CHUONG 1 VA 2.pdf

MN HCCHI TIT MY

GING VIN: NGUYN VN THNH

B MN: THIT K MY

KHOA C KH

TRNG I HC BCH KHOA TP.HCM

3/11/2011 GV:NGUYN VN THNH 2

CHNG 1 V CHNG 2

- NHNG YU CU CHUNG CA MY.

- NHNG CH TIU THIT KMY V CHI TIT MY


1.1. NHNG YEU CAU CHUNG CUA MAY (02)1.1. NHNG YEU CAU CHUNG CUA MAY (02)1.1. NHNG YEU CAU CHUNG CUA MAY (02)1.1. NHNG YEU CAU CHUNG CUA MAY (02)Bao gm nhng yeu cau chung ve thiet ke che tao va van hanh.

1.1.1. NHNG YEU CAU CHUNG VE THIET KE CHE TAO:1.1.1. NHNG YEU CAU CHUNG VE THIET KE CHE TAO:1.1.1. NHNG YEU CAU CHUNG VE THIET KE CHE TAO:1.1.1. NHNG YEU CAU CHUNG VE THIET KE CHE TAO:1)1)1)1) amamamam baobaobaobao khakhakhakha nangnangnangnang lamlamlamlam viecviecviecviec2)2)2)2) amamamam baobaobaobao tnhtnhtnhtnh congcongcongcong nghenghenghenghe caocaocaocao3)3)3)3) McMcMcMc oooo tieutieutieutieu chuanchuanchuanchuan hoahoahoahoa, qui , qui , qui , qui cachcachcachcach hoahoahoahoa caocaocaocao4)4)4)4) McMcMcMc oooo tieutieutieutieu haohaohaohao nguyennguyennguyennguyen vatvatvatvat lieulieulieulieu nhonhonhonho1.1.2. NHNG YEU CAU CHUNG VE VAN HANH:1.1.2. NHNG YEU CAU CHUNG VE VAN HANH:1.1.2. NHNG YEU CAU CHUNG VE VAN HANH:1.1.2. NHNG YEU CAU CHUNG VE VAN HANH:1)1)1)1) NangNangNangNang suatsuatsuatsuat maymaymaymay caocaocaocao2)2)2)2) GiaGiaGiaGia thanhthanhthanhthanh maymaymaymay thapthapthapthap3)3)3)3) oooo tin tin tin tin caycaycaycay caocaocaocao4)4)4)4) GiaGiaGiaGia thanhthanhthanhthanh giagiagiagia congcongcongcong hphphphp lylylyly5)5)5)5) ChatChatChatChat lnglnglnglng giagiagiagia congcongcongcong cao6cao6cao6cao66)6)6)6) TyTyTyTy suatsuatsuatsuat lililili nhuannhuannhuannhuan7)7)7)7) TnhTnhTnhTnh cccc ongongongong cuacuacuacua maymaymaymay Ngoai nhng yeu cau tren may thiet ke can phai thoa man cac yeu

cau khac nh: an toan, tien li, tham my va khong c anh hngen moi trng xung quanh (khong on, khong gay o nhiem moitrng).


1.2. KHA NANG LAM VIEC CUA MAY VA CHI TIET MAY:1.2. KHA NANG LAM VIEC CUA MAY VA CHI TIET MAY:1.2. KHA NANG LAM VIEC CUA MAY VA CHI TIET MAY:1.2. KHA NANG LAM VIEC CUA MAY VA CHI TIET MAY:o ben, o cng, o ben mon, o on nh dao ong, o chu nhiet, ochnh xac...

1.2.1. O BEN:1.2.1. O BEN:1.2.1. O BEN:1.2.1. O BEN:1.2.1.1. KHAI NIEM C BAN:1.2.1.1. KHAI NIEM C BAN:1.2.1.1. KHAI NIEM C BAN:1.2.1.1. KHAI NIEM C BAN: o ben la kha nang bao am cho may va chi tiet may khong b bien dang

d ln, gay hong hay be mat lam viec khong b pha huy khi chu tac dungcua tai trong trong qua trnh lam viec.

Nhng dang hong chu yeu lien quan en o ben cua chi tiet may: BienBienBienBien dangdangdangdang deodeodeodeo PhaPhaPhaPha huyhuyhuyhuy do do do do moimoimoimoi PhaPhaPhaPha huyhuyhuyhuy giongiongiongion HoaHoaHoaHoa giagiagiagia ((((laolaolaolao hoahoahoahoa)))) Tuy theo dang hong xay ra cho ca khoi vat the hay ch tren be mat tiep xuc

ngi ta phan biet 2 loai o ben: o ben the tch (o ben keo, nen, uon, xoan, cat...) va o ben tiep xuc (dap, tiep xuc).

Khi tnh toan o ben the tch hay tiep xuc ngi ta chu y en tnh chat thayoi cua ng suat sinh ra trong chi tiet may: neu ng suat khong oi (taitrong tnh) ta tnh theo o ben tnh, neu ng suat thay oi ta tnh theo o benmoi.


1.2.1.2. TAI TRONG VA NG SUAT 1.2.1.2. TAI TRONG VA NG SUAT 1.2.1.2. TAI TRONG VA NG SUAT 1.2.1.2. TAI TRONG VA NG SUAT (1)

a) a) a) a) TaiTaiTaiTai trongtrongtrongtrong ((((kykykyky hieuhieuhieuhieu chungchungchungchung lalalala Q)Q)Q)Q)+ Lc, momen do chi tiet may hoac bo phan may tiep nhantrong qua trnh lam viec.+ Tai trong tac dung len chi tiet may co the la khong oi hoacthay oi:

---- TaiTaiTaiTai trongtrongtrongtrong khongkhongkhongkhong oioioioi ((((taitaitaitai trongtrongtrongtrong tnhtnhtnhtnh)))) : tai trong khong thay oitheo thi gian hoac thay oi khong ang ke.

---- TaiTaiTaiTai trongtrongtrongtrong thaythaythaythay oioioioi:::: tai trong co phng, chieu hay cng o thayoi theo thi gian.

---- TaiTaiTaiTai trongtrongtrongtrong vavavava apapapap:::: tai trong thay oi ot ngot (ot nhien tangmanh roi giam ngay tc khac).

Trong tnh toan ngi ta con phan biet: tai trong danhngha, tai trong tng ng va tai trong tnh toan.


- TaiTaiTaiTai trongtrongtrongtrong danhdanhdanhdanh nghanghanghangha QdnQdnQdnQdn::::La tai trong c chon trong so cac tai trong tac dung len maytrong che o lam viec on nh (thng chon tai trong ln hay tac dung lau dai nhat lam tai trong dang ngha).

- TaiTaiTaiTai trongtrongtrongtrong tngtngtngtng ngngngng QtdQtdQtdQtd::::Gia tr tng ng khong oi cua tai trong thay the cho che othay oi cua tai trong.

QtdQtdQtdQtd = = = = QdnQdnQdnQdn . . . . KnKnKnKntrong o : Kn - He so phu thuoc vao che o tai trong

TaiTaiTaiTai trongtrongtrongtrong tnhtnhtnhtnh toantoantoantoan QttQttQttQtt::::La tai trong dung trong tnh toan thiet ke may va chi tiet may, phu thuoc vao t/c thay oi tai trong, s phan bo khong eu cuatai trong, ieu kien s dung...QttQttQttQtt = = = = QtdQtdQtdQtd . . . . KttKttKttKtt . . . . KdKdKdKd . . . . KdkKdkKdkKdk = = = = QdnQdnQdnQdn . . . . KnKnKnKn . . . . KttKttKttKtt . . . . KdKdKdKd . . . . KdkKdkKdkKdktrong o: Ktt- he so xet en s phan bo khong khong eu taitrong; Kd- he so tai trong ong; Kdk- he so ieu kien lam viec.


b) b) b) b) ngngngng suatsuatsuatsuat:::: Di tac dung cua tai trong trong chi tiet may sinh rang suat. Phu thuoc vao tnh chat cua tai trong ta cong suat tnh (ng suat khong thay oi theo thi gian) hay ng suat thay oi (ng suat co tr so hay chieuthay oi theo thi gian).

ng suat thay oi c ac trng bi nhng chu kyng suat.

Chu ky ng suat: mot vong thay oi cua ng suat t trso gii han nay sang tr so gii han khac roi tr ve vtr ban au. Chu ky ng suat c ac trng bi:

- Bin ng sut- T s ng sut


ng suat trong chi tiet may co the thay oi onnh hoac khong on nh:

ngngngng suatsuatsuatsuat thaythaythaythay oioioioi onononon nhnhnhnh: co bien o ng suatva ng suat trung bnh khong thay oi theo thigian.

ngngngng suatsuatsuatsuat thaythaythaythay oioioioi khongkhongkhongkhong onononon nhnhnhnh: co mot tronghai hay ca hai ai lng tren thay oi theo thigian


c) c) c) c) ngngngng suatsuatsuatsuat tieptieptieptiep xucxucxucxuc:::: ng suat tiep xuc sinh ra khi be mat lam viec cua chi tiet may tiep xuc trc tiep vi nhau. ng suat tiepxuc la nguyen nhan gay hien tng troc ro be mathay mai mon be mat tiep xuc.

ng suat tiep xuc gia hai hnh tru tiep xuc vi nhaukhi chu tai phan bo theo hnh Parabol trong mat catngang. Gia tr cc ai c xac nh theo cong thcHetz:


1.2.1.3. NG SUAT CHO PHEP VA HE SO AN TOAN:1.2.1.3. NG SUAT CHO PHEP VA HE SO AN TOAN:1.2.1.3. NG SUAT CHO PHEP VA HE SO AN TOAN:1.2.1.3. NG SUAT CHO PHEP VA HE SO AN TOAN:ng suat cho phep la gia tr gii han e am bao cho chi tiet may lam viec th ng suat phat sinh trong chi tiet may khong c vt qua gia tr cho phep nay:


b) b) b) b) HeHeHeHe sosososo an an an an toantoantoantoan S S S S vavavava hehehehe sosososo an an an an toantoantoantoan chochochocho phepphepphepphep [S]:[S]:[S]:[S]:


1.2.1.4. TNH BEN TRONG TRNG HP TAI TRONG TNH:1.2.1.4. TNH BEN TRONG TRNG HP TAI TRONG TNH:1.2.1.4. TNH BEN TRONG TRNG HP TAI TRONG TNH:1.2.1.4. TNH BEN TRONG TRNG HP TAI TRONG TNH:


1.2.1.5. TNH BEN TRONG TRNG HP TAI 1.2.1.5. TNH BEN TRONG TRNG HP TAI 1.2.1.5. TNH BEN TRONG TRNG HP TAI 1.2.1.5. TNH BEN TRONG TRNG HP TAI TRONG THAY OI TRONG THAY OI TRONG THAY OI TRONG THAY OI

a) Chi a) Chi a) Chi a) Chi tiettiettiettiet maymaymaymay chuchuchuchu chechecheche oooo ngngngng suatsuatsuatsuat thaythaythaythay oioioioi onononon nhnhnhnh:::: Chi tiet may se b hong do moi sau mot so chu ky lam viec

kha ln N, ng suat gii han ay la gii han moi . Quanhe gia va N theo phng trnh ng cong moi.


b) Chi tiet may chu che o ng suat thay oi b) Chi tiet may chu che o ng suat thay oi b) Chi tiet may chu che o ng suat thay oi b) Chi tiet may chu che o ng suat thay oi khong on nh:khong on nh:khong on nh:khong on nh:


Cac nhan to anh hng en sc ben moi cua chi tiet maCac nhan to anh hng en sc ben moi cua chi tiet maCac nhan to anh hng en sc ben moi cua chi tiet maCac nhan to anh hng en sc ben moi cua chi tiet may:y:y:y:


ng suat gii han khi co xet en cac nhan to ng suat gii han khi co xet en cac nhan to ng suat gii han khi co xet en cac nhan to ng suat gii han khi co xet en cac nhan to anh hng en sc ben moi:anh hng en sc ben moi:anh hng en sc ben moi:anh hng en sc ben moi:


c) Cac phng phap nang cao o ben moi cua chi tiet mayc) Cac phng phap nang cao o ben moi cua chi tiet mayc) Cac phng phap nang cao o ben moi cua chi tiet mayc) Cac phng phap nang cao o ben moi cua chi tiet may:::: o ben moi cua chi tiet may chu anh hng cua cac nhan to:

Vat lieu va phng phap nhiet luyen; hnh dang ket cau chi tiet; kch thc chi tiet; cong nghe gia cong be mat; ac tnh tai trong; trang thai ng suat...- Bien phap ket cau: tang kch thc tai cac thiet dien nguy hiem e giam tr so danh ngha cua cac ng suat; s dung ket cau hp ly e giam s tap trung ng suat (s dung goc ln vi ban knh ln tai cho chuyen tiep cac kch thc; vat mep cac be mat lap ghep...).- Bien phap cong nghe: s dung cac phng phap gia cong ac biet tang ben nh: dung nhiet luyen va hoa nhiet luyen vi cac chi tiet may co s tap trung ng suat; anh bong, mai nghien e san bang cac go ghe te vi lam giam tap trung ng suat; gaybien dang deo lp be mat nh phun bi, lan nen gay cng nguoi be mat lam tang o ben moi.


1.2.2. O CNG:1.2.2. O CNG:1.2.2. O CNG:1.2.2. O CNG:1.2.2.1. KHAI NIEM C BAN:1.2.2.1. KHAI NIEM C BAN:1.2.2.1. KHAI NIEM C BAN:1.2.2.1. KHAI NIEM C BAN: o cng la kha nang chong lai s bien oi hnh dang va kch thc cua chi tiet may di tac dung cua tai trong. Neu mot chi tiet may khong u o cng, khi lam viec se b bien dang an hoi vt qua tr so cho phep, do o se pha huy ieu kien lam viec bnh thng cua chi tiet may va cac chi tiet lap ghep (v du: truc b vong qua se lam cho cac banh rang tiep xuc khong tot, lam mon vet cac o).

Theo tnh chat cua tai trong la tnh hay ong ta co o cng tnh hay ong.

Ngi ta phan biet o cng the tch lien quan en bien dang cua toan bo vat lieu chi tiet va o cng tiep xuc, lien quan en bien dang cua cac lp be mat.


1.2.2.2. TNH TOAN O CNG:1.2.2.2. TNH TOAN O CNG:1.2.2.2. TNH TOAN O CNG:1.2.2.2. TNH TOAN O CNG: Tnh toan o cng la nham gii han bien dang trongpham vi cho phep, phu thuoc vao tai trong tac dung.

a) a) a) a) oooo cngcngcngcng thethethethe tchtchtchtch:::: Tnh toan o cng the tch xuat phat t ieu kien: chuyen v thc (chuyen v dai hoac goc) khong cvt qua gia tr cho phep.

b) b) b) b) oooo cngcngcngcng tieptieptieptiep xucxucxucxuc:::: o cng tiep xuc the hien moi quan he gia ap suatva bien dang tai cho tiep xuc tren be mat. Cho tiepxuc co the la iem (o bi...), ng thang (cap banhrang, o ua...).


1.2.2.3. CAC PHNG PHAP NANG CAO O CNG1.2.2.3. CAC PHNG PHAP NANG CAO O CNG1.2.2.3. CAC PHNG PHAP NANG CAO O CNG1.2.2.3. CAC PHNG PHAP NANG CAO O CNG::::- Dung vat lieu hp ly: vat lieu co moun an hoi cao, co the de dang che tao

cac chi tiet co hnh dang phc tap va thiet dien hp ly. Trong thc te thngdung thep, gang... (v co o cng ty le vi moun an hoi E,G).

- Chon hnh dang thiet dien ngang hp ly: ton t vat lieu ma co o cng vng cao(v o cng ty le vi momem quan tnh cua thiet dien J hay momen chongxoan Wo. Trong ket cau co the tao gan, sn ben trong e tang o cng uonva xoan.

- Chon ket cau chu tai hp ly ve o cng: s dung ket cau chu tai oi xng e tranh chuyen v an hoi theo phng tac dung cua tai trong; co gang s dungcang nhieu cang tot cac ket cau chu keo, chu nen v o cng cua chung lnhn nhieu so vi trng hp uon xoan.

- S dung va phan bo cac o truc hp ly ve so lng va the loai e tang o cng.- Co the tao ra cac bien dang ngc lai nh cac oi trong e can bang vi bien

dang do trong lng rieng cua cac bo phan may gay ra. - am bao s can bang cua he thong (dung cac chi tiet co o cng khong qua

trenh lech); giam bien dang cuc bo...


1.2.3. O CHU MON1.2.3. O CHU MON1.2.3. O CHU MON1.2.3. O CHU MON1.2.3.1. KHAI NIEM VE O MAI MON1.2.3.1. KHAI NIEM VE O MAI MON1.2.3.1. KHAI NIEM VE O MAI MON1.2.3.1. KHAI NIEM VE O MAI MON Mon la ket qua tac dung cua ng suat tiep xuc hoac ap suat khi cac

be mat tiep xuc trt tng oi vi nhau trong ieu kien khong udau boi trn (trong thc te co khoang 90% chi tiet may co be matlam viec tiep xuc b hong do mon).

Chi tiet may b mon gay ra nhng hau qua:- Lam viec khong chnh xac (may o khong bao chnh xac ket qua o

do mon...)- Giam hieu suat (cap Pittong-Xylanh b mon khien may lam viec

khong tot...)- Giam o ben cua chi tiet may (do b mon se tang s tap trung ng

suat)- Tang tai trong ong, gay on ln (mon lam khe h gia con lan va

vong cach ln sinh ra hien tng va ap va gay ra tieng on ln).


1.2.3.2. 1.2.3.2. 1.2.3.2. 1.2.3.2. CC DANG MONDANG MONDANG MONDANG MON- Mon hat mai: bui t ben ngoai, trong dau boi trn ri vao; nhng hat kim loai do qua trnh

mon tao ra.- Mon oxy hoa: oxy trong khong kh hay trong dung dch boi trn tac dung vi kim loai tao

thanh lp mang oxy hoa khi b troc ra gay mon.- Troc dnh: xay ra khi ma sat trt gia cac lp kim loai thuan khiet tiep xuc trc tiep vi

van toc tng oi nho va ap suat rieng vt qua gii han chay tai vung tiep xuc, kim loaitren be mat b dnh va troc ra khoi chi tiet.

- Troc nhiet: la ket qua cua qua trnh nung nong, lam mem bien dang va tiep xuc cua bemat kim loai thuan khiet trong qua trnh chu ma sat vi van toc ln va ap suat rieng ln.

- Pha huy do moi v tr tiep xuc: ng suat be mat tiep xuc bien oi theo chu ky gay moitren be mat tiep xuc lam lp kim loai tren be mat tiep xuc troc ra - be mat mon dan.

- Xoi mon kim loai: la s pha huy be mat chi tiet di tac dung lap lai nhieu lan cua dongchat long, chat kh, hat mai ...

- An mon kim loai: la s pha huy be mat tiep xuc di tac dung hoa va ien hoa trong moitrng.

- Mon troc r: la qua trnh pha huy be mat tiep xuc khi ong thi co hien tng an mon kimloai va s di ong tng oi cua chi tiet sinh ra dao ong vi bien o nho be mat tiepxuc.


1.2.3.3. CAC BIEN PHAP GIAM MON1.2.3.3. CAC BIEN PHAP GIAM MON1.2.3.3. CAC BIEN PHAP GIAM MON1.2.3.3. CAC BIEN PHAP GIAM MON- Chon ket cau cac chi tiet tiep xuc nham bao am che o boi trn ma sat t. - Trng hp khong the tao che o boi trn ma sat t, tnh toan ve o ben mon da tren c

s han che ap suat hoac ng suat tiep xuc khong cho vt qua gia tr cho phep: p [p].- Moi lien he gia ap suap p va quang ng ma sat L co the xac nh theo cong thc:pm L =

consttrong o: L- quang ng ma sat; m- so mu phu thuoc ieu kien boi trn: masat kho m=1;

masat na kho m=2; t m=3. NgoaiNgoaiNgoaiNgoai ra ra ra ra phaiphaiphaiphai chuchuchuchu yyyy enenenen nhngnhngnhngnhng bienbienbienbien phapphapphapphap giamgiamgiamgiam monmonmonmon sausausausau::::- S dung vat lieu giam ma sat (ong thanh ...) nhng bo phan co van toc ln (banh vt, o

trt...).- Giam tai cho be mat chu ma sat (dung c cau t la e phan tai eu tren be mat tiep xuc,

ket cau be mat tiep xuc sao cho khong tiep xuc nhng ni co ng suat ln).- Boi trn va lam nguoi tot- Giam lng hat mai ri vao trong be mat ma sat bang cach che chan kn- am bao mon eu cho cac chi tiet- Chuyen mon vao chi tiet t anh hng en o chnh xac cua may- S dung cac ket cau ieu chnh c khi mon...


1.2.4. O CHU NHIET1.2.4. O CHU NHIET1.2.4. O CHU NHIET1.2.4. O CHU NHIET La kha nang cua chi tiet may co the lam viec trong mot pham vi nhiet o can

thiet ma khong b nung nong qua mot gia tr cho phep. Nhiet sinh ra thngdo ma sat c cau, bo phan may...

Nhiet o cao cac chi tiet co the sinh ra mot so hien tng co hai:- Lam giam kha nang tai cua chi tiet may (do thay oi cac ac tnh c cua vat

lieu): vi vat lieu thep, t >300400oC; vi vat lieu bang chat deo, t 100150oC.

- Giam kha nang bao ve cua mang dau (giam o nht cua dau).- Lam thay oi khe h gia cac chi tiet lap ghep.- Lam thay oi tnh chat be mat lam viec (giam he so ma sat trong cac bo phan

ham...).- Lam giam o chnh xac cua may Tnh toan nhiet nham xac nh nhiet o sinh ra trong qua trnh lam viec va

cac bien phap han che no trong pham vi cho phep:t [t] e nang cao kha nang chu nhiet cua chi tiet may can che tao bang vat lieu

chu nhiet, ap dung cac bien phap boi trn lam mat...


1.2.5. O 1.2.5. O 1.2.5. O 1.2.5. O NNNN NH DAO ONGNH DAO ONGNH DAO ONGNH DAO ONG La kha nang cua chi tiet may co the lam viec trong mot pham vi van

toc can thiet ma khong b rung qua mc cho phep. Dao ong xuat hien cac tiet may quay khong can bang, khong u o cng, lam viec vivan toc cao...

Dao ong co the la cng bc (do lc tuan hoan t ben ngoai, khi cacchi tiet khong can bang, sai so do che tao, lc thay oi trong may copitong) hay t dao ong do lc nhieu gay nen khi dao ong (v du: dao ong masat khi giam ma sat khi tang van toc va cac nhan to khac).

Dao ong gay nen ng suat phu thay oi theo chu ky dan en hong do moi; gay on ln; giam o chnh xac cua chi tiet may...

Tnh toan dao ong nham xac nh tan so dao ong rieng cua may, ccau e tranh cong hng hay han che bien o trong pham vi cho phep.

Cac bien phap chong rung: triet tieu ngoai lc gay dao ong; thay oitnh chat ong lc cua he thong; dung cac thiet b giam rung, giam va ap...


1.3. O TIN CAY VA TUOI THO CUA MAY1.3. O TIN CAY VA TUOI THO CUA MAY1.3. O TIN CAY VA TUOI THO CUA MAY1.3. O TIN CAY VA TUOI THO CUA MAY1.3.1. KHAI NIEM VE O TIN CAY1.3.1. KHAI NIEM VE O TIN CAY1.3.1. KHAI NIEM VE O TIN CAY1.3.1. KHAI NIEM VE O TIN CAY o tin cay la kha nang cua may hoac chi tiet may thc hien chc nang cua mnh

va duy tr chc nang, nhiem vu o trong suot thi han a nh (o tin cay actrng cho kha nang lam viec cua may va xac suat duy tr kha nang o trong suotthi han quy nh).

1.3.2. CAC CH TIEU ANH GIA O TIN CAY CUA MAY1.3.2. CAC CH TIEU ANH GIA O TIN CAY CUA MAY1.3.2. CAC CH TIEU ANH GIA O TIN CAY CUA MAY1.3.2. CAC CH TIEU ANH GIA O TIN CAY CUA MAY1) Xac suat lam viec khong hong R(t): la xac suat khong xay ra hong hoc chi tiet

may hoac may trong thi han a nh.2) Mat o phan phoi hong f(t): xac suat hong tren mot n v thi gian3) Cng o hong (t): la so hong hoc tren mot n v thi gian va mot n v san

pham.4) Tuoi tho: la khoang thi gian lam viec cua chi tiet may t khi bat au lam hoat

ong cho ti khi at trang thai ti han, tc la b hong can sa cha, phuc hoi. 5) He so s dung Ks: la t so gia thi gian lam viec tlv vi tong thi gian th cua chu

ky lam viec cua chi tiet may .


1.3.3. CAC PHNG PHAP NANG CAO O 1.3.3. CAC PHNG PHAP NANG CAO O 1.3.3. CAC PHNG PHAP NANG CAO O 1.3.3. CAC PHNG PHAP NANG CAO O TIN CAY CUA MAYTIN CAY CUA MAYTIN CAY CUA MAYTIN CAY CUA MAY- Khi thiet ke tan dung kha nang s dung cac thiet b vi so

lng chi tiet t, n gian, o tin cay gan bang nhau.- Co bien phap dung hoa gia giam cng o chu tai (tang o

tin cay) vi giam khoi lng va kch thc cua chi tiet may: sdung vat lieu co o ben cao, nhiet luyen va hoa nhiet luyen, bien phap cong nghe nh phun bi, lan nen.

- Boi trn tot: chon ung loai dau, thiet ke he thong boi trn hply...

- S dung he thong t can bang (cac khuyet tat trong che tao tanh hng en s phan bo tai trong hn); dung ly hp an toanhay rle vi may hay xuat hien cac qua tai ngau nhien.

- S dung rong rai cac chi tiet, ket cau tieu chuan se tao ra cacsan pham co chat lng cao, de sa cha thay the.


1.4. TIEU CHUAN HOA CHI TIET MAY1.4. TIEU CHUAN HOA CHI TIET MAY1.4. TIEU CHUAN HOA CHI TIET MAY1.4. TIEU CHUAN HOA CHI TIET MAY

Tieu chuan hoa la viec quy nh nhng tieu chuan va quy pham hp ly, thong nhat ve hnh thc, loai, chat lng, phng phap th nghiem va chetao... cua chi tiet may va may

Tieu chuan hoa co y ngha kinh te ky thuat quan trong the hien nhng iemchnh sau:

- Han che chung loai, kch thc cac san pham cung loai, cung ten nen co the sdung nhng phng phap tien tien e che tao hang loat chi tiet may tieuchuan chat lng cao, ha gia thanh (giam sc lao ong, tiet kiem nguyen vatlieu, giam au t thiet b...)

- am bao tnh oi lan cua chi tiet may, nh o tao de dang cho cong viec sacha, thay the.

- Giam bt thi gian, cong sc thiet ke. Hien nc ta s dung 4 tieu chuan:

- Tieu chuan nha nc Viet Nan: TCVN- Tieu chuan nganh: TCN- Tieu chuan tnh, thanh pho: TCV- Tieu chuan c s: TC

ong thi ang ap dung nhieu tieu chuan cua to chc tieu chuan hoa the giiISO.


1.5. NOI DUNG, TRNH T THIET KE MAY 1.5. NOI DUNG, TRNH T THIET KE MAY 1.5. NOI DUNG, TRNH T THIET KE MAY 1.5. NOI DUNG, TRNH T THIET KE MAY VA CHI TIET MAYVA CHI TIET MAYVA CHI TIET MAYVA CHI TIET MAY1.5.1. NOI DUNG THIET KE MAY: 1.5.1. NOI DUNG THIET KE MAY: 1.5.1. NOI DUNG THIET KE MAY: 1.5.1. NOI DUNG THIET KE MAY:

Thiet ke may bao gom nhng noi dung:1) Xac nh nguyen ly hoat ong va che o lam viec cua may d nh thiet

ke2) Lap s o chung toan may va cac bo phan may thoa man cac yeu cau

cho trc. anh gia cac phng an e tm ra phng an thch hp nhat, ap ng tot nhat cac yeu cau a at ra.

3) Xac nh tr so va ac tnh cua tai trong tac dung len cac bo phan may.4) Chon vat lieu thch hp nham nang cao hieu qua va o tin cay lam viec

cua may.5) Tien hanh tnh toan ong hoc, ong lc hoc va tnh toan thiet ke nham

nh ra cac kch thc gan ung cua chi tiet may thoa man cac ch tieuchu yeu ve kha nang lam viec cua chung. Sau o ket hp vi cac yeucau ve tieu chuan hoa, lap ghep, cong nghe... e xac nh lan cuoi kchthc cua chi tiet may, bo phan may va toan may.

6) Lap thuyet minh, hng dan s dung, bao dng va sa cha may.


1.5.2. TRNH T THIET KE CHI TIET MAY1.5.2. TRNH T THIET KE CHI TIET MAY1.5.2. TRNH T THIET KE CHI TIET MAY1.5.2. TRNH T THIET KE CHI TIET MAYThiet ke chi tiet may la mot phan trong qui trnh thiet ke may tien hanh theotrnh t sau:

1) Lap s o tnh toan (cac ket cau c n gian hoa, cac lc c tap trunghay phan bo theo qui luat nao o).

2) Xac nh tai trong tac dung len chi tiet may (doc truc Fa, hng tam Fr, lcvong Ft).

3) Chon vat lieu thch hp vi ieu kien lam viec cua chi tiet may, kha nang giacong va co xet en cac yeu to kinh te.

4) Tnh toan cac kch thc chnh theo ch tieu ve kha nang lam viec.5) Tien hanh kiem nghiem theo cac ch tieu ve kha nang lam viec (nh he so an

toan cac tiet dien nguy hiem...) va so sanh vi cac tr so cho phep neukhong thoa phai xac nh lai kch thc.

6) Da theo tnh toan va cac ieu kien che tao lap ghep... ve ay u ket cau chi tiet may vi kch thc, dung sai, o nham be mat, cac yeu cau ve congnghe.


HT CHNG 1 V CHNG 2

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CHUONG 1 VA 2.pdf