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n cng ngh ctm Hong Minh Tin ctm6- k46

Li ni uTrong nhng nm gn y, chng ta chng kin s pht trin mnh m ca cc nghnh cng nghip mi ni chung v nghnh c s ca mi nghnh ni ring l nghnh C kh. L mt nghnh ra i t lu vi nhim v l thit k v ch to my mc phc v cho cc nghnh cng nghip khc. Do vy i hi k s v cn b nghnh C kh phi tch lu y & vng chc nhng kin thc c bn nht ca nghnh, ng thi khng ngng trau ri v nng cao vn kin thc , quan trong nht l phi bit vn dng nhng kin thc gii quyt nhng vn c th thng gp trong qu trnh sn xut thc tin.

Trong chng trnh o to k s C kh ti Trng i Hc Bch Khoa H Ni, sinh vin c trang b nhng kin thc c s ca nghnh Cng ngh Ch to my qua cc gio trnh : Cng ngh Ch to my, Chi tit my, Nguyn l my, g, Dao v cc gio trnh khc c lin quan n nghnh Cng ngh Ch to my. Nhm mc ch c th ho v thc t ho nhng kin thc m sinh vin c trang b, th mn n Cng ngh Ch to my nhm mc ch . Trong qu trnh thit k n mn hc sinh vin s c lm quen vi cch s dng ti liu, s tay cng ngh, tiu chun v c kh nng kt hp, so snh nhng kin thc l thuyt vi thc t sn xut. Mt khc khi thit k n, sinh vin c dp pht huy ti a tnh c lp sng to, nhng tng mi l gii quyt mt vn cng ngh c th. Do tnh quan trng ca n m mn bt buc i vi sinh vin chuyn nghnh C kh v mt s nghnh c lin quan.

Qua mt thi gian tm hiu vi s hng dn ch bo tn tnh ca PGS.TS.Nguyn Vit Tip, em hon thnh n mn hc Cng ngh Ch to my c giao. Vi kin thc c trang b v qu trnh tm hiu cc ti liu c lin quan v c trong thc t. Tuy nhin s khng trnh khi nhng sai st ngoi mun do thiu kinh nghim thc t trong thit k. Do vy, em rt mong c s ch bo ca cc thy c gio trong B mn Cng ngh Ch to my v s ng gp kin ca bn b hon thin hn n ca mnh cng nh hon thin hn vn kin thc ca mnh. Cui cng, em xin chn thnh cm n PGS.TS. Nguyn Vit Tip tn tnh hng dn em trong qu trnh thit k v hon thin n ny./.

Trng i hc bch khoa h ni

H ni 10 / 2005. Sinh vin thc hin : Hong Minh Tin.Phn I. u thit k.Thit k qui trnh cng ngh ch to chi tit: Gi .( hnh v trang trc).Vt liu: Gang xm GX15-32.Phn II. S liu ban u: Sn lng hng nm : N1=6000 chi tit. iu kin sn xut : T chn.Phn III. Ni dung cc phn thuyt minh v tnh ton.I. Phn tch chc nng lm vic ca chi tit.

Cn c vo bn v chi tit ta c nhn xt sau:

Gi c dng hnh tr trn,trong c khoan cc l , t ta thy gi l chi tit dng hp.

Gi dng cc trc quay trong my. B mt lm vic ch yu l cc l:

Dung sai ca ng knh l nh ( ) do vy yu cu gia cng t chnh xc cao.

Mt s b mt c yu cu bng cao : cp nhn bng 5 , 6, 7 .

Gi lm vic trong iu kin chu lc v chu tI trng kh ln do trc quay trn gi gy ra. Cc lc c th l lc dc trc, lc hng tm, trng lc ca cc chi tit t trn n.

Gi l chi tit chu nn ,do vy vt liu ch to l gang xm GX 15- 32 l hon ton hp l. Gi c c t gang xm.

II. Phn tch tnh cng ngh trong kt cu ca chi tit GI - Gi l mt chi tit c kt cu kh n gin, do vy ta khng th gim lc c kt cu hn na, phng php c kt cu ny vi vt liu l gang xm hon ton ph hp.

Nhng b mt trong ca cc l rt hay gp s r co trong qu trnh c.

Cc b mt chnh cn t chnh xc cao, b mt ph chnh xc khng cao.

III. Cc b mt cn gia cng: mt y, mt trn, 2 l , 2 mt bn, cc l 6 l M10, 1 l M16. Cc b mt chnh c cp chnh xc cao (5 , 6, 7).

IV. Xc nh dng sn xut.

Sn lng hng nm :

N=N1.m(1+ ) Trong :

N : S chi tit c sn xut trong 1 nm.

N1: S sn phm c( s my ) c sn xut trong mt nm. N1= 10 000.

m : s chi tit trong mt sn phm : m=1.

: s chi tit c ch to thm d tr: = 7%.

: s ph phm ch yu trong cc phn xng c v rn : = 6%. Do vy ta c : N= 6 000.1.(1+ ) = 6780 ( chi tit / nm).

Trng lng ca chi tit : Q1 = V. ( kG).

=( 6,8-7,4) (Kg/

EMBED Equation.3 ).

Th tch ca chi tit : V= V + V - V - V-V5 Trong :

V = 3,14.(150/4).54 = 954259 ( mm) = 0,9543 (dm).

V2 = 240.66.22 = 348480 ( mm) = 0,3485 (dm)

V3 = 3,14.(18/4).22.2 = 11191 (mm) = 0,0011 ( dm). V4 = 3,14.(1102 /4).39 = 370629 (mm) = 0,3706 (dm).

V5 = 3,14.(562 /4).15 = 36945 (mm) = 0,0369 (dm).

Vy : V = 0,9543 + 0,3485 0,0011 0,3706-0,0369 = 0,8942 ( dm).

Ta c : Q1= 0,8942 .7 =6,26 (kg).

Cc thng s : N = 11 300 ( chi tit / nm).

Q1 = 6,26 (kg).

Tra bng 2 (TK ACNCTM) ta xc nh dng sn xut : Hng khi.V. Chn phng php ch to phi.

chn c phng php c hp l ta phn tch li yu cu ca chi tit :

Mt s b mt cn t chnh xc cao.

Lng d ca cc b mt nh Do vy ta s dng phng php c trong v mng cp chnh xc cao ( cp 2) , nng sut cao v lng d gia cng ct gt nh.

VI. Thit k qui trnh cng ngh gia cng chi tit. (Lp th t cc nguyn cng).V s g t, k hiu nh v, kp cht, chn my, chn dao, k hiu chiu chuyn ng ca dao, ca chi tit.

A. Xc nh ng li cng ngh.

Dng sn xut xc nh l dng sn xut hng khi , do vy ta chn phng php gia cng nhiu v tr , nhiu dao v gia cng song song.

B. Chn phng php gia cng.

chuyn mn ho cao nhm t nng sut cao trong iu kin sn xut Vit Nam th ng li cng ngh thch hp nht l phn tn nguyn cng . Dng cc loi my vn nng kt hp vi cc g chuyn dng v cc my chuyn dng d ch to.C. Lp tin trnh cng ngh

Phn tch chun v chn chun.

Gi l mt chi tit dng hp , khi lng gia cng ch yu tp chung vo gia cng cc l. Do vy gia cng c nhiu l trn nhiu bmt khc nhau qua cc giai on th, tinh. Ta cn chn 1 chun tinh thng nht l mt phng y v 2 l chun tinh ph vung gc vi mt phng y .

Nguyn cng u tin l phi gia cng b mt to chun. Vic chn chun th cho nguyn cng ny rt quan trng . Vi chi tit ny ta c 3 phng n chn chun th :

Phng n 1: dng mt trn 2 l .

Phng n 2: dng mt th 2 l

Phng n 3: dng mt tr ngoi

Nhn xt : phng n 2 & phng n 3 chn mt chun th nh vy khng m bo mt s yu cu sau:

Khng m bo phn phi u lng d gia cng.

Rt kh m bo ng tm ca 2 l

B mt lm chun th l dng trn do vy vic g t kh kh khn v phc tp.

Vi phng n 1 a ra ta thy n m bo 1 s yu cu sau ca chun th :

B mt trn ny c lng d gia cng nh v u nn m bo phn phi v u lng d gia cng .

m bo v tr tng quan gia cc l & mt y vi dch chuyn sai khc l nh nht.

Do vy ta chn phng n 1 : Chn chun th l mt trn 2 l .

Tham kho hng dn trong gio trnh cng ngh ch to my v hng dn lm n cng ngh ch to my, ta lp th t cc nguyn cng nh sau:

Nguyn cng 1 : Phay mt y.

Nguyn cng 2 : Phay mt trn.

Nguyn cng 3 : Khoan, khot, doa 2 l

Nguyn cng 4 : Phay 2 mt bn.

Nguyn cng 5 : Tin cc l ,tin mt u, tin l nh hnh. Nguyn cng 6 : Khoan, tar 6 l M10, su 15.

Nguyn cng 7 : Khoan, tar l M16.

D. Nguyn cng 8 : Tng kim tra.1. Thit k nguyn cng.

2. Nguyn cng 1 : Phay mt y.2.1. nh v & kp cht.

nh v: Dng 3 cht t kha nhm nh v ln mt D ca chi tit khng ch 3 bc t do.

Dng 2 cht t chm cu nh v ln mt B khng ch 2 bc t do. Kp cht: Chi tit c kp cht bng bu lng qua bc ch C ln mt C ca chi tit.2.2. Hnh v trang bn:2.3. Chn my:Vi bng b mt y yu cu RZ=20 tra bng 5 cp nhn bng 52.4. Gia cng chi tit trn bng my phay ngang 6H82( cng sut ng c chnh 7 kW) , khi gia cng dao quay trn ti ch v bn my thc hin chuyn ng chy dao S. Kch thc t c thng qua c so dao lp trn g.2.5. Chn dao( dng c ct). Cc nguyn cng phay bng dao phay mt u th ng knh dao ly l: D=(1,25..1,5)BTrong : D: L ng knh dao. B: L chiu rng b mt gia cng. Chn dao phay mt u c D/Z=90/10, vt liu thp hp kim cng BK8.2.6. Tra ch ct.Cp nhn bng cn t c ca mt y l 5 (Bng 5_TK ACNCTM).

Nh vy ta chia nguyn cng phay lm 2 bc: (bng 3.142 STCNCTM)Bc 1: Phay th t=2,0 mm.

Bc 2: Phay tinh t=1,0 mm. Bc 1: Phay th: =2,0 mm;tra bng 5.33(2) (ST CNCTM) lng chy dao rng: =0,2 mm/rng.chy dao vng: S=SZ.Z =0,2.10 = 2 mm/vng.- Tc ct (trang 27 ST CNCTM_2)

V = kVCV, m, x, y, u, q, p : h s v cc s m tra bng 5-39 (STCNCTM) khi gia cng khng c dung dch trn ngui:

CV = 695

q = 0,22

x = 0,17

y = 0,32

u = 0,22

p = 0

m = 0,33

T: Chu k bn ca dao, tra bng 5.40 (STCNCTM)

T = 180 ( pht)

kV : h s iu chnh chung cho tc ct ph thuc vo cc iu kin ct c th.

kV = kMV.kNV.kUVtrong :

kMV : h s ph thuc vo cht lng vt liu gia cng

Tra bng 5-1 (STCNCTM) kMV =

HB ca gang xm 15-32 l 150

tra bng 5-2 (STCNCTM) c nv = 1

kMV = = 1,27

kNV : h s ph thuc trng thi b mt ca phi

Tra bng 5-5 (STCNCTM) kNV =0,85

kUV : h s ph thuc vt liu dng c ct

Tra bng 5-6 (STCNCTM) kUV = 0,83

Do kV =1,27.0,85.0,83 = 0,9

V = 0,9

V = 179,5 (m/pht)

S vng quay trc chnh ca my l:

n = = = 635 (vng/pht)

Tra tr s vng quay tiu chun : n =600 (vng/pht) (TT TKMCKL)

Tc ct thc t l

V = = = 188,4 (m/pht) .

- Lc ct:

Pz = .kMPkMP : h s iu chnh cho cht lng vt liu gia cng, tra bng 5-9 (STCNCTM)

kMP = = = 0,65

Cc h s tra bng 5-41 (STCNCTM) c :

CP = 54,5

x = 0,9

y = 0,74

u = 1

q = 1

w = 0

kMP = 0,65

Pz = .0,65

Pz = 1473 (N)

Momen xon: Mx = =662 (Nm)

Cng sut ct : Ne = = 4,76 (KW) Bc 2 Phay tinh:

Chiu su phay: chn t = Z = 1( mm)

Chiu rng phay B = 66 (mm)

Lng chy dao S tra theo bng 5-37 (STCNCTM) :

T Rz =10 tra bng 5 (TKACNCTM) v theo bng 5-37

S = 1(mm/vng)

- Tc ct

V = kVCV, m, x, y, u, q, p : h s v cc s m tra bng 5-39 (STCNCTM) khi gia cng khng c dung dch trn ngui:

CV = 695

q = 0,22

x = 0,17

y = 0,32

u = 0,22

p = 0

m = 0,33

T: Chu k bn ca dao, tra bng 5.40 (STCNCTM)

T = 180 ( pht)

kV : h s iu chnh chung cho tc ct ph thuc vo cc iu kin ct c th.

kV = kMV.kNV.kUVtrong :

kMV : h s ph thuc vo cht lng vt liu gia cng

Tra bng 5-1 (STCNCTM) kMV =

HB ca gang xm 15-32 l 150

tra bng 5-2 (STCNCTM) c nv = 1

kMV = = 1,27

kNV : h s ph thuc trng thi b mt ca phi

Tra bng 5-5 (STCNCTM) kNV =0,85

kUV : h s ph thuc vt liu dng c ct

Tra bng 5-6 (STCNCTM) kUV = 0,83

Do kV =1,27.0,85.0,83 = 0,9

V = 0,9

V = 120,68 (m/pht)

S vng quay trc chnh ca my l:

n = = = 426,8 (vng/pht)

Tra tr s vng quay tiu chun : n = 475 (vng/pht)

Tc ct thc t l

V = = =134,2 (m/pht) .

- Lc ct:

Pz = .kMP

kMP : h s iu chnh cho cht lng vt liu gia cng, tra bng 5-9 (STCNCTM)

kMP = = = 0,65

Tra bng 5-41 (STCNCTM) c :

CP = 54,5

x = 0,9

y = 0,74

u = 1

q = 1

w = 0

kMP = 0,65

Pz = .0,65

Pz = 472,7 (N)

Momen xon: Mx = = 212,7 (Nm)

Cng sut ct : Ne = = 1,03 (KW)

Kt qu tnh ch ct :

Phay tinh6H82

BK8134,2 475 1

Phay th6H82

BK8188,4 600 2

Bc CN My DaoV(m/ph) n(v/ph)S(mm/vng)

3. nguyn cng 2: phay mt trn.3.1. nh v & kp cht. nh v : Dng phin t nh v ln mt chun tinh chnh A khng ch 3 bc t do. Dng 2 cht t chm cu nh v ln mt y khng c lng d khng ch 2 bc t do.

Dng mt cht t chm cu nh v ln cnh khng c lng d cn li khng ch nt 1 bc t do cn li(hnh v):Vy tt c hn ch 6 bc t do. Kp cht:

Chi tit c kp cht bng c cu n kp vo mt trong l 110.3.2. Hnh v trang bn

Chn my.

Nguyn cng c thc hin trn my phay ng 6H12, khi gia cng dao quay trn ti ch v bn my mang chi tit thc hin chuyn ng chy dao S. Theo bng 19(1) ta c cc thng s ca my nh sau: S cp tc : m=18 Gii hn vng quay: 30 1500 (vng/pht). Cng sut ng c: N=10 kW.3.3. Chn dao.

Chn dao phay mt u hp kim cng BK8 c D/Z=75/10.

3.4. Tra ch ct.Bc 1: Phay th t=1,5 mm.

Bc 2: Phay tinh t=1 mm. Bc 1: Phay th: =1,5 mm ; chy dao =0,2mm/rng

Tra bng vn tc ct (bng 5.127 ST NCTM). =232m/ph ; h s iu chnh tc k=0,8

=232.0,8=185,6 m/ph

== = 778 v/ph

Tra theo my th =750 v/ph

T vn tc ct thc s l:

==750.3,14.75/1000 = 176,6 m/ph

Lng chy dao vng :

S=Z.=10.0,2=2 mm/vng

Lng chy dao pht :

= .S=750.2=1500 mm/ph Bc 2: Phay tinh: =1 mm tra bng 5.37 (ST CNCTM) lng chy dao vng S=1 mm/vng nn =0,1 mm/rng. Tra bng vn tc ct (bng 5.127 ST CNCTM)). =260m/ph ; h s iu chnh tc k=0,8

=260.0,8=208 m/ph

== = 883,22v/ph

Tra theo my th =950 v/ph

T vn tc ct thc s l:

==950.3,14.75/1000 =223,7 m/ph

Lng chy dao pht :

= .S=950.1=950 mm/ph

Kt qu tnh ton ch ct:

Phay tinh 6H12 BK8 188,4 950 1 0,5

Phay th 6K12 BK8 132,8 750 2 1,5

Bc CN My Dao V(m/ph) N(v/ph)S(mm/vng) t(mm)

4. nguyn cng 3: khoan, khot, doa 2 l 18.4.1. nh v & kp cht. nh v v kp cht chi tit ging nh trong nguyn cng 2, v tr chnh xc ca hai l c xc nh thng qua phin dn v bc dn.4.2. Hnh v trang bn Chn my.

Nguyn cng c thc hin trn my khoan cn 2H53. Theo bng 8 TK ACNCTM ta c cc thng s ca my khoan cn 2H53: S cp tc : m=21 Gii hn vng quay: 25 2500 (vg/ph) S cp tc chy dao: 12

Gii hn chy dao: 0,056 2,5 (mm/vg) Cng sut ng c: N = 3 kW.4.3. Chn dao.

Chn mi khoan thu thuc v tng bc hn di y.4.4. Tra ch ct.

Cc bc thc hin nguyn cng:

Bc 1: Khoan l 16,5Bc 2: Khot l 17,85.Bc 3: Doa l 18. Bc 1: Khoan l 16.5:

Chiu su ct t:

t ==8,25 mm. Theo bng 5.94(ST CNCTM): Vt liu dao BK8

Khoan xong a vo khot v doa, nhm chy dao I:

=0,4..0,48 mm/vng.

Theo bng 5.95(ST CNCTM): Vt liu gang xm GX15-32 c cng HB=170190,

=0,41 mm/vng.Th =72 m/ph

Vy ==1000.72/(3,14.16,5)=1389 v/ph

Tra theo my th =1250 v/ph

T vn tc ct thc t s l:

==1250.3,14.16,5/1000 = 64,80 m/ph Bc 2: Khot l 17,85:

Chiu su ct t:

t == (17,85-16,5)/2 =0,675 mm

Theo bng 5.107 (ST CNCTM): HB