NGHIEN CU'U-TRAO D 6 I
ANH Hl/dNG CUA BOI TRON LAM NGUOl T 6 I THifeU (MQL) T 6 | MON DAO VA Op NHAM B i MAT KHI GIA C 6 N G GANG CAU
EFFECTS OF MINIMUM QUANTITY LUBRICATION (MQL) ON TOOL WEAR AND SURFACE ROUGNESS WHEN MACHINING
NODULAR CAST IRON
ThS. Nguyln Thai Binh Trudng Cao ding Cdng nghiep Thii Nguyen
TOM TAT
Bdi viet ndy tom tat qud trinh gia cdng gang cdu cd dp cung cao duac img dung cdng nghe boi tran - ldm nguoi tdi thiiu (MQL) vai dung dich tran ngudi Id ddu thuc vgt, cdc thdng so cong nghe gia cdng duac lua chpn truac. Ket qud cda phuang phdp ndy dd mang lpi hiiu qud tot ve mon dao, nhdm be mgt chi tiit vd gdp phdn gidm thieu d nhiem mdi tru&ng.
Til khda: Gang cdu; Bdi tran - ldm ngudi tdi thiiu (MQL).
ABSTRACT
This paper presents a study on the application of Minimal Quantity Lubrication (MQL) technology in high hardness Nodular Cast Iron Machining using vegetable oil as a liquid coolant.
During the experiment process the machining parameters are preselected. The results shown thai the surface quality was improved, the tool life increased and environmental pollution was minimized.
Keywords: Nodular Cast Iron; Minimal Quantity lubrication (MQL).
2. GlOfI THIEU nhien, lire cat khi gia cdng gang tuang ddi nho va cho phoi vun. Do viy, gang dupc xep vao Theo cdng nghe truyen thdng, khi gia nhdm vat lieu de gia cdng cit gpt, tuy nhien cdng vEit lieu gang, thdng thudng ngudi ta gia khi gia cdng cat gpt gang ciu cd dp ciing cao cdng khd (khdng bdi ttan) do die dilm biln (tii 150HB) thudng gap mdt sd vin de nhu:
dang va cau tao hinh thu ciia gang. Phin Idn
gang cd kit ciu d dang ferit hoic peclit cd tir - Mdn dao do tap chit ciing lln troag 3- 5% graphit d dang bdng, tam, phien hoic gang gay ra;
cau. Chinh vi cd graphit len tinh deo cua gang
giim, ttong qua trinh gia cdng lam phoi d l - Cd hien tugng phoi chay deo va dioli giy v i hoat ddng nhu mdt loai chit bdi ttan tu bim len mat sau;
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- Mdi trudng lam viec ddc hai va nguy hiem ddi vdi ngudi cdng nhan [7].
De khic phuc cac nhugc diem ke tten, cac tic gii de xuat iing dung cdng nghe bdi ttan tdi thilu (MQL) [S] khi gia cdng vat lieu gang ciu vdi dung dich ttan ngudi la diu thuc vat (diu lac) v i che dp gia cdng, bdi ttan dugc tinh toan lua chpn trudc (tdi uu) vl nhimg uu diem ndi bit cua cdng nghe niy nhu:
- Giam lire cat va mdn dao;
- Ning cao tudi ben ciia dung cu cat.
- Khdng gian lim viec sach, gdp phin giam d nhilm mdi trudng, khdng inh hudng xiu den siic khde ngudi thp [2].
Sau day la tien trinh th\rc nghiem gia cdng gang ciu vdi phuang phip MQL v i cac ket qua dat dupc:
3. TIEN TRINH THI NGHIEM
<^
IL^
1) Binh khi nen (dat 10 kg/cm^);
2) B9 on dtnh ap suat;
3) Van diSu dp,
4) Buong tao chan khSng va tron;
5) Dao phay mat dSu;
6) Chl tifil gia cong;
7) Van dieu chinh, 8) Binh chiia dung dich troTi ngugi Hinh 1. Sa do thi nghiim
Dieu kien thi nghiem:
M^y cong cii Phoi mau:
- Vat lieu - Kich thuac
- Hinh ve
Dao
Cac thong s6 gia cong Cung cap MQL
May ptiay dung Showa •- Nhat Ban Gang cau. B H 5 0 ( C = 0,62 - 0,70%, Si = 0,17 - 0,37%, 0,035%, S < 0,035%, Cr < 0,025%, Ni < 0,025%, Cu < 0,20 HB;
Lx WxH= 250 X 100 X 10 (mm)
Ijlgi
vin = 0,9 ^ 1,2%, P <
/o), do Cling: 170 - 220
Dao phay m | t dau gan manh HKC BK8 ciia Nga (8% Coban va 92% Cacbit Volf- ram); do ciing : 90 HRA)
N= 400vg/ph; V c - 200m/ph; S= 28mm/ph; 1= 1,7mm
- Dung dich tran nguoi: Dau thuc vat (dau lac) phun vao viing cat a dang suong mil);
- Ap sail phun (P) thay d6i, ISn luat la: P = 4KG/cm-, P= 5 KG/cm' va P = 6KG/
cm^;
- Luu luong dau boi tron (Q) la khong doi: Q = 0,25 ml/phiit du(?c phun vao mat sau Clia dao.
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NGHIEN CU'U-TRAO DOI
- Diu phun: Diu phun NOGA (Cdng hda Lien bang Diic).
- Dung cii do kich thudc:
+ Thudc cap dp phin giai 0,01- Mittutoyo (Nhat Ban).
+ May do nhim: SJ-201 Mittutoyo (Nhit Bin).
- Dling cu do luu lugng; Loai vach chia 5ml, thd tich 500 ml.
- Thiet bi dn dinh va dieu chinh ip suit (ddng hd oxygen);
-MiychiptgviSEM:TM-1000(NhatBan).
3.2. Trinh t y ti^n hanh thi nghiem [1]
Phay mat phang chi ti8t gang ciu cd kich thuac phdi: 2S0 x 100 x lOmm bing dao phay mat dau cac bit vdi cic thdng sd cdng nghe: N= 400vg/ph; Vc= 200ni/ph; S= 28nim/
ph; t= 1,7mm va BT-LN tdi thidu cd: P = 4 KG/cm^ luu lugng Q = 0,25 ml/phut.
-Sau thdi gian cit 16,S phut vdi 02 lan chay dao (tuang iing chidu dii cit: 2 x 250 ^ 500 mm), minh dao dugc lay ra dd chup SEM mdn dao va tien hanh do mdn dao.
-Sau mdi thdi gian cit 8,25 phut vdi 01 lin chay dao (tuang iing chidu dii cit l i 250 mm) tien hanh do nham bd mat chi tiet.
- Cic lin gia cdng ti6p theo, tidn hanh thay ddi thdng sd ip suit phun (P), cu thd: P=
SKG/cm^ va P - 6KG/cm^ Luu lupng Q va thdng sd cdng nghe gia cdng giii nguyen (Q
= 0,2Sml/ph; n= 400vg/ph; Vc= 200m/ph; S=
28mm/ph; t= 1,7mm).
4. KET QUA THI NGHIEiVI 4.1. Mdn va Cff che mon m^t trir^yc dao
Chup te vi mat trudc dao bing kinh hiln VI dien tii TM-1000- Nhat (hinh 2).
c) '^^ . Hinh 2. Anh mon mat tru&c cUa dao v&i 2 luat cat
(16,5ph) v&i cdc thong so P khdc nhau:
a) Mdnh dao cat v&i P= 4al;
b) Mdnh dao cdt v&i P=5at;
c) Mdnh dao cdt v&i P=6at;
d) Anh mdnh dao phdng to khi cat v&iP=6at
Quan sit hinh anh, nhin thay:
Mdn mat trudc cd thd chia thanh 3 vung;
+ Vung 1 cd vdt mdn rd ret theo phucmg thoat phoi thdng qua mtic dp bam dinh ciia vat Iidu gia cdng vdi miit trudc. ChiSu dai mon tiep xuc giira phoi vdi mat trudc tang dan theo thdi gian cat; Dpc theo luoi cit chiSu sau mon va vdt cao xudc thiy cd bim dinh vat lieu gia cdng nhiSu nhit.
+Vung 2 la vung tidp theo vdi chieu sau mdn, vdt xudc v i dinh bam vat lieu gia ISSN 0866-7056
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cdng nhd horn.
+Vung 3 la yiing thoat phoi khdi mat trudc dao, d d i y thiy cd nhiing vdt xudc v i dinh bam v^t lieu gia cdng it. Vdi sir xuit hien cua cac vdt cao xudc chiing td mat trudc dao bi mdn do cic hat ciing tao ra trong qua binh cit.
- Su dinh bim vit lieu gia cdng va mdn manh tren mat trudc d vung 1 va vung 2 chiing td mat trudc dao bi mdn tidp xiic.
- Muc dp mon mat trudc khi gia cdng vdi MQL(P = 6at) l i thip nhit, sau do ddn gia cdng vdi MQL(P^5at).
- Khi cat vdi MQL(P=4at) mdn mat midc cua MQL(P= 4at) la ldn nhit.
- Khi gia cdng vdi MQL(P = 5a)t, be rpng vimg mdn mat trudc tang dan die biet chieu siu mon viing 1 phat trien rit nhanh.
- Khi gia cdng vdi MQL(P^6at) bd rdng vung mdn tang cham, chieu siu mdn viing 1 nhd han nhieu so vdi MQL(P=5at).
- Khi gia cdng vdi MQL(P=4at) thi bd rdng v i chieu sau mdn cua vung 1 va viing 2 tang nhanh, dac biet bd mat mdn mat trudc rit ghd ghe do niit va trdc vay cua vit lieu dao.
Nguyen nhin din den ket qui niy cd the do ap suit cua dung dich MQL cao nen cac phan tit MQL d l dang x i m nhap vio vimg tiep xuc giiia dao va phoi de bdi tran v i lim ngudi, nen giim dupc ma sat tiep xiic dao-phoi dan den giam dugc mdn mat trudc dao so vdi gia cdng d ap suit thip. Ddi vdi diu thuc vat (dau lac), do dp nhdrt cao nen cac phan bi dau khd xim nhap vao vung tidp xuc dao-phoi va bao quanh viing cit lam nhidt frong viing cat khdng thoit ra ngoai dugc, din ddn chdnh lech ldn vd nhiet dp giiia vung cat vdi viing xung quanh gay ra ung suit nhiet lim mit va va trdc v i y manh dao cacbit.
4.2. M6n mat sau va co che mdn [1].
Chup te vi mat sau cua dao bang kinh hidn vi dien tii TM-1000- Nhit (hinh 3) [3].
c) ^ d) Hinh 3. Anh so sdnh mdn mat sau ciia dao v&i 2
luot cdt (16,5ph) • a) Mdnh dao cdt v&i 4at;
b) Mdnh dao cdt v&i Sat;
c) Mdnh dao cat v&i 6at;
d) Anh mdnh dao phong to khi cdt v&i 6at
Quan sat hinh inh, nhin thiy:
- Tren vung mdn mat sau dao cd dinh bam vit lieu gia cdng va cac vet xudc chiing td ca che mdn mat sau la mdn do hat mai va mdn tiep xiic.
- Do mdn mat sau dao khi gia cdng cd MQL nhin thiy, mdn mat sau iing vdi MQL(P= dat) l i thip nhat, sau do den gia cdng vdi MQL(P=5at) va mdn mat sau vdi MQL (P= 4at) la ldn nhit.
- Be rdng v i miic dp phat tridn vdt mdn mat sau ciia vdi MQL(P^6at) nhd ban. Bd rdng v i miic dp phat trien vet mdn mat sau vdi ^
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NGHIEN CU'U-TRAOD61 MQL(P=4at) ldn ban nhidu so vdi gia cdng bing MQL(P-5at) va MQL(P=-6at).
Nguyen nhin cua ket qua nay cd the do dp nhdt ciia dau thuc vit cao nen tao sue cing bd mat ldn, vi vay cac phin tu dung dich va ap suit ddng khi khd xam nhip vio vung cat de bdi tran lam ngudi m i bao quanh vung cat giy chenh lech nhiet dp v i tao iing suit lim nut vd va trdc viy dao cacbit. Ngoii ra, ciing cd the do cd phin ling hda hpc giiia kun loai dinh ket Cohan vdi cic axit hiru ca cd trong diu lac lam mat lien ket cic hat ndn TiC cua dao cicbit.
4.3. Mdn va tuoi ben dao [1]
Mdn mat sau anh hudng den dp chinh xac kich thudc gia cdng va dp nham be mat cua chi tiet. Do dd can thiet phii xem xet miic dd mdn mat sau cua dao. Ket qui do mdn mat sau dugc tdng hgp trong bing 1:
Bdng J. Sd lieu do mdn mat sau dao sau 2 luat cdt.
TT 1 2
Thtri gian (phut)
8.15 16.3
Dd mdn mat sau (mm) Ap suat
4at 0.2 0.37
Ap suat Sat 0.1 0.2
Ap suat 6at 0.06 0.14
Dung phim mem EXCEL xu ly ket qua mdn ta cd bieu dd quan he giira mdn mat sau dao vdi thdi gian cat (hinhh4):
1.';
1 _ _ « -.-!. -^a.
; 4 a S 10 12 14 16 T l w l | l . . . . l l ( | ) l »
Hinh 4. Quan he giira do mon mat sau dao vd thai gian cdl t v&i 2 luat cdt Tir bidu dd hinh 4, ta thay miic do mdn mat sau vdi cic miic ap suit khi gia cdng xep theo chidu ting li: MQL(P- dat), MQL(P=5at) v i MQL(P=4at). Dp mdn mat sau ling vdi gia cdng MQL (P=6at) l i thip nhit.
4.4. Do nham b^ mat chi tiet R^
Tien hinh do nhim be mat chi tiet sau 02 lugt cat, ket qua do nham be mat chi tiet d Bing 2:
Bdng 2 So lieu dp nhdm R^ R^ sau 2 luat cat:
TT 1 2
ThM gian (pliiit)
8.15 16.3
Ap suat 4at R. (lira)
0.74 0.88
R.()ini) 7.96 9.46
Ap su4t Sat R.(fni)
0.72 0.75
R (nm) 6.65 6.63
Ap suat 6at R. (^m)
0.65 0.68
R (nm) 5.89 5.33 Dung phim mem EXCEL xii ly ket qui, ta cd bidu dd quan he giiia do nham bd mat chi tidt vdi thdi gian cat cd cac hinh sau:
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J o t ; . [
Hinh 5.a. Quan hi giira dp nham bi mat cht tiit R^ vd th&i gian cat t
iB
Hinh 5.b. Quan h^ giUa do nhdm bi mat cht tiit R^ vd so luat cdt
-Tu bieu dd hinh 5.a v i hinh S.b, ta thay do nham be mat chi tiet khi cit 2 lupt cit bang mdt manh dao vdi cac miic i p suit thay ddi (P = dat; P - Sat va P = 4at). Ta nhin thiy, dp nham be mat chi tiet khi cat vdi MQL vdi ip suit ddng khi = dat cd gii tri nhd nhit.
-De cd dugc kdt qui n i y l i do vdi phun dung dich tran ngudi MQL dudi ap suit ldn diy dugc cac hat ciing sinh ra trong q u i trinh cat ra khdi vung gia cdng v i giim dupc iing suit du be mat do nhiet cat.
5. KET L U ^ N
Ca che mdn dao phay mat dau cacbit khi phay gang ciu li mdn do hat mii va tiep xuc. Ngoai ra, cin ke den hien tugng dao cdn bi mdn do iing suit nhiet hinh thanh hi su chenh Idch ldn nhiet dp giiia vung tiep xiic dao - phoi vdi vung xung quanh lien quan den dp nhdt cao cua dung dich tron ngugi, hoac do phan ling hda hgc ciia dung dich tran ngupi vdi kim loai dinh ket cdban trong dao Cacbit.
Thdng sd i p suit P= 6at l i thdng sd tdi uu Cling vdi cac thdng sd cdng nghe khac dugc chpn lua trudc nhu; Q - 0,25ml; n= 400vg/ph;
V^= 200myph; S - 28mni/ph; t= 1,7mm.
Cdng nghe MQL sir dung dau thuc vit mang lai hieu qui khi phay gang ciu bing dao phay mat dau cacbit, thdng qua cac chi sd ve dp mdn dao; dp nhim be mat chi tiet gia cdng.
D i e biet la khi gia cdng vdi MQL, dieu kien lam viec da dugc cii thien dang ke nhu: Giam thieu gay d nhidm mdi trudng do bui gang bin ra xung quanh giy ddc hai va nguy hiem cho ngudi thp. •
Ngay nhin bii: 25/5/2017 Ngiy phin bien: 25/6/2017
Tai li€u tham khao:
[5].
[6].
PGS,TS. Nguyln Dang Binh ciing hpc vien NCS va hgc vien cao hpc; '^Nghien cicu thifc nghi&m toi mi hoa khi gia cang gang cdu vai MQL", Ba.\ hpc Ky thuat Cong nghiep Thai Nguyen, 2009 va 2011.
Tran Minh Dire; Nghiin ciru icng dung cong nghe boi Iran ldm nguoi toi thieu Iwn^ gia cong cat got, De tai nghien cihi khoa hpc cap Bg trong diem B2005-01-61TD, Trudmg D91 hoc Ky thuSt Cong nghiep. Thai Nguyen, 2007.
Nikhil Ranjan Dhar, Sumaiya Islam, Mohammad Kamruzzaman. Effect of minimum quantity lubricalion (MQL) on tool wear, surface roughness and dimensional deviation in turning AISI-4340 steel, G.U. Joumal of science, 2007.
Master chemical corporation. Fluid application - MQL (minimum quantity lubrication), www, masterchemical com, 2006.
Jim lorincz, Senior, The right solutions for coolant, service@sme org, 2007
Prof.Dr -Ing M Schneider, Grinding with Internal Cooling Lubricant Supply, Institute of Production and Machining Technology, University of Applied Sciences, Giessen-Friedberg, Germany A Iqbal 1*, N U Dar, N He, I Khan, and L Li, Optimizing cutting parameters in minimum quantity qflubricalion milling af hardened cold work tool sleel. Department of Mechanical Engineering, University of Engineering and Technology, Taxila, Punjab, Pakistan & College of Mechanical and Electncal Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing, People's Republic of China.
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