thuyetminh1
TRANSCRIPT
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TRNG I HC BCH KHOA TPHCM
KHOA C KH
B MN THIT K MY
====o0o====
LUN N TT NGHIP
TI:
THIT K MY P NHA 250 TN
Gio vin hng dn : Th.S Nguyn Vn Thnh
Sinh vin thc hin : Nguyn Tun Huy
Lp : CK08TKM
MSSV : 20800798
TPHCM, thng 12 2012
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I HC QUC GIA TP. HCM CNG HA X HI CH NGHA VIT NAM
TRNG I HC BCH KHOA c Lp T Do Hnh Phc
NHIM V LUN N TT NGHIP
Khoa : C KH
B mn: THIT K MY
H v tn : NGUYN TUN HUY MSSV : 20800798
Ngnh : K THUT CH TO Lp : CK08TKM
1. u lun n:
THIT K MY P NHA 250 TN
2. Cc s liu ban u :
- Th tch phun : 500 cm3
- Lc kp khun: 250 Tn
3. Ni dung cc phn thuyt minh v tnh ton:
- Tng quan v my p nha
- Phn tch v chn phng n thit k cho my.
- Tnh ton thit k cc b phn truyn ng v h thng thy lc trong my.
- Vn hnh v bo dng h thng my p.
4. Cc bn v:
- Bn v kt cu chung ca my p nha.
- Bn v cc phng n cm kp khun.
- Bn v s nguyn l my p.
- Bn v s mch thy lc trong my.
- Bn v s in in hnh iu khin my.
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5. Cn b hng dn : TH.S NGUYN VN THNH
6. Ngy giao nhim v lun n : /09/2012
7. Ngy hon thnh nhim v : 19/12/2012
Ngy .. thng . nm 2012
Ch nhim b mn Ngi hng dn chnh
( K v ghi r h tn ) ( K v ghi r h tn )
PGS. TS. PHM HUY HONG TH.S NGUYN VN THNH
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Kt qu nh gi lun n tt nghip.
- im hng dn lun n : .
- im duyt : .
- im bo v hi ng : .
Ngy . thng . nm 2012
Ch tch hi ng Sinh vin thc hin
(K v ghi r h tn) (K v ghi r h tn)
NGUYN TUN HUY
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NHN XT CA GIO VIN HNG DN
....
Tp. Hcm, ngy . thng . nm 2012
Gio vin hng dn
TH.S NGUYN VN THNH
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NHN XT CA GIO VIN DUYT
. Tp. Hcm, ngy . thng . nm 2012
Gio vin duyt
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LI NI U
Trong s nghip cng nghip ho v hin i ho t nc, cc ngnh cng nghip
k thut ng vai tr ht sc quan trng, trong ngnh cng nghip vt liu cht do
l mt trong nhng ngnh gi vai tr quan trng trong nn kinh t quc dn. Ngy
nay, trn th gii cng nh Vit Nam, nhu cu cc sn phm cht do trong k thut
cng nh trong dn dng ngy cng tng. Da trn c s khoa hc k thut cng
ngh, thnh tu v s pht trin mnh m ca ngnh vt liu Polymer, cc nh sn
xut cht do a ra th trng mt s lng ln cht do phong ph v chng loi,
c nhiu tnh cht v ng dng khc nhau v c nhng u nhc im nht nh. Tnh
cht chung ca cht do l nh, bn, p, d gia cng, to c nhiu mu m a dng
hn, gi thnh r hn cc vt khc c cng cng dng cho nn n c tnh cht thay th
mt s vt liu truyn thng nh g, thp. Do s xut hin mt s lng ln cht do
nn hng lot sn phm c ngun gc cht do c sn xut v vt liu cht do rt
a dng v phong ph. Gi tr s dng ca loi sn phm ny xm nhp vo mi
lnh vc ca nn kinh t v trong dn dng. Nhu cu v cht lng ca sn phm cng
nh ng dng ca n ngy cng tng. Hin nay, vn cht lng v a ra ng dng
ca loi vt liu ny mt cch rng ri trong ton nn cng nghip v dn dng l vn
quan trng v cn thit. Cht lng v gi thnh chnh l yu t quyt nh n kh
nng cnh tranh ca cc doanh nghip sn xut v gia cng. Vic xc nh nhu cu th
trng cn phi tm hiu trc. c s phong ph v a dng, cht lng cao ca
sn phm trn th trng cn phi c hng lot cc phng php cng ngh, my mc,
thit b, dy truyn,... Gia cng cht do ngy cng hon thin v ci tin vi s ng
dng ca khoa hc hin i nh in t, tin hc... nng cao sn xut, cht lng v
gim gi thnh sn phm l nhng yu t k thut phi gn lin vi yu t kinh t.
nc ta, ngnh cng nghip sn xut v gia cng vt liu cht do bt u pht trin.
Dn a ra th trng nhiu sn phm phong ph v a dng, cht lng v phc
tp ca sn phm ngy cng hon thin hn. my mc v thit b hin nay ngy cng
c ci tin. Trong tng lai ngnh cng nghip cht do c xu hng ngy cng
pht trin. Nu c chin lc pht trin lu di th ngnh cng nghip cht do ca
nc ta s c rt nhiu trin vng.
thc hin c nhng yu cu pht trin th cng ngh tnh ton thit k v
ch to ra cc loi my p phun nha ang l mt nhu cu cp thit cn phi c
gii quyt, o to v chuyn giao m khng ai khc chnh l nhng nhim v ca
cc k s Cng Ngh Ch To My phi m nhim.
gp phn nh b ca mnh vo cng cuc pht trin ca ngnh cng nghip
cht do ca Vit Nam. Sau mt thi gian tm hiu v di s hng dn tn tnh ca
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Thy Nguyn Vn Thnh. Em chn ti Thit k my p nha 250 tn" lm
ti cho lun n tt nghip.
Do kin thc cn hn hp nn trong qu trnh thit k v tnh ton em khng trnh
khi nhng sai st do thiu thc t v kinh nghim thit k nn em rt mong c s
hng dn ch bo ca cc thy em c th cng c v hon thin kin thc ca
mnh khi bc vo thc t sn xut trong tng lai.
Em xin by t lng bit n su sc ti Thy Nguyn Vn Thnh tn tnh hng
dn, du dt em trong sut qu trnh thc hin lun n tt nghip ny. Nhn y, em
cng xin chn thnh cm n cc thy, cc c trong khoa C Kh cng ton th cc
thy cc c trong trng i Hc Bch Khoa Thnh Ph H Ch Minh trong sut thi
gian qua dy d em thnh ngi c tri thc c th cng hin v phc v x hi
trong tng lai.
TPHCM, Ngy 19 Thng 12 Nm 2012
Sinh vin thc hin
Nguyn Tun Huy
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MC LC
LI NI U ...................................................................................................... 1
MC LC............................................................................................................. 3
Chng 1. TNG QUAN MY P NHA ...................................................... 5
1.1. Thc trng v xu hng s dng my p phun hin nay: ......................... 5
1.2. Gii thiu cng ngh p phun: ................................................................ 7
1.2.1. Cng ngh p phun: .......................................................................... 7
1.2.2. Nhu cu thc t v hiu qu kinh t ca cng ngh p phun: ............ 7
1.2.3. Kh nng cng ngh: ........................................................................ 7
1.2.4. Phn loi my p phun: .................................................................... 8
1.3. Cc b phn c bn ca my: .................................................................. 8
1.3.1. H thng h tr p phun: .................................................................. 8
1.3.2. H thng phun: ................................................................................. 9
1.3.3. H thng kp: ................................................................................. 13
1.3.4. H thng khun: ............................................................................. 15
1.3.5. H thng iu khin: ...................................................................... 16
Chng 2. PHN TCH V CHN PHNG N THIT K ...................... 18
2.1. Kh nng ng dng my p phun ti cc cng ty Vit Nam: .............. 18
2.2. Chn ng c in v bm thy lc cho h thng my p: ................... 18
2.2.1. Chn ng c in: ........................................................................ 18
2.2.2. Chn bm thy lc: ........................................................................ 19
2.3. Chn ng c to chuyn ng quay cho trc vis:................................. 21
2.4. Phn tch u nhc im cc phng n thit k: ................................. 21
2.4.1. Phng n 1: .................................................................................. 21
2.4.2. Phng n 2: .................................................................................. 23
2.4.3. Phng n 3: .................................................................................. 24
2.4.4. Phng n 4: .................................................................................. 26
2.5. Chn phng n thit k v nguyn l hot ng ca phng n: .......... 27
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Chng 3. TNH TON - THIT K MY P NHA 250 TN .................. 30
3.1. Cc thng s c bn ca my: ............................................................... 30
3.2. Tnh ton h thng phun: ...................................................................... 32
3.2.1. Tnh ton chn bm v ng c in cho my: ............................... 32
3.2.2. Tnh ton chon ng c du lm quay trc vis: ............................... 39
3.2.3. Tnh ton cho b phn cp nhit: .................................................... 42
3.2.4. Tnh ton xylanh y i phun v b dy xylanh bm nha:........... 45
3.3. Tnh ton h thng kp:......................................................................... 47
3.3.1. H thng c hc cm kp: .............................................................. 47
3.3.2. H thng thy lc cm kp: ............................................................ 58
3.4. Cc b phn ph trong my p nha: .................................................... 60
3.4.1. B phn tip liu: ........................................................................... 60
3.4.2. B phn iu chnh dy khun: .................................................. 61
3.4.3. Cnh tay robot ly sn phm: ......................................................... 62
3.4.4. Thanh dn trt: ............................................................................. 63
3.5. Kim nghim bn un cho cc tm km: .......................................... 63
Chng 4. VN HNH V BO DNG H THNG ............................... 67
4.1. Hng dn s dng bng iu khin vn hnh my p phun: ................ 67
4.2. Yu cu trong vic vn hnh h thng: .................................................. 69
4.2.1. Yu cu v lp rp: ......................................................................... 69
4.2.2. Qui trnh khi ng ban u: .......................................................... 71
4.3. Bo dng h thng: ............................................................................. 72
PH LC ............................................................................................................ 75
KT LUN ......................................................................................................... 78
TI LIU THAM KHO ................................................................................... 79
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Chng 1. TNG QUAN MY P NHA
1.1. Thc trng v xu hng s dng my p phun hin nay:
Trn th gii hin nay c nhiu cng ty ch to my p phun phc v cho ngnh
cng nghip p cc sn phm v nha nh cc gia dng, cc loi chai l m phm,
chai l y t, chai l thc phmTuy nhin tnh a dng trong khu thit k cc my
ny cha c, v l do nhu cu s dng cc mt hng ny khng nhiu. Nn a s cc
cng ty chuyn sn xut my p lun sn xut theo n t hng ca i tc. iu ny
dn n thc trng nc ta cha c cng ty no thit k v ch to ra my p hon
chnh. Do kinh nghim cng nh cng ngh l cha , m cc cng ty ch yu l
phn phi li sn phm ca cc cng ty nc ngoi hoc nhn n t hng ti Vit
Nam ri a v cng ty chnh ch to.
Qua tm hiu cc cng ty chuyn sn xut v ch to my p phun ch yu tp
trung nhng nc c nn cng nghip pht trin mnh nh M c cng ty Denison,
ti n c cng ty Velan, cng ty Chuan Lih Fa ca i Loan, cng ty YUKEN ca
i Loan chuyn cung cp cc loi van v bm thy lc kh nn, cng ty Krauss
Maffei ca c. Ti Vit Nam c cng ty c phn Cng Ngh Qunh, cng ty T.A.T
ti TP HCM, cng ty Long Qun ti H Ni l cc cng ty chuyn v phn phi, lp
t, thit k, t vn h thng thy lc kh nn hng u ti Vit Nam.
Di y l mt s loi my p phun ang c s dng phc v cho ngnh nha
ti Vit Nam.
Hnh 1.1: My p phun JSW - Nht
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Hnh 1.2: My p phun Krauss Maffei - c
Hnh 1.3: My p phun CLF - i Loan
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1.2. Gii thiu cng ngh p phun:
1.2.1. Cng ngh p phun:
Mt cch n gin nht, cng ngh p phun l qu trnh phun nha nng chy in
y lng khun. Mt 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 mt phn ng ha hc no.
1.2.2. Nhu cu thc t v hiu qu kinh t ca cng ngh p phun:
Bng cch quan st thng thng nht, chng ta c th thy c rt nhiu sn phm
nha xung quanh chng ta. T cc sn phm n gin l dng c hc tp nh: thc,
bt, compa hay chi tr emcho n nhng sn phm phc tp nh: bn, gh, v
tivi hay cc chi tit dng trong t v xe myu c lm bng nha. Hu ht cc
sn phm ny c hnh dng v mu sc rt phong ph v chng gp phn lm cho
cuc sng ca chng ta tr nn p v tin nghi hn. iu ny ng ngha vi vic
sn phm nha m phn ln c to ra bng cng ngh p phun tr thnh mt
phn khng th thiu trong cuc sng chng ta. Vi cc tnh cht nh: do dai,
nh, c th ti ch, khng c nhng phn ng ha hc vi khng kh trong iu kin
bnh thng.Vt liu nha thay th cc loi vt liu khc nh: st, nhm, gang,
ng thauang ngy cng cn kit trong t nhin. Do ta c th ni rng nhu cu
s dng vt liu nha trong tng lai s cn rt ln. iu ny a n hiu qu l gi
thnh khun s khng s khng c cho l qu t bi li nhun m n mang li l
rt ln v t mt khun p phun ta c th cho ra hng chc thm ch hng trm ngn
sn phm nh my p nha.
Tm li, nhu cu v sn phm nha ca con ngi l mi mi cho n khi no
ngi ta c th tm c vt liu khc c nhng c tnh tng t v tt hn c th
thay th cho nha. Tuy nhin, song song vi nhu cu y, iu chng ta cn quan tm
thm na l phi s dng nha mt cch hp l nht trnh nhng h ly khng tt
cho mi trng.
1.2.3. Kh nng cng ngh:
+ To ra nhng sn phm c hnh dng phc tp ty .
+ Trn cng mt sn phm hnh dng gia mt trong v mt ngoi c th khc nhau (y l mt th mnh so vi cc cng ngh sn xut nha khc).
+ Kh nng t ng ha v chi tit c tnh lp li cao.
+ Sn phm sau khi p phun c mu sc rt phong ph v nhn bng b mt cao nn khng cn gia cng li.
+ Ph hp cho sn xut hng khi v n chic (trong trng hp c bit).
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1.2.4. Phn loi my p phun:
a. Phn loi my p phun theo kt cu:
- Theo lc ng khun: 50 10000 tn.
- Theo kh nng mt ln phun ti a.
- Theo kiu c cu cu to phun.
- Theo kiu trc vt.
- Theo kiu b tr b phn phun.
b. Phn loi my p phun theo qu trnh pht trin:
- My p phun piston.
- My p phun c trc do ha s b.
- My p phun trc vis
1.3. Cc b phn c bn ca my:
My p phun gm cc b phn c bn sau y :
H thng h tr phun p phun.
H thng phun.
H thng kp.
H thng khun.
H thng iu khin.
1.3.1. H thng h tr p phun:
L h thng gip vn hnh p phun, h thng ny bao gm:
- Thn my (Frame)
- H thng in (Electrical system)
- H thng thu lc (Hydraulic system)
- H thng lm ngui (Cooling system)
Hnh 1.4: H thng h tr p phun
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Thn my: Lin kt cc h thng trn my li vi nhau.
H thng thy lc: Cung cp lc ng, m khun, to ra v duy tr lc kp
lm cho trc vt quay, chuyn ng ti lui. To lc cho cht y v s trt
cho li mt bn. H thng ny bao gm bm, valve, motor, h thng ng, thng
cha nhin liu.
H thng in: Cp ngun cho motor in v h thng iu khin cho khoang
cha vt liu nh cc bng gia nhit, m bo s an ton in cho ngi vn
hnh my bng cc cng tc. H thng ny gm t in v h thng dy dn.
H thng lm ngui: Cung cp nc hay dung dch ethyleneglycol. lm
ngui khun, du thy lc v ngn khng cho nha th cung phu b nng
chy th phn nha th pha trn kh chy vo khoang cha liu. Nhit trao i
cho du thy lc vo khong 90-120 F. B iu khin nhit nc cung cp 1
lng nhit, p sut, dng chy thch hp lm nha nng trong khun.
1.3.2. H thng phun:
H thng phun lm nhim v a nha vo khun thng qua h thng cp nha,
nn, kh kh, gia nhit lm chy do nha trong xilanh, to lc p dng nha nng
chy vo trong khun. Di chuyn c,c p lc p cht vo khun khng x
u l. 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).
- Van mt chiu (Non-return-assembly).
- Vi phun (Nozzle).
Hnh 1.5: H thng phun
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Cc b phn chi tit ca h thng phun:
a. Phu cp liu (Hopper): Cha vt liu dng vin cp cho khoang trn.
b. Khoang cha liu (Barrel): L ng bao quanh trc vis, xung quanh c bao
bi cc bng in tr (Heater band) chia thnh cc vng iu khin ring tng
ng vi cc vng trn trc vis. 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. Nhit xung quanh khoang cha liu cung cp
t 20% n 30% nhit cn thit lm chy lng vt liu nha.
c. Cc bng gia nhit (heater band): Gip duy tr nhit khoang cha liu
nha bn trong lun trng thi do.
d. Trc vt (screw): C chc nng nn, lm chy do v to p lc y nha
chy do vo lng khun
+ Nm trong nng.
+ L b phn np liu, ha do v y nguyn vt liu trong nng vo khun.
+ C kh nng trn nng chy tt, t lm sch nhanh.
+ C nhiu loi thit k khc nhau ty vo loi nguyn liu.
Trc vt c cu to gm 3 vng: Vng cp liu, vng nn, v vng nh lng.
+ C chiu di / ng knh = 1220 (LS= 20 D).
+ C ng knh v bc ren khng i sut chiu di.
+ T s nn t hF/ hM = 2,2; 2,5(t s nn cng cao th gia cng cng d).
+ Trn trc vis c chia lm 3 vng phn bit
Hnh 1.6: Cu to trc vt
Vng cp liu (feed zone): Vng gn phu cp liu nht, chim khong 50%
chiu di hot ng ca trc vt (c ti liu cho l 60%) v c chc nng lm
cho vt liu c li thnh khi v chuyn vt liu qua vng nn. Chiu su ca
cc cnh vt vng ny l ln nht v hu nh khng i.
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Vng nn p (transition zone): Chim khong 25% chiu di hot ng ca
trc vt (c ti liu cho l 20%). vng ny, ng knh ngoi ca trc vt
khng i nhng chiu su cc cch vt thay i nh dn t vng cp liu n
cui vng nh lng. Chnh nh cu to c bit ny m cc cch vt lm cho
nha b nn cht vo thnh trong ca khoang cha liu, iu ny to ra nhit
ma st. Nhit ma st ny cung cp khong 70 n 80% lng nhit cn thit
lm chy do vt liu.
Vng nh lng (metering zone): Chim khong 25% chiu di hot ng ca
trc vt (c ti liu cho l 20%), c chc nng cung cp nhit vt liu
chy do mt cch ng nht v lm bn vt liu chy do vo khun qua
cung phun. Chiu su cnh vt vng ny l b nht v hu nh khng i.
nh gi c kh nng lm chy do vt liu ca trc vt cao hay thp
ngi ta da vo hai thng s chnh l: L/D v Df/Dm. T l L/D nh nht l
20:1, t l Df/Dm thng l 3:1; 2,5:1 v 2:1.
Thng s thit k trc vt tiu chun:
ng knh vis
(mm)
Chiu su ren
np liu (mm)
Chiu su ren
nh lng (mm) T s nn
h so vi
xylanh (mm)
30 4.3 2.1 2 : 1 0.15
40 5.4 2.6 2.1 : 1 0.15
60 7.5 3.4 2.2 : 1 0.15
80 9.1 3.8 2.4 : 1 0.20
100 10.7 4.3 2.5 : 1 0.20
120 12 4.8 2.5 : 1 0.25
>120 Max 14 Max 5.6 Max 3 : 1 0.25
e. B t hi hay van mt chiu (Non-return-assembly): B phn ny gm c vng
chn hnh cn u trc vt n c chc nng to ra dng nha bn vo khun.
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Hnh 1.7: Van mt chiu
Khi trc vt li v th vng chn hnh nm di chuyn v hng vi phun v cho
php nha chy v u trc vt. Cn trc vt di chuyn v pha trc th vng chn
hnh nm s di chuyn v pha phu v ng kn vi seat khng cho nha chy v pha
sau.
f. Vi phun: C chc nng ni khoang trn vi cung phun v phi c hnh dng
m bo bt kn khoang trn v khun. Nhit vi phun nn c ci t
ln hn hoc bng nhit chy ca vt liu. 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 phn lm ca bc cung phun thng qua vi nh v m bo
nha khng b phun ra ngoi v trnh mt p.
C nhiu loi vi phun khc nhau, ty vo tng trng hp ng dng c th m ta dng loi vi phun no cho thch hp. Thng thng ngi ta quan tm n mt s thng s nh:
+ ng knh l ca u vi phun phi nh hn ng knh l ca bc cung phun mt cht (khong 0,125 - 0,75mm) cung phun d thot ra ngoi v trnh cn dng.
+ Chiu di ca vi phun nn di hn chiu su ca bc cung phun (to dng n nh trc khi vo bc cung phun).
+ cn ty thuc vo vt liu p phun.
Hnh 1.8: Vi phun
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1.3.3. 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 thot khi khun khi kt thc mt chu k p phun.
H thng ny gm:
+ Cm y ca my (Machine ejectors).
+ Cm km (Clamp cylinder).
+ Tm di ng (Movable platen)
+ Tm c nh (Station platen).
+ Trc dn hng (Tie bars).
Hnh 1.9: H thng kp
Cc b phn trong h thng kp:
a. Cm y (Machine ejection): Gm xy lanh thy lc, tm y v cn y.
Chng c chc nng to ra lc y tc ng vo tm y trn khun y sn
phm ra khi khun.
b. Cm km (Clamp cylinders): Thng c 2 loi chnh l loi dng c cu khuu
v loi dung cc xylanh thy lc. H thng ny c chc nng cung cp lc
ng m khun v lc gi khun (km khun) ng trong sut qu trnh
phun.
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Hnh 1.10: H thng kp khun
u nhc im ca cm km dng xylanh thy lc v c cu khuu:
Loi km u im Nhc im
Xylanh thy lc
- Lp t khun nhanh.
- Bit r p sut km.
- D bo dng.
- t lm vng tm khun.
-Lc km tp trung vo gia tm khun.
- Cn lng ln du thy lc
- Tn nhiu nng lng.
- Chu nh hng bi h s
nn ca du.
C cu khuu
- Gi thnh thp.
- Di chuyn c cu km nhanh.
- T hm gim va p.
- Cn bo dng thng
xuyn
- Lc km khng tp trung
vo gia tm khun.
- Kh iu chnh.
c. Tm di ng (Movable platen): L 1 tm thp ln vi b mt c nhiu l thng
vi tm di ng ca khun. Chnh nh cc l thng ny m cn y c th tc
ng lc vo tm y trn khun. Ngoi ra trn 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.
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Page | 15
Hnh 1.11: Tm di ng v v tr ca n trn my p phun
d. Tm c nh (Stationary platen): Cng l 1 tm thp ln c nhiu l thng vi
tm c nh ca khun. Ngoi 4 l dn hng v cc l c ren kp tm c
nh ca khun tng t nh tm di ng, tm c nh cn c th l vng nh
v nh v tm c nh ca khun v m bo s thng hng gia cn y v
cm phun (vi phun v bc cung phun).
e. Trc dn hng (Tie bars): C kh nng co gin chng li p sut phun khi
km to lc. Ngoi ra chng cn c tc dng dn hng cho tm di ng.
Hnh 1.12: Trc dn hng
1.3.4. H thng khun:
Sau qu trnh nha ha, nha nng chy c phun vo khun, lc p khun phi
ln ng khun ti khi no nha ngui v ng rn sau khun c m
ly sn phm
-
Page | 16
Cu to gm:
- Hai tht c nh v 1 tht di ng m khun.
- Trc dn hng 4 trc hnh tr song song.
- Xilanh kha khun: To lc ng m khun.
- Xilanh thy lc n sn phm ra.
- B phn iu chnh b dy khun: Dn ng bng motor in hoc thy lc.
- Ca an ton ca trc v ca sau.
Cu to chung ca h thng khun bao gm cc b phn sau:
Hnh 1.13: Cu to chung ca khun
1.3.5. H thng iu khin:
H thng iu khin gip ngi vn hnh my theo di v iu chnh cc thng s
gia cng nh: nhit , p sut, tc phun, vn tc v v tr ca trc vt, v tr ca cc
b phn trong h thng thy lc. Qu trnh iu khin c nh hng trc tip n cht
-
Page | 17
lng sau cng ca sn phm v hiu qu kinh t ca qu trnh. H thng iu khin
giao tip vi ngi vn hnh my qua bng nt iu khin (Control Panel) v mn
hnh my tnh (Computer screen).
Bn trong h thng iu khin l 1 b vi x l cc rle, cng tc hnh trnh, cc b
phn iu khin nhit , p sut, thi gian..
Bng iu khin: Gm cc cng tc v nt nhn dung vn hnh my. Mt bng
iu khin in hnh gm c nt nhn iu khin bm thy lc, nt nhn tt ngun
in hay dng khn cp v cc cng tc iu khin bng tay.
Mn hnh my tnh: Cho php nhp cc thng s gia cng trnh by cc d liu ca
qu trnh p phun, cng nh cc tn hiu bo ng v cc thng ip.
Hnh 1.14: Mn hnh my tnh
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Page | 18
Chng 2. PHN TCH V CHN PHNG N THIT K
2.1. Kh nng ng dng my p phun ti cc cng ty Vit Nam:
Vi s cch tranh trn th trng hin nay, yu cu mi cng ty mun tn ti u
phi lun i mi v cng ngh sn xut, iu dn n cn c s u t trang
thit b my mc hin i s dng cng ngh mi vo sn xut.
Tuy nhin khng phi bt c cng ty no u c th thay i cng ngh mt cch
d dng m cn ph thuc tim nng kinh t v chin lc sn xut ca cng ty.
Vit Nam cc cng ty nha ang dn pht trin l do cc vt dng trong nh ni ring
v cc dng c s dng cho cng nghip ni chung u nha ha bi v sn phm
nha to ra c tnh nng bn, r, v nh nn d s dng. Nn my p phun s l la
chn hng u ca cc cng ty sn xut cc sn phm bng nha.
2.2. Chn ng c in v bm thy lc cho h thng my p:
2.2.1. Chn ng c in:
ng c in l thit b in c hc gip chuyn in nng thnh c nng. C
nng ny c s dng quay bnh cng tc ca bm. Do tnh cht lm vic ca
my p phun nn ta chn ng c in xoay chiu (AC).
Thng dng nht l ng c khng ng b 3 pha v chng c thit k n gin, r
tin v d bo tr, c th ni trc tip vi ngun xoay chiu v c s dng hu ht
trong h thng cng nghip hin nay.
Hnh 2.1: ng c khng ng b 3 pha
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Page | 19
2.2.2. Chn bm thy lc:
Chn bm cho my p da vo bng phn tch sau y:
Bm bnh rng Bm cnh gt Bm piston
Tnh
cht
-Bm bnh rng c
dng rng ri nht.
- Phm vi p sut s dng
ca bm bnh rng hin
nay c th t 10 ti 200
bar (ph thuc vo
chnh xc ch to).
-Trong nhng h thng
thy lc c p sut cao
bm bnh rng thng
c dng lm bm c s.
-Bm cnh gt c dng
rng ri sau bm bnh rng.
- Lu lng bm c th thay
i bng cch thay i
lch tm.
-Phm vi s dng trong h
thng cc my cng c.
-S cnh t 4 12 cnh.
-i vi bm cnh gt n,
p sut t c l 70 bar v
i vi bm cnh gt kp,
p sut t c l 175 bar.
- Qp t n 600 l/ph
-Bm piston c s
dng rng ri trong h
thng thy lc lm vic
p sut cao.
-p sut ln nht c th
t c l 700 bar.
-Bm piston thng dng
nhng h thng du p
cn p sut cao v lu
lng ln: My trut,
my xc, my nn.
u
im
-Kt cu n gin, trng
lng nh.
- tin cy cao, kch thc
nh gn.
-S vng quay v cng
sut trn 1 n v trng
lng ln.
-C kh nng chu qu ti
trong mt thi gian ngn.
-Gi thnh thp.
-So vi bm bnh rng, bm
cnh gt m bo mt lu
lng u hn, hiu sut th
tch cao hn.
-Lm vic t n.
-iu chnh c lu lng
-Gy nn lc hng knh
lch ( t khoang y).
-Gi thnh thp.
-C th iu chnh c
lu lng hoc lu lng
c nh.
-Bm piston c kh nng
lm kn tt hn so vi
bm cnh gt v bnh
rng.
-V b mt lm vic ca
c cu ny l mt tr, do
d dng t c
chnh xc gia cng cao,
bo m hiu sut th tch
tt, c kh nng thc hin
vi p sut lm vic cao.
Nhc
im
-S dng bm bnh rng
ch yu nhng h thng
c p sut nh, trung bnh
-Khng iu chnh c
lu lng v p sut khi s
vng quay c nh.
-Ch yu thng dng h
thng c p sut thp v
trung bnh.
-Yu cu vic lc cht lng
kht khe khi lm vic
-Gi thnh cao.
-Lm vic gy ting ng
ln do s va p ca cc
piston.
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Page | 20
Da vo tnh cht ca my p phun lm vic vi p sut cao nn ta chn bm
Piston thit k my p phun.
Bm piston l loi bm da trn nguyn tc thay i th tch ca c cu piston
xy lanh. C th ch to vi lu lng c nh hoc lu lng iu chnh c. Ph
thuc vo v tr ca piston i vi roto, c th phn bit chng thnh bm hng knh
v hng trc.
- Bm pittong hng knh:
Bm piston hng knh c cc piston chuyn ng hng tm vi trc quay
ca rto. Ty thuc vo s piston ta c lu lng khc nhau.
Hnh 2.2: Bm piston hng knh
- Bm hng trc:
Bm piston hng trc l loi bm c cc pittong t song song vi trc roto
v bm c truyn bng khp ni vi trc quay ca ng c in. Bm
Pittong hng trc c u im l kch thc nh gn v hu ht iu chnh
c lu lng nh gc nghing ca kt cu a nghing trong bm
Hnh 2.3: Kt cu ca bm piston hng trc
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Page | 21
2.3. Chn ng c to chuyn ng quay cho trc vis:
ng c du l loi ng c khc so vi bm thy lc mt im c bn l bin
i nng lng thnh ng nng to nn chuyn ng quay trn trc ng c.
Trc vt ca my p nha quay nh ng c in hoc 1 ng c thy lc c ni
vi b gim tc bnh rng. ng c truyn dn cho trc vt c th t gia piston thu
lc v trc vis hoc theo mt phng n b tr khc.
T ta chn ng c piston hoc mt ng c in da vo s tc quay ca
trc vis do c cu to chuyn ng quay ch l mt chuyn ng c s ca my cn
thit k.
2.4. Phn tch u nhc im cc phng n thit k:
Cc phng n thit k c a ra u da trn nhng ch tiu sau: Gi thnh,
kch thc ca my p, tin cy ca h thng, kh nng bo tr, h s an ton, ch s
kh nng sn sng
2.4.1. Phng n 1:
Hnh 2.4: S nguyn l phng n 1
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Page | 22
Hnh 2.5: Phng n thit k 1
y l phng n thit k vi 2 bm thy lc truyn nng lng du cho h thng
my. Vi phng n thit k ny th b phn phun v kp hot ng c do 2 bm
khc nhau.
Hin nay, phng n thit k ny rt t s dng v ch to trong hu ht cc loi
my p trn ton th gii.
u im:
- C th p c sn phm ln vi lc km ln.
- Hiu sut tt.
- Di chuyn c cu km nhanh.
- T hm gim va p.
Nhc im:
- Cng knh, tn ph ch to.
- Thit lp h thng iu khin phc tp, do hot ng c gia c cu kp &
phun nn kh iu chnh bng iu khin.
- Bo dng nh k thng xuyn.
- Cn mt lng du rt ln.
- Lm vic n o v my bm phi lun hot ng vi nng sut ti a.
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Page | 23
2.4.2. Phng n 2:
Hnh 2.6: S nguyn l phng n 2
Hnh 2.7: Phng n thit k 2
y l dng my p phun trc vis vi c cu kp khun bng trc khuu, hot
ng vi 1 bm piston duy nht do ng c in khng ng b 3 pha cp vo
chy bm, bm du t b cha du ra h thng van iu khin ton b h thng my
thng qua bng iu khin trn mn hnh.
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Page | 24
Hu ht my p phun hin nay c ch to theo phng n ny nh my CHUAN
LIH FA ca i Loan v my JWS ca Nht.
Thit b phun trc vis hot ng vi vis quay ho do nha v khuy trn nha
cho u nh 1 ng c du, chuyn ng tnh tin nh xylanh piston phun nha
nng chy vo khun.
u im:
- Kh nng khuy trn tt do trc vis hot ng va tnh tin va quay, nhit
nng chy phn b u hn phng n 4 l dng c cu xylanh Piston
do ha nha.
- C th ch to c nhng my c lc km ln.
- c s dng rng ri hin nay trong hu ht cc c s sn xut nha Vit
Nam.
- Gi thnh thp.
- Di chuyn c cu km nhanh.
- T hm gim va p.
Nhc im:
- Phi thng xuyn bo dng nh k.
- Lm vic n o v my bm phi lun hot ng vi nng sut ti a.
- Lc km khng tp trung vo gia tm khun.
- Kh iu chnh.
2.4.3. Phng n 3:
Hnh 2.8: S nguyn l phng n 3
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Page | 25
Hnh 2.9: Phng n thit k 3
Vi phng n ny th hot ng c hc ca my khng khc g my p phng
n 2 nhng khc mt im c bn l c cu kp khun phng n ny l c cu
xylanh piston trc tip vo tm ng ( Moving platen ).
Hin nay my p loi ny, Krauss Maffei Germany cung cp ch to my p
thy lc loi ny trn ton th gii.
u im:
- Hiu sut tt hn so vi cc phng n khc do lc kp khun tp trung
gia.
- Lm vic t n hn so vi my trc khuu.
- Cht lng sn phm tt.
- Lp t khun nhanh.
- Bit r p sut km.
- D bo dng.
- t lm vng tm khun.
Nhc im:
- Kt cu my cng knh, trng lng my rt ln.
- Gi thnh cao.
- Lm vic nhit thp khong 25C th my s chy n nh.
- Cn lng ln du thy lc nn tn nhiu nng lng.
- Chu nh hng bi h s nn ca du.
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Page | 26
2.4.4. Phng n 4:
Hnh 2.10: S nguyn l phng n 4
Hnh 2.11: Phng n thit k 4
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Page | 27
Nguyn l hot ng ca phng n 4 ch yu bng h thng thy lc. Lm nng
chy nha bng cch cp nhit t thnh, y nha bng piston thu lc.
B tr mt bm thy lc cng vi mt ng c in khng ng b ba pha ging
phng n 2 v phng n 3.
y l thit b c phun n cp piston (single stage plunger), phng n ra i
sm nht nn cn nhiu hn ch cho kh nng ng dng ngy nay, t c chn so vi
cc phng n trc
u im:
- Gi thnh r.
- Kt cu gn nh, khng cng knh, hot ng n gin.
- Dng ch yu cho sn phm nh, p sut lm vic thp nn c th s dng
bm cnh gt hoc bm bnh rng.
Nhc im:
- Lng nha phun nh (
-
Page | 28
a. 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 li hon ton (khng xy ra ting ng ln). Khi
khun ang ng cng l p lc km rt ln c to ra chng li p lc 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 p c to ra chc chn
s gp khuyt tt.
Hnh 2.12: Din bin giai on kp
b. 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 trong lng khun s 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 s co rt cho ti khi ming phun ng cng li. Qu trnh ny ngn khng
cho dng chy ngc ca nha qua ming phun.
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Page | 29
Hnh 2.13: Giai on p phun
c. 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 cng, c th y
ri khi khun. Trong sut qu trnh ny trc vt vn quay v li li cho ln phun k
tip. Thi gian tiu tn trong giai on ny ph thuc vo lng nha m ta p.
d. 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 li y sn phm ca my y v pha trc
sn phm rt ra ngoi khi khun. Khi sn phm ri ra khi khun th cn y s
hi v chun b cho chu trnh k tip.
Hnh 2.14: Giai on y
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Page | 30
Chng 3. TNH TON - THIT K MY P NHA 250 TN
3.1. Cc thng s c bn ca my:
Th tch phun:
y l thng s quan trng nht ca my, n quyt nh kch thc ca my v cc
c tnh cng ngh ca my. Th tch phun ca my cng ln th nng lng tiu tn
cng ln v kch thc ca my cng ln.
Thng s ny coi l thng s d liu. Hin tn ti cc my p phun c th tch c
t 2 30.000cm3. My p phun thng hay s dng nht l loi my c th tch 6,
125, 250, 500 cm3.
Tc phun:
Thng s ny cn c m bo l ti u, sao cho trong qu trnh in y
khun no khng cng (c ngha vi vn tc khng c qu nh) v ng thi
cng khng qu ln xy ra hin tng phn hu vt liu do ma st. Tc phun
c n v (cm3/s).
Vic iu chnh tc phun t gi tr cc i ti gi tr ti u c thc hin
bng cch thay i lu lng cht lng trong h thng thu lc.
Tc phun ph thuc ch yu vo th tch phun ca my.
p lc phun:
p lc phun c n nh khi my hot ng. N c xc nh trong tng
trng hp c th c th tnh n kt cu khun, tnh cht ca vt liu v nhit gia
cng.
p lc phun nh hng n cht lng v tch cht ca chi tit.
p lc cn thit in y khun, ph thuc vo thi gian phun. p lc phun
cao c s dung khi sn xut chi tit c thnh mng v vt liu c nht cao. Song
cng cn lu rng p lc tao hinh (p lc phun) m nh n ta nhn c sn phm
tt th khng cao. Phn ln cc trng hp p lc vo khong 2500 5000 N/cm3.
Thng s p lc ca my thng l p lc ln nht.
Din tch p:
L hnh chiu b mt chi tit ln mt khun theo phng tc dng ca lc p. Din
tch p ca cc sn phm khc nhau c gia cng trn cc my c th tch phun danh
ngha xc nh th khc nhau.
Din tch p c xc nh cho loi chi tit ring bit v n l mt trong nhng
thng s c bn c my c phun. Thng s ny c nh hng ti lc kp khun,
kch thc khun kh bn kp v tip theo l chi s kinh t k thut ca my.
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Page | 31
Khi xc nh thng s ny cn tnh n nh hng ca n ti kh nng s dng
rng ri ca my sn xut cc chi tit khc nhau c cng trng lng v nh hng
n ch s cng ngh k thut ca my.
Tng din tch p l tng tnh tng hp ca my c thit k, song ch nh
hng xu ti ch tiu kinh t k thut ca my.
Bn kp:
Bn kp c nh hng r rt ti trng lng ca my. Trng lng ca tm ph
thuc vo cu trc (c, hn, ) ca bn kp, vo s phn b v cu trc l kp, vo
di lng ca l trung tm.
Khun c kp trn bn nh cc l ren hoc cc rnh dc ch T hoc cc phng
tin khc nhau phn b trn bn kp.
Rnh ch T to s thun tin nht cho vic kp khun, ng thi gim c kch
thc khun. Song s c mt ca n lm cho tm phi tng b dy ln 40 50 mm v
do vy tng lng tm nht l i vi cc my ln. Chnh v vy phn ln cc trng
hp bn kp s dng dng tm hn, c l kp, c ren. i vi my khng ln th
phng n bn kp phi hp gia rnh kp v l ren l cch gii quyt tt nht. L
kp thng phn gia bn kp cn phn rnh kep th vng bin bn kp.
Kt cu b phn kp khun ca my c phn bit theo s trc v s b tr
ca n. i vi my c th tch p khng ln thng c hai tr phn b theo
phng ngang hoc cho. Trn my ln hn thng c bn ci.
Lc kp khun:
Lc kp khun ca my c xc nh bi din tch p v s phn b p lc
trong khun. Lc kp khun c th tnh gn ng theo biu thc:
P = po. S (N )
Nhn xt vi s tng din tch p lm xut hin kh nng tng lc kp khun.
Lc kp khun quyt nh n kt cu ca b phn kp ca my.
Gi tr lc kp khun ph thuc vo cng ngh c, tch cht ca vt liu v
nhiu yu t khc ca qu trnh p. Lm vic trn my c lc kp khun nh c th
thu nhn chi tit c cht lng tt vi iu kin ch cng ngh c bit v trnh
sn xut cao.
Khong cch gia cc tm kp v hnh trnh ca tm ng:
Hai thng s ny ph thuc vo mt hng ca sn phm p. Khong cch ln
nht gia hai bn kp khun v hnh trnh bn di ng s quyt nh n chiu cao
khun v tip in chiu cao sn phm c th thu nhn c trn my p phun
cho.
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Page | 32
i lng khong cch c th iu chnh c gia hai bn kp quyt nh n
chiu cao ca khun p t trn n. Khong cch ny c th iu chnh trong mt
gii hn rng, c chn trong tng loi my. Vi gi tr ti u ca khong iu
chnh trng lng khun s gim, d dng cho vic vn hnh, gim bt s cn thit
phi s dng nhng phn thm c bit trong khun.
Vt liu cht do c cho vo phu nh lng v cp liu t trn xylanh ca
my i vo rnh vt nm trong xi lanh. Do chuyn ng quay ca trc vt vt liu
c dch chuyn ln pha trc v pha vi phun, trong sut qu trnh vt liu
tip nhn nhit t xylanh do cc nhn t cung cp ( hi nng in tr,in t ).
Nh c nhit lng v nhit sinh ra do qu trnh chuyn ng c hc ca vt
liu nng chy. Vt liu nng chy c trc vt chuyn ln pha trc nh p lc
c hnh thnh trong qu trnh quay lm cho n b ko li v pha sau . Nh vy
lng vt liu cn thit in y khoang to hnh ca khun s tp kt khong
trng pha trc trc vt. Trong qu trnh in y khun, trc vt thc hin chuyn
ng dc trc v pha trc v y khi vt liu nng chy qua vi phun vo
khun. Vt liu c lm ngui trong khun tr nn ng cng, sau hai na
khun c m ra th sn phm c y ra ngoi.
3.2. Tnh ton h thng phun:
Yu cu tnh ton a ra l thit k my p cho sn phm c th tch vt p chn
theo tiu chun l 500 cm3, [1 trang 145]
Ta c cng thc: Fc(tn) = P . A [6 trang 6 ]
Trong :
- A l din tch hnh chiu b mt ca sn phm theo phng lc p (cm2)
- Fc l c kp ca my (Tn hoc KN), Fc = 250 Ton
- P l p sut gy nn trong khoang do vt liu gy nn, chn vt liu l nha
Polypropylen (PP) c P = 250 kg/cm2.
Thay vo cng thc: Fc(tn) = 250 . A
A = 1000 cm2 Tng din tch hnh chiu ca sn phm A = 1000 cm2 ph hp vi my 250 Tn.
3.2.1. Tnh ton chn bm v ng c in cho my:
xc nh c ng knh xylanh bm nha, phi xut pht t iu kin m
bo th tch c ca my. Th tch cha ca xylanh bm nha c xc nh theo
cng thc sau:
V = K1 . V [1 trang 156]
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Page | 33
Trong :
- K1 = 1,25 1,3 : H s cha.
- V: Th tch phun (cm3). Thc t, ngi ta thng ch to my vi n v th
tch vt p theo dy s V = 8, 16, 32, 64, 125, 250, 500, 1000 cm3
Thay vo cng thc: V = 1,25 . 500 = 625 cm3.
Mt khc th tch cha vt liu ca xylanh bm nha cn c xc nh bi cng
thc [1 trang 156]:
=
4 . . = .
4.
Trong : H Hnh trnh piston y trc vis (mm)
D ng knh xylanh bm nha (mm)
K2 H s hnh trnh, K2 = 2 3
Cn bng 2 phng trnh tnh th tch xylanh bm nha, ta c:
= 4. .
.
6,4
Tra bng thng s thit k trc vt tiu chun chng 1. Ta chn ng knh trc
vt D = 60 mm, vi h gia xylanh bm nha v trc vt th = 0,15 mm, t s nn
Hf/Hm = 2,2:1
Do , hnh trnh xylanh bm nha: H =
. =
.
. 22,11 cm
Vy ta chn hnh trnh ca trc vt: H = 4.D = 24 cm. [1 trang 157].
Vy th tch cha vt liu ti a ca xylanh bm nha thc t:
=
4 . 6. 24 = 679
p sut ln nht trong xylanh phun nha l P = 1800 (kg/cm2), [1 trang 145].
Do cng sut phun nha vo khun c xc nh nh sau :
N = .
=
.
. (KW)
-
Page | 34
Trong : V Th tch sn phm (cm3).
t Thi gian phun = 3s.
Lu lng nha vo khun: Q =
=
= 226 cm3/s
Tc phun di: v =
=
.
=
.
= 80 mm/s
N = .
. =
. . .
. = 41 (KW)
Vy cng sut phun nha vo khun : N = 41 KW
Cc thng s quan trng v trc vis:
Hnh 3.1: Trc vt
- ng knh trc vis DTV = 6 cm
- Chiu di trc vis L = 20.D = 120 cm
Chiu di vng np liu L1 = 50%.L = 60 cm
Chiu di vng nn L2 = 25%.L = 30 cm
Chiu di vng nh lng L3 = 25%.L = 30 cm
S vng quay: n = ..
. . () (vng/pht) [1 trang 159]
-
Page | 35
Trong :
- D: ng knh trc vis (cm)
- : Gc ma st gia vt liu v trc vis . Tan = f = 0,28 = 15,64
- : Gc nghing ca cnh vis. Tan =
. [1 trang 159]
Vi t = ( 0,8 1).D = 0,9 . 6 = 5,4 cm
= 16
Vy n = ..
. . () =
., .
. . (,)
= 57 vng/pht
Chn n = 57 vng/pht
Vi n = 57 vg/ph, ph hp s vng quay trc vis 48 181 vg/ph, [2 trang 63].
- B dy cnh vis e = 0,1 . D = 0,6 cm = 6 mm
- Khe h gia trc vt v xylanh bm nha: = 0,15 mm.
- Tc ha do 30 kg/h.
Cng sut tiu hao lm quay trc vt xc nh bi cng thc [1 trang 159]:
Pt = 0,736.C.Dm
Trong : m = 2,5 s m thc nghim v C = 0,15 0,2, C h s
Pt = 0,736 . 0,2 . 62,5 = 13 KW Momen xon trn trc vt :
= 9,55. 10.
= 9,55. 10.
13
57= 2178
Tnh ton b phn thy lc tnh tin trc vis:
C cu chp hnh b xylanh-piston t cui my lm nhim v to chuyn ng
tnh tin cho trc vt cng vi ng c du lm quay trc vis to nn p sut cho qu
trnh phun nha vo khun. Qu trnh tnh ton chn xylanh to chuyn ng tnh tin
cho trc vt sao cho tha mn cng sut bm theo [9 trang 7].
Chn theo tiu chun ng knh xylanh, [5 trang 140].
Chn 3 phng n cho b xylanh piston l:
= 14 = 9
, = 16 = 10
v = 18 = 11
-
Page | 36
Phng n 1: = 14
= 9.
Hnh 3.2: S p sut cm phun
Ta c cng thc [3 trang 134]:
ATV . P2 = Axylanh . P1
P1 = .
=
..
. =
..
. 330,6 bar
Phng n 2: = 16 = 10
Tnh ton tng t:
Pl = .
=
..
. =
..
. 253 bar
Phng n 3: = 18 = 11
Tnh ton tng t:
Pl = .
=
..
. =
..
. = 200 bar
T ba phng n chn xylanh thy lc nh trn, ta chn s b phng n 2.
thu gn kch thc cng nh cng knh, ta s dng cp xylanh tnh tin b tr song
song xylanh bm nha. T chn ra c bm thy lc cho ton h thng my vi
p sut va phi tit kim chi ph v ph hp vi my c th tch c 500 cm3.
Theo phng n 2 va c chn, ta tnh c tit din mt ct t bng 16 cm
i vi my loi c.
chiu di my c thu gn, ta b tr 2 dn xylanh song song to chuyn ng
tnh tin cho trc vis, tra [5 trang 140] ta chn cp xylanh vi sai = 22 = 14
.
-
Page | 37
Theo cng thc : Qtl = .
.
. [1 trang 160]
Qtl = ..
. = 1608,5 cm3/s = 96,5 (l/ph).
Cng sut cn thit ca b phn thy lc xylanh piston: Ntl = .
, Kw
Vy cng sut thy lc cn thit: Ntl = .
=
, .
= 41 Kw.
T phng n c chn ta c:
ng knh xylanh to chuyn ng tnh tin D = 22 cm
p sut lm vic t ti xylanh P = 253 bar
chn bm cho ton h thng thy lc ca my, ta da vo ni p sut lm vic
cao nht trong cc cm ca my p phun. p sut lm vic ln nht chnh l cm
phun, ni quan trng nht ca my p.
chn c bm ph hp cho my p 250 tn, ta phi tnh c tn tht p sut
ln nht ca h thng. Tnh ton s b tn tht p sut da vo phn mm Pipe flow
wizard.
Chn ng knh trong ng dn 25 mm, vt liu lm ng l thp khng g, chiu
di tng th ng ng L = 7 m, cao ni t bm so vi b phn lm vic h = 2 m,
s on un cong, s lng van thy lc trong h thng, lu lng Q = 96,5 l/ph v
loi du s dng cho h thng.
Hnh 3.3: Tn tht p sut
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Page | 38
T , ta tnh s b tn tht p sut: P 4 bar .
Vy chn bm sao cho p sut ca bm ln hn tng p sut t ti c cu lm
vic v tn hao p sut: Pp > P + P = 253 + 4 = 257 bar
Nhn xt my 250 tn l my c lc kp mc trung bnh so vi cc my loi ln
khc, theo [7 trang 1] ca hng YUKEN th bm n loi A ph hp vi my ang
thit k.
Da vo [7 trang 27], chn bm loi A70 p sut lm vic ti a Pmax = 280 bar
v lng iu chnh t 32 bar, lu lng ring Dp = 70 cm3/vng, s vng quay
n = 600 1800 vg/ph, hiu sut th tch
= 0,92; lm vic nhit 0 60.
Lu lng ca bm Qp =
. Dp . n = 0,92 . 70 . 1500 = 96,6 (l/ph).
Cng sut bm Np = .
=
, .
= 45 Kw.
Tha iu kin [9 trang 7], do ta chn phng n 2 hp l.
Do , th tch thng du V = (3 5).Qp = 483 (lit)
Chn thng du V = 500 lt
Ngoi ra ta c th tra th hnh 3.4, cc thng s c bn ca bm do hng
YUKEN cung cp [7 trang 42].
Hnh 3.4: th bm
Do , tnh ton s b bm cn thit cho my 250 tn v chn bm cho my da
vo th rt ph hp.
T ta chn ng c in c cng sut N =
,, = 56,25 70 (Kw).
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Page | 39
3.2.2. Tnh ton chon ng c du lm quay trc vis:
truyn chuyn ng quay cho trc vt, ng c du phi thng qua mt hp tc
c t s truyn ph hp vi tnh ton cc thng s ca trc vis trn.
Tnh ton v chn hp gim tc trn my p:
Ta s dng hp gim tc n gin l hp gim tc bnh rng tr.
Hp gim tc bnh rng tr c s dng rng ri hn c nh cc u im: Tui
th v hiu sut cao, kt cu n gin, c th s dng trong mt phm vi rng ca vn
tc v ti trng.
- Hp gim tc bnh rng tr mt cp: c s dng khi t s truyn i 7 8
(nu dng bnh rng tr rng thng th i 5).
Hnh 3.5: Hp gim tc bnh rng tr mt cp
- Hp gim tc bnh rng tr hai cp: c s dng nhiu nht, t s truyn
chung ca hp gim tc thng bng t 8 40. Chng c b tr theo 3 s
: S khai trin, s phn i v s ng trc. Ta chn s khai
trin v hp gim tc kiu ny n gin nht v c s dng nhiu nht trong
thc t. Tuy nhin, n vn c nhc im l cc bnh rng b tr khng i
xng vi cc , do lm tng s phn b khng u ti trng ln chiu di
rng, kh nng chy mn ca bnh rng km.
Hnh 3.6: Hp gim tc bnh rng tr hai cp khai trin
-
Page | 40
Tuy nhin vi kt cu ca cc hp gim tc va nu khng c tnh i xng d
dng thit k b nng v di trt trong qu trnh p phun nn ta khng chn cc loi
hp gim tc thng thng. d dng trong vic thit k b nng di trt trong qu
trnh p, ta s dng hp gim tc c bit bnh rng hnh tinh va c c tnh i xng
v nh hn hp gim tc thng thng rt nhiu nhng vn m bo t s truyn hp
l v c chn trong hu ht cc my p nha ang s dng hin nay.
Hp gim tc bnh rng hnh tinh c thit k khi trc vo v ra ca hp ng
trc vi nhau, vi rt nhiu phng n phn b theo [14 trang 35].
Vi u im vt tri so vi cc phng n phn b bnh rng khc, ta chn hp
gim tc phng n (hnh 3.7) ti cng ty VAICO.
Hnh 3.7: Hp gim tc bnh rng hnh tinh
Trong bnh rng Z1, Z3, Z5 l cc bnh trung tm vi bnh rng Z3 c nh,
bnh rng Z2, Z4 l cc bnh v tinh v cn 0. Hp gim tc loi ny c th t c t
s truyn t 20 200, s bnh v tinh c = 3 v hiu sut = 0,7 0,9. Yu cu t ra l chn mt hp tc sao cho trc cng tc truyn chuyn ng
quay cho trc vis thng qua khp ni tha mn s vng quay trn trc cng tc m
bo n 57 vg/ph.
Tnh ton chn ng c du lm quay trc vis:
Cc yu cu chn ng c: P P , n n
ng c m ta s dng y l ng c piston hng knh vi s piston l 5.
Z3
0
Z1
Z2
Z5
Z4
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Page | 41
Hnh 3.8: ng c piston hnh sao
Tra bng 3.1 [2 trang 63], cng sut ca ng c c gi tr 15 33 Kw ng vi
ng knh trc vis 60 mm, t c th chn ra ng c du thch hp lm quay cho
trc vis.
c im ca hp gim tc bnh rng hnh tinh phn b nh hnh 3.6 c t s
truyn t t u = 20 200.
Chn s b usb = 20 tnh ton chn mua cho ph hp.
S vng quay trn trc vo ca hp gim tc n1 = usb . n5 = 20 . 57 = 1140 vg/ph
Tra [8 trang 4], chn ng c du MR93 vi cc thng s sau:
- S vng quay ndc = 1150 vg/ph
- Lu lng ring Dm = 93 cm3/vg
- Cng sut P = 33,5 HP = 25 KW
- Trng lng m = 83,78 lb = 38 kg
- p sut lm vic Pm = 3626 Psi = 3626 . 0,0629 = 228 (bar)
Ta c hiu sut quy nh theo [14 trang 35], = 0,7 0,9:
=
=
13
25= 0,52 < 0,7 0,9
Hiu sut lm vic qu thp
Do ta phi chn li t s truyn, cng sut v s vng quay ph hp.
Chn usb = 22, do ta tnh c n1 = usb . n5 = 22 . 57 = 1254 vg/ph.
-
Page | 42
Tra [8 trang 4], chn ng c du MR57 vi cc thng s sau:
- Lu lng ring Dm = 57 cm3/vg.
- p sut lm vic Pm = 3626 Psi = 3626 . 0,0629 = 228 (bar)
- S vng quay trn trc ng c ndc = 1300(vg/ph)
- Cng sut lm vic 22,8 HP = 17 Kw
- Trng lng m = 66,14 lb = 30 kg.
Ta c:
=
=
13
17= 0,75
Hiu sut lm vic tha mn = 0,7 0,9
Vy ng c du MR57 ph hp cho my.
B qua hiu sut ng c du, ta c lu lng ng c Qm = Dm . nm
Trong :
Dm Lu lng ring ng c (cm3/vg)
nm s vng quay trn trc ng c (vg/ph)
Lu lng motor Qm = Dm.nm = 57.1300 = 74100 (cm3/ph) = 76,95 l/ph.
3.2.3. Tnh ton cho b phn cp nhit:
B phn cp nhit trong my p phun l cc bng gia nhit c b tr hng
phu cp liu v dc trn thnh xylanh bm nha. Thng thng trn cc my p
phun, s lng bng gia nhit lun lun ln hn hoc bng 4 bng dc trn thnh,
c gi l s vng nhit ca my.
Song song vi vic nung nng, trnh hin tng qu nhit so vi nhit chy
ra ca vt liu nha, ta lp rp thm h thng lm ngui xung quanh xylanh bm
nha, c th lm ngui bng nc.
Ta chn bng gia nhit loi MBH serial (hnh 3.9)
-
Page | 43
Hnh 3.9: Bng gia nhit TEMCO
Nhit lng do cc bng gia nhit to ra c tnh bng cng thc:
Q = K. V. . c. (t t).
, [1 trang 161]
Trong :
- K1 : H s k n lng d, K1 = 1,2 1,3.
- V : Th tch vt c, V = 650 cm3
- : Khi lng ring ca vt liu = 0,9 0,91 kg/cm3
- c : nhit dung ring ca vt liu nha PP, c = 1700 1900 W/kg.
- tc & t : Nhit cui v u ca vt liu ,
t = 10 80
tc = 220 235
- tck : Chu k p phun , giy
Tnh ton chu k p phun:
Chu k p phun l thi gian hon thnh 1 ln p c tnh bng cng thc:
Tck = Tk + Tp + Tl + Tln + Tmk (s)
Trong :
Tk Thi gian ng khun, Tk = 5s
Tp Thi gian phun in y sn phm vo khun, Tp = 3s
Tl thi gian li trc vis, Tl = 4s
Tmk Thi gian m khun v y sn phm, Tmk = 6s
Tln Thi gian lm ngui.
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Page | 44
Hnh 3.10: Chu k p phun mt sn phm
Thi gian lm ngui ph thuc b dy sn phm c tnh theo cng thc:
=
. ln
8
.
Trong : h s khuch tn nhit, 10-7 (m2/s)
h B dy sn phm, h = 2 mm
TE nhit ca li y sn phm, TE 100C
TM Nhit chy lng ca vt liu, TM 170C
Tv Nhit nc gii nhit. Thp hn nhit khun 10 20C
tc =
.ln
.
=
(. )
.ln
.
5s
Tck = Tk + Tp + Tl + Tln + Tmk = 5 + 3 + 4 + 6 + 5 = 23s
Vy nhit lng do cc bng gia nhit to ra:
Q = K. V. . c. (t t).1
t= 679 . 0,91. 10 . 1800 . (235 20).
1
23
10,5 KW
Do ta s dng 5 vng nhit tng ng vi 5 vng bng gia nhit
-
Page | 45
Nhit lng ta ra ca mt vng bng:
=
5=
10,5
5= 2,1
T ta lm c s chn loi bng gia nhit ph hp vi tnh ton s b trn v
ng knh trong ca bng sao cho ti thiu phi bng ng knh ngoi ca xylanh
bm nha. Ta chn bng ca hng TEMCO theo ti liu [17] sao cho loi c nhit
lng ln hn gn nht gi tr 2,1 KW, do loi bng BCH00068 c thng s sau:
- ng knh trong d = 158,8 mm
- B rng B = 152 mm
- Nhit lng = 2430 W.
- Mt nhit = 5,1 W/cm2
- S dng cho ngun 240 Vn.
Vy nhit lng thc t cc bng ta ra: Q = 2430 . 5 = 12,15 Kw
3.2.4. Tnh ton xylanh y i phun v b dy xylanh bm nha:
Tnh ton xylanh y i phun:
Do i phun nha c y trt trn hai rnh, thun li cho qu trnh y
v d b tr xylanh trn my. Ta b tr mt xylanh nm di xylanh bm nha ca
i phun nha.
Khi lng ca i phun nha ta c th c lng l m = 3,5 tn. Khi trt
trn hai rnh, s c ma st gia hai b mt ca i phun nha v b mt m n
trt nn. H s ma st gia hai b mt vi nhau ta c th ly f = 0,3
Lc cn tc dng y i phun nha cn phi ln hn lc ma st
F N.f = 3500.0,3 = 1050 kg
ng knh ca xylanh y i:
4.
.
Trong : - P l lc cn thit y i phun nha.
- p l p lc du a vo trong xylanh, p = 253 bar
4.1050
. 253= 5,29 ()
Chn ng knh ca xylanh y i theo tiu chun: D = 6 (cm)
-
Page | 46
Do xylanh y i lm vic c lp vi cc ch khc. Trong khi xylanh y
i lm vic th cc b phn khc khng lm vic. Do cng sut v lu lng
ca bm cung cp cho xylanh lm vic. Hnh trnh ca piston th tu thuc
vo cu to ca my.
Tnh ton cho b dy thnh xylanh bm nha:
Thc cht, xylanh bm nha l mt ng dy c t c nh tn mt gi .
Xylanh bm nha l chi tit chu p lc ln, chu mi mn v chu nhit, c lm
bng thp c gii hn bn b > 700 MPa, nhit luyn t cng > 60HRC. Vt
liu ca xylanh phi c thit k ch to sao cho m bo yu cu v bn mi,
chng mn v bn c hc. Do , ngi ta thng ch to xylanh bm nha
bng thp hp kim, bn cao v b mt lm vic thng c thm Nit.
Hnh 3.11: Xylanh bm nha
B dy ca thnh xylanh bm nha c tnh da vo thuyt bn ng sut tip
ln nht th ta c iu kin bn, [11 trang 326 ].
=2.
. []
Trong :
- td l ng sut tng ng (N/mm2)
- b l bn knh ngoi ca xilanh (mm)
- a l bn knh trong ca xilanh (mm)
- p p sut tc dng vo thnh trong ca ng
- [] l ng sut cho php (N/mm2). Ta chn thp ch to l thp
40XH nn [] = 310 420(N/mm2), [10 trang 392 ].
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Page | 47
Do suy ra:
[]
.
[]
2
Thay cc s liu vo ta c:
[]
.
[]
2
=
. 30
2
= 79,37 ()= 7,937 ()
Ta chn theo tiu chun ng knh ngoi xylanh bm nha: D = 160 cm.
Ph hp cho ng knh bng gia nhit chn trn D = 158,8 mm.
Chiu dy ca thnh xylanh bm nha:
t = b - a = 80 30 = 50 (mm)
3.3. Tnh ton h thng kp:
3.3.1. H thng c hc cm kp:
Tnh ton cho c cu trc khuu:
Hnh 3.12: C cu kp khun bng h thng thy lc trc khuu kp
Da vo hnh 3.12, ta c s (hnh 3.13) nguyn l sau y:
-
Page | 48
Hnh 3.13: S nguyn l trc khuu
Trong : Khu 1 l khu c nh (Tm ).
Khu 5 l khu ch ng (Cn piston).
Cc khu 2,3,4 l cc khu dn (Tng ng l cc thanh truyn).
Khu 6 l khu b ng (Tm ng).
Nguyn l hot ng ca c cu trn:
Khi khu ch ng 5 chuyn ng tnh tin ra vo tc ng vo cc khu dn l 2,
3, 4 truyn chuyn ng tnh tin ra vo cho khu b ng 6, thc hin qu trnh ng
m khun.
thc hin kt ni gia cc khu, ta s dng khp bn l to cc khu quay
quanh khp chuyn ng thnh mt qu tch l cung trn, trong cc khu trn th khu
dn l khu 2.
Khi lc gi khun t n mc cn thit th lc nn tc dng vo cc khu theo s
phn tch lc (hnh 3.14):
3 61 2 4
5
-
Page | 49
Hnh 3.14: S phn tch lc ln cc khu
Gi T2 l lc nn trn tay n phi, T2 c tnh theo biu thc sau :
=
2. ()
Phng trnh cn bng nt C ca cc tay n c vit nh sau:
T3.cos3 T1.sin1 T2.sin2 = 0
T3.sin3 + T1.cos1 T2.cos2 = 0
Nhn phng trnh trn vi sin3 v phng trnh di vi cos3 ta c:
T3.cos 3sin 3 T1.sin 1sin 3 T2.sin 2sin 3 = 0
T3.sin 3cos 3+ T1.cos 1cos 3 T2.cos 2cos 3 = 0
Tr hai phng trnh ny cho nhau v bin i rt gn ta c:
= .cos ( + )
cos ( )
Nh vy ta bit T1 v T2 ta tnh c T3 nh sau:
=.. + .
cos
T l gia 2 tay n AC : CB = 0,5 1 [1 trang 174]
1 =22 = 3 (3 5) [1 trang 176]
Vy ta chn: AC : CB = 0,75 v 1 = 4
a 1 a 2
a 3
T2
T3
T1 P/2C
D
bD
P/2
AB
T2
T1
T3
-
Page | 50
Cn bng cho nt D ta tnh c lc y ca piston thu lc T4 l:
T4 = 2T3.sin3
H s tng lc ca c cu tay n: K=
[1 trang 176]
Sau khi thay cc gi tr ca P v T4 vo v rt gn ta c kt qu sau :
=
tan . ()
() +
Thay 1 = 4 vo biu thc trn ta tnh c K 137 ln
Qua h s K = 137 ln, ta thy kh nng tng lc ca h thng tay n ny l rt
ln, do c th tit kim c nng lng cho h thng thu lc rt nhiu v lm
gim kch thc ca cc phn t thu lc trong my.
Trc khuu kp c chn trong lun vn ny dng tng lc kp h tr cho xylanh
thy lc pha sau tm lm nhim v y tm ng c gi mt na khun (khun
ng) p st vo na khun cn li (khun tnh) kt hp qu trnh phun thc hin
qui trnh p phun to ra sn phm. S dng c cu trc khuu kt hp vi h thng
thy lc nhm mc ch to ra c lc kp khun ln v ph hp vi cc my thng
dng hin nay.
i vi my 250 tn, tra bng [9 trang 7], dy khun c gi tr nm trong
khong 200 600 mm. Chn dy khun ln nht Hk = 600 mm.
Khong dch chuyn tm ng L = m . Hk [1 trang 164] Vi m H s dch chuyn , m = 0,8 1,2
L = (0,8 1,2) . Hk = 1 . 600 = 600 (mm)
Vy khong dch chuyn ca tm ng ln nht: L = 600 mm.
T ta c c s tnh ton cho trc khuu (hnh 3.15):
-
Page | 51
Hnh 3.15: S tnh ton trc khuu
Trn s tnh ton trn, ta c qung ng di chuyn ca tm ng l
600mm, tay n tri AC, tay n phi CB, hnh trnh ca Piston thy lc L,
khong cch ln nht ca AB lc kp khun L1, khong cch AB lc m khun
ti a L2.
Xt ti v tr ang kp khun:
Ti v tr ny c cu kp trng thi gin ti a. Lc ny CB v AB to vi
nhau mt gc l 1, AC v AB to vi nhau mt gc l 2
L1 = CB.cos 2 + AC.cos 1= AC.(
.cos 2 + cos 1 )
Xt ti v tr my ang m khun vi lng m ln nht 600 mm:
Ti v tr ny ta coi gc 2 ang m cc i, mt khc gc 2 cc i khi tam
gic ABC l tam gic vung ti A.
C BA
C
BA
D
O
a 1 a 2
L1
600
L2
L
D
b
a 3
I
I
O
-
Page | 52
= = =
= .
1 = AC.
L1 - L2 = AC.(
.cos 2 + cos 1 ) - AC.
= 600
AC = 414,32 mm Vy ta chn tay n tri AC = 400 mm v tay n phi CB = 500 mm, do thc t
tay n AC ch sp s vung gc vi AB.
xc nh chiu di khu CD, da vo hnh v ta tnh nh sau:
2= + . + .
= + . 4+ . 4
400= + . 4+ 400. 4
Do khu OD l con trt nn ta chn OD = 125 mm, thay vo biu thc trn:
CD = 247,8 mm Ta chn chiu di khu dn trt CD = 250 mm.
Do , ta xc nh c chiu di on IA:
IA = = 250 125 = 216,5 ()
Chn chiu di on IA = 220 mm.
Vy kt qu tnh ton cho trc khuu:
- Chiu di khu dn chnh AC = 400 mm.
- Chiu di khu dn trc CB = 500 mm.
- Chiu di khu dn trt CD = 250 mm.
- Chiu di con trt = 250 mm.
- Chiu di IA = 220 mm.
- Hnh trnh ca Piston:
L = IA + AC.cos1 CD.sin3
= 220 + 400.cos4 250.sin4 600 (mm)
Do khi lc kp khun l cc i th cc khu dn chnh v khu dn trc chu
lc tc dng l T1 v T2 :
22
250125 tn
2 os 2. os2
PT
c c
Trong :
- T2 l lc tc dng vo khu dn trc
- P l lc kp khun
-
Page | 53
Tng din tch mt ct ngang ca khu dn trc:
22
n
TF
Trong :
F l tng din tch cc mt ct ngang
[n] l ng sut nn cho php
Thp ch to l thp C45 nn [n] = 19 25(kg/mm2),[10 trang 392].
Thay cc s liu vo cng thc trn ta c :
32 22.125.10 13158( ) 131,6( )
19F mm cm
Nhn trn s ca my ta thy khu dn trc gm 6 thanh .Vy din tch ca
mi thanh:
S F / 6 = 125 : 6 22 (cm2)
Vy ta chn din tch ca mi thanh S = 50 cm2.
Tng din tch mt ct ngang ca khu dn chnh: F
[]
Ta c lc tc dng ln khu dn chnh T1 :
2 3
1 2
1 3
os( + ) os(2+4). 125. 124
cos( - ) cos(4 - 4)
c cT T
(tn)
Thay cc s liu vo ta c: F
[]=
..
[] 131 cm
Khu dn chnh gm 8 thanh, nn din tch ca mi thanh:
F F
n=
131
8= 16,5 cm
Vy ta chn din tch mi thanh S = 40 cm2.
Tng din tch mt ct ngang ca khu dn trt: F
[]
Lc tc dng m khu dn trt phi chu:
1 1 2 23
3
.sin sin
os
T TT
c
-
Page | 54
Thay s vo cng thc trn ta c:
2
124.sin 4 125sin 213,05
os4T
c
(tn)
Tng din tch ca khu dn trt:
32 23
2. 2.13,05.101373,7( ) 13,74(cm )
19n
TF mm
Nhn trn s ca my th khu dn trt gm 3 thanh, nn din tch ca mi
thanh: 213, 74
4,6( )3
FF cm
n
Vy ta chn din tch mi thanh dn trt S = 20 cm2.
Lu :
Din tch ca con trt ta ly bng din tch ca khu dn trt v c hai thanh
nm ng song song vi nhau, c ni trc tip vi cn Piston y trc khuu.
Vi cc gi tr tnh ton v chn cho trc khuu p ng iu kin bn do
cc ng sut v cc va p gy nn trong qu trnh lm vic.
Do ta chn din tch cc thanh ca trc khuu ln hn din tch tnh ton rt
nhiu b cho sai s tnh ton v tng tui th lm vic lu di cho my, tn
chi ph bo tr cho trc khuu.
Tnh ton cho trc dn hng v cc tm thp:
Trc dn hng:
Khi lm vic cc trc dn hng chu lc b ko nn iu kin bn ca n c
tnh bng cng thc sau:
K kc
P
F
[1 trang 174]
Trong :
- k l ng sut ko xut hin khi lm vic
- [k] l ng sut ko cho php ca vt liu lm trc
- P l lc kp khun, P = 250 tn
- Fc l tng din tch mt ct ngang ca cc trc dn hng
-
Page | 55
Din tch ca mt trc: C kP
Fn
Vi n l s trc chu lc, thng th trong my p phun s trc l n = 4.
bn ko thp C45: [k] = 200 (N/mm2) [10 trang 392]
Thay cc s liu vo ta c:
4
2 2250.10 3125( ) 31, 25 cm4.200
CF mm
Cc tr u l hnh tr nn ng knh ca mt ct ngang:
4. 4.31, 25
6,31 cmF
D
V u trc phi tin ren iu chnh dy ca khun v khun c dy
khc nhau.V khi chuyn ng th tm ng lun trt trn trc nn ng knh
ngoi nhng ch c ren phi bng ng knh ca nhng ch khng c ren , do
ng knh m ta va tnh l ng knh ca chn ren. Do ng knh ngoi
ca trc dn hng c tnh bng cng thc:
D =D
0,85
Trong : - D l ng knh ngoi ca trc
- Dcr l ng knh ca chn ren
Do ng knh ngoi trc dn hng:
D =6,31
0,85= 7,4 (cm)
Ta chn ng knh ngoi ca trc: D = 8 (cm)
Cc tm thp (tm di ng v tm c nh):
Tm di ng:
Ngy nay, hu nh cc tm c ch to c hnh dng l hnh vung v c lp
ngay sau tm (hnh 3.16):
-
Page | 56
Hnh 3.16: Tm ng
Gi H l kch thc tm ng, h l khong cch gia 2 trc dn hng
Da vo tnh ton ban u phn trc khuu, ta c:
b = 2 . AC = 2 . 400 = 800 (mm) = 80 (cm)
Vy ta ch to bng km c kch thc 90 x 90 (cm) l ph hp.
Ta c cng thc sau:
= 2 2
v t = (1/2 1) . D
Vy khong cch gia 2 trc dn hng h = 90 2.8 2.(1/2 1).8 = 62 (cm).
Tm tnh:
Tm tnh l mt khi c tit din hnh vung nm pha cm phun, gia tm l
mt l trn i phun tin st u bc vo v phun nha vo trong khun c c
nh trn tm tnh (hnh 3.17):
Cc gi tr K & M l cc gi tr tnh c do lng d phn bc ca tm tnh
lp c nh trn bn my. Do ta chn K = 1000 mm v M = 960 mm.
h
H
4xR
t
-
Page | 57
Hnh 3.17: Tm tnh
Tnh ton dy cho cc bng km:
Trong qu trnh lm vic cc bng km chu tc ng ca cc ni lc v ngoi lc,
v th ta phi ch to sao cho p ng c bn ca n lm vic tt trong mt
thi gia di.
Trong thc t, ngi ta ch to sao cho b dy cc tm bng 25% chiu cao hoc
b rng tm , [13 trang 200].
- Tm tnh: B dy = 900 . 25% = 225 (mm).
- Tm ng: B dy = 900 . 25% = 225 (mm).
- Tm : B dy = 900 . 25% = 225 (mm).
Hu nh trng lng ca cc tm km chim gn 50% trng lng my. Do ta
tnh c trng lng ca cc tm theo cng thc:
M = V . , (kg)
Trong : - V l th tch cc tm , m3
- l khi lng ring thp ch to tm. Thp C45 = 7850 kg / m3.
Khi lng cc tm: M = 0,9 . 0,9 . 0,225 . 7850 = 1430,66 (kg).
Do , ta tnh c tng trng lng cc tm:
= 3.1430,66 = 4292 = 4,292
h
H
4xR
t
K
M
-
Page | 58
3.3.2. H thng thy lc cm kp:
H thng y trc khuu:
Ta c h thng khuu tng lc cho xylanh thy lc K = 137 ln.
Do lc tc dng vo cn piston: T4 =
=
.
= 18467,2 (N)
Mt khc, ta c cng thc [1 trang 177]:
[]
Din tch ca cn Piston tc ng vo con trt:
[]=
18467,2
20 9,234 ()
Do ta tnh c ng knh ca cn piston:
4.
=
4.9,234
= 3,43 ()
Vy ng knh cn piston chn theo tiu chun d = 3,6 cm
Tra [5 trang 140], ta chn ng knh xylanh tiu chun D = 6,3 cm.
Lu lng du trong xylanh y trc khuu:
Q =. D. L
T=
. 6,3. 60
5= 3014 (cm/s) 90 (l/ph)
H thng y sn phm:
Qu trnh y sn phm l qu trnh cui cng ca chu k p phun. cho t
ng ho hon ton cho qu trnh to ra sn phm, ta phi thit k thm h thng
xilanh y sn phm, lm cho qu trnh ly sn phm c d dng hn v nng
cao nng sut ca qu trnh sn xut.
Do my ch tao c nhiu sn phm khc nhau, nn mi sm phm s c ch
y ra khi khun l khc nhau. Tu vo tng sn phm v vt liu lm sn
phm. Trn u ca piston y sn phm ta b tr cc ti li. Khi piston chuyn
ng s y ti li vo sn phm v y sn phm ra khi lng khun.
-
Page | 59
Nh ni trn lc y v ch y sn phm mi sn phm l khc
nhau nn y ta tnh lc y ca sn phm l ln nht v tu thuc vo tng sn
phm c th m ta c th iu chnh cho ph hp.
Lc y sn phm cn thit l P = 5 tn, thun tin trong b tr my v thun
tin cho qu trnh lm vic ca c cu. i vi xylanh y sn phm ta dng mt
xylanh v c lp ngay sau tm ng ca b phn kp khun.
ng knh ca xylanh y sn phm:
4.
.
PD
p
Trong : - P l lc cn y sn phm, P = 5 tn
- p l p lc du a vo trong xilanh, p = 200 bar
Thay cc s liu trn vo ta c:
4.50005, 64( )
.200D cm
Ta ly ng knh ca xylanh y sn phm l D = 6,3 (cm)
Hnh trnh li do xylanh y sn phm tc ng H = 150 mm. Do , ta tnh
c lu lng ca xylanh y sn phm trong 2 giy:
=.
3.4. =
. 6,3
2.4. 15 30 (
).
Hnh trnh li y sn phm c th iu chnh c nh bng iu khin ty
thuc vo khong m khun ng vi tng loi khun. (Hnh 3.18) m t mt s
loi li y kt hp vi xylanh ly sn phm ra khi khun.
Hnh 3.18: Mt s loi cht y dng li sn phm
-
Page | 60
3.4. Cc b phn ph trong my p nha:
3.4.1. B phn tip liu:
B phn tip liu l b phn c nhin v nh lng nguyn liu np vo my. Ty
theo tnh cht ca nguyn liu m chn c cu tip liu.
Nguyn liu dng ht th c kh nng ri d dng nn ngi ta dng b phn tip
liu trc tip l phu y hnh cn (hnh 3.19).
Chiu di ca tip liu ly ln hn ng knh xylanh L = (2,5 5).D
Gc y cn ca phu ly t 60 80.
Hnh 3.19: Phu tip liu trc tip dng ht
i vi nguyn liu dng bt nh, kh nng t ri km nn trong khi tip liu d
sinh ra hm ch th dung c cu tip liu c cnh o, thng gn cc cnh o trn
trc quay thng ng (hnh 3.20). ng c in (1) quay thng qua hp gim tc (2)
lm cho trc (3) quay. Khi trc quay cc cnh (4) s gt vt liu ri xung ri vo
xylanh ca my c. Hp gim tc thng dung kiu hnh tinh v n gn v c t s
truyn ln, c th t i = 50.
D
55
a
485,88
L
-
Page | 61
Hnh 3.20: C cu tip liu dng bt
3.4.2. B phn iu chnh dy khun:
dy khun i vi my p 250 tn c gi tr 200 600 mm. lm cng vic
ny, ngi ta ch to thm c cu hp bnh rng nm cui my, vi b truy vt me
ai c c thit k, nhm bin chuyn ng quay thnh chuyn ng tnh tin ca
bnh rng truyn ng (hnh 3.21).
B truyn vt me ai c lm vic theo nguyn l n khp ca cp ren (gia ren
trong trn ai c vi ren ngoi trn vt me) bin chuyn ng quay thnh chuyn
ng tnh tin.
V th cui on trc dn hng, ta ch tao sao cho tnh cht ca n tng t vt
me vi on ren di cui trc. Chuyn ng quay l do bnh rng ch ng truyn
ng vo ai c lp trn trc dn hng, khi bnh rng quay truyn n b truyn vt
me ai c to nn chuyn ng tnh tin y tm ra vo ty vo dy khun m
ta mun iu chnh.
D
1
2
3
4
-
Page | 62
Hnh 3.21: C cu iu chnh dy khun
3.4.3. Cnh tay robot ly sn phm:
Cnh tay robot l b phn t ng trong cc my p hin nay t ng ha hon
ton qu trnh sn xut (hnh 3.22).
Hnh 3.22: Cnh tay robot
-
Page | 63
3.4.4. Thanh dn trt:
Trong qu trnh chuyn ng ca tm ng khi thc hin qu trnh kp khun cng
nh khi tm chuyn ng tnh tin to nn b dy ng vi tng loi khun thay
i, chng ta phi cn mt thanh trt cho h thng kp khun.
V th ta s dng c cu thanh dn trt kiu ng ray ca hng (hnh 3.23). Vi
u im cc cao, gim ma st, chu ti trng ln, t mi mn. Ta b tr nm dc hai
thnh my p, c cu ny ta chn ca hng EITEC.
Hnh 3.23: C cu thanh dn trt
3.5. Kim nghim bn un cho cc tm km:
Trong sut qu trnh lm vic ca my p nha, b phn chu lc ln nht trong
my l cc tm km nm trn bn my. Do khi lng v kt cu cng knh nn ta
phi thit k sao cho m bo bn ca n trnh hin tng cong vnh v s
dng lu di, tn ph bo tr v cc tm km trng lng qu ln.
Hu nh trong qu trnh lm vic, cc tm chu lc tc dng rt ln to nn lc un
vi m hnh phn tch lc khi lc p ln nht khi hai na khun st nhau (hnh 3.24).
-
Page | 64
Hnh 3.24: M hnh phn tch lc ln cc tm lc cn bng
1 Tm ; 2 Tm ng ; 3 Tm tnh
thc hin vic kim tra bn cho cc tm, ta xem cc tm nh nhng dm t
trn 2 gi t do chu un (hnh 3.24)
Do cc tm hu nh thit k ging nhau, nn ta chn tm tnh kim nghim vi
s phn tch lc tc dng ln dm (hnh 3.25)
Hnh 3.25: S phn tch lc tc dng ln dm
T kt cu my ta c th biu din s (hnh 3.24) kim nghim bn ln dm.
Trong :
- Khong cch gia 2 trc dn hng = AD
- Chiu cao ti a i vi khun ca my =
. Chiu cao tm 600 mm.
Ta c: = 0
/ = 0
+ = 250 250.350= . 700
+ = 250
250.350= . 700
vA vD
A
B
D
C
-
Page | 65
= 125
= 125
T cc gi tr tnh c ta v biu dm cho tm tnh:
Biu lc ct:
Biu momen:
Da vo biu ta tm c tit din nguy him nht ca dm ngay trung im.
Do , ta cn tnh bn cho tm tnh vi moment un ln nht:
Mmax = 25000 (Tn.mm) = 25000.104 (N.mm)
Ta c cng thc kim nghim bn un theo [10 trang 146]:
=
[ ]
=
=
6.25000. 10 (. )
. [250]
=6.25000. 10 (. )
900. 225 33 [250]
Vy tm tnh ta thit k m bo c bn un vi lc p 250 tn.
-
Page | 66
Do cc tm c ttht k m bo c bn un trong sut qu trnh lm
vic.
Vic kim nghim bn cho cc tm km rt quan trng cho my p nha. Trng
hp khng bn s tn mt chi ph rt ln thay th mt bng km khc v trng
hp ny c m t qua (hnh 3.26).
Hnh 3.26: Bng km chu un
Kt lun: Sau khi thit k tnh ton xong my p nha 250 tn, d dng
thun tin cho nh sn xut, khch hng v ngi th ng my, ta lp mt
bng thng s k thut trn khung dn my. Cc thng s c th tra
cui thuyt minh vi my em va thit k v cc my hot ng trong thc
t ca cc dng my p nha trn ton th gii, ta c th tra cc ph lc.
-
Page | 67
Chng 4. VN HNH V BO DNG H THNG
4.1. Hng dn s dng bng iu khin vn hnh my p phun:
C 3 ch iu khin:
Bng tay: Dng nt n hoc dng bt/tt to ra cc chuyn ng c lp. Thc
hin cc chuyn ng.
- Quay trc vt
- Tin li trc vt, tin li cm do ha.
- ng m khun, y sn phm.
- iu chnh dy khun.
Bn t ng: Khi ng ca kp khun th my hot ng tun t cc
chuyn ng: Khun ng li phun nha - trc vt quay- khun m- y
sn phm-my dng. y l quy trnh cng ngh t sn, chu trnh ny ch
c lp li khi ca kp khun c m ra (ly sn phm)v ng li.
T ng hon ton: My chy t ng lin tc theo quy trnh cng ngh t
sn. Tn hiu cho chu trnh cng ngh tip theo l sn phm ri ra chy qua
b phn cm nhn (mt thn).
- Tn hiu iu khin (bt/tt): Bng in (tn hiu in).
+ Bt/tt: Ch bng tay
+ Cng tc hnh trnh cho ch t ng hay bn t ng.
- Mch iu khin: Mch rle, in t, vi in t c ci t sn chng
trnh.
H thng iu khin c tc dng lm cho qu trnh vn hnh my n nh v
lp i lp li. H thng hin th v iu khin cc thng s ca qu trnh p phun
nh: Nhit , p sut, tc phun, v tr v tc quay ca trc vt, v tr ca h
thng thu lc. Qu trnh iu khin nh hng trc tip n cht lng cui cng
ca sn phm v tnh kinh t.
Di y l cch s dng cc nt nhn trn bng iu khin:
-
Page | 68
S dng ln, xung, tri, hoc sang phi di chuyn n v tr mong mun la
chn v thay i p sut, tc , lu lng
- S dng 0 - 9 v mt du thp phn nhp gi tr thit lp s dng nhp chnh cho gi tr bt k thit lp. - S dng * la chn (c, khng c) mt trong mt s chc nng h tr.
S dng la chn tng loi hnh hot ng cho my p thun tin cho vic ci t my hay cho my chy t ng. C 3 loi hnh hot ng: Hot ng bng tay, bn t ng v t ng hon ton.
- Bm on/of - Nhit on/of
- S dng bt u & dng my bm. - S dng bt u & dng vic gia nhit.
- Mold adj: S dng iu chnh dy khun. - Inject: S dng vn hnh vic phun nha khi ta kch hot vn hnh bng tay ci t trong vic ln khun - Temp: iu chnh nhit Eject: S dng y sn phm ra khi khun.
-
Page | 69
- Mold close: iu khin ng khun. - Mold open: iu khin m khun.
- I.U FWD: iu khin dn i phun tin v pha trc. - I.U BWD: iu khin dn i phun li v pha sau.
- Door close: iu khin ng ca an ton. - Door open: iu khin m ca an ton.
FWD / BWD Screw RO Screw
- FWD / BWD Screw: iu khin trc vis tnh tin ti lui trong xylanh bm nha. - RO Screw: iu khin to chuyn ng quay cho trc vis n nha ra.
4.2. Yu cu trong vic vn hnh h thng:
4.2.1. Yu cu v lp rp:
1. iu quan trng nht phi tun th khi lp rp cc h thng thy lc l cng tc
v sinh sch s. Nhng h hng nghim trng c th xy ra rt nhanh chng trong h
thng, nu c nhng vt liu bn ngoi xm nhp vo h thng.
2. Lun lun lm kn tt c nhng khe h ca bnh cha sau khi v sinh bnh
cha. Chu k v sinh thay du mi phi l mt phn trong thi kha biu bo dng
h thng.
Mold close Mold open
I.U FWD I.U BWD
Door close Door open
-
Page | 70
3. Khi h thng thy lc c m ra, phi y hoc bt kn tt c cc cng ni
khng cho cht bn v khng kh m lt vo h thng. Phi lun lun gi chng bt
kn ngoi tr khi sa cha hoc lp rp.
4. Kim tra cc khp ni ca ng pipe, ng tube, ng mm, chc chn rng
khng c s hin din ca cu bn, ba v, vy cn v khng b co tht, c kha, c
ngn. Cc loi ng mm v ng tube phi c chp kn bng np cc u khi lu
tr.
5. Phi gi cc loi xng trng, cht ty ra trong nhng thng cha an ton.
6. S dng cc vi khng kh nn lm sch cc khp ni.
7. Doa li cc u ng pipe v ng tube trnh cc vt liu b chn qu nhiu s
lm hn ch dng chy hoc gy ra trng hp chy ri.
8. Khng s dng nhng khp ni p sut cao cc ng ng np bi v chng
c ng knh trong nh hn v c th lm hn ch dng chy.
9. Khng nn s dng hn in hoc ct gt ng ni h thng thy lc ang
tho rp sa cha.
10. Khng s dng nhng hn hp lm kn ng cc loi ren tr.
11. Khi s dng cc khp ni mm trn cc trc bm v ng c thy lc chng ta
phi thc hin nh sau:
- iu chnh cc na khp ni st vi nhau, lun lun phi trong khong 0.20
inch (5.08mm).
- Cho php c khe h khong 1/32 n 1/16 inch (0.79 n 1.59mm) gia cc
na khp ni, hoc thc hin theo s cho php ca nh ch to i vi cc khe h.
- Khng c ng cc khp ni vo trc. Cc khp ni phi lun lun c lp
trt hoc c lp p nng bng cch s dng du nng lp rp.
12. Bi m y vo cc rnh then, then trt lc lp rp tng tui th cho
chi tit.
13. Khi s dng cc khp ni vn nng kp lin kt, ch nn to ra gc quay
theo mt hng.
14. Khi lp rp cc chi tit trong h thng, phi ph mt lp du thy lc vo chi
tit tng s bi trn ban u, cho n khi h thng c chun b tt lm vic.
Nht hoc m bi trn l nhng cht d tan v c th c s dng d dng gn
cc chi tit vi nhau nu cn thit.
-
Page | 71
4.2.2. Qui trnh khi ng ban u:
Nhng loi bm v ng c thy lc c cu to khi ng tnh trng khng
ti. iu quan trng l chng c khi ng vi cc ca thot c thng vi p sut
kh tri loi b khng kh h thng thy lc. Mt khc bm khng th mi v c
th b h hng do thiu cht bi trn.
Khng bao gi khi ng cc bm cnh van khi:
Van b ng kn.
B tch tr ang c np.
Vng lm vic kn vi ng c thy lc.
Cc van iu khin hng thng thng l loi c mch nhnh, v vy bm c th
c khi ng mt cch n gin bng cch nh tm cc li van. Nhng nu du
thy lc khng th tun hon c p sut, nn c mt van nh trong ng ng p
sut hoc mt khp ni trong ng ng v s m ra khi ng. Phi cng thot
c thng vi khng kh cho n khi dng thy lc chy ra ngoi. S x kh t ng
c th c thc hin bng cch lp mt van x kh, van ny s m ra x khng kh
nhng s ng li khi dng thy lc bt u chy ra.
Cc im lu khi vn hnh bm:
Trnh vn hnh qu tc .
Vn hnh bm tc qu cao th ma st gia cc b phn trong bm s tng
cao do kh nng bi trn gim. iu ny s lm cho my bm b h hng sm. Vn
hnh bm qu tc cng gy ra nguy c hng v thiu ht du trong bm.
Trnh hin tng thiu ht du:
Thiu ht du l tnh trng du khng np y vo mi ng np ca bm.
Khi tnh trng ny xy ra, du thot ra khi bm s c bt kh. Du p lc c cha bt
kh s dn n nhng sai lch trong truyn ng.
Nguyn nhn ca tnh trng ny ngoi vic vn hnh bm qu tc cn c th
do mt s nguyn nhn khc nh: ng ng du b nght mt s v tr, mc du
trong bnh cha thp hn ca np hoc nht ca du qu cao.
C chn khng ng np ca bm.
i vi a s cc my bm thy lc, chn khng ti a cho php ng np l 5
in.Hg. L tng l khng c chn khng ng np.
Nu c chn khng ng np s xy ra tnh trng thiu ht du. Tnh trng ny
s gy ra s n mn kim loi bn trong bm v tng kh nng bin cht ca du thy
lc. Ngoi ra tnh trng thiu ht du cn gy ra ting n. iu nguy him l ting
-
Page | 72
n ch c pht hin khi chn khng ng np l 10 in.Hg, nhng lc ny th tc hi
xy ra.
hn ch tnh trng thiu ht du cn dng cc ng dn du ln, chiu di
ngn nht (c th c), hn ch nhng ch gp khc, nn vn hnh bm tc
danh nh. C th l to ra p sut ng np ca bm bng cch t bnh cha pha
trn bm hoc dng bm ph cp du cho bm.
C th t ng h o chn khng kim tra chn khng ng np ca bm.
4.3. Bo dng h thng:
Nhiu h thng thy lc c thit k khng xem xt n vn bo dng mt
ln trong qu trnh s dng. Thng thng yu cu ban u l gi thnh sn phm nh
nht, nh hng n vic u t bo dng cho h thng. Hu qu ca cng vic trn
l:
- Cc b lc trong h thng s khng thch hp.
- S khng phng tin kim tra gim st mc mi mn.
- Van v cc thit b khc s khng t ng v tr thch hp.
Cng vic bo dng cn thit lm sch thng du trc khi chc chn rng cc
thit b c th c kim nghim v thay th.
H thng lc du v sch:
Thng k cho rng 80% cc h hi trong h thng thy lc trc tip hay khng
trc tip u bt u t ngun nhim du thy lc. Bng cch s dng b lc ph
hp c th lm gim c phn ln mc nhim du.
Chc chn rng cc b phn lc c gn vo h thng mt cch tng i v kch
thc ca n chuyn ton b lu lng cht lng m bm cung cp trong iu
kin khi ng lnh.
Kim tra thng cha du tht kn cha v tt c nhng m kn lm vic trong iu
kin tt. Kim tra xem np thng hi ca thng du c sch khng v kch thc ph
hp vi mc x l lu lng kh cn trao i hay khng.
Khi np du cho thng du hoc y np th dng mt b lc chuyn du vo,
khng nn dng bnh du trc tip vo nh bnh ti nc.
Thng du phi c gn vi kha x du c th chy ht mt cch tun hon
v lm sch cng vi b ht.
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Gim st ch :
Thit b:
Ch hot ng ca bm, motor thy lc v cc van iu khin vi cc l ngoi
c th d on bng cch o lng dng r r trn cc ng ng dn. Cc kha
ng ng dn nn lp t c th d dng ngt dng r r khi c s c, cc dng r
r c thu gom v mt bnh o lng v tc dng r r ca cc thit b phi c
gim st.
Cht lng:
Gim st nhim cht lng thy lc c th c ch rt ln. Nhng kim tra thng
thng t ra l cn phi xc nh cp sch bo dng v cung cp hng hn
ng cho vic hot ng ca my. Thng cha, ng dn v nhng dng c lm mu
nn cn thn lau sch.
Mi mn thit b:
Mi mn trong h thng thy lc l nguyn nhn chnh ca s nhim du.
N lm cho hiu sut lc v bo dng gim i ti mc thp. Mi mn xy ra hin
ti c th xc nh bng cch gim st s thay i lu lng dng r r v bng cch
phn tch thnh phn vt liu trong du.
Nhng nguyn nhn khc gy mi mn thit b l do s x dch ca bm v b
phn tc ng. Bng cch sit cht cc bulong lng, ng ng lm vic v cc van
trt gy nn dao ng trong h thng. Nhng h hng vt l c th xy ra l do kt
qu ca s lm dng sai, v tr lp t sai v bo v khng tng xng vi tng thit
b b phn.
K hoch bo dng:
- Kim tra trc quan nhng h hng hoc r r ng ng, khp ni v thit b.
- Kim tra mc cht lng trong thng du v c tnh ca cht lng.
- Kim tra p sut hot ng, b ch th ch ca b lc.
- Kim tra s an ton ti ni lm vic.
- Kim tra hot ng ca h thng v sn xut.
- Bo dng theo chu k (hng tun, hng thng, ph thuc vo iu kin hot
ng ca my).
- Kim tra n nh ca tt c cc thnh phn.
- Kim tra ch s p sut ti lc kim tra trong h thng.
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Page | 74
- Kim tra mc ting n ca bm v nhit hot ng.
- Kim tra ton b b phn tc ng (xylanh - piston) nh h hng, mc n,
nhit hot ng, vn tc u ra v lc.
- Bo dng hng nm.
- Lm sch thng du, kim tra c tnh ca du.
- Lm sch thng du bn trong v bn ngoi, kim tra s r st.
- Lm sch b lc.
- Lm sch ng ng dn kh ca b phn lm mt.
- Kim tra tt c ng mm, ng pipe v khp ni c h hng khng. Thay th
nh yu cu.
- Kim tra m t in.
- Kim tra nhng mi lin kt mm gia bm v m t.
- Kim tra cc phn t lc, thay th cc thit b s dng c 12 thng.
- Lm sch phu lc.
- Kim tra s r r ca bm v m t bng cch vn hnh di ch bnh
thng v so snh vi mc r r m nh ch to khuyn co cho php. Nu nh
s r r qu mc cn phi em n nh ch to i tu.
- Kim tra s r r m kn gia cylinder v piston.
- Mt s qui tc chung trong k thut bo dng h thng thy lc:
- Trc khi vn hnh my cn phi kim tra nh hng ca cc phn n khp
hoc c cu my.
- Cylinder phi c gi cht khng b ri di tc dng ca trng lc.
- Ngt dng in cung cp v m bung iu khin.
- Ngt bm v chc rng bm khng bt ng khi ng.
- Ghp tt c phn cui ca ng pipe vi cng vo ca cc thit b gi khng
nhim ra ngoi.
- Cc thit b c tho ra phi c nh du gim c cng on lp rp.
- S dng cn sit lc c nh cc thit b, trnh khng sit qu cng.
- S dng ti a cng on bo dng khi ln u i i tu.
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Page | 75
PH LC
Ph lc A: Cc thng s k thut my p 250 tn
B phn Chi tit n v Thng s
Km
Kch thc bng km mm 900x900
Khong cch trc dn hng mm 620x620 dy khun mm 200600 Hnh trnh li mm 150
p lc km Kg/cm2 250
Bm keo
ng knh co ln (trc vt) mm 60
Th tch bm keo Cm3 697 Tc bm keo Cm3/s 226 p sut bm keo Kg/cm2 1800
Khi lng bm keo PP gam 635
Tng qut
S vng nhit Vng 5
Nhit lng bng gia nhit Kw 17 Cng sut motor chnh Kw 45
Kch thc my m 6,5 x 1,5 x 2,6 Khi lng my Kg 12000
Th tch thng du lit 500
Lu :
- Khi lng my ta c th so snh vi cc my c ch to.
- Kch thc my l kch thc bao trn bn v.
- S vng nhit l s bng nhit c chn nm dc xylanh bm nha.
- Nha c s dng tnh ton trong my ny l loi nha PolyPropylen (PP)
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Page | 76
Ph lc B: Thng s k thut my p 250 tn CHUAN LIH FA
My CLF 250 TWR:
B phn Chi tit n v Thng s
Km
Kch thc bng km mm 880x880 Khong cch trc dn hng mm 610x610
dy khun mm 200600 Hnh trnh li mm 155
p lc km Kg/cm2 250
Bm keo
ng knh co ln (trc vis) mm 65 Th tch bm keo Cm3 995 Tc bm keo Cm3/s 254 p sut bm keo Kg/cm2 1479
Khi lng bm keo PP l thuyt
gam 730
Khi lng bm keo PP thc t gam 720
Tng qut
S vng nhit Vng 6 Cng sut nhit Kw 23
Cng sut motor chnh Kw 40 Kch thc my m 7 x 1,62 x 1,78 Khi lng my Kg 12000
Th tch thng du lit 505
My CLF 250 TX:
B phn Chi tit n v Thng s
Km
Kch thc bng km mm 900x9