ANH HNG CUA IU KIN UC

N CHT LNG SAN PHM 1

DIECASTING LA GI ? 2 1. inh nghia Diecasting

La phng phap nguyn liu long vao trong khun uc cac san phm co chinh xac cao vi s lng ln. Ngoai ra

Diecasting con c dung chi nhng san phm uc o.

2. Hoat ng cua 1 chu ky t ng (May uc nhm)

Phun cht tach khun Kep khun nguyn liu long vao Phun nhm Lam mat M khun y san phm

Gp san phm Bi trn Plunger

Hinh dang san phm iu kin uc c tinh cua hp kim

Phng an uc X ly nhm long

Phng phap Diecasting

Khun May uc Nguyn liu

3. Phng phap Diecasting la 1 trong nhng phng phap uc La phng phap dung tc cao y hp kim long vao thay th cho khng khi trong

khun, dung ap lc cao nen trc khi hp kim ng cng lai.

4. San phm Diecasting

San phm tt cua Diecasting se khng co l rng, ngoai quan ep, kich thc chinh xac

(hardware desk drive )

iu kin uc Circle time 28 giy

D liu khun :

ng kinh Tip 70 mm

Chiu day san phm 2.0 mm

Trong lng san phm 430 g

Tit din ln nht 430 cm2

Nguyn liu ADC12

Nhit nhm long 680

Tc thp

(m/s)

Tc cao

(m/s)

Khoang

cach tc

cao (mm)

Tng tc tc

cao (ms)

Giam tc

(m/s)

Thi gian

tng ap (ms)

Ap lc uc

(Mpa)

0.20 3.2 67 4 1.5 30 65

CNG OAN PHUN NHM CUA DIECASTING 3

TC THP :

- Nhm long t gau muc vao

Sleeve va c a n cng

Gate.

- Luc nay, gi cho b mt nhm

long khng bi gn song, y khi

bn trong Sleeve ra ngoai qua

cng thoat khi cua khun. Vy se

phong nga c vic khi ln

vao trong nhm long.

- Tuy nhin nu chm qua thi

nhm se bi ng cng lai mt.

(Tc thp).

TC CAO :

- Tao hinh dang san phm.

- Tai vi tri Sleeve va Runner c in

y bi nhm long, bt u chuyn qua

tc cao.

( trang thai khng khi trong Sleeve va

Runner a thoat ra ngoai ht).

(Vi tri chuyn i tc cao, khu vc tc

cao).

- Nhm long c phun nh sng vao

cac chi tit manh cua san phm tao

lp da ep (Tc cao).

- Khng khi trong san phm khng thoat

ra ngoai kip se ong lai trong san phm.

TNG AP :

- Nen san phm.

- Nen ap lc trc khi nhm

long ng cng lai.

(Thi gian tng ap).

Cac l rng bn trong san

phm se nho lai, tng s kt

dinh vi khun.

(Ap lc uc).

LY LUN UC C BAN 4

(2). Thi gian rot

- a nhm long vao trong Cavity trc khi ng cng lai

Thi gian rot = 0.01 x chiu day san phm x chiu day san phm

(cng thc n gian)

Tc cao Tit din Tip Thi gian rot Mt nhm long

San phm + Over-flow

(4). Tc cao

(5). Xac nhn tc tai cng Gate

Tit din cng

Tit din Tip

Tc Gate Tc cao Khoang 4060 m/s la va

(3). Khoang cach tc cao

Tit din Tip Mt nhm long

San phm + Lng Over-flow

(Trong lng rot)

Khoang cach tc cao

Ty sut rot cua Sleeve =

Trong lng uc

Tit din Tip x Hanh trinh x Mt nhm

(1). Ty sut rot cua Sleeve

La ty l chim ch cua nhm long bn trong Sleeve.

ANH HNG CUA KHOANG CACH TC CAO 5

San phm bi thiu nhm : thc t sau khi rot nhm vao Sleeve, bn nhm dng vi tri chuyn i tc cao.

Trc cng - Tc cao Ngay cng Tc cao Sau cng Tc cao

ANH HNG CUA PHUN TC CAO 6

Kic

h t

h

c

ti

a

cu

a l

r

n

g

Tc phun

(m/s)

Pham vi cai t

may trc y

Pham vi cai t

siu cao tc

4 m/s

Co hiu qua vi trng hp dong chay keo dai va lam giam kich

thc cac l rng.

(Ngoai quan)

Tc phun

m/s m/s

AZ91 0.7100300

(Cht lng bn trong)

CHUYN NG CUA NHM LONG TRONG KHI

PHUN TC CAO 7

Dung Camera tc cao chup anh t mt trc may & t trn xung

Tc chup : 40000[fps]

MEMRECAM GX-8

sang :8 - 900000[lux]

T phia trn

T mt trc may

Anh Camera tc cao Anh Camera

CHUYN NG CUA NHM LONG TRONG KHI

PHUN TC CAO 8

Tc phun 1.0m/s

(Tc cng 24m/s)

Ch

iu

da

y c

n

g 2

.0m

m

T

it

di

n 1

.6cm

2

Theo inh nghia J.Wallace, trang thai nhm long

phun ra tai cng Gate : Kt qua tinh toan : (trong lng ring ly la 2.4)

Chiu day cng 3.5, tc hn 17.4m/s Chiu day cng 2.0, tc hn 24.2m/s La con s phu hp vi quan sat bng mt thng

59.0

t

1064

ggv

Tc cng

Chiu day cng

Trong lng ring nhm long

Tc phun 2.0m/s

(Tc cng 48m/s)

Tc phun 3.0m/s

(Tc cng 72m/s)

Tc phun 3.5m/s

(Tc cng 84m/s)

Ch

iu

da

y c

n

g 3

.5 m

m

T

it

di

n 2

.8 c

m2

Tc phun 1.0m/s

(Tc cng 13.7m/s)

Tc phun 2.0m/s

(Tc cng 27.5m/s)

Tc phun 3.0m/s

(Tc cng 41.25m/s)

Tc phun 3.5m/s

(Tc cng 48.13m/s)

ANH HNG CUA TNG TC TC CAO 9

Thi gian

tng tc

10[msec]

Thi gian

tng tc

15[msec]

Chuyn ng cua nhm long t cng Chuyn ng tc thp cua nhm long

Trng hp mun co tc cao sau khi

qua cng, phai cai t tng tc tht

nhanh am bao dong chay.

Gia inh rng sau khi qua cng chuyn

thanh tc cao, thi nu gia tc cua phun

chm, se khng thng c bc tng

nhm long tc thp, dn n tinh lu

ng se kem i.

ANH HNG CUA AP LC UC 10

200 800 600 400

10

20

30

40

50

60

[ms]

[MP

a]

100ms 50ms

97msec 52msec

Giam c Time-lag (lch gi)

Anh CT

Ki u 2 xi lanh

Van Check cu a Toshiba

Phng thc 2 xi lanh c lp se giup tng ap trong thi gian ngn

CHIU DAY SAN PHM VA THI GIAN NG KT 11

K

Tstm

tmtx2

2tmKTs

Vit lai la :

Tai thi im s ng kt kt thuc, 2 lp ng kt t 2 phia

se cham nhau vung gia nn co cng thc sau y :

tx : Chiu day lp ng kt tm : Chiu day san phm

K la h s

(Tc thp)

(Tc cao)

Chuyn i

tc cao

(Gate)

Ap lc phun

Tc

Thi gian T

San

phm

ng kt ng cong

tng ap

2

Chiu day

lp ng kt

2

Thi gian

ng kt Ts

K

Tstm

Ngoai ra, chiu day san phm va thi gian ng kt

con co cng thc kinh nghim sau :

San phm co chiu day tw, thi bn

phai hin thi thi gian ng kt va iu

kin uc sao cho hoan tt phun va gia ap

trong thi gian o.

MT S CNG THC TINH THI GIAN PHUN 12

Cng thc tinh thi gian phun do NADCA xng :

Cng thc thi gian phun F.C.Bennett :

q = { qa + c Tm Ts } S T

t = k [ T T + FZ / T T ]T i d

t = 0.7 S Ti T

q T

Cng thc thi gian phun G.Ulmer

(thi gian ng kt) :

Cng thc thi gian phun G.Lievy :

t =0.005e2

t A = t Zn =0.033e2

Thi gian phun theo cach tinh c

Cng thc thi gian phun cua Toshiba Machine : t =0.01e2

Chiu day

mm

1.5

1.8

2.0

2.3

2.5

3.0

3.8

5.0

6.4

Thi gian phun

sec

0.010.03

0.020.04

0.050.12

0.060.20

0.080.30

0.020.06

0.030.07

0.040.09

0.050.10

THI NG P-Q2 LA GI ? 13

Cng thc c ban Die-line :

)(22

22

constCZg

V

g

PZ

g

V

g

Ppg

gg

2

2

gVP

Theo cng thc Bernoulli, quan h cua ap lc & tc

cua nhm long se la :

V

Vg Ag

Ap

Pg

P

y, ZgZp0, VVg, Pg0, cho nn nu gian lc Zg, Zp, V, Pgthi ta c :

y c goi la cng thc c ban cua Die-line.

Theo cng thc Bernoulli trn, nu gian lc Zthi se c cng thc sau : 2

2VCP

y c goi la cng thc c ban cua Machine-line.

Theo cng thc Bernuolli thi tng nng lng cua ap lc, tc , vi tri cua may tac ng ln nhm

long la khng i. Vy nn nu mun tng tc thi ap lc se giam. Ngc lai mun tng ap lc

thi tc se giam. Vi du khi chay khng tai khoang cach tc cao thi co tc nhng khng

co ap lc. Ngc lai khi phun xong thi tc giam nhng lai co ap lc.

Tip theo, tim hng s C, ta gia inh khi Q=0V=0 khi phun xong), luc nay P=Pt (ap lc uc theo ap lc n), nhp gia tri vao ta se co C=P.

2

2VPP t

Trn thi, ke ng Die-line va ng Machine-line tim giao im. T o tim

ra tc phun gii han cua khun va may.

Cng thc c ban Machine-line :

THI NG P-Q2 LA GI ? 14

Tai y, cng thc lin tuc gia Sleeve va cng Gate se la :

pgg

g

pggg

A

QV

AC

QV

VAVACQ

22

2

2 gg AC

QP

p

tA

QPP

2

2

Ve 2 cng thc nay ln thi :

- Tai vung phu cn cng, tit din giam t ngt nn chung ta

phai xem xet h s chay Cg.

Thay cac gia tri V,Vp vao cac cng thc c ban Die-line & Machine-line ta se c cac cng thc sau :

Die-line

Machine-line

thi PQ2

Q2

P

Q2

P

Q2

P

22

2

2 gg AC

QP

p

tA

QPP

2

2P P

O O O Q02 Q0

2

T thi P-Q2 , oc gia tri truc lu ng cua giao im 2 cng thc, t o se bit c :

(1). Tc phun gii han.

(2). Chon c ng kinh Tip hiu qua.

Die-line Machine-line

THAM KHAO THI NG P-Q2 15

Q2

P

Q2

P

Tc phun

gii han giam

Tng ng kinh Tip

Ap lc n giam P giam

Q2

P

Q2

P

Tng tit din cng

Giam lc can tai cng nghing Die-line giam

Q2

P

P

Q02

P

Q02

P

Q02

P

Q02

O

O O O O

Giam ap lc ACC Ap lc n giam Pgiam Tc phun giam Q0

2 giam

Xit van phun lai

Tc phun giam Q0

2 giam

22

2

2 gg AC

QP

p

tA

QPP

2

2

Die-line Machine-line

Tc phun gii han giam Tc

phun gii

han giam

Tc phun

gii han tng

TINH TOAN P-Q2 TRONG TOSCAST 16

p

tA

QPP

2

2

Machine-line

Hin thi kt

qua tinh toan

Khng cn tinh toan phc tap, man hinh TOSCAST se hin thi kt qua.

ANH HNG CUA CAI T GIAM TC 17

Surge phun

K ca khu vc siu cao tc, nu giam tc nhay thi se giam c Bavia.

Tc cui cung Nhanh Chm

0 10 20 30 40 50 60 Thi gian [ms]

1

5

2

3

4

10

20

30

40

50

60

Tc

[

m/s

]

Ap

lc[M

Pa

]

0 10 20 30 40 50 60 Thi gian [ms]

1

5

2

3

4

10

20

30

40

50

60

Tc

[

m/s

]

Ap

lc [M

Pa

]

Ht bi Surge

AP LC SURGE 18

2

V

A

A

A

A1

A

AAPAP

A

A

tA

VmV

2A

AP

PPPP

2

c2

og

2

c

2

o

og

h

rhrhh

c

h

c

c2

c2

g

2

cm

lsdm

Ap lc ng cua

nhm long Tn tht t khun Ap lc tinh cua nhm long

( Cng thc ly lun cua Surge )

Theo hi nghi Diecasting cua Toshiba Machine 2006 : Anh hng cua iu kin khun & iu kin uc n cht lng san phm va xut phng phap anh gia mi

Mt nhm long A p lc phia Head xi lanh phun A p lc phia Rod cua xi lanh phun A p lc cua Tip ln nhm long A p lc nhm long Tc Plunger (tc cao) Tc cng Tc OF Gate Tit din Head cua xi lanh phun Tit din Rod cua xi lanh phun Tit din cng Tit din OF Gate Tit din OF Tit din Tip

Nhm long

Ag

Ph Ah Ar

Vc

Ac

Vg

Pm

Pc

Aog

Ao Vog

Du thuy lc

I SACH CHO AP LC SURGE 19

(1). Giam P

(2). Giam V

(3). Giam A/A

(4). Tng Pl

(5). Tng Pr

(Phng phap giam ap lc khi hoan tt phun)

Giam ap lc uc

Giam tc cao

Thay i iu kin khun

Thay i iu kin khun

Dung may uc bm Servo

Giam ap lc ACC

Giam tc Plunger

Thay i Gate hoc Tip

Tng tn tht t khun

Giam tc nhay ben

2

V

A

A

A

A1

A

AAPAP

A

A

tA

VmV

2A

AP

PPPP

2

c2

og

2

c

2

o

og

h

rhrhh

c

h

c

c2

c2

g

2

cm

lsdm

Ap lc ng cua

nhm long Tn tht t khun Ap lc tinh cua nhm long

Theo hi nghi Diecasting cua Toshiba Machine 2006 : Anh hng cua iu kin khun & iu kin uc n cht lng san phm va xut phng phap anh gia mi

THI PHUN KHI S DUNG GIAM TC 20

VI DU SO SANH THI GIAN ROT KHI S DUNG HOC KHNG S

DUNG PHANH HAM

Khoang 30msec Hu nh khng co khac bit v thi gian phun.

Khng co anh hng n cht lng san phm. Nu co Bavia se gy anh hng xu n cht lng san phm.

(Nen nhm khng u, kich thc thay i)

Dung phanh ham

Khng dung phanh

ham Nhn thy c tac

dung cua phanh ham

Dung phanh ham thi

ap lc Surge thp

H S LU XUT TAI CNG 21

H s lin quan n ap lc rot va lu lng i qua cng

thi P-Q2 Die-line

V c ban, nu chiu day cng cang ln, hoc khun cang phc

tap, thi h s lu xut cng se cang nho.

Vi du o thc t h s lu xut cng

P : ap lc phun (Mpa)

: Trong lng ring nhm

long (g/cm3)

Q : Lu lng cng (cm3/s)

Ag : Tit din cng (cm2)

Cg : H s lu xut cng

Vg : Tc cng (m/s)

MACH THUY LC CUA VAN SERVO 22

thi cua ap lc uc cua Meter-out la thi kt hp cua phia Rod va phia Head cua xi lanh phun

P Ph A Pr Ah A

Ah [MPa]

Dung phanh ham co nghia la giam ap lc phia Rod, nn thi se i xung.

thi cua ap lc uc cua Meter-in se hin thi nh phia Head cua xi lanh phun.