

8/10/2019 TK khuon

15/63

- Khun c nhiu lng.

- Khun c mt lng khun nhng phc tp nn cn hnmt vtr

phun.

- Kh khn cho vic chn mt vtr phun khc.

- V cn cn bng dng nha gia cc knh dn vi nhau nn cn

phi thit k h thng knh dn khng cng nm trn mt mt

phng phn khun

c im ca khun 3 tm l tct ui keo.

Hnh 7.2 : 1,2,3 Trnh tmkhun 3 tm

8/10/2019 TK khuon

16/63

u im:

- Gi thnh rhn so vi khun 2 tm c knh dn nng.

- t bhng khun hn so vi khun 2 tm c knh dn nng.

- C thph hp hn vi loi vt liu chu nhit km.

Nhc im :

- Quy trnh p phun tng do thi gian dng nha i n c lng

khun lu.

- Lng ph nhiu vt liu.

- Cn p sut phun rt ln in y vt liu.8. Khun nhiu tng

Cc h thng khun kp ny cng c kt cu chung kh ging vi h

thng khun nhiu tng knh dn ngui, tr h thng knh dn trong

khun nhiu lng khun. Cc h thng ny c nng sut rt cao nhs

lng khun c thit ktng gp i, gp 3 ln hay thm ch gp 4 ln s

lng khun so vi khun thng thng trong khi ch tng lc kp vchiu dy khun ln rt t. iu ny c thc hin bng cch thm vo

nhiu mt phn khun cc vtr i xng nhau. c thdng cc loi

khun ny th my p cng cn c h thng kp cng nh cc chuyn

ng kp c bit. Hthng kp thng sdng l cc thanh n kp hay

cc thanh rng.

8/10/2019 TK khuon

17/63

Hnh 8.1 : Khun nhiu tng

9. Khun khng rnh dn: l khun c t bgia nhit vo vng u rt

hoc rnh dn, lm cho vt liu lun trng thi lu ng, khng ng

cng.

Hnh 9.1 : Khun khng rnh dn

lm nng chy vt liu, nha thng c nung nng trong trc vt.

Tuy nhin khun khng rnh dn p dng phng php dn nng : lm

tan chy vt liu bng bgia nhit.

C 2 kiu lm rnh dn nng :

8/10/2019 TK khuon

18/63

Kiu nung nng tbn trong : dng nung nng vt liu tch

hng phun ph.bi nhng tm kim loi c iu chnh nhit

cao cnh. Ngoi ra mt khong trng dn khng trong khun,

nm chnh gia knh phn nhnh v knh dn nha lng s bc

chung quanh thanh in tr. Theo cu trc ny th dc theo thnh

knh phn nhnh s to nn mt lp nha ng do tip xc vi

phn lnh ca khun.Hiu sut cao, cn trdng chy nhiu, kh

thay i mu (do cn lp ng cng bn trong).

Hnh 9.2 : Hthng t nng tbn trong

1 : knh dn nng.

2 : ng cha thanh in tr.

3,4 : thanh in tr, dy in.

Kiu nung nng ngoi : nung nng vt liu tngoi hng phun

bi nhng tm kim loi c iu chnh nhit cao cnh. Ngoi

ra mt khong trng dn khng kh c btr gia tm kim loi

v phn khun lnh gi nhim v cch ly trnh hin tng hiu

ng do skhc bit qu ln gia hai vng nhit . Hiu sut cao,

t cn trdng chy.

8/10/2019 TK khuon

19/63

Hnh 9.3 : Hthng t nng tbn ngoi.

1: knh nng.

2 : khong trng cch ly.

3 : vt thc phun.

4 : u lt bng ng.

5 : tm kim loi dn nhit.

6 : dy dn in

iu kin thch hp ca vt liu trong khun rnh dn nng:

- Khng nhy cm vi nhit , n nh cao v dc nhit

thp.

- Khng nhy cm vi p sut, c phun phi c lm nhit

thp

- Nhit lm bin dng nhit cao c thnhanh chng ly vt

c ra.

- dn nhit cao.

- Nhit dung ring thp.

u im:

- Do rnh dn khng c ly ra m chc phn chi tit c tho ra

nn khng cn c bphn tho rnh. Khng phi loi brnh dn.

- u ngt hoc rnh dn lun c nung nng bi bgia nhit, do

nha nng chy in y tt.

8/10/2019 TK khuon

20/63

- N ph hp cho qu trnh tng ha v c hiu qucao khi sn xut

vi slng ln.

Nhc im :

- Kt cu khun phc tp.

- Gi thnh khun cao.

- Np liu mt nhiu thi gian.

10. Khun cho cc sn phm c ren:

i vi nhng vt th c ren vt bn trong nh np y chai,

l..vv..ngi ta ng dng khun quay tch ri vt thra khi khun.

Trong trng hp ny li bn trong c cu trc ging nh mt trc vt,khi khun mra li sko theo vt thra khi phn na khun cnh

v ng thi quay chung quanh trc ca chnh n to c tc mtrc vt

tch ri vt thra khi li. Chuyn ng quay ca li c khi ng

bi ng c, tc ng vo trc quay chnh c cu trc trn c, hthng

bnh rng ginhim vtruyn lc quay ttrc quay chnh n cc trc

phni lin vi li.

a b

Hnh 10.1.a : mt ct ca khun lm sn phn c ren.

Hnh 10.1.b : sn phm c ren c lm tkhun.

8/10/2019 TK khuon

21/63

CHNG 2

HTHNG Y SN PHMI. GII THIU CHUNG:

Sau khi sn phm c cng thnh hnh v lm ngui xung, n phi c

ly ra khi khun. L tng nht l nu trng lc c thtch c sn phm

khi lng v li khun sau khi khun m. Tuy vy, sn phm lun bgili

bi undercuts, bm dnh , ni ng sut v vy chng cn c tch v ly ra

bng hthng chuyn dng.

Hthng y thng thng c t na khun ng. Khun mra, h

thng y chuyn ng vpha trc qua ng phn khun, sn phm c

y ra. Tt nhin, sn phm strn hoc trong na khun ng sau khi m

khun bi khun bn trt, bi sco ngt ca sn phm vo li khun. Tt

nhin bmt cn c lm cn v xl sao cho gim thiu sbm dnh snphm n thp nht c th. Cn vic gisn phm trn na khun ng sl

vn nu li khun li nm trn na khun tnh, vic ny nn trnh c s

tt hn.

- Khong y: khong y phi ln hn t510 mm so vi chiu cao ca

sn phm c ly ra tkhun sau. (ch khng nn lm khong y

qu di.

8/10/2019 TK khuon

22/63

- Thit khthng y phi m bo l khng lm yu khun sau, ( c th

thm cht (thng dng), mt khi m, mt khi c)

II. CC LOI HTHNG Y.

1. Hthng y thng thng:

1.1y bng cht.

Cht y l phng thc phbin nht dng y sn phm. Cc cht

y c gai cng chnh xc v c chn theo tiu chun. cng cathan cht khong 60 - 65 Rc, cng ca u cht khong 3035 Rc.

Hnh : Cc phn ttrong hthng y

- Kch thc v hnh dng ca cht y phthuc vo kch thc ca sn

phm, khun.

8/10/2019 TK khuon

23/63

- D > 3

- Phn nh ca cht y vl thuyt chnm ngang mc so vi lng

khun nhng trong thc t, c tht trn hoc di 0.050.1 mm.

- Cc cht y nn btr gc, cnh, gn ca sn phm.

Mt sloi cht y v tiu chun ca n.

Chiu di ca ldoa c ng knh D c ly nh sau:

- i vi nhng lnhit luyn trc khi gia cng L = 4 x D

- i vi nhng l nhit luyn L = 3 x D

Max L = 20mm, Min L = 6mm

Cht y

8/10/2019 TK khuon

24/63

8/10/2019 TK khuon

25/63

Cht c mt cam.

Cht c mt cam

Cht do.

8/10/2019 TK khuon

26/63

Cht do

Kt hp cht xin v cht tr.

8/10/2019 TK khuon

27/63

Cht xin

Cht y kiu a

Thng dng y bng ci np. Khi n d

ch to v c b mt tip xc ln. Tuy nhin kh

lm ngui cht.

y kiu a

y vu.

Nu c vu hoc gn, nn b tr cht ti nh ca

vu hoc gn, Nu t cht xung quanh bu hoc

gn c th c lm rn nt khi y bng cht.

8/10/2019 TK khuon

28/63

y vu

1.2Hthng y dng li y.

Li y dng y cc sn phm c thnh mng v hnh dng phc

tp. Trong trng hp ny nu dng cht y trn th skhng hiu qu

v skhng lc y, nu c lc y i na th mt sn phm sb

c du ln vo.

C iu bt li l nhng ly hnh chnht rt kh lm v cn t

chng tcc ming ghp ln ng phn khun. V vy, vic mi nhng

ly l to nn mt bmt rt phng cho cc li y i qua. Cc

li y yu hn cc cht y trn, nn ta c thtng cng cho n:

8/10/2019 TK khuon

29/63

Hnh : hthng y dng li y

1.3

Hthng y dng ng y.

8/10/2019 TK khuon

30/63

ng y dng y nhng sn phm c dng trng xoay hoc tm

mng.

Cc ng y rt thun li cho qu trnh y quanh cc cht li.

Hnh : hthng y dng ng y

Cc kiu ng y:

- ng y thng

- ng y kiu cn

- ng y kiu bc

8/10/2019 TK khuon

31/63

8/10/2019 TK khuon

32/63

2. Hthng y c gia tc.

2.1Dng c cu thanh rng bnh rng gia tc thm cho cht y.

Hthng y c gia tc sgip cho sn phm bt ra khi li khun

nhanh hn.

Hnh : hthng y c gia tc thm cho cht y

Bgia tc cho cht y

2.2 Dng c cu thanh rng bnh rng gia tc thm cho tm y.

8/10/2019 TK khuon

33/63

Hthng y ny siu khin mt tm y pha trn.

Hnh : hthng y c gia tc thm cho tm y

Bgia tc thm cho tm y

2.3Tm y c n by.

tng chiu cao y mt pha gip sn phm ri ra mt cch d

dng.

8/10/2019 TK khuon

34/63

Hnh : tm y c n by

n by

2.4y kp.

i vi nhng sn phm c hnh dng phc tp cn phi y tun tth

dng hthng y kp.

Phng php y chi tit ny gm 2 bc : thng sdng kt hp tm

y v cht y.

8/10/2019 TK khuon

35/63

8/10/2019 TK khuon

36/63

Hnh : 1, 2, 3 Qu trnh y ca cht y 2 tng kiu 1

Cht y 2 tng kiu 1

Kiu 2:

8/10/2019 TK khuon

37/63

Hnh : 1, 2, 3 Qu trnh y ca cht y hai tng kiu 2

Cht y 2 tng kiu 2

3.2Hthng y knh dn trong khun 3 tm.

C cu hot ng nhhthng iu khin bng kh nn gip a knh

dn ra khi khun ddng .

8/10/2019 TK khuon

38/63

Hnh : c cu y knh dn trong khun 3 tm

Hnh : 1, 2, 3, 4 Nguyn l hot ng ca c cu

4. Hthng y bng c kh.

4.1y bng hthng trc khuu.

Phng php ny c dng kim sot lc nhiu hn v ddng

hn

8/10/2019 TK khuon

39/63

Hthng y bng trc khuu

8/10/2019 TK khuon

40/63

8/10/2019 TK khuon

41/63

Hthng y c kh in hnh

Tch cc bphn bng cch ko tm y t na trc ca chi tit

8/10/2019 TK khuon

42/63

y bng ng tna trc ca chi tit

4.3Hthng y bng thy lc.

Ngi ta sdng mt thit bthy lc y chi tit. Phng php

ny c nhiu u im : nh vic chng t thi im y hay tc

y.

N cng c sdng mt thit ban ton ngn nga cnh cht

y vng vo khun nhvic hthp p sut thy lc hoc trnh

lm hng khun bng cch dng khi iu kin ti trng khung c

php hot ng.

8/10/2019 TK khuon

43/63

Hthng y thy lc

5.

y sn phm c Ren.

5.1

y cho sn phm c Ren trong.5.1.1 Tho ren cng bc:

Sn phm c y khi khun nhlc y ca vnh y. Cch

tho ren cng bc chphn hp vi nhng loi nha c n hi cao,

chnh nhtnh n hi ca nha m sn phm y ra skhng bhng

hay cong vnh. Loi ren khuyn dng cho cch tho ren ny l ren trn.

8/10/2019 TK khuon

44/63

Tho ren trong bng lc cng bc

5.1.2 Tho ren bng cht gp.

Cht gp dng tho ren trong cho cc sn phm nh

Cu to cht gp v vtr ca n trn khun

Lp cht gp trn khun v nguyn l hot ng ca ton hthng

8/10/2019 TK khuon

45/63

Lp cht gp trn khun

8/10/2019 TK khuon

46/63

Nguyn l hot ng ca cht gp trn khun

5.1.3 Tho ren bng thanh rng -bnh rng

Tho ren bng thanh rng bnh rng cho php tho ren cnglc nhiu sn phm trn khun v m bo ren c chnh xc

cao hn hai phng php tho ren trn. Ngoi ra, c cu ny cn

ph hp vi nhng sn phm c kch thc ln trong sn xut

hng lot.

8/10/2019 TK khuon

47/63

Tho ren trong bng thanh rng - bnh rng c truyn lc bng c

Tho ren trong bng thanh rng bnh rng c truyn lc bng thy lc hoc

kh nn

8/10/2019 TK khuon

48/63

Nguyn l hot ng ca hthng tho ren trong dng thanh rng bnh rng

c truyn lc bng thy lc hoc nn kh

5.1.4 Tho ren bng tay.Phng php tho ren bng tay ph hp vi nhng sn phm

nhnhng cn ren c chnh xc cao. Theo phng php ny ,

sn phm c tho ra khi li bng tay v chph hp vi sn

xut n chic.

Tho ren bng tay

5.2

Kiu y cho sn phm c Ren ngoi.

8/10/2019 TK khuon

49/63

5.2.1 Tho ren cng bc.

Khi khun mli sc gitm cnh v sn phm c

y ra khi khun nhcht y

Tho ren bng cng bc

5.2.2 Tho ren bng cht nh.

Cht nhdng tho ren cho cc sn phm c kch thc nh.

8/10/2019 TK khuon

50/63

Tho ren ngoi bng cht nh

5.2.3 Tho ren bng btruyn bnh rng

Tho ren bng btruyn bnh rng

6.

y knh dnCung phunMing phun.

8/10/2019 TK khuon

51/63

6.1Sy cung phun.

Hthng ny phi thc hin hai qu trnh. Thnht l ko cung

phun ra ngoi khun khi khun m, thhai l y knh nha, cung phun

v ming phun ra khi khun sau. i vi qu trnh thnht ta cn mt

bphn ko cung phun:

a, Dng cung phun c ko nhcn ngc ( tt nht)

b, Dng cung phun chZ (tt)

c, Dng cung phun c ko nhrnh vng (t dng)

d, Dng cung phun c ko nhcht y u bi (t dng)

a- Kiu chct sau dng cn ngc: y l kiu thng dng. N dng

nh mt vng thn ngui. Nn gicho cht y thp xung 1mm vtrong nhiu trng hp slng nha ln vic lm ngui srt chm.

Ta hcht y thp xung to nn bmt ln hn, ng thi cng

to nn 1mm vt liu an ton trc khi cht y i vo trong nha

trong qu trnh y.

8/10/2019 TK khuon

52/63

b-Bphn ko cung phun c rnh vng: theo thit kny, mt hoc

nhiu rnh vng c ct trong thn ngui sau to khnng ko

cung phun

c- Bphn ko cung phun kiu chZ: y l kiu n gin nht.

Nhc im l cung phun thng khng lun lun ri ra khi cht

y kiu ny. phun khun tng th vtr ca bphn hnh Z

phi c xc nh vtr chnh xc.

6.2

Sy knh nha.

Cn ChZ Rnh vng

6.3Sy ming phun.

8/10/2019 TK khuon

53/63

y ming phun

Ming phun bche khut hoc t ngm. Vtr t cc cht y l rt

quan trng. y sn phm ra mt cch dnht, trnh blch khi y.

Dng 2 cht y

7. Hthng y bng Kh nn.

Lc y c tc dng bng cch : p lc kh trc tip ln bmt sn

phm thng qua mt van kh nh. phng php ny hot ng hiu

8/10/2019 TK khuon

54/63

quth dnh gia thnh sn phm v li phi c tch ra thng phn

cho kh nn hot ng. Tuy nhin c mt sy ngc trran gay lp

tc lm cho kh nn thot ra nn lc y hiu qunhanh chng bhn

ch. Do phng php ny c bit hiu qucho cc loi hnh hp.

Hnh : hthng y bng kh nn

i vi nhng sn phm nh x, chu c lng khun su, khi sn

phm ngui th chn khng trong lng khun v li khun l rt ln

nn sn phm kh c ththot khun. Do , cn mt lc y ln v

phn bu y sn phm thot khun. Li khuyn l ta nn dng kh

nn kt hp vi tm tho y sn phm.

Nguyn l hot ng:

8/10/2019 TK khuon

55/63

Hnh : kt hp tm y v van kh

8/10/2019 TK khuon

56/63

Cu to van kh

Nu cm thy kh khn khi thit kthm tm tho th c thbtr hai dngkh qua hai van kh trn chai tm khun y sn phm.

Thi kh trn chai tm y sn phm

Hai van kh dng trn dng cho hthng y kh trn hai na khun

III.

TNH TON LC Y CA HTHNG Y:

1.

Nhn tnh hng ti lc y:

8/10/2019 TK khuon

57/63

8/10/2019 TK khuon

58/63

Hnh nh quan st di knh hin vi

Trong khun vi nhm bmt Ra = 0.689 m n 0.092 m. Vt

xc l do nhm ca li, trong khun vi nhm bmt li l

0.689 m th thy c nhng vt xc su, cn Ra = 0.016m th

nhng vt xc khng nhn thy.

Lc y ln nht ( khi nhm bmt li 0.016 mRa) th khng c

vt xc. Hin tng ny l do y xut hin mt vi lc y khcln hn lc y khi bmt btrhay bxc ( nh khum lc hoc

lc van der Waals).

1.2nh hng ca lp mi vi lc y.

Lc y tng l nguyn nhn chnh khin vt c bkhuyt tt, bin

dng, rn nt. Khi li khun c mmt lp th lc y gim.

8/10/2019 TK khuon

59/63

Mt skiu m:

Kiu cng dy lp m nhm bmt

Khng m 0.036 m Ra

TiN (Arc) Hv2000 2.7 m 0.031 m Ra

TiN (HCD) Hv2000 3.0 m 0.025 m Ra

CrN Hv1800 2.5m 0.031 m Ra

WC/C Hv1100 1.3m 0.022 m Ra

DLC Hv3500 1.0m 0.018 m Ra

Cr Hv1000 10m 0.045 m Ra

Lc y ca PP khi li c m

Biu cho thy: li c mlp Cr cng v lp DLC c lc y

nh li khng c m.

Dng lp mngoi Cacbon WC/C thy nhiu hiu qugim lc y

nht.

Kiuph

Lc y

8/10/2019 TK khuon

60/63

8/10/2019 TK khuon

61/63

dng kch thc ca m hnh hnh hc sn phm nha, hng dng

chy, bdy thnh sn phm.

co ngt ca sn phm xy ra ngay ckhi cn nm trong khun

kn cng nh sau khi n tch khi khun ci n khi by ra khi

khun c. Do xut hin lp khng kh gia sn phm v lng

khun ci nn tt ccc kch thc ngoi ca sn phm bb i.

Nhng mt trong tip xc vi khun c kch thc khng bb i,

do trong tit din tn ti ng sut ko.

Lc bm dnh ca vt ln bmt khun c phthuc vo tnh

cht ca vt liu, nhm tvi bmt khun v gi trp sut dtc dng vo mt khun sau khi rt y vt c.

PP PS ABS

co ngt (%) 12.5 0.20.5 0.40.8

M un n hi (N/

) (1.11.4).

(2.83.5).

60

1.4Lc ma st: lc y phthuc vo hsma st gia cht do v thp.

Hsma st nh hng bi lp nha cng bn ngoi v bmt li

khun ti thi gian tho khun.

Hsma st phthuc vo nhm bmt. nhm bmt cao th

lc ma st ln, nn khi y rt kh khn, cn lc ln thng lc mast.

2.

Th nghim xc nh lc y.

2.1S nguyn l.

Bphn cung cp kh qua ng dn kh, van chnh p sut, van chnh

tc kh, v mt kha K( ng - m) n hthng y thc

nghim.(nh hnh v)

8/10/2019 TK khuon

62/63

2.2Thit bth nghim gm:

- Khun : trtrn: D = 40mm, h = 60mm, t = 2mm.

- Hthng th nghim o lc: dng hthng y kh nn: mt bnh

cung cp kh, van chnh p sut, van chnh tc , mt kha K iu

chnh lu lng kh khi y.

2.3Kt quo c.

3. Cng thc thc nghim tnh ton hthng y.

Fe =

=

(*)

Felc y (N)

hsgin nnhit ca vt liu (cm/)

Em un n hi (N/)

= -

- nhit chy ca vt liu

- nhit khi y

din tch tip xc gia lng khun v li khun theo hng y

(

- hsma st gia vt liu v li

hspossion

ng knh ca li khun (cm)

bdy ca sn phm (cm)

Hoc : Cng thc (*) c thvit theo cch khc:

Ll chiu di ca li khun

Fe =

8/10/2019 TK khuon

63/63