NGHIEN CUU - TRAO 001 / XnC DINH DO TiN CQY TREN CO SO MON V^ CQC BIEN PHI^P NdNG CAO DO TIN CQY cun CHflY TRiN KHUdN EP GQCH CERAMICS CUQ NHfl MQY GflCH MIKADO THQI BiNH (*) NGUYEN DINH MAN dd, khudn ep la mdt nhiing cum chi tiet rat quan trong, lam \iec mdi trudng an mdn, ap lire cao, ma sat xa mdn manh TOM T A T Hien nay, Nha may gach Mikado Thai Binh dang san xuat gach ceramics tren day chuyen t d dong cua Italia va dang ap dung tieu chuan ISO 9001-2000 quan ly va kiem dinh chat lu'gng san pham Trong day chuyen do, khudn ep la mgt nhufng cum chi tiet rat quan trong, lam viec mdi tru'dng an mdn, ap lUc cao, ma sat va mdn manh Bg khudn ep bao gdm: Chay tren, Chay dudi va Vanh khudn, do, Chay tren la mot nhdng chi tie't quan cua khudn, quyet djnh chat lugng san pham gach cua nha may Nguyen nhan hdng cua nd chu ye'u la mdn Bai bao gidi thieu ke't qua nghien cUu tin cay tren ca sd mdn cua Chay tren; cac bien phap nang cao tin cay, dong thdi xac dinh chu ky thay the cua nd theo yeu cau ve tin cay cua ngUdi sd dung Bd khudn ep bao gdm Cha}- tren, Cha}- dudi va Vanh khudn, dd Cha}- tren la chi tiet rat ha}' xay hu hong, thudng xm'dn phai tha}' the, ga}' anh hudng xau den qua trinh san xuat Mdt nhirng ngu}-en nhan ga}- su hong la be mat mep ngoai tai cac gde cua khudn bi mdn nhanh, lam giam tudi thg ciia Chay So \ di nhirng khudn ep nhap ngoai, nhiing khudn san xuat nude hien na}- cd tudi thg va tin cay tuong ddi thap ngm-en nhan hong chii yeu la mdn Mdn khudn ep ndi chung chu }-eu la mdn cao xudc ket hgp xai mdn hoa hgc Hien na}', Nha ma}' gach Mikado (Thai Brnh) dang san xuat loai gach tren da} chu}'en tu ddng cua Italia va dang ap dung tieu chuan ISO 9001 - 2000 quan ly va kiem dinh chat lugng san pham Vi xax, DTC cua cac chi tiet va cac thiet bi da} chu}'en cang trd nen quan trgng De nang cao sire canh tranh, hien tai, Nha may dang su dung khudn ep san xuat nudc (Nhu khudn I M O DAU cua Cdng t}' Kim Thinh, Cdng t}- Lien doanh San xuat khudn ep FOSHAN, ) Cho den na}-, a Viet Nam van Trong cac da}" chm'en san xuat hien dai dd tin ca}chua cd cdng trinh nao nghien cim ve DTC cua khudn (DTC) cd }' nghia A d cimg quan trgng Neu mdt chi tiet ep gach Ceramics dua tren ca sa mdn dugc cdng bo Vi hoac thiet bi nao dd da}- chm'en cd DTC thap \'a}' \'iec nghien cim DTC tren co sd mdn cua Cha}' tren ha}- xa} hong hdc thi se lam dinh tre ca da}" chu}-en khudn ep gach Ceramics cd y nghia khdng nhd ve gia san xuat tri khoa hgc xa thuc tien Cac ket qua cdng bd da giiip Hien na}' o Viet Nam da cd -^'ai chuc nha ma}cho nha ma}' xac dinh dugc chu ky tha}- the cua Cha}san xuat gach Ceramics, cac da}- chu}'en san xuat chu tren khudn ep gach Ceramics theo yeu cau xe DTC cua }-eu nhap tir Italia, Tnmg Qudc Trong cac da}' chm'en ngudi su dung, ddng thdi nha che tao khudn hoan toan cd the biet dugc chat Iugng khudn cua minh de cd bien phap de nang cao tin ca} cua khudn (*) TnioTig Cao dang Kuili te - Ki thuat Dai hoc Thai Nguyen TAP CHI c a KHi VIET NAM V So 1+2 - Tliang 1+2 nam 2011 NGHIEN CUU - TRAO DOI n N O I D U N G VA PHU^OTVG P H A P N G H I E N ctru 2.1 Do mon Chay tren tai cff sff san xuat Chay tren cd hinh dang nhu hinh Vi tri Chay tren, Chay dudi va Vanh d trang thai ep nhu hinh Qua khao sat thuc te mdt sd Iugng ldn Chay tren khudn ep da hdng mdn tai cac nha may san xuat gach Ceramics, nhu Nha may gach men Mikado (Thai Binh), Cdng ty Cd phan Prime (Thai Nguyen), Nha may Gach dp lat Viet-Y (Thai Nguyen) thay rang, Chay tren mdn nhieu nhat tai be mat ben la tai vi tri lan can cac gde cua Chay Idn (1.800 tSn) nen thuc hien hanh trinh ep Chay tren cd the hi ep xd ve mdt phia hoac mgt gde nao dd anh hudng cua ciing viing he thdng va chinh xac lap ghep cua cac ca cau may Bdn Id: Do ranh thoat hanh trinh ep dugc bo tri d cac gde Chay tren nen khi thoat mang theo nguyen lieu ep dudi dang bui chuyen ddng vdi tdc cao la mdt tac nhan dan den cac gde cua Chay bi mdn manh hon Ndm Id: Do sai sd lap dat, Chay dugc lien ket vdi piston bi lech so vdi Chay dudi va ldng khudn, khe hd ban dau giiia Chay va cac Vanh khudn khdng thdng nhat, lam viec tai nhiing vi tri cd khe hd nhd se mdn nhanh hon Mac du da}' chi la ngu}-en nhan chu quan nhung qua khao sat thuc te cd rat nhieu Chay tren hdng bdi nguyen nhan (nghia la bdn gde Chay se cd mdt gde nao dd cd lugng mdn ldn nhat) 2.1.L Xac dinh vi tri mon Qua nghien cuu ket cau cua Chay tren va khao sat thuc te hien tugng mdn ciia nd d nhieu ca sd san xuat gach Ceramics nhu da trinh bay d tren, tac gia lua ehgn phuang an mdn tai diem M nhu hinh 3: M each gde Chay 5mm va each mep dudi ciia Chay Imm Hinh 1: Hinli anli Chay tren 1: Tam dem tren, 2: Chay tren: 3: Chay dual, Tam dem duai, Vanh kliuon Hinh 2: Vi tri Chay tren, Chay duoi va Vanh 6- trang ttiai ep M Cd the giai thich dieu nhu sau: Mgt Id: Mac dii nguyen lieu dugc xe cap lieu rai deu, nhung dp luc dp ldn lam cho nguyen lieu xd ve cac gde nhieu hon, hon niia, thirc hien hanh trinh ep thi Chay tren la chi tiet chu}'en dgng nen chiu lire ma sat Idn ddi vdi Vanh khudn va vat lieu Chay tren phai chiu ma sat rat Idn ngu} en lieu bi ep cac khe hd giiia Chay va Vanh khudn Tai cac gde, nguyen lieu hi dp chat hon nen ma sat Idn hon cac vi tri khae M Hinh 3: Vi tri mon ciia Chay tren Hai Id: Do td chuc vat lieu tai cac vi tri lan can cac gde kem ben -viing hon cac vi tri khae, da}- la nguyen nhan chinh lam cho khudn mdn nhieu tai cac xi tri lan can cac gde Ba Id: Do Cha}- tren dugc ep xudng vdi luc ep rat Hinh 4: Hinh anh vung mon nhieu nhSt tren bS mat ben ciia Chay tren va vi tri "M" TAP CHi c a KHi VIET NAM 30 de khao sat mdn, thdi diem mdn: sau ehay may 460 gid; phuang sai mau s- dugc xac dinh theo cdng thirc: that each chac chan Buoc 4: Ghi sd lieu va xac dinh ket qua tir cac sd lieu trung gian 2.1.8 Xac dinh lu-ffng mon gidi han U , (2)s^ = — ^ i ; ( u , - u ) Qua mdn ciia 150 Chay tren khudn ep da hi m - i=i Nha may loai mdn (tai diem nhu da xac dinh Trong dd: w u_- Iugng mdn ciia mau thu thir i d muc 2.1.1), thay rang, lugng mdn cua cac Chay w U - gia tri trung binh ciia Iugng mdn: tren dao ddng khoang tir 0,26 + 0,32mm Do vay, cd the xac dinh dugc lugng mdn gidi han cua Chay tren la: U ^ = 0,26mm Dieu cd nghia, la (3) U = (u,+ u,+ u,+ + u )/m lugng mdn tai vi tri > 0,26 mm thi Chay tren m - so lugng man khao sat sa bd: lay m = 32 Theo ket qua khao sat sa bd ta cd: U = 0,099mm, s2=0,00I68mm- De khao sat mdn cua Chay tren khudn ep gach ceramics, chon xac suat tin ca}- (3 = 0,95, tuong ung bi loai bd 2.1.9 Thffi diem khao sat Khi xac dinh tin cay tren ca sd mdn, ve nguyen tac cang nhieu thdi diem thi tin cay cang dugc dam bao Tuy nhien eang nhieu thdi diem thi cang cd u = 1,96 Chgn s = 0,0I2mm Ta cd: tdn kem kinh te va mat nhieu thdi gian Can cir vao n > 1,96^0,00168/0,012-= 44,6945 lugng mdn gidi han va thdi gian Iam viec ciia khudn Chgn n = 45 nghia la sd lugng Cha}- tren dugc chgn de mdn la 45 chiec theo khuyen cao cua nha san xuat Can cir vao thdi gian Iam viec thuc te eua Chay tai nha may (23 gid/ 2.1.6 Gioi han khao sat ngay), chgn phuong an Iugng mdn tai thdi diem: Khao sat lugng mdn eua Chay tren dieu Tai thdi diem gid va sau thdi gian lam viee 230 gid, kien lam viec thuc te: Luc ep P = 1800 tan; Sd lan ep: 460 gid, 690 gid va 920 gid (khoang each giiia hai lan Ulan/phut lien riep la khoang 10 ngay) Tai thdi diem gid San pham gach Ceramics cd kich thudc 250inm x 200mm x 7,5 mm Mdi Ian dp dugc 10 vien lugng mdn U = 2.1.10 Kit qua mon Chay tren tai co sd sdn xudt Gia thiet rang cac Chay tren dugc che tao dam bao Sau xac dinh ket qua tir cac so lieu trung } eu cau ky thuat nhu va quy Iuat mdn cua chimg gian va khir cac sai sd thd ta cd bang so lieu nhu la gidng sau (bang I) TAP CHi c a KHi VIET NAM V So 1+2 - Thang 1+2 nam 2011 NGHIEN cuu • TRAO 001 22 Phutmg phap xac dinh DTC cua Chay tren theo Iuong mon [3] Bang 1: Ket qua mdn cua Chay tren ^^ ""• ^^.-ic r ^-^^^^ 2^ :, • - • : -i:^ G ; : Q • : t Q s '•I = '.1 C ij 14 15 ''= '^ 2C 2' '.^ l i 2^ 2"^ J4 K X a 0 : ; ~ ' ~ ;'J 32 33 u '^ ~~ : : z~ •J^ K 40 4l a •^ s0