,^=" •- NGHIEN ctru ANH Hl/OfNG CUA CAC T H 6 N G SO C 6 N G NGHE DEN f" [SI i DO NHAM BE MAT KHI GIA CONG TRiN MAY PHAY CNC \ ' ^ / THEO PHl/ONG PHAP THIET KETHlTC NGHIEM '•'^^^ RESEA
Trang 1,^=" •- NGHIEN ctru ANH Hl/OfNG CUA CAC T H 6 N G SO C 6 N G NGHE DEN
f" [SI i DO NHAM BE MAT KHI GIA CONG TRiN MAY PHAY CNC
\ ' ^ / THEO PHl/ONG PHAP THIET KETHlTC NGHIEM
'•'^^^ RESEARCH THE EFFECTS OF TECHNOLOGICAL PARAMETERS TO
SURFACE ROUGHNESS IN PROCESSING THE CNC MILLING
MACHINE BY DESIGN OF EXPERIMENTS METHOD
Nguyen Trgng Hiing', Pham Vdn Tiian^
1 Truang Dgi hoc Suphgm Ky thugt Hung Yen
2 Trudng Cao ddng nghe Co gi&i vd Thuy lgi
Tomtit:
Bdi bdo ndy trinh bdy phuang phdp nghiin ciru dnh huong eua ede yiu td cdng nghi din dp nhdm
be mat khi gia cdng tren mdy phay CNC theo phuong phdp thiet ke thue nghiem (DOE), ldm gidm sd lugng thuc nghiem, tgo ra sdn phdm chdt lugng eao vai ehi phi thdp cho cdc nhd sdn xudt Ket qud nghien ciru cho quan he giira dd nhdm be mat vdi cdc thdng sd cdng ngh4 gdm van tdc edt, lugng chgy dao, chiiu sdu cat
vd xdc dinh duge thdng sd cdng nghi tdi uu cue bp (trong phgm vi khdo sdt) cd dp nhdm be mat nhd nhdt khi gia cdng tren mdy phay CNC Do dd, ndng cao chdt lugng be mat vd ndng sudt gia cdng
Ti^ khda: Anh hu&ng yiu td cdng nghi Do nhdm bi mat gia cdng, Thiit ki thuc nghiim Ma trgn tritrc giao, Vdn lde cat Lupng chgy dao vd Chiiu sdu cat Mdy phay CNC
1 Md dau
Viec nghien cuu anh huflng eac thflng sfl
cflng nghe den dp nham be mat khi gia cong tren
may phay CNC, theo phuang phap thilt kl thue
nghiem (DOE) sir dyng ma tran true giao cap I, dl
dam bao do nham bl mat nhfl nhat (dp bdng cap
mat vdi cac thflng sfl cflng nghe gom van tflc cat,
lugng chay dao va chieu sau eat, trong dieu kiln
san xuat hang loat theo phuang phap dilu chinh san
tren may phay CNC Do dfl, nang cao chdt lugng
lam vile cua cac chi tilt may, dac biet la eae ehi tiit
may tham gia vao mfli lap ghep va nang suit gia
eflng Theo phuang phap nay, hien nay dang dugc
ling dyng nghien ciru d nude ngoai va hien cae eflng
trinh chua nghiin cim mgt cdch ddy du ve van de
nay trong ITnh vyc che tao may (vi dy, moi chi dimg
lai d vile su dung phuang phap hfli quy ham so rati,
hoac nghiin ciiu dnh huong theo timg biln riing re
va chua xet din cac he so tuang tac)
Qua nghien eiiu nit ra nhiing vdn de cd tinh
quy luat, kilm ehiing tren thyc te Tir d6, xay dung
san xuat tuang tu, giiip cho nguoi thao tac dl dang
ling dyng, nham tfli uu cac thflng sfl cflng nghe
trong pham vi khao sat
2 Cu sd phu-ong phdp nghien cihi theo thiet ke
thuc nghif m (DOE)
Phuong phap quy hoach thyc nghiem la rapt
trong nhirng phuong phap diiit ki thye nghiera
{DOE) dang dugc img dyng trong linh vyc ehi tao
may [2]
Phuong trinh hfli quy {md hinh todn hpc)
nhan dupe bang phuang phap quy hoaeh thyc nghiem cfl the dung de xae dinh eac thflng sfl dau
nhdt hodc nhd nhdt)
2.1 Phuwng phap quy hoach su di^ng ma triin true giao
Theo phuong phap nay, cap ciia ma tran true giao phy thudc vao bae eua biln sfl khao sat, nfl co dang cap I khi bien so la bac nhat va cap 2 khi bien sfl Idbeichai
- Mien bien thien:
Z"'" < Zj < Zj"""
- Tdm quy hoaeh:
Zj" = 0.5(Z,'™ + Z,'™)
- Phuang phdp phan tich hfli quy:
Cac phuang phdp phan tieh hfli quy gflm cfl
Phuong phdp binh phuong nhd nhdt: Hdi quy tuyin
vd Hdi quy nhiiu bien
Chd y rdng, su dgng hdm nhiku biin tdng qudt vd cho ket qud v&i dp chinh xac cao han
Khi tiln hanh quy hoach sd dyng ma tran tryc giao cipl vdi ba thdng sfl nghien cdu, ham hfli quy nhilu bien cfl dang nhu sau:
y = fio + h\X\ + b2X2 + &3X3 + 612X13:2 + + 1)23X2X3 + 6133:13:3 + bi23 X{.X2.Xi
Trong dfl:
x^- Biln khao sat bae 1
dj,-He sfl hfli qui
Trang 2b^ - H I sfl tuyin tinh
6,.' 6, ( - H I sfl tuong tdc cap vd tuong tdc ba
- Thgc hien N = 2*^ thi nghigm, roi tmh toan
cac h | sfl hfli quy b b i n g phuong phap binh phuong
nhfl nhat
- Kiim djnh sy cfl y nghia cua cac he sfl hoi
quy b theo tieu ehuan Student, bang each thyc hien
thi nghiem song song, lap lai Loai bo ede he sfl b
khong CO nghia, tinh toan I91 eac b va kiem dinh lai
cho tdi khi chi cdn cac b co nghia
- Kiem djtih sy cfl nghia cua phuang trinh
hfli quy voi chudn Fisher
2.2 Thm: nghidm y i u to toan phan N = l""
- Phuong phdp tfl chue thi nghiem tryc giao
cap I:
+ Sfl thi n g h i | m can thye hien:
N = 2''
+ Muc ea ban {tdm phucmg dn):
^j 2
Trong do:
^mex _ ^Q ^ ^ ^ ^^f, ij.g|, (miic eao),
^min ^ 2y — /I: Mue dudi (muc thap);
^, = —^—^—-—: Khoang biin thiin theo
true Z
- Biin khflng thii nguyen x^:
Ma hod duae thyc hien nhd vile chgn tam
Z° ciia m i i n nghien ciiu lam gflc he true tga dfl
' zr-z'
_zr'Z°
~ Al
_Zl-yZl
Trong do:
6 - HI so thuy trong phuong trinh hdi qui 5j - Sai lech binh phuong trung binh ciia he sfly
3 Xdy dung bai toan nghien cuu va thuc nghiem 3.1 Bai todn nghiin cuu
Nghien cim anh budng cua c h i dfl cflng nghe den nham be mat cua loat ehi tiit gia cong thu tren may phay CNC khi thay dfli che dp cflng nghe: Van
tflc cat V (vg/ph), Lugng chay dao S (mra/vg) va
Chilu sau cat ((mm)
3.2 Lua chgn gid tri cdc thdng s^ cong nghe
Vi|c lya chpn cae thflng sfl cflng nghe phy thupc vao phuang phap gia cong, thiet bj, dung cy cat, vat lieu lam dao, vat lieu duoc gia cong va efl thi dupe tra cuu tu tdi lieu [5], [6]
Dieu kien thuc nghiem •
- Su dung mdy phay 3 true CA'C - DMC635V
do Hang DECKEL MAHO Cflng Hoa Lien Bang Ddc che t^o, he dieu hanh FANUC32i
- Dao phay mat diu SESCO R220.43-005A,
lam bang hgp kim, sfl rang z = 8
- Vat lieu phfli' thep cacbon C45
- Chi tiit gia cong cfl dang be mat phang (hinh I)
Tu cac tai lieu [5], [6], [7] va [8], voi myc
dich nham b i mat ciia mau thu nghiera nhfl {do bdng cao) trong thyc nghiera d day lya ehgn cac
thong so eflng nghe gflra van toc cat (V), lugng chay dao (S) va chiiu sau cit (t) theo eac so lieu trong bang 1
Bang 1
y = I , 2 , ,k
- Xdy dung ma tran thue nghiera:
+ Sfl thi nghiem xac dinb theo eflng thirc N
= 2'', c5t Xg lufln bdng 1
+ Lap eho timg y i u tfl anh hudng va lan
lugt hi JT; dinjc^;
+ Dua cac thi nghiem d tara vao raa tran
2.3 "i nghia cua h i so b trong phirong trinh hoi
Tinh y nghia ciia eac he so b dugc kilm dinh
theo chuin Student (t) xac djnh nhu sau:
M
'' 5.,
Thong s6 cdng nghf
I Muc cao
2 Muc trung binh
3 Muc thap
V
(m/min)
81
71
61
S (mm/vong)
0.45
0.3
0.15
t (mm) 1,0
0,6
0.2
Hinh 1 Bi mat mdu sau khi phay tinh
Trang 33.3 Thiet ke thuc nghiem
3.3.1 Thiit ke thuc nghiim nghiin cuu anh
hudng eiia thong so cong nghe den dg nhdm be
mat
a Phuong phdp td chuc thuc nghiem true
giao cdp I
- Sd thuc nghiem:
Sfl yiu tfl anh hudng den dp ehinh xac kich
thudc gflm 3 yeu tfl la van tflc eat, ehieu sau cat va
luang chay dao
k = 3
So thyc nghiem tai tam: N^ = 4
Suy ra, tflng sfl cugc thyc nghiim:
N E = N , + N , , - 8 + 4 = 1 2
- Mirc CO bdn •
u day chon:
V^^^ = 6 ! m/ph; S^^^ = 0,15 mm/vong; t^^^
-0,2 mm.'"'
F ^ = 81 m/ph; 5"^^ = 0,45 mm/vong; t^ =
1,0 mm
Suy ra: Vj = 71 m/ph; ^ j = 0.3 mm/vong;
t, - 0.6 mm
- Khodng bien thiin:
Xi=lOra/ph;AJ = 0 1 5 mm/vong;/I; = 0 4
mm
- Cdc biin Ichdng thu nguyin:
+ Bien khflng thd nguyen v | n toc: ij™ — 1; i j " " =— 1 ; Xj" = 0 + Biln khflng thd nguyen lupng chay dao
x^"" = I ; Xj~° = 1; xf -0
b Ma trgn thuc nghif m
Tir phuang trinh hfli quy lya ebon:
- Chpn hara hfli quy cap I tuyen tinh cfl dang:
y - 6o + bixi + 623:2 + ^3X3 + 612X1X2 +
+ 623X2X3 + &13X! 3:3 + 6123 Xl X2.3:3 Trong do:
6g - h | sfl hfli qui
b - h i sfl tuyen tinh
b^.' 6,, - he so tuong tac cap va tuong tac ba
Suy ra, ma tran thi nghiem vdi k = 3 vd 4 thue nghiera tai tam phuang dn vdi cac thong sfl ddu
vao {V S t) va cac bien raa hfla l a ^ ^ X^ X.^ vaX^
dupe chi dan tren bang 2
TT
!
2
3
4
5
6
7
8
9
10
11
12
X, X,
-1
0
0
0
0
X,
0
0
0
0
X,
-1 -1
0
0
0
x,.x
0
0
0
0
x,.x,
0
0
0
0
x,.x,
1 -1
1 -1 -1
1 -1
1
0
0
0
0
x,.x,.x,
-1
0
0
0
0
V
61
81
61
81
61
81
61
81
71
71
71
71
S 0.15 0.15
0 45 0.45 0.15 0.15 0.45 0.45 0.3 0.3 0.3 0.3
t 0.2 0.2 0.2
02 1.0 1.0 1.0 1.0 1.0 0.6 0.6 0.6
Trong do:
X^ - biln ao dupe dua thera vao ma tran;
X^ - bien ma hoa img vdi van tflc cat,
X.^ - biln ma boa img vdi lugng chay dao
X.^ ' biln ma boa img vdi chieu sau cat
3.3.2 Lua chgn phuong phap va thiet bj do
- Phuang phap do: do nham b i mat theo
phucmg phdp dau dfl
- Thiet bl do (hinh 2):
+ May do nham be mat Mitutoyo SJ-4Q0,
cfl bfl phan ghi kit qua do ciia Hang Mitutoyo (Nhat
+ Dp phan giai do 0,000I25pm
Hinh 2 Do nhdm mdu trin mdy Mitutoyo SJ-400
Trang 4- Ket qua do gia tri nhdm 12 mau doi vdi mfli phuang an ciia 12 cuflc thi nghiem theo ma tran thyc nghiem duge chi ddn trin bdng 3
TT
(Cupc
Ihi
nghiem)
1
2
3
4
5
6
7
8
9
10
11
12
(nm)
0,156
0,184
0,192
0,204
0,318
0,210
0,338
0,134
0,297
0,223
0,242
0,242
Gia In
m l u 2
y,2
(nm)
0,342
0,168
0,193
0,187
0,202
0,223
0,344
0,268
0,198
0,270
0,234
0,225
Gia tri
nhlim
y,!
(nm)
0,145
0,166
0,197
0,195
0,299
0,232
0,511
0,294
0,240
0,393
0,235
0,263
Gia hi
y,4
(nm) 0,136 0,168 0,193 0,160 0,195 0,418 0,555 0,281 0,292 0,211 0,273 0,272
G i a t n
y.s (nm) 0,198 0,170 0,216 0,231 0,435 0,345 0,552 0,537 0,195 0,189 0,275 0,273
Gia hi
mau 6 y.6
(nm) 0,341 0,168 0,192 0,203 0,591 0,397 0,579 0,542 0,305 0,164 0,274 0,303
Gia tri
y,7
(nm) 0,159 0,169 0,237 0,194 0,289 0,593 0,752 0,537 0,495 0,340 0,255 0,322
G i a m
y,
(nm) 0,169 0,168 0,227 0,156 0,574 0,364 0,850 0,530 0,429 0,340 0,314 0,257
mlu 9 y,»
(nm) 0,259 0,169 0,229 0,159 0,427 0,296 0,920 0.524 0,457 0,340 0,222 0,262
10 y.io
(nm) 0,170 0,169 0,228 0,147 0,389 0,386 0,464 0.626 0,359 0,449 0,486 0,316
11 y.ii
(nm) 0,142 0,170 0,230 0,169 0,478 0,346 0,437 0,631 0,259 0,545 0,322 0,312
G i a t n
12 y,i2
(nm) 0,130 0,170 0,238 0,144 0,570 0,171 0,606 0,623 0,392 0,235 0,500 0,318
Gia tri trung binh nham (nm) 0,195 0,169 0,214 0,179 0,397 0,3317 0,575 0,460 0,3265 0,308 0,302 0,280
3.3.3 X u ly va kiem tra s6 lilu thuc nghifm
- Vdi ham hfli quy cap I tuyen tinh da chpn
CO dang:
y = 6o + 6i Xl + 62X2 + 63X3 + 612X1X2 +
+ 623X2X3 + 613XL X3 + 6123 Xl.X2.Xi
Suy ra, dang eua phuang trinh hfli quy can
tim:
r - 6 , ) + 6 i Z , + 6 2 X 2 + 63 X^ + bn.Xi.X2 +
+ ba X2.X3 + bu Xl X3 + 6123 • ^i X2.X3
- Theo phuang phap binh phuang nhfl nhat,
cac he sfl b trong phuong trinh hfli quy cua quy
hoach tryc giao cdp I tuang img vdi k = 3 yeu td
anh huflng ed gia tri nhu sau:
6 0 = 0 , 3 1 1 4
6 1 — 0 , 0 2 0 1
bi = 0,0279
6 3 - 0 , 1 1 1 1
6 1 2 — 0 , 0 0 4 8
623 = 0,0231
613 = - 0 , 0 1
,6123 = - 0 , 0 0 3 4
Sau khi k i l m tra y nghia cua eac he b trong
phuong trinh hfli qui theo phuang an thyc nghiem
tai tam va y nghia cua cac he sfl b dugc kiem dinh theo chudn Student (t) Suy ra, cdc he sfl by by by
by b efl y nghia vd deu dugc giii lai trong phuong
trinh hoi quy
Do dfl, Phuong trinh hfli quy cfl dang nhu sau:
Y = 0,3114 - 0,0201 Xl + 0,0279 ;i"2 + + 0, n i l X3 - 0,0048 X1.X2 + 0,0231 X2 Xz +
- 0 , 0 1 X i X 3 - 0 , 0 0 3 4 X i X 2 ^ 3
- Kiem tra sy tuong thich cua phuang trinh hfli quy vdi thyc nghiem theo bang gia tn gidi ban
cua chi tiiu Fissher F
Ft, .Si
Sih
0,003440
^ 0 1 8 0 F(0,95)(f,,f,) = F(0,05)(6,3) - 5,3!
F < F^^, phuang trinh hdi quy tim dugc la tuong thich vdi thyc nghiem vdi mdc y nghia 95%
- Kiim tra su dflng nhdt eua eac phuong sai theo bang gia tn gidi han ciia chi tieu Cochoren
Gtn =
Zs,-:
0,, = 0,547
Suy ra, G,^ < G^
Trang 53.3.4 Do thi thuc nghiim
Su dyng phdn mera Microsoft Excel - 2007
di tinh toan va phdn mem Tableeurve 3D V4.0.0 1
di ve biiu dfl quan he gma eac thflng so cflng nghe
din nham bi mat khi gia eflng tren may phay CNC
hoc cua nfl Chu y rang, phan mem Tableeurve 3D
V4.0.0.1 chi biiu dien dugc quan he giiia ba thong
sfl
Do do, anh huflng cua cdc thflng sfl cflng
nghe bao gflm van toc cat V, lugng chay dao S vd
chilu sau cat f den nham be mat ehi tilt khi gia cflng
trin raay phay CA'C se dugc bieu tren cac hinh (3a,
b va c)
Trin hinh 3a, ede diem ma gia tri nham eiia mdu thu dng vdi 12 phucmg an cflng nghe phy thuflc
vao gia tri cua V \k S theo ma tran thyc nghi?m (bang 2) va gid tri ciia no tuong dng vdi cot gid tri trung binh cua nham trong bang 3
Trin hinh 3b, ede dilm gia tri nhdm eiia mau thu nhd (ddng 2, 4, 1 va 3 - bang 3) phu thuoc vao Kva / hrong ung voi bon phuang an cong nghe 2,4,
I va 3 trong bang 2
Trin hinh 3c, cae dilm gid tri nham cua mdu thli nho (dong 2, 4, 1 va 3 - bang 3) phu thugc vao
S vd t tuong img voi bon phuang an eong nghe 2,4,
1 va 3 trong bang 2
- Anh hudng eiia van tflc cat va lugng chay dao den nhdm be m§t:
%^ O.J ^.opW Hinh 3a Anh huang ciia Vvd S den nhdm be mat tuong ung voi 12 cugc thu nghiem
- Anh huong cua van tflc eat va ehieu sau eat din nham be mat:
Hinh 3b Anh hu&ng eiia Vvd I din nhdm be mat tucmg ting vdi 12 eudc thu nghiim
Trang 6- Anh hudng cua lugng chay dao vd chiiu sdu edt din nhdm bi mat:
Hinh 3c Anh huang ciia Svd t din nhdm bi mat luang img vai 12 cupc thic nghiem
4 Kit qua thuc nghidm vd danh gid ket qua
nghiin cuu
Tu kit qua nghien euu thay rdng, che do
cflng nghe tdi tm cue bg {trong phgm vi khdo sdt)
efl dfl nham be mat nhfl nhat {dp bdng cao nhdt) khi
cae thflng sfl cong nghe dugc lya chgn:
- Van tdc cat: V = 81 (m/phut); lugng ehay
dao: S ^ 0,15 mm/vong (hinh 3a)
- Van toe eat: V = 81 (m/phiit); chilu sau cat:
t = 0,3 mm (hinh 3b)
- Lugng chay dao: S = 0,15 mm/vong; chieu
sdu cat: t = 0,3 mm (hinh 3c)
Do dfl, theo phuang phap thiet ke thue
nghiem {DOE) sit dung ham hfli quy nhieu biin,
phuong trinh boi quy thu dugc cfl eae he sfl tuong tac cap va tuong tac ba ke den anh hudng ciia eae thflng sfl cflng nghe den do nham be mat cht tiit gia cflng Day la dilm mfli va khac biet so vdi cdc cflng
Bfl thflng sfl cflng nghe tfli uu eye bg (trong phgm vi khdo sdt), khi do nham bl mat cfl gia tri nhfl nhat {do bdng cao nhdt) nhu sau: V ^ 81 (m/phut);
S = 0.15 mm/vong, t = 0.3 mm
Tai lieu tham khao
[I] Tran Van Dich, Nghien ciru dp chinh xdc gia cdng bdng thuc nghiem, NXB Khoa hgc va ky
thuat, Ha Noi 2003
[2] Nguyen Trgng Himg, Thiit ki thuc nghiem trong chi tgo mdy, Truong Dai hgc Su pham ky thudt
Hung Yen, Hung Yin 2013
[3] Pham Van Tudn, Nghien ciru dnh hu&ng cua che do edng nghe den nhdm be mdt khi gia cdng trin mdy phay CNC, Luan van Thac sy ky thu|t, Truong Dai hgc Su pham ky thuat Hung Yen, Hung
Yin 2013
[4] Ninh Due Tfln, Nguyin Trgng Hiing, iCyf/iuarifo Tdp I Dung sai lap ghep vd Tieu ehudn hda,
NXB Giao due Viet Nam, Ha Npi, 2006
[5] Nguyin Ddc Lfle va cae tae gia, Sd tay Cdng nghe che tgo mdy, NXB KHKT, Ha Ndi 2000 [6] NTU, Tra ciru chi do cat, Khoa Co khi, Truflng Dai hoc Nha Trang
[7] LulzimBalal.AfrimGjelajI, Avdyl Bunjaku2 and AvdiSalihul,5«r/acei?o«gArt^sso/Matena;
Processing during Milling Process, Joumal of Mechanics Engineering and Automation 2 (2012)
601-605
[8] Nitin Agarwal, Surface Roughness Modeling with Machining Parameters (Speed, Feed & Depth
of Cut) in CNC Milling, MIT IntemationalJoiunal of Mechanical Engineering, Vol 2, No lU, Jan
2012, pp (55-61)
Trang 7Abstract:
This article presents a research method the effects of the technological parameters to surface roughness in processing the CNC milling machine by design of experiments (DOE) method, which reduces the number of experiments, produces high quality products with low cost for manufacturers Results of
speed, feed intake ranging, depth of cut and determine the local optimum technological parameters (within the survey) with minimum surface roughness when processing on CNC milling machines Therefore, the the quality of surface and productivity in processing are improved
Keywords: Effect factors of technology Surface roughness Design of experiments (DOE) Orthogonal array Cutting velocity Flow range and Depth of cut, CNC milling machine
Nguoi phan b i l n : GS.TSKH Bdnh Tien Long