SCIENCE TECHNOLOGY!
MO HINH HOA ANH Hl/CfNGCUACHEDQCATDEN LI/CCAT TRONG GIA CONG PHAY CAO TOC BANG DAO PHAY NGON
MODELINGTHE INFLUENCE OF CUTTING PARAMETERS ON THE CUTTING FORCE IN HIGH SPEED MILLING USING END-MILL
Hoang Tien Dung, Tran Van Djch, Nguyen Huy Ninh
Tom t i t
Bai bao trinh bay viec khjo sat va mo hinh hoa anh hirdng cua che So dx Sen lye dt trong qua trlnh gia eong cao toe ThiTe nghiem do luc cSt trong qua trinh gia cdng bien dang vat lieu thep C45 b k g dao phay ngon It^n khoi, i ^ g dung philtmg phap phan tich phuong sai (ANOVA) xay dung moi quan he phu thugc cQa cac thanh phan life cat v ^ die So cat trong gia eong phay cao tdc bSng dao phay ngon. Tren co sd phurnig trinh mo hinh hoa anh hUdng do giijp nha cfing nghe thiTc hien tol Uu hoa tfnh va dong trong qua trinh gia eong. Qua do hifdng tdi sin pham may gia eong thong minh tif thkh nghi trong qua trinh san xuat.
Tilf khda: Li/c cat, che do cat, phay cao toe, dao phay ngon, thep C45, phan tich phuong sai.
Abstract
This paper presents a sun/ey and modeling the effects of cutting parameters to cutting force in high speed machining process. Experimentally measured oitring forces when cutting contour on C45 steel by the solid end-mill tool and application ANOVAR (Analysis Of Variance) are used to build a dependence of the components of cutting force with cutting parameters In high speed milling by solid end-mill tool. Based on this model the machining process is optimized and the self-optimizing control for Intelligent CNC Machine Tools in machining process is earned out
Keywords: Cutting forces, cutting parameters, high speed milling, end mill, steel, ANOVA.
•(M—
ThS. Hoang Tien DOng • Tnrcmg Dai hoc Cong nghiep H^ N6i GS.TS.Tr3n(ftnflidi,TS. Nguyen Huy Ninh TrUdng Dai hoc Bach khoa ifa Noi Email: tiendunghaui#gmaJl.eom
I.DATVANOg
Hudng tdi to! Uu hoa trong qua trlnh gia c6ng dem lai chat laong san pham, nang suat gia eong. Van de nghien cCTu cac thong so eong nghe anh hifdng tdi dong lac hoc gia eong trong qua trinh gia eong la rat can thiet, dac biet hon nC^a la doi vdi ITnh vac gia eong toe do cao. Bdi vl gia eong cao toe dang dUdc nghien ciJu va iJfng dung manh trong
Ngay nhan bai: 20/8/2014 Ngdydiap nhan dang: 20/10/2014
s^n xuat. Sd do phan tfch anh hudng dpng luc hoc may va ddng lye hpe gia eong trong he thong gia cdng (hinh 1).
Trong gia eong nghien ciJu dpng lac hoc eat la van de khd va no cung la van de de gi^i quyet cot loi bai toan gia cdng. Dae biet la trong gia eong tdc do cao ddng lye hoc may va dong lac hpc gia cdng het sdc quan trong.
De dat dupe chat lapng be mat yeu
Kinh 1. Anh hudng dong lire hpc may va dpng liic gia eong tren he thong gia eong
cau hay khi nghien cau toi Uu hda eac dieu kien gia cdng tang ehat lupng be mat gia eong va nang suat gia cdng.
Qua nghien cOu cac nha khoa hpc cung daa ra cac yeu to chinh lien quan va anh hadng tdi chat laong be mat trong qua trinh gia eong (hlnh 2). Lue cat la thong sd gian tiep anh hadng tcifi ehat lupng be mat gia cdng. Va luc eat la thdng so rat quan trpng trong md hinh hda he thdng.
Hinh2.Cacvandechinii anh hucrng den do chinh xac be mat thuan
Muc dich chinh nghien cijfu khoa hpc va cdng nghe trong van de gia cdng la xay dang dupe md hinh hda, md phdng, tdi Uu hda va dieu khien
S624.2014-TapchiKHOAHpC&CONGNGHE 2
CONG NGHE
^^
qua trinh gia cdng (hinh 3).
Qua trlnh gia cdng va mifc do phtfc tap eua cdng nghe ngay nay ddi hdi he thdng dieu khien thue hien xCf ly chinh xac bang cac phaong phap khac nhau nham muc dich tang ehat lUpng va hieu qua. Nghien cau nay xay dang ham toan hpc dp tin cay cao va cac hien tapng xuat hien trong qua trlnh gia cdng tdt nhat cd the. Ky thuat gia cdng chinh xac khdng ehi daa tren ecf sd kinh nghiem va sa tinh thdng ma con phai hieu nguyen ly gia cdng va moi quan he toan hoc cac thdng so ^nh hadng trong qua trinh gia cdng. Qua trinh gia eong daoc xac dinh bdi mdi quan he cua eac gia trj dau vao va hieu qua do daoc qua gia tri dau ra. Hinh 4 md hlnh qua trinh gia eong dUde sir dung nghien cau trong bai bao vdi thdng sd dau vao va danh gia dau ra. Muc dich cua nghien cau nay la tim mo hinh toan hpe lien quan den nham be mat (RJ, cac thanh phan lUe eat vdi ba thong so che dp cat: tdc dd cSt (v), laong chay dao (f), chieu sau cat theo phaong hudng kinh {a) trong gia cdng bien dang b^ng cJao phay ngon.
Nghien ciJu nay tiep can vdi phaong phap phan tfch phacJng sai (ANOVA) va cac phan mem ang dung thdng ke trong quy hoach thuc nghiem de xay dung md hlnh toan hoc.
2. P H A N TfCH HI|N Tl/ONG CO BAN TRONG QUATRINH GIA CONG
Trong qua trinh gia eong ed nhieu hien tapng xay ra anh hadng tdi chat laong va nang suat gia cdng. Mdt trong nhufng hien tapng quan trpng xay ra trong qua trinh gia eong la chat ladng be mat, lUc c3t... Md hinh hda hien tapng trong qua trinh gia cdng de cung cap thong tin quan trpng trong lap quy trinh cdng nghe gia cdng ehi tiet va toi Uu hda qua trinh gia cdng. Co ehe hinh thanh be mat trong qua trlnh ddng lac hpc phay dape xac dinh la lac c3t. Kiem soat sa thay doi qua trinh gia cdng la lac cat, nd phan anh rd net nhat gia
p . M . , * , . ,
• • [^DIib[«10l
-• " " b l T
1
J \r
1 1
Qulirirti
^ U
i
j n dinh gii cOig
i
- diculdufn
o . * , -
i
b i i D | i < ; l d u i i d c
-.T
MatalnbMa
i
T^inibfia
1
M6Uidi
T
Ctllliifi^lii m l t g u e t a g
• '
d^ n h ^ bj Dj|t
Hinh 3. So do ve mo hinh hoa, mo phong, toi ifu hoa va dieu khien qua trlnh gia eong tren casd ding hot gia eong
eong khdng binh thudng nhu vd dung cy eat, rung ddng va anh hudng tdi chat luong be mat gia cdng. Qua dd phan tieh mdi lien he giOa lUe eat thay doi vdi dd nham, lapng mdn dao (hlnh 5) [10],111].
Trong qua trinh gia cdng sCtdung dao phay ngon lye cat thay doi lien tuc trong sudt qua trlnh gia cdng. Cac thanh phan lye c^t tiJe thdi dupe tinh toan daa tren sa thay doi cua dien tieh eat. Trong qua trinh gia cdng cd rat nhieu thdng so anh hadng tdi lUc cat dupe the hien trong bieu do xaong ea(hinh6)[10],[n].
Lye cat la mpt trong thdng so vat ly danh gia qua trinh gia cdng nhU hien tupng mdn vddung cu c^t, rung dpng cua may, dp chinh xac gia eong va chat lupng be mat. Lye cat la mpt thdng so trung gian trong qua trinh gia cdng de thye hien toi uu hda thich nghi.
Hinh 4. Scf do mo hlnh nghien cihi
Da cd nhieu nghien cijfu, khao sat eac yeu to anh hadng tdi lye cat va nham be mat trong qua trinh gia eong.
Trong bai bao n^y tac gil gidi h^n nghien cyu anh hadng cCia ch^ do ck Toe dp eat (v), lapng chay dao (f), chieu sau theo phaong hadng kinh (a^ tdi liJc cat va dp nham be mat (R^) khi gia cfil^
phay cao tdc b i n g dao phay ngon l i ^ khoi.
3. CO s d LV T H U Y E T Lire CAT CI)A QUA TRiNH PHAY CAO T 6 C BANG DAO PHAY N G O N L I ^ N KHdi
Hinh 5. Bieu do xuong ca the hien anh hi/6ng thong so tdi do nham be mat va mon dao
SCIENCE TECHNOLOGY I
•^ ^^
Hinh 6. Bieu 66 Xlfong ca the hien cac yeu to anh hi/Sng Jen luc cat trong qua tnnh gia eong
Hinh 7. Vung tiep xiJc dung cu cat va phoi thuan 3.1. Mo hinh lire cSt
Qua trinh gia cdng phay la phUPng phap pho bien nhat trong cdng nghe gia cdng. Cd kha nang gia cdng rong va gia cdng daoc nhieu dang b^ mat khac nhau nhu: phay mat phling, phay ranh, phay bae, phay dinh hinh ..
Cd nhieu thdng sd anh hudng den lye eat tac dung len ludi cat cua dung eu eat. Cac thdng so tac dpng lam thay doi lac cat ma khdng d y doan dupe trade dan den kich thydc gia cdng, chat laong gia cdng khdng dat yeu cau trong qua trlnh gia cdng.
Lye eat la mdt trong cac thdng so dau ra can dape kiem soat va da bao de dieu ehfnh cac thdng sd toi Uu dat dape chat laong va nang suat, dac biet trong dieu khien tdi du hda thich nghi.
Vung tiep xiic trong qua trinh gia eong bang dao phay ngon dape the
Hinh 8. Mo hinh phan tich luc dao phay ngon tien hanh phay thuan
hien tren hlnh 7 [9].
Qua trinh gia cdng phay bang dao phay ngdn la qua trinh nhieu diem tham gia cM tac thdi, ludi cat va phdi tiep xuc khdng lien tue, chieu day phoi thay doi trong qua trinh gia cdng.
3.2. Phan tich mo hinh lUc cat trong qua trinh phay
Trong qua trinh gia cdng phay bang dao phay ngon qua trinh tiep xuc ludi cat va phdi tyc thdi, khdng lien tue khi true chinh quay. Hlnh 8 the hien qua trinh gia cdng phay thuan, lye cat thay doi theo dich ehuyen cua ban may t y gia tri Idn nhat den gia trj 0. Chieu day cOa phoi Idn nhat xay ra tai diem tiep xuc ban dau cua ludi cat va phdi. Sy thay ddi chieu day phoi trong qua trinh gia eong dan den sa thay doi ve lye cat
tae ddng len tudi cat cOa dung eu eat khi vao cat va ra khdi vung cat cua ludi eat.
Trong suot qua trinh bde tach vat lieu dung ey cat chiu tac ddng bdi thanh phan lye e^t tac thdi theo phaong tiep tuyen F,, theo phuong phap tuyen F^ theo phaong doc true Fa (he thdng lye c^t dao phay ngdn khi phay bien dang}. Xet tai mdt diem tiep xuc gida dung cu eat va phoi ed ba thanh phan lye tac dung len dung cu eat (Luc cat theo phuong x: F^ Idc cSt theo phaong y: F^ theo phUOng z F^
trong he tpa dd Oecae OXYZ duoc xae dinh nhu sau:
F^
["F F = T FTrong dd:
cos(p sinep 0 T = sincp-coscpO
0 0 0
Gdc vao ep^, cua ludi cat trong qua trinh phay thuan xac dinh nha sau:
(p^, = 90°-Faresin[(r-a^/r] (3) Trong dd: r la ban kinh eua dung cu cat va a_ chieu s^u eat theo phaong hudng kinh.
Gdc thoat ra cua ladi cat cd gia tri xap xi bang (p^^=180'' va chieu day eua phoi tai diem nay bang 0. Can chu khi ludi eat tiep xuc vdi phdi de thpc hien gia eong ed ba thanh phan lye F_^, F, F^ tdn tai trong qua trlnh gia cdng. Ba thanh phan lac khac khdng phuong trinh (1} Viet nhu sau:
khi cp^^ < cp < (p F - T F
F^ F^
4. KHAO SAT Lire CAT KHI PHAY CAO T6C BANG DAO PHAY NGON LIEN K H O I
4.1. Oleu kien khao sat
So24.2014.TapchiKHOAHOC&CONGNGHE 2 3
- i l
' 1 Tnjr
C:NC
m n-n^
T
rrtngt r ^ r
Phfin r n A t i D A S Y L a b 1 0 0 ) Hinfi
Bang
So do va mo hinh thifc nghiem 1. Ket qua do life tat theo 3 phirong X,Y,Z
Thii
1 2 3 4 5 6 7 3 9 10 11
Bien mUc ma hoa
-1 } -1 1 -1 1 -1 1 0 0 0
K!
-1 -1
!
1
•1 -1 1 1 0 0 0
"
0 0 0
Toe do
v,!m/pl
370 595 370 595 370 595 370 595 495 495 495
Luong chayddo f(nim/p)
2357 2357 3790 5790 2357 2357 3790 3790 3153 3153 3153
Chieu sau cat
phuong hiiong kinh a.(mm)
0,1 0,1 01 01 0 95 0,95 0 95 0 95 06 06 06
Luc cat F, IN)
12891 97 57 148 44 104,57 397 34 347,99 485-5 367 64 2 9 6 1 296 9 296 72
Luc cat F, (N)
214,9 172 26 272 68 212 69 79943 6 1 8 0 7 8 3 1 5 653 19 51185 513,63 514 63
LKccat f ,
25 41 15 46 26 52 22 54 1 3 1 9 6 89,22 173-16 98 23 90 7 90.8 90.56
InM
5,91350 6 38856 5 91350 6 38856 5,91350 6 38856 5,91350 6 38856 6 20456 6 20456 6,20456
L n ( f )
7 76514 7 76514 8.24012 8 24012 7 76514 7 76514 8,24012 8 24012 8 05611 8 05611 8 05611
Ln(ar)
2,30259 2 30259 2 30259 2.30259 0 05129 0 05129 0,05129 0 05129 0.51083 0 51083 0 51083
Ln(F,l
4SS911 4 58057 5 00018 4.64986 5 98479 5 85217 6,18518 5 90710 5.69070 5 69340 5 69279
Ln{F,)
5 37017 5,14900 5.60830 5 35984 6.68390 6.42660 6 72323 6,48187 6.23803 6 24150 6 24345
Ln(F,|
3,23514 2 73826
mm
3 11529 4.E8250 4.49111 5,15422 4.5S731 4.50756 4.S0S66 4.50601
May phay CNC cao toe: HS S u p e r TC500, tdc dp quay true chinh:
100-30000(v/p), tdc do dich ehuyen cua ban may cat got; 1^30000(nim/p), toe dp chay khong Idn nhat: 48000(mm/p).
Hanh trinh dich ehuyen cCia ban may:
XxYxZ-500x400x300(mm).
Dung cu cat: Sd dung dung cu cat dao phay ngdn lien khoi gia cdng bien dang. Cat di/oc thep cd dd cyng < 48 HRC. Oudng kinh dao (D) = di/dng kinh chuoi ^ 20 mm So ladi cat- 4 Chieu dai
doan lam viec: 26,5 mm.Tong chieu dai:
92 mm, Ldp phu Cooltop (TiAIN - Titan Nhdm Nito). Gdc nghieng Helix: 35 dp.
Chieu sau cat theo phaong hadng kinh a, < 0,05.0-0,05.20-1 (mm).
Chi tiet gia cdng: Vat lieu gia eong thep C45 kich thadc mau thi nghiem LxWxH-70x70x40(mm)-
Thiet bi do luc: Thiet bi do lye cat 3 thanh phan cua hang Kisler - Thuy Sy, sy dung cam bien do lye 9257B-Kisler.
Dai do luc (F-1500N, F-1500N,
F^=5000N). Do nhay cua cam bien theo phdeJng X,Y: 7,39 pC/N, phUOng Z: 3,72 pC/N. Thiet bi ehuyen doi tfn hieu A/D va thu thap vao may tfnh sd dung phan mem DASYlab 10.0.
4.2. Ket qua va thao luan Qua md hinh nghien cau, tien hanh thf nghiem vdi v, f, a_ thay doi, chieu sau cat doc true a -10(mm) khdng thay doi.
Mo hlnh toan hpc lac cat ichi gia cdng dao phay ngdn khi gia cdng ptiay
J
SCIENCE TECHNOLOGY!
B a n g 2 . T 6 m t a t k e t q u a iJng d u n g p h a n m e m M a t l a b va Excel b a n g p h i r o n g p h a p ANOVA a n h hifcfng cua v, 1
Regression S t a t i s t i c Multiple R R Square Adjusted R Square SbndanJ Error Observations
0.997860295 0.99S72S168 0.993893097 0.O45020821 11
a d e n lire c3t t h e o p h i / o n g x (F_)
ANOVA
Regression Residual Total
Intercept X V a r i a b l e l X Variable 2 XVariable3
df 3 7 10 Coefficients 7.490523586 - 0 3 5 3 2 6 3 5 3 0.238912613 0.5339BS076
SS 3.3048 0 0 1 4 1 9 3 31899 Standard Error
0,67048 0.0666 0.06661 0.01353
MS 1.1016 0002027
t S t a t 11.17185 -8.307584 3 586764 39 47835
F 543.497109
P-value 1.026E-05 71581E-05 0.OO889547 1 7426E-09
Significance F 1.18718E-08
Lower 95%
5.905086069 -0710741376 O.0814O6122 0 502001117
Upper 95%
9.0759611 -0.3957857 0,3964191 0 56596903
Lower 98.0%
5.480451632 -0 75291933 0,039220493 0,493434719
Upper 98 0%
9 500595539 - 0 353607737 0 438604733 0 574535433
cao toe trong gidi han eua cae thdng so cung nha eac phaong phap gia cdng truyen thdng ddpc mieu ta ehung nha sau:
F_=C1 .v^'.f .a^"', F^=C2.v".f ^a^'"^
F,=C3.v'^.f^a ™^ ' ' (5) Trong do: F^ F^ F^: lye cat tdong dng theo cac phaong X, Y, Z; v: tdc dp e^t (m/p); f: lapng chay dao (mm/p), a\
ehieu sau cat theo phaong hudng kinh (mm); C,, k,, I,, m,, q , k^, !^, m,, C^, k^, 1^, m,: he so dape xac dinh trong qua trlnh thye nghiem. €)e xae dinh hang so va so mu cCia phdpng trlnh, md hlnh toan hpc nay daoc tuyen tinh hda bang ham logarit va phaong trinh dupe viet lai nhdsau:
InF,= lnC,-^k,.lnv-^-l,lnf-^-m,lna,(6) InF =lnC^-i-kj.lnv-f-ljlnf-i-mJna,(7) InF^ = InCj -I- kj.lnv -h g n f + m3lna,(8) Va md hinh tuyen tinh eua phUdng trlnh cd dang nha sau:
Y = b^ -fb, jc, -^bJ.XJ + by-x.^ (9) Bai toan trd thanh xae djnh ham hoi quy thye nghiem, thye hien 11 thi nghiem, 3 thf nghiem tai diem tam dape ket qu5 nha trong bSng 1.
Cfng dl ing Matlab v^ Excel sif dung
I
i
Hinh 10. Do Ihi bieu diln moi quan he cac thong so v, f, a^ vdi F^
I -15.-_ It t
ifinh 11.65 thj bieu dien mot quan he cac thong so v, f, a_ vdi F
Hinh 12. Do thi bteu dien moi quan he cac thong sd v, f, a^ voi F^
phaong phap phan tich phaong sai y - 7 , 4 9 0 5 2 3 5 8 6 - 0 , 5 5 3 2 6 3 5 3 . (ANOVA) tfnh toan va danh gia ham hoi x,-(-0,238912613.Xj+0,533985076.X3 quy thac nghiem[8] (bang 2). Ham lye eSt theo phuong X (F_) phy
Ham hdi quy thye nghiem r.hasau: thude vao v, f, a_.
5 6 2 4 , 2 0 1 4 • Tap diiKHOAHpC&CONG NGHE 12!
^niESS5Sc6NGJSLGHi_
F__-1 7 9 1 .V^.»3i6M3_f0.2389U613 3 0,533985076 Tuong t a dng dung phUOng phap phan tich phuong sai (ANOVA) xac d n h duoc ham lye eat theo cac phaong Y (F) va lye cat theo phuong Z (F^) phu thude vao v,f,a,.
F =2163.v'''""''lf • ' ' " " ^ a , " ' " ' " ' " * F'=639.v^'«^«'"'.P-"^"2°.a,''™""
Theo 10,11, 12 ta ed nhan xet nhu sau: neu tang chieu sau c3t (a^) anh hadng manh tdi tang eua lye cat trong qua trlnh gia cdng, mdc dd anh hadng cua tdc dp cat (v) va luong chay dao (f) nhd hon; lUc c^t theo phaong Y cd gia tri Idn hon theo phUdng X va phuong Z.
Trong bai toan khao sat, da doan va toi Uu qua trinh gia cdng bien dang bang dao phay ngdn hen khdi ed the sddung lye c i t theo phuong Y de giam sat qua trinh gia cdng dam bao chat iupng, rung ddng, mdn dao.,.
5. KET L U A N
Bai bao phan tich khao sat anh hadng thdng so che dd cat {v, f, a,) tdi th^nh phan lye cat. Va sy thay doi cua
lUe cat trong gia eong phay cao tdc bSng dao phay ngdn lien khdi khi gia cdng vat lieu thep C45 bang phaong phap phay thuan. Qua ket q u ^ do va phan tich trong suot qua trlnh gia cdng phay cao tdc Idc cat theo phaong Y la mpt trong thanh phan lue chu yeu dape the hien bang gia tri do cao hon thanh phan lye theo phaong X va phaong Z.
Qua dd cd the sy dung thanh phan lUc eat theo phUong Y de kiem soat trong qua trlnh gia eong va tdi au hda thich nghi trong qua trinh gia cdng (chat lupng be mat gia eong, mon dao...) tren may gia cdng thdng m i n h t a t h i c h nghi.
Phan bien khoa hoc PGS. TS. Vii Toan Th^nq
TAI LIEU THAM KHAO
[1], Nguyen Thefiat, Ky thuat san xuat trong ehe tao may, NXB Khoa hoe va ky thuat, Ha Noi, 2007.
[2] Tran Van Bich, Cong nghe ehe tao may, NXB Khoa hoe va ky Ihuat, Ha NOP, 2006.
[3| Tran Van flich, Nghien cdu do chinh xae gia cdng bang thuc nghiem, NXB Khoa hoc va ky thuat,
HaNgi,2003.
[4). Banh Tien Long, Nguyen ly gia cdng valBeu, NXB Khoa hoe va ky thuat. Ha Ngi, 2001,
[6]. Pham Thi Nggc Yen, Co sd Matlab va is^
dung, NXB Khoa hpe va ky thuat. Ha Noi, 2009.
[7]. S. Zhang & J. F. Li & J. Sun & F, Jiang,Ti]il wear and cutting forces variation in high-speed aid- milling TI-6A1-4V alloy. Springer, 2010.
[8]. Turnad L GINTA, A.K.M. Nurul AMIN,A.N, Mustafizul KARIM, M. H. ISHTIYAa Modeling for Surftee Roughness in End-Milling of Tiiaiiiim Alloy Ti-6AI-4V Using Uncoated WC-Co and Pf,l) ln5ert5,Department of Manufacturing and Mateiisli Engineering, HUM, Malaysia.
[9]. Wen-Hsiang Lai, Modeling of Cutting Farai in End Milling Operations,Tamkang Journal of Sdence and Engineering, Vol. 3, No, 1, pp. 15-22, (2000).
[10] B. C. Routara & A Bandyopadhyay & P.
Sahoo, Roughness modeling and optimization In CN[
end milling using response surface method; rffect of workpiece material variation, Int J Adv ManufTediml 40:1166-1180,2009.
[11] Benardos PG, Vosniakos GC, PredicBng surface roughness in machining, Int J Msdi Tooli Manuf 43:833-844,2003.
HOI T H I T H O Gidl NGANH CO KHI CAC KHU CONG NGHIEP VA CHE XUAT HA NOI NAM 2014
Ngay 26,27/9/2014, tai tn/dng fiai hoc Cong nghiep Ha Noi da dien ra Hoi thi tho gidi nganh Co khi danh cho cdng nhan vien chdc lao dong (CNVCLf)) cac khu eong nghiep va the xuat (KCN&a)Ha N6i nam 2014. flen du Hoi thi cd cac dong chi dai dien cho Tong Lien doan Lao dpng Viet Nam, Lien doan Lao dong thanh pho Ha Noi, Lanh dao Ban quan ly cac KCN&a Ha Noi, dai dien c^t cdng
:6TS. Pham Van Bfi|.
ty, doanh nghiep cd thi sinh tham di/.Vephia Nha truong CO TS.P -Pho Hieu tru'cmg den dif.
Hpi thi tho gidi nganh Co khi do Cong doan cac KCN&CX Ha Noi to ehiJc. Trtfimg Bai hpc Cong nghiep Ha Noi vdi co sd vat chat, may moc hien dai, flac biet,NM tri/dng eo Trung tam Sanh gia ky nang nghe va Quan he doanh nghiep la trung tam duoc long Cue Day nghe, Bp Lao dpng -ThifOng binii va Xa hoi ehtlng nhlil la Trung tam danh gia ky nang nghe Quoc gia. Ben canh do, Nha tri/6ng cungfi cd kinh nghiem to chde eac hpi thi, ky thi tay nghe tri/dc day nen da flangaito chde Hoi thi tho gidi nganh Co khi nam 2014.
Tdi tham gia Hpi thi Thp gidi nganh Co khi cd 34 thf sinh dai dien cho CNVllfl trong cac KCN&CX ddng tren dia ban Ha Npi, Cac thi sinh tham gia hai phan Ihi ly tliuyet va thi/c hanh vdi cae npi dung thi: Cat got kim loai tren may CNC Phay (20 thisinh),Catgotkim loai tren may CNC tien (14thisinh]. Hpi thi la sandiili, CO hoi de ngudi lao dong noi ehung va cac thi sinh noi rieng difpc on ly thuyet, luyen tay ngheva thi tho gidi.
