E E a B s a c S N G N G H l
Si-15. or I C ' l o
NGHIEN cufu ANH Hl/dNG CUA CHE DO CAT DEN DO NHAM BE MAT KHI GIA CONG TREN MAY PHAY CNC
INFLUENCES OF CUTTING MODE ON SURFACE ROUGHNESS PROCESSED BY CNC MILLING MACHINE
N g u y i n H u y KiSn, Pham Van Ddng, Pham Van Bong, Tran V3n Bich
T6m t^t
Bai bao trinh bay ket qua nghien cihi anh hifdng cua che do cat den do nham be mat khi gia cong tren may phay CNC. Ket qua nghien cdu la co sd cho cac nha cdng nghe lUa chon che do cat toi inj nham nang cao chat lu'gng be mat, dd cliinh xac va nang suat gia cong khi gia cdng tren may phay CNC.
Td khda: Che do cat, do nham.
Abstract
The article presents influences of cutting mode on surtice roughness when milling by CNC milling machine. The research result is the basis for technologists to select optimum cutting mode to raise the surface quality, accuracy and processing capacity ofthe parts when processing by CNC milling machine.
Keywords: Cutting mode, roughness.
ThS. Nguyen Huy Kien,TS. Pham Van {)6ng,TS. Pham Van Bong Tnfcmg E)ai hoc Cong nghiep Ha Ngi
GS.TS. Iran VSn Dich -TriTflng Oai hoc Bach khoa Ha Ndi Email: nguyenhuykienl 981 ggmalLcom
Ngaynhanbai: 06/01/2014 Ngiy chl[p nhan dang: 20/03/2014
I.OATVAND^
Chat lu'dng be mat ehi tiet sau khi gia cong tr^n may phay CNC phu thupc vao nhieu yeu to, nha: vat lieu gia cong, phirong phap gia cong, dung cu cSt, lue eit, nhiet eat, he thong cong nghe, ehe do cat... Khi dieu Icien va thiet bj gia eong khong doi, de nang eao nang
suat, chat li/ong be mat ehi tiet va dp ehinh xac sau khi gia eong thi viec lUa chon ehe do e l t la het siic can thiet.
Cae nghien cu'u da chi ra moi quan he giCfa do nham be mat (R^) vdi che d6 cat (V, S, t) la quan he ham luy thiia [4]:
R ^ ^ C p . V ^ S ^ f (1) Trong do: C la hang so; a, b, e la cae
Hinhl.May phay D00SANDNM400 Hinh 2. May do dd nham Mitutoyo SJ - 400
so mu. Hang s6 C va eac so mu a, b, c difOe xac dinh b i n g thiie nghi&m.Doi vdi dieu kien gia cong ehi tiet cu the thi viee xae djnh eac gia tri C , a, b, c se giup nha eong nghe tinh toan, lUa chon duoc che do c i t hdp ly tuy theo yeu eau ve do chinh xac gia cong.
2.THU'CNGHI|M
2.1 .Vat lieu va thiet bj thu'c nghiem 2.1.1. Mdy gia cdng vd dung at ck - May gia eong: SCf dung may phay CNC nhan hieu DOOSAN DNM4O0 (hlnh 1) do Han Qu6c san xuat.
- Dung cu elt: Dao phay ng6n, s6 rang Z = 2, dudng kinh D = 26 mm, lUdi c i t g i n manh hop kim eufng nhom 3 cae bit ky hieu 490R-08T308-PM cua hang Sandvik (Thuy Dien).
2.T.2. Vgt lieu gia cong vd che do tudi ngudi
- Vat lieu gia eong la thep 40Cr, thep hoa tot, dUdc sCf dung rdng rai trong che tao may. Kich thifdc mau thi nghiem: 50x30x25 mm.
- Lam mat: Diling dung dieh Emunxy 4%, luu lUdng 20 lit/phut.
2.7.3. Thiit bj do do nhdm - May do dp nham Mitutoyo SJ - 40C (hinh 2).
- Thong so do: ehi tieu danh giS i{
nham R^ theo tieu ehuan ISO; chi^uda chuan: 0,8 mm, do tren 5 ichocing; lo?
dau do: kim cUdng (R = 2 mm) do tjfl xuc; ap luc do: 0,75 N; toe dp: 0,05mif|
2.2. Phuong phap thUc nghiSm
5 Tap dii KHOA HOC & CONG NGHE. S o 2 2 . 2 0 1 4
SClENCETECHNQLOGYl
Nghien eijfu dupe thuc hien tren 11 mau, vat lieu 40Cr. Sau khi eac mau dUdc xac dinh mac thep bang phUdng phap quang pho, tien hanh phay tho, phay ban tinh, kiem tra eae th6ng so hinh hoe va phay tinh; sCrdung phUdng phip quy hoach thuc nghiem, ehpn dang phuong trinh h6i quy, xac djnh th6ng so thi nghiem va tien hanh thuc nghiem. Do, kiem tra danh gia do nham; xay dUng cong thu'c xae djnh moi quan he giufa cae thong so ehe do eat vdi 66 nham be mat chi tiet sau khi gia cong.
2.3. Ca sd danh g\A s6 lieu thuc nghiem
2.3.1. Chgn dgngphuang trinh hoi quy
Di nghien cu'u moi quan he giO'a eae thong so ch^ dp e l t vdi dp nham be mat ehi tiet sau gia edng, tae gia stf dung phUdng phap binh phUdng nh6 nhat (BPNN) vdi bien so k va dang ham hoi quy thUe nghiem:
y = au-Ha,x, +a^Xj-f + ^^\ (2) 2.3.2. S6 thi nghiim va thong so thi nghiem
• So t h i nghiem:
- Mdi quan he giQa eae t h o n g sd dupc m d t l theo sd d o (hinh 3):
Bang 1. Thong so che dp cat thu'c nghiem
X,
X,
^
V
Hlnh 3. Sddo moi quan he giOa thong so dau vao
^a dau ra
+ Cac bi^n dau v a o x, dieu khien Sugc:
x,:Van tdc e l t V (m/ph) x^: Budc tien d a o S ( m m / p h ) Xj: Chieu sau e l t t (mm) + Bien d a u ra bj dieu khien:
y: e p n h a m be mat R, (nm) + Bien k h d n g dieu khien dUpe:
Thong so Gia tn min Gi^tri trung binh Gia tn max
vantocdt V(m/pli) 163 212 261
Tocflocat n (v/ph)
2000 260O 3200
Bode tien dao S (mm/ph)
400 600 800
Chieu S3U cat (mm)
0,1 0,2 0,3 Bang 2. Ket qua thuc nghiem
TT
1 2 3 4 5 6 7 8 9 10 11
Bien ma hoa X,
+1 +1 +1 +1 0 0 0
X2 -1 -1 +1 +1 -1 -1 +1 +1 0 0 0
X, -1 -1 -1 -1 +1 +1 +1 +1 0 0 0
Thong so rang nghe Toe do cat V (m/ph)
163 261 163 261 163 261 163 261 212 212 212
n (v/ph) 2000 3200 2000 3200 2000 3200 2000 3200 2600 2600 2600
Budc tien S (mm/ph)
400 400 800 800 400 400 800 800 600 600 600
Chieu sau c3tt (mm) 0,1 0,1 0,1 0,1 0,3 0,3 0,3 0,3 0,2 0,2 0,2
Do nham theoR.
(pm) 0,45 0,53 1,38 0,88 0,42 0,29 1,24 0,57 0,55 0,59 0,60
^: Bien ngau nhien
- Sd thi nghiem dUdc xac dinh [3]
theo cdng thu'c:
N = 2'' = 8
Vdi bien dau vao k = 3 ta cd sd thi nghiem chinh N = 8, de nang eao do ehinh xac tac gia them 3 thi nghiem 6 tam.Tong sd thi nghiem N = 8 -i- 3 = 11
• Thong so thi nghidm:
Can cijf vao thdng sd ky thuat cCia may, pham vi cho phep stf dung cua dung cu elt eua nha san xuat... eae thong sd ehe do e l t diXOe ehpn trong vung sau:
-h Van tde e l t V: 163 -261m/ph (n = 2000-3200 v/ph).
-I- BUdc tien S: 400 - 800 mm/ph.
+ Chieu sau e l t t: 0,1 - 0,3mm.
Thdng sd eh^ dp e l t thuc nghiem the hien trong b i n g 1.
Mdi quan he gifla dp nham va che do e l t the hien qua edng thtifc (1), dd la:
R^ = C^.\J\S\t'
Logarit cdsdephUcJng trinh (Dta duoe:
ln(R; = In(Cp) -1- a.ln(V) + b.ln(S) +
c.ln(t) (3) Cat y = ln(RJ; a^, = In(C^); a, = a; a^ = b; 83 - c; X, - ln(V); x^ = ln(S); Xj = ln(t)
Ta dupe: y = a^ + a,x, -t- a^x^ -1- a^x^
Mu'c tren la x/"taed;x"' = l n x ^ j Mufc dudi lax"":x"" = lnx^|^;
Mufc cdsd lax,™:
^W. = -(lnx,„
Khoing bien thien la p^ ta ed:
p, =-(lnx,^^,-lnx„„,n) 2.4. Ket qud thUc nghiem Chuyen eae bien tCf t u nhien sang eae bien ma hda khdng thLf nguyen.
Vdi thue nghiem 3 bien dau vao thay doi, tien hanh lam 8 thi nghiem tai cac dinh ddn hlnh deu va 3 thi nghiem d tam; sau khi gia eong xong cae mau, tien hanh do dp nham tren may do dp nham Mitutoyo SJ - 400. Ket qua thuc nghiem (bing 2).
2.4.1. Quy hoach so liiu thi/cnghiem Theo phUdng phap BPNN ta cd ham hoi quy thuc nghiem tdng quat:
y = ag + a^ x, -i-a^Xj-i-.. " + a^,X|^
Xac djnh a,^ a,, a,... a. sao cho S dat
So 22.2014-TapchiKHOAHOC&CONGNGHl 1
laihyjihWCONG NGHE
Bang B. Ket qua tinh logarit cac thong so thi nghiem
TT I 2 3 4 5 6 7 8 9 10 11
VantdcV (m/ph) 163 261 163 261 163 261 163 261 212 212 212
Budc tien S (mm/ph)
400 400 800 800 400 400 800 800 600 600 600
Chieu sau cat t (mm)
0.1 01 0.1 0.1 0.3 0.3 03 0.3 0.2 0.2 0.2
Bd nham theo
».(pm) 0.45 0.53 1.38 0 88 0.42 0.29 124 0.57 0.55 0.59 0.60
in(V)
5.09375 5.56452 5.09375 5.56452 5.09375 5.56452 5.09375 5 56452 5.35659 5 35659 5.35659
ln(S) Xj 5.99146 5.99146 6.68461 6.68461 5.99146 5.99146 6.68461 6 68461 6.39693 6.39693 6.39693
ill(t) Xj -2.30259 -2.30259 -2.30259 -2.30259 -1.20397 -1.20397 -1.20397 -1.20397 -1.60944 -1.60944 -1.60944
InR,
M
-0.79851 -0.634IU 0.3220B -0.12713 -0.86750 -1.23717 0.21511 -0.56212 -0.59714 -0.52763 -0.51083 gia tri nhd nhat:
Cae gia tn a^^, a,, a^... a^ la eae he sd tuong u'ng cCia ma tran [A]:
[A]=
Vdi: [X]. [A] = [Y] (5) + Ma tran thdng sd dau vao [X] la logarit cd sd e eae gia trj V, S, t diing trong thi nghiem.
+ Ma tr§n thdng sd dau ra [Y] cd cac he sd la logarit eo sd e eae gia trj 66 nham do dupe tren eae mau thf nghiem.
Nhan hai ve cua (5) vdi ma tran chuyen vi X^ cua ma tran X:
[xr.[x].[A]-txr.[Y]
eat [M] = [X]^. [X] ta cd:
[M]. [A] = [XV.m
Gil si:rdet(M) ^^ 0 thi [M] la ma tran khci nghieh.Tacd;
[A]-[MI-'.[X]\[Y] (6) Logarit ca sd e eae gia tn V, S, t va R^
ta dUdc ket qua trong b i n g 3.
TCf b i n g 3 va phuang trinh hoi quy thue nghiem (2) ta cd:
M=
1 5.09375 1 5.56452 1 5.09375 1 5.56452 1 5.09375 1 5.56452 1 5.09375 1 5.56452 1 5.35659 1 5.35659 1 5.35659
5.99146 5.99146 6.68461 6.68461 5.99146 5.99146 6.68461 6.68461 6.39693 6.39693 6.39693
-2.30259"
-2.30259 -2.30259 -2.30259 -1.20397 -1.20397 -1.20397 -1.20397 -1.60944 -1.60944 -1.60944 SCf dung phan mem Excel tinh toan ta daoc ma tran [A]:
^-0.7985ll -0.63488
0.32208 -0.12783 -0.86750 Vdi [Y]= -1.23787 - » [ A ] =
0.21511 -0.56212 -0.59784 -0.52763 -0.51083
Cac he so cua phi/ong trinh h6i quy thuc nghiem:
a, = -4,52911-.C =e-'."'" =0,01079 a =-0,77396; a-= 1,20887;
"-4.52911' -0.77396
1.20887 -0.28811
a^
a, a.
. S j .
I TapdiiKHOAHOC&CONGNGHE. S o 2 2 . 2 0 1 4
SClENCETECHNOLOGYl
BSng 4. Ket qua tinh to^n So tin cay TT
1 2 3 4 5 6 7 8 9 10 11
Xl 5.09375 5.S6452 5.09375 5.56452 5.09375 5.56452 5.09375 5.56452 5.35659 5.35659 5.35659
X;
5.99146 5.99146 6.68461 6.68461 5 99146 5.99146 6.68461 6.68461 6.39693 6.39693 6.39693
Xi -2.30259 -2 30259 -2.30259 -2.30259 -1.20397 -1.20397 -1.20397 -1.20397 -1.60944 -1 60944 -1.60944 Totig
Trung binh
y.
-0.799
•0.635 0322 -0.128 -0.868
•1.238 0.215 -0562 -0.598
•0.528 -0.511 - 5 . 3 2 8
Y.
0.56517 0.92953 0.27276 0.09160 0.88169 1.24605 0.04377 0.40812 0.47814 0.47814 0.47814
y « . -0.484
y.-y:
•0.23334 0.29465 0.04933 -0.03623 0.01419 0.00817 0.25888 -0.15400 -011970 -0.04949 -0.03268
( y - y . . ) ' 0.098697 0.403070 0.650330 0.127102 0.146807 0.567804 0.489242 0.006049 0 012880 0.001874 0.000701 2 . 5 0 4 5 5
(y-y;)' 0.054447 0.086817 0.002433 0.001313 0.000201 0.000067 0.067018 0.023714 0.014327 0.002449 0.001068 0 . 2 5 3 8 6
a , = - 0 , 2 8 8 1 1
Ta CO p h u o n g t r i n h h o i q u y t h u c n g h i e m ; y = - 4 , 5 2 9 1 1 - 0 , 7 7 3 9 6 X,-1-1,20887 X j O , 2 8 8 1 1 X 3 (7) P h u o n g t r i n h q u a n h e giOa d o n h a m R^ v a c a c t h o n g s o c h e d p c 3 t :
R, = 0,01079.V"">»'.S''»".t*"'" (8)
2.4.2. Danh gid do tin cay ciia ham hoi quy thttc nghiem . Oanh gia do tin cay:
£)6 tin cay duoc d^nh gia theo [5] cong thu'c:
oJ
0.25046-0.02539 025046 - = 0.905
5d.'
oJ (9) Trong do:
" ^ - ^ - I f y . - y i . ) "
o'J = ^ . Z ( y , - y , ) '
Vdi; y - la logarit ca sd e gia tri dp nham R^ thUe nghiem 5odUde(y, = lnRJ;
y - gia tri trung binh logarit cd sd e dp nham R^ theo :huc nghiem do dupc;
y ' - l a logarit dp nham R^ theo ham hdi quy thue nghiem;
N - s d t h i nghiem.
SCrdung phan mem Excel ta tinh dupe ket qu5 dp tin cay :he hien trong b^ng 4.
^l = r r 7 - I t > ' i -yi*^' = - ^ - 2 . 5 0 4 5 5 =0.25046 ' N-1 I \\-i
CT'^ = — . Z ( y i - y ' i ) ' = — ' — *0.25386 = 0.02539 ' N - 1 I 11-1
Op tin cay: r = 90,5%
• Kiem djnh cac he so a,:
- Xac dinh phUdng sai dU S^^:
5^ (A)
N - k - 1 (10) Trong dd:N la sd thi nghiem (N = 11);
k la sd thdng sd can xac dinh trU a^;
S'(A) = ([Y]-[X].[A])M[YI-[X].[A])
Dung phan mem Excel giai eae bai toan ma tran ta tinh duae: S^(A) = 0,25386
S'(A) 0.25386
5 i - 0.036265813
N - k - 1 1 1 - 3 - 1 - > 5^^=0,19043585
- Xac djnh sU tdn tai eCia cac he sd a^:
Cac he so a, tdn tai [51 xae dinh theo edng thtfc:
W=
| S j . > . (11)p t t . . , ( N - l < - l , r )
Trong do: m^^ la so hang thuf ii (dudng cheo chinh) cua ma tran M ' v6i: [(M] = [XF. [Xj;
^106.76821 -11.95875 -6.53236 0 7 8 8 0 3 ' . . . -11.95875 2.24794 -0.00804 -0.00782 M =
-6.53236 -0.00804 1.03272 -0.00773
0.78803 -000782 -0.00773 0.40674
S o 2 2 . 2 0 1 4 . Tap dii KHOA HOC & CONG NGHt 1S
B!Wilil«Wc6NG NGHE ^
Hlnli4.e6thiqiianhegiiiaR^v61VvaS Hinii 5. Do till quan lie giifa R^ vdi V va t Hinli 6. Do thj quan he giCa R^ vdi S vl t
Taed:
l^""''l~|Sj^7m„|~|0.19O43585.Vl06.7682l|
= 1-2.30167| = 2.30167
1 1 1-1 ^' I I -0.77396 I I Sdu V m „ I ~ 10.19043585.V2.247941
= 1-2.710681 = 2.71068
tren may phay DOOSAN DNM400:
R^ = 0,01079. V ^ " ' " . S ^ ' " " ' . t ° - ' " "
Ket qua nghien cOfu se giup cho viec tinh toan, lUa chgi ehe dd cat hop ly, nang cao dUde nang su^t, ehit luong^
mat va dd ehinh xac gia edng. J Phan hien khoa lioc: TS. Hoang V i n ^
""""' IS^^Vm^jl '|o.19043585.Vl.03272|
= 16.246531 = 6.24653
|.;,J
S j , J n \ 7 ] |o.l9043585.V0.40674l 1.20887|-2.37219| = 2.37219
Theo bang phan bo Student [3] vdi t^^^ (N - _^j=l,943.
Nhan thay:
|.;»1
= > t t ^ „ g ( N - k - U ) v ^ i i - 0 - ^ 3 Do dd eae he sd a thuc sU tdn tai, phuong trinh hoi quy thuc nghiem (7) tdn tai, nen tdn tai mdi quan he giCfa dd nham be mat vdi che dp eat nhu sau:R, = 0.01079. V"'"^»*. S'-^""". f»''*«"
2.2.3. Do thf quan he gida do nhdm vdi ^dng so chi do cat Dijng phan mem MatLab ve dd thj bieu dien mdi quan he giCfa dp nham R^ vdi 2 gia tri cua thdng sd che dp cat. fid thi mdi quan he giCfa R^ vdi V va S (hlnh 4). Dd thi mdi quan he giCfa R^^ vdi V va t (hinh 5). Do thj mdi quan he giij'a R^ vdi S vat (hinh 6).
3. K^T L U A N
Ket q u i nghien ciJu, thUc nghiem va xd ly sd lieu thuc nghiem da xac djnh dupe mdi quan he toan hpc giufa dd nham be mat chi tiet sau gia cdng (RJ vdi cac thdng sd cdng ngh§ ve ehe dp eat (V, S, t) khi gia cdng chi tiet vat lieu 40Cr
TAILIEUTHAMKHAO
[1]. Nguyen Trong Binh, Nguyen Tlie Bat, Tran Van flich, Cong nghi may, I4XB Khoa hoc va Ky thuat, Ha Noi, 2002.
[2]. Pham Van Bong, Luan an tien sT ky thuat, 2007.
[3].Tran Van Bich, Cac phifong phap xac dinh do chinh xacgia c6ng,l hocva Kythuat, Ha Noi, 2010.
[4). Tran Sy Tuy, Nguyen Duy, Trinh Van Tit, Nguyen 1)/ c3t got kim lo^HB Khoa hoc va Ky thuat. Ha Noi, 1997.
[51. Nguyen Doan % Quy hoadi thifc nghiem, NXB Khoa hoc va Ky t h u ^ ii,2003.
[6] P A.Barabasup, Ngucri dich Tran Van Djch, Ky thuat phay, NXB ',, thuat, Ha Noi, 1984.
[7]. Mike S. Lou, Joseph C. Chen, Caleb M. Li, Surface Roughness technique for CNC End Milling, Joumal of industrial technology, 1999.
[8]. M. Alauddln, M. A. El Baradie v M. S. J. Hashmi, Optimization of Sllto finish m end milling Inconel, Journal of Materials Processing Technology, 2(KI%j [9]. M 0 flKo6coH, TexHOJiomfi CTaHKOCTpoeniw, HsflareiHiW
"MauiHHOCTpoeHiie", MocKBa, 1996.
[10]. A. r. KocMnoBoii it P. K. MeuiepoKOBa, CnpaBOHHH TexHOnora.
MaujHHOCTpoHTenfl, M3flaTenbciBo"MaiiiHHocTpoeHne", MocKBa 2001.
2 0 ' T a p d i i K H O A HOC&CONG N G H E - S o 2 2 . 2 0 1 4
